FFMPEG(1) FFMPEG(1) NAME ffmpeg - ffmpeg video converter SYNOPSIS The generic syntax is: ffmpeg [global options] [[infile options][B<-i> <infile>]]... {[outfile options] <outfile>}... DESCRIPTION ffmpeg is a very fast video and audio converter that can also grab from a live audio/video source. It can also convert between arbitrary sample rates and resize video on the fly with a high quality polyphase filter. ffmpeg reads from an arbitrary number of input "files" (which can be regular files, pipes, network streams, grabbing devices, etc.), specified by the "-i" option, and writes to an arbitrary number of output "files", which are specified by a plain output filename. Anything found on the command line which cannot be interpreted as an option is considered to be an output filename. Each input or output file can in principle contain any number of streams of different types (video/audio/subtitle/attachment/data). Allowed number and/or types of streams can be limited by the container format. Selecting, which streams from which inputs go into output, is done either automatically or with the "-map" option (see the Stream selection chapter). To refer to input files in options, you must use their indices (0-based). E.g. the first input file is 0, the second is 1 etc. Similarly, streams within a file are referred to by their indices. E.g. "2:3" refers to the fourth stream in the third input file. See also the Stream specifiers chapter. As a general rule, options are applied to the next specified file. Therefore, order is important, and you can have the same option on the command line multiple times. Each occurrence is then applied to the next input or output file. Exceptions from this rule are the global options (e.g. verbosity level), which should be specified first. Do not mix input and output files -- first specify all input files, then all output files. Also do not mix options which belong to different files. All options apply ONLY to the next input or output file and are reset between files. · To set the video bitrate of the output file to 64kbit/s: ffmpeg -i input.avi -b:v 64k output.avi · To force the frame rate of the output file to 24 fps: ffmpeg -i input.avi -r 24 output.avi · To force the frame rate of the input file (valid for raw formats only) to 1 fps and the frame rate of the output file to 24 fps: ffmpeg -r 1 -i input.m2v -r 24 output.avi The format option may be needed for raw input files. DETAILED DESCRIPTION The transcoding process in ffmpeg for each output can be described by the following diagram: _______ ______________ _________ ______________ ________ | | | | | | | | | | | input | demuxer | encoded data | decoder | decoded | encoder | encoded data | muxer | output | | file | ---------> | packets | ---------> | frames | ---------> | packets | -------> | file | |_______| |______________| |_________| |______________| |________| ffmpeg calls the libavformat library (containing demuxers) to read input files and get packets containing encoded data from them. When there are multiple input files, ffmpeg tries to keep them synchronized by tracking lowest timestamp on any active input stream. Encoded packets are then passed to the decoder (unless streamcopy is selected for the stream, see further for a description). The decoder produces uncompressed frames (raw video/PCM audio/...) which can be processed further by filtering (see next section). After filtering the frames are passed to the encoder, which encodes them and outputs encoded packets again. Finally those are passed to the muxer, which writes the encoded packets to the output file. Filtering Before encoding, ffmpeg can process raw audio and video frames using filters from the libavfilter library. Several chained filters form a filter graph. ffmpeg distinguishes between two types of filtergraphs - simple and complex. Simple filtergraphs Simple filtergraphs are those that have exactly one input and output, both of the same type. In the above diagram they can be represented by simply inserting an additional step between decoding and encoding: _________ __________ ______________ | | | | | | | decoded | simple filtergraph | filtered | encoder | encoded data | | frames | -------------------> | frames | ---------> | packets | |_________| |__________| |______________| Simple filtergraphs are configured with the per-stream -filter option (with -vf and -af aliases for video and audio respectively). A simple filtergraph for video can look for example like this: _______ _____________ _______ _____ ________ | | | | | | | | | | | input | ---> | deinterlace | ---> | scale | ---> | fps | ---> | output | |_______| |_____________| |_______| |_____| |________| Note that some filters change frame properties but not frame contents. E.g. the "fps" filter in the example above changes number of frames, but does not touch the frame contents. Another example is the "setpts" filter, which only sets timestamps and otherwise passes the frames unchanged. Complex filtergraphs Complex filtergraphs are those which cannot be described as simply a linear processing chain applied to one stream. This is the case e.g. when the graph has more than one input and/or output, or when output stream type is different from input. They can be represented with the following diagram: _________ | | | input 0 |\ __________ |_________| \ | | \ _________ /| output 0 | \ | | / |__________| _________ \| complex | / | | | |/ | input 1 |---->| filter |\ |_________| | | \ __________ /| graph | \ | | / | | \| output 1 | _________ / |_________| |__________| | | / | input 2 |/ |_________| Complex filtergraphs are configured with the -filter_complex option. Note that this option is global, since a complex filtergraph by its nature cannot be unambiguously associated with a single stream or file. A trivial example of a complex filtergraph is the "overlay" filter, which has two video inputs and one video output, containing one video overlaid on top of the other. Its audio counterpart is the "amix" filter. Stream copy Stream copy is a mode selected by supplying the "copy" parameter to the -codec option. It makes ffmpeg omit the decoding and encoding step for the specified stream, so it does only demuxing and muxing. It is useful for changing the container format or modifying container-level metadata. The diagram above will in this case simplify to this: _______ ______________ ________ | | | | | | | input | demuxer | encoded data | muxer | output | | file | ---------> | packets | -------> | file | |_______| |______________| |________| Since there is no decoding or encoding, it is very fast and there is no quality loss. However it might not work in some cases because of many factors. Applying filters is obviously also impossible, since filters work on uncompressed data. STREAM SELECTION By default ffmpeg includes only one stream of each type (video, audio, subtitle) present in the input files and adds them to each output file. It picks the "best" of each based upon the following criteria; for video it is the stream with the highest resolution, for audio the stream with the most channels, for subtitle it's the first subtitle stream. In the case where several streams of the same type rate equally, the lowest numbered stream is chosen. You can disable some of those defaults by using "-vn/-an/-sn" options. For full manual control, use the "-map" option, which disables the defaults just described. OPTIONS All the numerical options, if not specified otherwise, accept in input a string representing a number, which may contain one of the International System number postfixes, for example 'K', 'M', 'G'. If 'i' is appended after the postfix, powers of 2 are used instead of powers of 10. The 'B' postfix multiplies the value for 8, and can be appended after another postfix or used alone. This allows using for example 'KB', 'MiB', 'G' and 'B' as postfix. Options which do not take arguments are boolean options, and set the corresponding value to true. They can be set to false by prefixing with "no" the option name, for example using "-nofoo" in the command line will set to false the boolean option with name "foo". Stream specifiers Some options are applied per-stream, e.g. bitrate or codec. Stream specifiers are used to precisely specify which stream(s) does a given option belong to. A stream specifier is a string generally appended to the option name and separated from it by a colon. E.g. "-codec:a:1 ac3" option contains "a:1" stream specifier, which matches the second audio stream. Therefore it would select the ac3 codec for the second audio stream. A stream specifier can match several streams, the option is then applied to all of them. E.g. the stream specifier in "-b:a 128k" matches all audio streams. An empty stream specifier matches all streams, for example "-codec copy" or "-codec: copy" would copy all the streams without reencoding. Possible forms of stream specifiers are: stream_index Matches the stream with this index. E.g. "-threads:1 4" would set the thread count for the second stream to 4. stream_type[:stream_index] stream_type is one of: 'v' for video, 'a' for audio, 's' for subtitle, 'd' for data and 't' for attachments. If stream_index is given, then matches stream number stream_index of this type. Otherwise matches all streams of this type. p:program_id[:stream_index] If stream_index is given, then matches stream number stream_index in program with id program_id. Otherwise matches all streams in this program. #stream_id Matches the stream by format-specific ID. Generic options These options are shared amongst the av* tools. -L Show license. -h, -?, -help, --help [arg] Show help. An optional parameter may be specified to print help about a specific item. Possible values of arg are: decoder=decoder_name Print detailed information about the decoder named decoder_name. Use the -decoders option to get a list of all decoders. encoder=encoder_name Print detailed information about the encoder named encoder_name. Use the -encoders option to get a list of all encoders. demuxer=demuxer_name Print detailed information about the demuxer named demuxer_name. Use the -formats option to get a list of all demuxers and muxers. muxer=muxer_name Print detailed information about the muxer named muxer_name. Use the -formats option to get a list of all muxers and demuxers. -version Show version. -formats Show available formats. The fields preceding the format names have the following meanings: D Decoding available E Encoding available -codecs Show all codecs known to libavcodec. Note that the term 'codec' is used throughout this documentation as a shortcut for what is more correctly called a media bitstream format. -decoders Show available decoders. -encoders Show all available encoders. -bsfs Show available bitstream filters. -protocols Show available protocols. -filters Show available libavfilter filters. -pix_fmts Show available pixel formats. -sample_fmts Show available sample formats. -layouts Show channel names and standard channel layouts. -loglevel loglevel | -v loglevel Set the logging level used by the library. loglevel is a number or a string containing one of the following values: quiet panic fatal error warning info verbose debug By default the program logs to stderr, if coloring is supported by the terminal, colors are used to mark errors and warnings. Log coloring can be disabled setting the environment variable AV_LOG_FORCE_NOCOLOR or NO_COLOR, or can be forced setting the environment variable AV_LOG_FORCE_COLOR. The use of the environment variable NO_COLOR is deprecated and will be dropped in a following FFmpeg version. -report Dump full command line and console output to a file named "program-YYYYMMDD-HHMMSS.log" in the current directory. This file can be useful for bug reports. It also implies "-loglevel verbose". Note: setting the environment variable "FFREPORT" to any value has the same effect. -cpuflags flags (global) Allows setting and clearing cpu flags. This option is intended for testing. Do not use it unless you know what you're doing. ffmpeg -cpuflags -sse+mmx ... ffmpeg -cpuflags mmx ... ffmpeg -cpuflags 0 ... AVOptions These options are provided directly by the libavformat, libavdevice and libavcodec libraries. To see the list of available AVOptions, use the -help option. They are separated into two categories: generic These options can be set for any container, codec or device. Generic options are listed under AVFormatContext options for containers/devices and under AVCodecContext options for codecs. private These options are specific to the given container, device or codec. Private options are listed under their corresponding containers/devices/codecs. For example to write an ID3v2.3 header instead of a default ID3v2.4 to an MP3 file, use the id3v2_version private option of the MP3 muxer: ffmpeg -i input.flac -id3v2_version 3 out.mp3 All codec AVOptions are obviously per-stream, so the chapter on stream specifiers applies to them Note -nooption syntax cannot be used for boolean AVOptions, use -option 0/-option 1. Note2 old undocumented way of specifying per-stream AVOptions by prepending v/a/s to the options name is now obsolete and will be removed soon. Codec AVOptions -b[:stream_specifier] integer (output,audio,video) set bitrate (in bits/s) -ab[:stream_specifier] integer (output,audio) set bitrate (in bits/s) -bt[:stream_specifier] integer (output,video) Set video bitrate tolerance (in bits/s). In 1-pass mode, bitrate tolerance specifies how far ratecontrol is willing to deviate from the target average bitrate value. This is not related to min/max bitrate. Lowering tolerance too much has an adverse effect on quality. -flags[:stream_specifier] flags (input/output,audio,video,subtitles) Possible values: mv4 use four motion vector by macroblock (mpeg4) qpel use 1/4 pel motion compensation loop use loop filter qscale use fixed qscale gmc use gmc mv0 always try a mb with mv=<0,0> input_preserved pass1 use internal 2pass ratecontrol in first pass mode pass2 use internal 2pass ratecontrol in second pass mode gray only decode/encode grayscale emu_edge don't draw edges psnr error[?] variables will be set during encoding truncated naq normalize adaptive quantization ildct use interlaced dct low_delay force low delay global_header place global headers in extradata instead of every keyframe bitexact use only bitexact stuff (except (i)dct) aic h263 advanced intra coding / mpeg4 ac prediction cbp Deprecated, use mpegvideo private options instead qprd Deprecated, use mpegvideo private options instead ilme interlaced motion estimation cgop closed gop -sub_id[:stream_specifier] integer () -me_method[:stream_specifier] integer (output,video) set motion estimation method Possible values: zero zero motion estimation (fastest) full full motion estimation (slowest) epzs EPZS motion estimation (default) esa esa motion estimation (alias for full) tesa tesa motion estimation dia dia motion estimation (alias for epzs) log log motion estimation phods phods motion estimation x1 X1 motion estimation hex hex motion estimation umh umh motion estimation iter iter motion estimation -extradata_size[:stream_specifier] integer () -time_base[:stream_specifier] rational number () -g[:stream_specifier] integer (output,video) set the group of picture size -ar[:stream_specifier] integer (input/output,audio) set audio sampling rate (in Hz) -ac[:stream_specifier] integer (input/output,audio) set number of audio channels -cutoff[:stream_specifier] integer (output,audio) set cutoff bandwidth -frame_size[:stream_specifier] integer (output,audio) -frame_number[:stream_specifier] integer () -delay[:stream_specifier] integer () -qcomp[:stream_specifier] float (output,video) video quantizer scale compression (VBR). Constant of ratecontrol equation. Recommended range for default rc_eq: 0.0-1.0 -qblur[:stream_specifier] float (output,video) video quantizer scale blur (VBR) -qmin[:stream_specifier] integer (output,video) min video quantizer scale (VBR) -qmax[:stream_specifier] integer (output,video) max video quantizer scale (VBR) -qdiff[:stream_specifier] integer (output,video) max difference between the quantizer scale (VBR) -bf[:stream_specifier] integer (output,video) use 'frames' B frames -b_qfactor[:stream_specifier] float (output,video) qp factor between p and b frames -rc_strategy[:stream_specifier] integer (output,video) ratecontrol method -b_strategy[:stream_specifier] integer (output,video) strategy to choose between I/P/B-frames -ps[:stream_specifier] integer (output,video) rtp payload size in bytes -mv_bits[:stream_specifier] integer () -header_bits[:stream_specifier] integer () -i_tex_bits[:stream_specifier] integer () -p_tex_bits[:stream_specifier] integer () -i_count[:stream_specifier] integer () -p_count[:stream_specifier] integer () -skip_count[:stream_specifier] integer () -misc_bits[:stream_specifier] integer () -frame_bits[:stream_specifier] integer () -codec_tag[:stream_specifier] integer () -bug[:stream_specifier] flags (input,video) workaround not auto detected encoder bugs Possible values: autodetect old_msmpeg4 some old lavc generated msmpeg4v3 files (no autodetection) xvid_ilace Xvid interlacing bug (autodetected if fourcc==XVIX) ump4 (autodetected if fourcc==UMP4) no_padding padding bug (autodetected) amv ac_vlc illegal vlc bug (autodetected per fourcc) qpel_chroma std_qpel old standard qpel (autodetected per fourcc/version) qpel_chroma2 direct_blocksize direct-qpel-blocksize bug (autodetected per fourcc/version) edge edge padding bug (autodetected per fourcc/version) hpel_chroma dc_clip ms workaround various bugs in microsofts broken decoders trunc trancated frames -lelim[:stream_specifier] integer (output,video) single coefficient elimination threshold for luminance (negative values also consider dc coefficient) -celim[:stream_specifier] integer (output,video) single coefficient elimination threshold for chrominance (negative values also consider dc coefficient) -strict[:stream_specifier] integer (input/output,audio,video) how strictly to follow the standards Possible values: very strictly conform to a older more strict version of the spec or reference software strict strictly conform to all the things in the spec no matter what consequences normal unofficial allow unofficial extensions experimental allow non standardized experimental things -b_qoffset[:stream_specifier] float (output,video) qp offset between P and B frames -err_detect[:stream_specifier] flags (input,audio,video) set error detection flags Possible values: crccheck verify embedded CRCs bitstream detect bitstream specification deviations buffer detect improper bitstream length explode abort decoding on minor error detection careful consider things that violate the spec and have not been seen in the wild as errors compliant consider all spec non compliancies as errors aggressive consider things that a sane encoder should not do as an error -has_b_frames[:stream_specifier] integer () -block_align[:stream_specifier] integer () -mpeg_quant[:stream_specifier] integer (output,video) use MPEG quantizers instead of H.263 -stats_out[:stream_specifier] string () -qsquish[:stream_specifier] float (output,video) how to keep quantizer between qmin and qmax (0 = clip, 1 = use differentiable function) -rc_qmod_amp[:stream_specifier] float (output,video) experimental quantizer modulation -rc_qmod_freq[:stream_specifier] integer (output,video) experimental quantizer modulation -rc_override_count[:stream_specifier] integer () -rc_eq[:stream_specifier] string (output,video) Set rate control equation. When computing the expression, besides the standard functions defined in the section 'Expression Evaluation', the following functions are available: bits2qp(bits), qp2bits(qp). Also the following constants are available: iTex pTex tex mv fCode iCount mcVar var isI isP isB avgQP qComp avgIITex avgPITex avgPPTex avgBPTex avgTex. -maxrate[:stream_specifier] integer (output,audio,video) Set max bitrate tolerance (in bits/s). Requires bufsize to be set. -minrate[:stream_specifier] integer (output,audio,video) Set min bitrate tolerance (in bits/s). Most useful in setting up a CBR encode. It is of little use elsewise. -bufsize[:stream_specifier] integer (output,audio,video) set ratecontrol buffer size (in bits) -rc_buf_aggressivity[:stream_specifier] float (output,video) currently useless -i_qfactor[:stream_specifier] float (output,video) qp factor between P and I frames -i_qoffset[:stream_specifier] float (output,video) qp offset between P and I frames -rc_init_cplx[:stream_specifier] float (output,video) initial complexity for 1-pass encoding -dct[:stream_specifier] integer (output,video) DCT algorithm Possible values: auto autoselect a good one (default) fastint fast integer int accurate integer mmx altivec faan floating point AAN DCT -lumi_mask[:stream_specifier] float (output,video) compresses bright areas stronger than medium ones -tcplx_mask[:stream_specifier] float (output,video) temporal complexity masking -scplx_mask[:stream_specifier] float (output,video) spatial complexity masking -p_mask[:stream_specifier] float (output,video) inter masking -dark_mask[:stream_specifier] float (output,video) compresses dark areas stronger than medium ones -idct[:stream_specifier] integer (input/output,video) select IDCT implementation Possible values: auto int simple simplemmx libmpeg2mmx mmi arm altivec sh4 simplearm simplearmv5te simplearmv6 simpleneon simplealpha h264 vp3 ipp xvidmmx faani floating point AAN IDCT -slice_count[:stream_specifier] integer () -ec[:stream_specifier] flags (input,video) set error concealment strategy Possible values: guess_mvs iterative motion vector (MV) search (slow) deblock use strong deblock filter for damaged MBs -bits_per_coded_sample[:stream_specifier] integer () -pred[:stream_specifier] integer (output,video) prediction method Possible values: left plane median -aspect[:stream_specifier] rational number (output,video) sample aspect ratio -debug[:stream_specifier] flags (input/output,audio,video,subtitles) print specific debug info Possible values: pict picture info rc rate control bitstream mb_type macroblock (MB) type qp per-block quantization parameter (QP) mv motion vector dct_coeff skip startcode pts er error recognition mmco memory management control operations (H.264) bugs vis_qp visualize quantization parameter (QP), lower QP are tinted greener vis_mb_type visualize block types buffers picture buffer allocations thread_ops threading operations -vismv[:stream_specifier] integer (input,video) visualize motion vectors (MVs) Possible values: pf forward predicted MVs of P-frames bf forward predicted MVs of B-frames bb backward predicted MVs of B-frames -cmp[:stream_specifier] integer (output,video) full pel me compare function Possible values: sad sum of absolute differences, fast (default) sse sum of squared errors satd sum of absolute Hadamard transformed differences dct sum of absolute DCT transformed differences psnr sum of squared quantization errors (avoid, low quality) bit number of bits needed for the block rd rate distortion optimal, slow zero 0 vsad sum of absolute vertical differences vsse sum of squared vertical differences nsse noise preserving sum of squared differences w53 5/3 wavelet, only used in snow w97 9/7 wavelet, only used in snow dctmax chroma -subcmp[:stream_specifier] integer (output,video) sub pel me compare function Possible values: sad sum of absolute differences, fast (default) sse sum of squared errors satd sum of absolute Hadamard transformed differences dct sum of absolute DCT transformed differences psnr sum of squared quantization errors (avoid, low quality) bit number of bits needed for the block rd rate distortion optimal, slow zero 0 vsad sum of absolute vertical differences vsse sum of squared vertical differences nsse noise preserving sum of squared differences w53 5/3 wavelet, only used in snow w97 9/7 wavelet, only used in snow dctmax chroma -mbcmp[:stream_specifier] integer (output,video) macroblock compare function Possible values: sad sum of absolute differences, fast (default) sse sum of squared errors satd sum of absolute Hadamard transformed differences dct sum of absolute DCT transformed differences psnr sum of squared quantization errors (avoid, low quality) bit number of bits needed for the block rd rate distortion optimal, slow zero 0 vsad sum of absolute vertical differences vsse sum of squared vertical differences nsse noise preserving sum of squared differences w53 5/3 wavelet, only used in snow w97 9/7 wavelet, only used in snow dctmax chroma -ildctcmp[:stream_specifier] integer (output,video) interlaced dct compare function Possible values: sad sum of absolute differences, fast (default) sse sum of squared errors satd sum of absolute Hadamard transformed differences dct sum of absolute DCT transformed differences psnr sum of squared quantization errors (avoid, low quality) bit number of bits needed for the block rd rate distortion optimal, slow zero 0 vsad sum of absolute vertical differences vsse sum of squared vertical differences nsse noise preserving sum of squared differences w53 5/3 wavelet, only used in snow w97 9/7 wavelet, only used in snow dctmax chroma -dia_size[:stream_specifier] integer (output,video) diamond type & size for motion estimation -last_pred[:stream_specifier] integer (output,video) amount of motion predictors from the previous frame -preme[:stream_specifier] integer (output,video) pre motion estimation -precmp[:stream_specifier] integer (output,video) pre motion estimation compare function Possible values: sad sum of absolute differences, fast (default) sse sum of squared errors satd sum of absolute Hadamard transformed differences dct sum of absolute DCT transformed differences psnr sum of squared quantization errors (avoid, low quality) bit number of bits needed for the block rd rate distortion optimal, slow zero 0 vsad sum of absolute vertical differences vsse sum of squared vertical differences nsse noise preserving sum of squared differences w53 5/3 wavelet, only used in snow w97 9/7 wavelet, only used in snow dctmax chroma -pre_dia_size[:stream_specifier] integer (output,video) diamond type & size for motion estimation pre-pass -subq[:stream_specifier] integer (output,video) sub pel motion estimation quality -dtg_active_format[:stream_specifier] integer () -me_range[:stream_specifier] integer (output,video) limit motion vectors range (1023 for DivX player) -ibias[:stream_specifier] integer (output,video) intra quant bias -pbias[:stream_specifier] integer (output,video) inter quant bias -color_table_id[:stream_specifier] integer () -global_quality[:stream_specifier] integer (output,audio,video) -coder[:stream_specifier] integer (output,video) Possible values: vlc variable length coder / huffman coder ac arithmetic coder raw raw (no encoding) rle run-length coder deflate deflate-based coder -context[:stream_specifier] integer (output,video) context model -slice_flags[:stream_specifier] integer () -xvmc_acceleration[:stream_specifier] integer () -mbd[:stream_specifier] integer (output,video) macroblock decision algorithm (high quality mode) Possible values: simple use mbcmp (default) bits use fewest bits rd use best rate distortion -stream_codec_tag[:stream_specifier] integer () -sc_threshold[:stream_specifier] integer (output,video) scene change threshold -lmin[:stream_specifier] integer (output,video) min lagrange factor (VBR) -lmax[:stream_specifier] integer (output,video) max lagrange factor (VBR) -nr[:stream_specifier] integer (output,video) noise reduction -rc_init_occupancy[:stream_specifier] integer (output,video) number of bits which should be loaded into the rc buffer before decoding starts -inter_threshold[:stream_specifier] integer (output,video) -flags2[:stream_specifier] flags (input/output,audio,video) Possible values: fast allow non spec compliant speedup tricks sgop Deprecated, use mpegvideo private options instead noout skip bitstream encoding local_header place global headers at every keyframe instead of in extradata chunks Frame data might be split into multiple chunks showall Show all frames before the first keyframe skiprd Deprecated, use mpegvideo private options instead -error[:stream_specifier] integer (output,video) -qns[:stream_specifier] integer (output,video) deprecated, use mpegvideo private options instead -threads[:stream_specifier] integer (input/output,video) Possible values: auto detect a good number of threads -me_threshold[:stream_specifier] integer (output,video) motion estimaton threshold -mb_threshold[:stream_specifier] integer (output,video) macroblock threshold -dc[:stream_specifier] integer (output,video) intra_dc_precision -nssew[:stream_specifier] integer (output,video) nsse weight -skip_top[:stream_specifier] integer (input,video) number of macroblock rows at the top which are skipped -skip_bottom[:stream_specifier] integer (input,video) number of macroblock rows at the bottom which are skipped -profile[:stream_specifier] integer (output,audio,video) Possible values: unknown aac_main aac_low aac_ssr aac_ltp aac_he aac_he_v2 aac_ld aac_eld dts dts_es dts_96_24 dts_hd_hra dts_hd_ma -level[:stream_specifier] integer (output,audio,video) Possible values: unknown -lowres[:stream_specifier] integer (input,audio,video) decode at 1= 1/2, 2=1/4, 3=1/8 resolutions -skip_threshold[:stream_specifier] integer (output,video) frame skip threshold -skip_factor[:stream_specifier] integer (output,video) frame skip factor -skip_exp[:stream_specifier] integer (output,video) frame skip exponent -skipcmp[:stream_specifier] integer (output,video) frame skip compare function Possible values: sad sum of absolute differences, fast (default) sse sum of squared errors satd sum of absolute Hadamard transformed differences dct sum of absolute DCT transformed differences psnr sum of squared quantization errors (avoid, low quality) bit number of bits needed for the block rd rate distortion optimal, slow zero 0 vsad sum of absolute vertical differences vsse sum of squared vertical differences nsse noise preserving sum of squared differences w53 5/3 wavelet, only used in snow w97 9/7 wavelet, only used in snow dctmax chroma -border_mask[:stream_specifier] float (output,video) increases the quantizer for macroblocks close to borders -mblmin[:stream_specifier] integer (output,video) min macroblock lagrange factor (VBR) -mblmax[:stream_specifier] integer (output,video) max macroblock lagrange factor (VBR) -mepc[:stream_specifier] integer (output,video) motion estimation bitrate penalty compensation (1.0 = 256) -skip_loop_filter[:stream_specifier] integer (input,video) Possible values: none default noref bidir nokey all -skip_idct[:stream_specifier] integer (input,video) Possible values: none default noref bidir nokey all -skip_frame[:stream_specifier] integer (input,video) Possible values: none default noref bidir nokey all -bidir_refine[:stream_specifier] integer (output,video) refine the two motion vectors used in bidirectional macroblocks -brd_scale[:stream_specifier] integer (output,video) downscales frames for dynamic B-frame decision -keyint_min[:stream_specifier] integer (output,video) minimum interval between IDR-frames -refs[:stream_specifier] integer (output,video) reference frames to consider for motion compensation -chromaoffset[:stream_specifier] integer (output,video) chroma qp offset from luma -trellis[:stream_specifier] integer (output,audio,video) rate-distortion optimal quantization -sc_factor[:stream_specifier] integer (output,video) multiplied by qscale for each frame and added to scene_change_score -mv0_threshold[:stream_specifier] integer (output,video) -b_sensitivity[:stream_specifier] integer (output,video) adjusts sensitivity of b_frame_strategy 1 -compression_level[:stream_specifier] integer (output,audio,video) -min_prediction_order[:stream_specifier] integer (output,audio) -max_prediction_order[:stream_specifier] integer (output,audio) -timecode_frame_start[:stream_specifier] integer (output,video) GOP timecode frame start number, in non drop frame format -request_channels[:stream_specifier] integer (input,audio) set desired number of audio channels -bits_per_raw_sample[:stream_specifier] integer () -channel_layout[:stream_specifier] integer (input/output,audio) Possible values: -request_channel_layout[:stream_specifier] integer (input,audio) Possible values: -rc_max_vbv_use[:stream_specifier] float (output,video) -rc_min_vbv_use[:stream_specifier] float (output,video) -ticks_per_frame[:stream_specifier] integer (input/output,audio,video) -color_primaries[:stream_specifier] integer (input/output,video) -color_trc[:stream_specifier] integer (input/output,video) -colorspace[:stream_specifier] integer (input/output,video) -color_range[:stream_specifier] integer (input/output,video) -chroma_sample_location[:stream_specifier] integer (input/output,video) -log_level_offset[:stream_specifier] integer () set the log level offset -slices[:stream_specifier] integer (output,video) number of slices, used in parallelized encoding -thread_type[:stream_specifier] flags (input/output,video) select multithreading type Possible values: slice frame -audio_service_type[:stream_specifier] integer (output,audio) audio service type Possible values: ma Main Audio Service ef Effects vi Visually Impaired hi Hearing Impaired di Dialogue co Commentary em Emergency vo Voice Over ka Karaoke -request_sample_fmt[:stream_specifier] integer (input,audio) sample format audio decoders should prefer Possible values: u8 8-bit unsigned integer s16 16-bit signed integer s32 32-bit signed integer flt 32-bit float dbl 64-bit double u8p 8-bit unsigned integer planar s16p 16-bit signed integer planar s32p 32-bit signed integer planar fltp 32-bit float planar dblp 64-bit double planar -pkt_timebase[:stream_specifier] rational number () Format AVOptions -avioflags flags (input/output) Possible values: direct reduce buffering -probesize integer (input) set probing size -packetsize integer (output) set packet size -fflags flags (input/output) Possible values: ignidx ignore index genpts generate pts nofillin do not fill in missing values that can be exactly calculated noparse disable AVParsers, this needs nofillin too igndts ignore dts discardcorrupt discard corrupted frames sortdts try to interleave outputted packets by dts keepside dont merge side data latm enable RTP MP4A-LATM payload nobuffer reduce the latency introduced by optional buffering -analyzeduration integer (input) how many microseconds are analyzed to estimate duration -cryptokey hexadecimal string (input) decryption key -indexmem integer (input) max memory used for timestamp index (per stream) -rtbufsize integer (input) max memory used for buffering real-time frames -fdebug flags (input/output) print specific debug info Possible values: ts -max_delay integer (input/output) maximum muxing or demuxing delay in microseconds -fpsprobesize integer (input) number of frames used to probe fps -audio_preload integer (output) microseconds by which audio packets should be interleaved earlier -chunk_duration integer (output) microseconds for each chunk -chunk_size integer (output) size in bytes for each chunk -f_err_detect flags (input) set error detection flags (deprecated; use err_detect, save via avconv) Possible values: crccheck verify embedded CRCs bitstream detect bitstream specification deviations buffer detect improper bitstream length explode abort decoding on minor error detection careful consider things that violate the spec and have not been seen in the wild as errors compliant consider all spec non compliancies as errors aggressive consider things that a sane encoder shouldnt do as an error -err_detect flags (input) set error detection flags Possible values: crccheck verify embedded CRCs bitstream detect bitstream specification deviations buffer detect improper bitstream length explode abort decoding on minor error detection careful consider things that violate the spec and have not been seen in the wild as errors compliant consider all spec non compliancies as errors aggressive consider things that a sane encoder shouldnt do as an error -use_wallclock_as_timestamps integer (input) use wallclock as timestamps -avoid_negative_ts integer (output) avoid negative timestamps Main options -f fmt (input/output) Force input or output file format. The format is normally auto detected for input files and guessed from file extension for output files, so this option is not needed in most cases. -i filename (input) input file name -y (global) Overwrite output files without asking. -n (global) Do not overwrite output files but exit if file exists. -c[:stream_specifier] codec (input/output,per-stream) -codec[:stream_specifier] codec (input/output,per-stream) Select an encoder (when used before an output file) or a decoder (when used before an input file) for one or more streams. codec is the name of a decoder/encoder or a special value "copy" (output only) to indicate that the stream is not to be re-encoded. For example ffmpeg -i INPUT -map 0 -c:v libx264 -c:a copy OUTPUT encodes all video streams with libx264 and copies all audio streams. For each stream, the last matching "c" option is applied, so ffmpeg -i INPUT -map 0 -c copy -c:v:1 libx264 -c:a:137 libvorbis OUTPUT will copy all the streams except the second video, which will be encoded with libx264, and the 138th audio, which will be encoded with libvorbis. -t duration (output) Stop writing the output after its duration reaches duration. duration may be a number in seconds, or in "hh:mm:ss[.xxx]" form. -fs limit_size (output) Set the file size limit, expressed in bytes. -ss position (input/output) When used as an input option (before "-i"), seeks in this input file to position. When used as an output option (before an output filename), decodes but discards input until the timestamps reach position. This is slower, but more accurate. position may be either in seconds or in "hh:mm:ss[.xxx]" form. -itsoffset offset (input) Set the input time offset in seconds. "[-]hh:mm:ss[.xxx]" syntax is also supported. The offset is added to the timestamps of the input files. Specifying a positive offset means that the corresponding streams are delayed by offset seconds. -timestamp time (output) Set the recording timestamp in the container. The syntax for time is: now|([(YYYY-MM-DD|YYYYMMDD)[T|t| ]]((HH:MM:SS[.m...])|(HHMMSS[.m...]))[Z|z]) If the value is "now" it takes the current time. Time is local time unless 'Z' or 'z' is appended, in which case it is interpreted as UTC. If the year-month-day part is not specified it takes the current year-month-day. -metadata[:metadata_specifier] key=value (output,per-metadata) Set a metadata key/value pair. An optional metadata_specifier may be given to set metadata on streams or chapters. See "-map_metadata" documentation for details. This option overrides metadata set with "-map_metadata". It is also possible to delete metadata by using an empty value. For example, for setting the title in the output file: ffmpeg -i in.avi -metadata title="my title" out.flv To set the language of the first audio stream: ffmpeg -i INPUT -metadata:s:a:1 language=eng OUTPUT -target type (output) Specify target file type ("vcd", "svcd", "dvd", "dv", "dv50"). type may be prefixed with "pal-", "ntsc-" or "film-" to use the corresponding standard. All the format options (bitrate, codecs, buffer sizes) are then set automatically. You can just type: ffmpeg -i myfile.avi -target vcd /tmp/vcd.mpg Nevertheless you can specify additional options as long as you know they do not conflict with the standard, as in: ffmpeg -i myfile.avi -target vcd -bf 2 /tmp/vcd.mpg -dframes number (output) Set the number of data frames to record. This is an alias for "-frames:d". -frames[:stream_specifier] framecount (output,per-stream) Stop writing to the stream after framecount frames. -q[:stream_specifier] q (output,per-stream) -qscale[:stream_specifier] q (output,per-stream) Use fixed quality scale (VBR). The meaning of q is codec-dependent. -filter[:stream_specifier] filter_graph (output,per-stream) filter_graph is a description of the filter graph to apply to the stream. Use "-filters" to show all the available filters (including also sources and sinks). See also the -filter_complex option if you want to create filter graphs with multiple inputs and/or outputs. -pre[:stream_specifier] preset_name (output,per-stream) Specify the preset for matching stream(s). -stats (global) Print encoding progress/statistics. On by default. -progress url (global) Send program-friendly progress information to url. Progress information is written approximately every second and at the end of the encoding process. It is made of "key=value" lines. key consists of only alphanumeric characters. The last key of a sequence of progress information is always "progress". -stdin Enable interaction on standard input. On by default unless standard input is used as an input. To explicitly disable interaction you need to specify "-nostdin". Disabling interaction on standard input is useful, for example, if ffmpeg is in the background process group. Roughly the same result can be achieved with "ffmpeg ... < /dev/null" but it requires a shell. -debug_ts (global) Print timestamp information. It is off by default. This option is mostly useful for testing and debugging purposes, and the output format may change from one version to another, so it should not be employed by portable scripts. See also the option "-fdebug ts". -attach filename (output) Add an attachment to the output file. This is supported by a few formats like Matroska for e.g. fonts used in rendering subtitles. Attachments are implemented as a specific type of stream, so this option will add a new stream to the file. It is then possible to use per-stream options on this stream in the usual way. Attachment streams created with this option will be created after all the other streams (i.e. those created with "-map" or automatic mappings). Note that for Matroska you also have to set the mimetype metadata tag: ffmpeg -i INPUT -attach DejaVuSans.ttf -metadata:s:2 mimetype=application/x-truetype-font out.mkv (assuming that the attachment stream will be third in the output file). -dump_attachment[:stream_specifier] filename (input,per-stream) Extract the matching attachment stream into a file named filename. If filename is empty, then the value of the "filename" metadata tag will be used. E.g. to extract the first attachment to a file named 'out.ttf': ffmpeg -dump_attachment:t:0 out.ttf INPUT To extract all attachments to files determined by the "filename" tag: ffmpeg -dump_attachment:t "" INPUT Technical note -- attachments are implemented as codec extradata, so this option can actually be used to extract extradata from any stream, not just attachments. Video Options -vframes number (output) Set the number of video frames to record. This is an alias for "-frames:v". -r[:stream_specifier] fps (input/output,per-stream) Set frame rate (Hz value, fraction or abbreviation). As an input option, ignore any timestamps stored in the file and instead generate timestamps assuming constant frame rate fps. As an output option, duplicate or drop input frames to achieve constant output frame rate fps (note that this actually causes the "fps" filter to be inserted to the end of the corresponding filtergraph). -s[:stream_specifier] size (input/output,per-stream) Set frame size. As an input option, this is a shortcut for the video_size private option, recognized by some demuxers for which the frame size is either not stored in the file or is configurable -- e.g. raw video or video grabbers. As an output option, this inserts the "scale" video filter to the end of the corresponding filtergraph. Please use the "scale" filter directly to insert it at the beginning or some other place. The format is wxh (default - same as source). -aspect[:stream_specifier] aspect (output,per-stream) Set the video display aspect ratio specified by aspect. aspect can be a floating point number string, or a string of the form num:den, where num and den are the numerator and denominator of the aspect ratio. For example "4:3", "16:9", "1.3333", and "1.7777" are valid argument values. -croptop size -cropbottom size -cropleft size -cropright size All the crop options have been removed. Use -vf crop=width:height:x:y instead. -padtop size -padbottom size -padleft size -padright size -padcolor hex_color All the pad options have been removed. Use -vf pad=width:height:x:y:color instead. -vn (output) Disable video recording. -vcodec codec (output) Set the video codec. This is an alias for "-codec:v". -same_quant Use same quantizer as source (implies VBR). Note that this is NOT SAME QUALITY. Do not use this option unless you know you need it. -pass[:stream_specifier] n (output,per-stream) Select the pass number (1 or 2). It is used to do two-pass video encoding. The statistics of the video are recorded in the first pass into a log file (see also the option -passlogfile), and in the second pass that log file is used to generate the video at the exact requested bitrate. On pass 1, you may just deactivate audio and set output to null, examples for Windows and Unix: ffmpeg -i foo.mov -c:v libxvid -pass 1 -an -f rawvideo -y NUL ffmpeg -i foo.mov -c:v libxvid -pass 1 -an -f rawvideo -y /dev/null -passlogfile[:stream_specifier] prefix (output,per-stream) Set two-pass log file name prefix to prefix, the default file name prefix is ``ffmpeg2pass''. The complete file name will be PREFIX-N.log, where N is a number specific to the output stream -vlang code Set the ISO 639 language code (3 letters) of the current video stream. -vf filter_graph (output) filter_graph is a description of the filter graph to apply to the input video. Use the option "-filters" to show all the available filters (including also sources and sinks). This is an alias for "-filter:v". Advanced Video Options -pix_fmt[:stream_specifier] format (input/output,per-stream) Set pixel format. Use "-pix_fmts" to show all the supported pixel formats. If the selected pixel format can not be selected, ffmpeg will print a warning and select the best pixel format supported by the encoder. If pix_fmt is prefixed by a "+", ffmpeg will exit with an error if the requested pixel format can not be selected, and automatic conversions inside filter graphs are disabled. If pix_fmt is a single "+", ffmpeg selects the same pixel format as the input (or graph output) and automatic conversions are disabled. -sws_flags flags (input/output) Set SwScaler flags. -vdt n Discard threshold. -rc_override[:stream_specifier] override (output,per-stream) Rate control override for specific intervals, formatted as "int,int,int" list separated with slashes. Two first values are the beginning and end frame numbers, last one is quantizer to use if positive, or quality factor if negative. -deinterlace Deinterlace pictures. This option is deprecated since the deinterlacing is very low quality. Use the yadif filter with "-filter:v yadif". -ilme Force interlacing support in encoder (MPEG-2 and MPEG-4 only). Use this option if your input file is interlaced and you want to keep the interlaced format for minimum losses. The alternative is to deinterlace the input stream with -deinterlace, but deinterlacing introduces losses. -psnr Calculate PSNR of compressed frames. -vstats Dump video coding statistics to vstats_HHMMSS.log. -vstats_file file Dump video coding statistics to file. -top[:stream_specifier] n (output,per-stream) top=1/bottom=0/auto=-1 field first -dc precision Intra_dc_precision. -vtag fourcc/tag (output) Force video tag/fourcc. This is an alias for "-tag:v". -qphist (global) Show QP histogram -vbsf bitstream_filter Deprecated see -bsf -force_key_frames[:stream_specifier] time[,time...] (output,per-stream) Force key frames at the specified timestamps, more precisely at the first frames after each specified time. This option can be useful to ensure that a seek point is present at a chapter mark or any other designated place in the output file. The timestamps must be specified in ascending order. -copyinkf[:stream_specifier] (output,per-stream) When doing stream copy, copy also non-key frames found at the beginning. Audio Options -aframes number (output) Set the number of audio frames to record. This is an alias for "-frames:a". -ar[:stream_specifier] freq (input/output,per-stream) Set the audio sampling frequency. For output streams it is set by default to the frequency of the corresponding input stream. For input streams this option only makes sense for audio grabbing devices and raw demuxers and is mapped to the corresponding demuxer options. -aq q (output) Set the audio quality (codec-specific, VBR). This is an alias for -q:a. -ac[:stream_specifier] channels (input/output,per-stream) Set the number of audio channels. For output streams it is set by default to the number of input audio channels. For input streams this option only makes sense for audio grabbing devices and raw demuxers and is mapped to the corresponding demuxer options. -an (output) Disable audio recording. -acodec codec (input/output) Set the audio codec. This is an alias for "-codec:a". -sample_fmt[:stream_specifier] sample_fmt (output,per-stream) Set the audio sample format. Use "-sample_fmts" to get a list of supported sample formats. -af filter_graph (output) filter_graph is a description of the filter graph to apply to the input audio. Use the option "-filters" to show all the available filters (including also sources and sinks). This is an alias for "-filter:a". Advanced Audio options: -atag fourcc/tag (output) Force audio tag/fourcc. This is an alias for "-tag:a". -absf bitstream_filter Deprecated, see -bsf Subtitle options: -slang code Set the ISO 639 language code (3 letters) of the current subtitle stream. -scodec codec (input/output) Set the subtitle codec. This is an alias for "-codec:s". -sn (output) Disable subtitle recording. -sbsf bitstream_filter Deprecated, see -bsf Advanced Subtitle options: -fix_sub_duration Fix subtitles durations. For each subtitle, wait for the next packet in the same stream and adjust the duration of the first to avoid overlap. This is necessary with some subtitles codecs, especially DVB subtitles, because the duration in the original packet is only a rough estimate and the end is actually marked by an empty subtitle frame. Failing to use this option when necessary can result in exaggerated durations or muxing failures due to non-monotonic timestamps. Note that this option will delay the output of all data until the next subtitle packet is decoded: it may increase memory consumption and latency a lot. Advanced options -map [-]input_file_id[:stream_specifier][,sync_file_id[:stream_specifier]] | [linklabel] (output) Designate one or more input streams as a source for the output file. Each input stream is identified by the input file index input_file_id and the input stream index input_stream_id within the input file. Both indices start at 0. If specified, sync_file_id:stream_specifier sets which input stream is used as a presentation sync reference. The first "-map" option on the command line specifies the source for output stream 0, the second "-map" option specifies the source for output stream 1, etc. A "-" character before the stream identifier creates a "negative" mapping. It disables matching streams from already created mappings. An alternative [linklabel] form will map outputs from complex filter graphs (see the -filter_complex option) to the output file. linklabel must correspond to a defined output link label in the graph. For example, to map ALL streams from the first input file to output ffmpeg -i INPUT -map 0 output For example, if you have two audio streams in the first input file, these streams are identified by "0:0" and "0:1". You can use "-map" to select which streams to place in an output file. For example: ffmpeg -i INPUT -map 0:1 out.wav will map the input stream in INPUT identified by "0:1" to the (single) output stream in out.wav. For example, to select the stream with index 2 from input file a.mov (specified by the identifier "0:2"), and stream with index 6 from input b.mov (specified by the identifier "1:6"), and copy them to the output file out.mov: ffmpeg -i a.mov -i b.mov -c copy -map 0:2 -map 1:6 out.mov To select all video and the third audio stream from an input file: ffmpeg -i INPUT -map 0:v -map 0:a:2 OUTPUT To map all the streams except the second audio, use negative mappings ffmpeg -i INPUT -map 0 -map -0:a:1 OUTPUT Note that using this option disables the default mappings for this output file. -map_channel [input_file_id.stream_specifier.channel_id|-1][:output_file_id.stream_specifier] Map an audio channel from a given input to an output. If output_file_id.stream_specifier is not set, the audio channel will be mapped on all the audio streams. Using "-1" instead of input_file_id.stream_specifier.channel_id will map a muted channel. For example, assuming INPUT is a stereo audio file, you can switch the two audio channels with the following command: ffmpeg -i INPUT -map_channel 0.0.1 -map_channel 0.0.0 OUTPUT If you want to mute the first channel and keep the second: ffmpeg -i INPUT -map_channel -1 -map_channel 0.0.1 OUTPUT The order of the "-map_channel" option specifies the order of the channels in the output stream. The output channel layout is guessed from the number of channels mapped (mono if one "-map_channel", stereo if two, etc.). Using "-ac" in combination of "-map_channel" makes the channel gain levels to be updated if input and output channel layouts don't match (for instance two "-map_channel" options and "-ac 6"). You can also extract each channel of an input to specific outputs; the following command extracts two channels of the INPUT audio stream (file 0, stream 0) to the respective OUTPUT_CH0 and OUTPUT_CH1 outputs: ffmpeg -i INPUT -map_channel 0.0.0 OUTPUT_CH0 -map_channel 0.0.1 OUTPUT_CH1 The following example splits the channels of a stereo input into two separate streams, which are put into the same output file: ffmpeg -i stereo.wav -map 0:0 -map 0:0 -map_channel 0.0.0:0.0 -map_channel 0.0.1:0.1 -y out.ogg Note that currently each output stream can only contain channels from a single input stream; you can't for example use "-map_channel" to pick multiple input audio channels contained in different streams (from the same or different files) and merge them into a single output stream. It is therefore not currently possible, for example, to turn two separate mono streams into a single stereo stream. However splitting a stereo stream into two single channel mono streams is possible. If you need this feature, a possible workaround is to use the amerge filter. For example, if you need to merge a media (here input.mkv) with 2 mono audio streams into one single stereo channel audio stream (and keep the video stream), you can use the following command: ffmpeg -i input.mkv -filter_complex "[0:1] [0:2] amerge" -c:a pcm_s16le -c:v copy output.mkv -map_metadata[:metadata_spec_out] infile[:metadata_spec_in] (output,per-metadata) Set metadata information of the next output file from infile. Note that those are file indices (zero-based), not filenames. Optional metadata_spec_in/out parameters specify, which metadata to copy. A metadata specifier can have the following forms: g global metadata, i.e. metadata that applies to the whole file s[:stream_spec] per-stream metadata. stream_spec is a stream specifier as described in the Stream specifiers chapter. In an input metadata specifier, the first matching stream is copied from. In an output metadata specifier, all matching streams are copied to. c:chapter_index per-chapter metadata. chapter_index is the zero-based chapter index. p:program_index per-program metadata. program_index is the zero-based program index. If metadata specifier is omitted, it defaults to global. By default, global metadata is copied from the first input file, per- stream and per-chapter metadata is copied along with streams/chapters. These default mappings are disabled by creating any mapping of the relevant type. A negative file index can be used to create a dummy mapping that just disables automatic copying. For example to copy metadata from the first stream of the input file to global metadata of the output file: ffmpeg -i in.ogg -map_metadata 0:s:0 out.mp3 To do the reverse, i.e. copy global metadata to all audio streams: ffmpeg -i in.mkv -map_metadata:s:a 0:g out.mkv Note that simple 0 would work as well in this example, since global metadata is assumed by default. -map_chapters input_file_index (output) Copy chapters from input file with index input_file_index to the next output file. If no chapter mapping is specified, then chapters are copied from the first input file with at least one chapter. Use a negative file index to disable any chapter copying. -debug category Print specific debug info. category is a number or a string containing one of the following values: bitstream buffers picture buffer allocations bugs dct_coeff er error recognition mb_type macroblock (MB) type mmco memory management control operations (H.264) mv motion vector pict picture info pts qp per-block quantization parameter (QP) rc rate control skip startcode thread_ops threading operations vis_mb_type visualize block types vis_qp visualize quantization parameter (QP), lower QP are tinted greener -benchmark (global) Show benchmarking information at the end of an encode. Shows CPU time used and maximum memory consumption. Maximum memory consumption is not supported on all systems, it will usually display as 0 if not supported. -benchmark_all (global) Show benchmarking information during the encode. Shows CPU time used in various steps (audio/video encode/decode). -timelimit duration (global) Exit after ffmpeg has been running for duration seconds. -dump (global) Dump each input packet to stderr. -hex (global) When dumping packets, also dump the payload. -re (input) Read input at native frame rate. Mainly used to simulate a grab device. By default ffmpeg attempts to read the input(s) as fast as possible. This option will slow down the reading of the input(s) to the native frame rate of the input(s). It is useful for real-time output (e.g. live streaming). If your input(s) is coming from some other live streaming source (through HTTP or UDP for example) the server might already be in real-time, thus the option will likely not be required. On the other hand, this is meaningful if your input(s) is a file you are trying to push in real-time. -loop_input Loop over the input stream. Currently it works only for image streams. This option is used for automatic FFserver testing. This option is deprecated, use -loop 1. -loop_output number_of_times Repeatedly loop output for formats that support looping such as animated GIF (0 will loop the output infinitely). This option is deprecated, use -loop. -vsync parameter Video sync method. For compatibility reasons old values can be specified as numbers. Newly added values will have to be specified as strings always. 0, passthrough Each frame is passed with its timestamp from the demuxer to the muxer. 1, cfr Frames will be duplicated and dropped to achieve exactly the requested constant framerate. 2, vfr Frames are passed through with their timestamp or dropped so as to prevent 2 frames from having the same timestamp. drop As passthrough but destroys all timestamps, making the muxer generate fresh timestamps based on frame-rate. -1, auto Chooses between 1 and 2 depending on muxer capabilities. This is the default method. With -map you can select from which stream the timestamps should be taken. You can leave either video or audio unchanged and sync the remaining stream(s) to the unchanged one. -async samples_per_second Audio sync method. "Stretches/squeezes" the audio stream to match the timestamps, the parameter is the maximum samples per second by which the audio is changed. -async 1 is a special case where only the start of the audio stream is corrected without any later correction. This option has been deprecated. Use the "asyncts" audio filter instead. -copyts Copy timestamps from input to output. -copytb mode Specify how to set the encoder timebase when stream copying. mode is an integer numeric value, and can assume one of the following values: 1 Use the demuxer timebase. The time base is copied to the output encoder from the corresponding input demuxer. This is sometimes required to avoid non monotonically increasing timestamps when copying video streams with variable frame rate. 0 Use the decoder timebase. The time base is copied to the output encoder from the corresponding input decoder. -1 Try to make the choice automatically, in order to generate a sane output. Default value is -1. -shortest (output) Finish encoding when the shortest input stream ends. -dts_delta_threshold Timestamp discontinuity delta threshold. -muxdelay seconds (input) Set the maximum demux-decode delay. -muxpreload seconds (input) Set the initial demux-decode delay. -streamid output-stream-index:new-value (output) Assign a new stream-id value to an output stream. This option should be specified prior to the output filename to which it applies. For the situation where multiple output files exist, a streamid may be reassigned to a different value. For example, to set the stream 0 PID to 33 and the stream 1 PID to 36 for an output mpegts file: ffmpeg -i infile -streamid 0:33 -streamid 1:36 out.ts -bsf[:stream_specifier] bitstream_filters (output,per-stream) Set bitstream filters for matching streams. bistream_filters is a comma-separated list of bitstream filters. Use the "-bsfs" option to get the list of bitstream filters. ffmpeg -i h264.mp4 -c:v copy -bsf:v h264_mp4toannexb -an out.h264 ffmpeg -i file.mov -an -vn -bsf:s mov2textsub -c:s copy -f rawvideo sub.txt -tag[:stream_specifier] codec_tag (per-stream) Force a tag/fourcc for matching streams. -timecode hh:mm:ssSEPff Specify Timecode for writing. SEP is ':' for non drop timecode and ';' (or '.') for drop. ffmpeg -i input.mpg -timecode 01:02:03.04 -r 30000/1001 -s ntsc output.mpg -filter_complex filtergraph (global) Define a complex filter graph, i.e. one with arbitrary number of inputs and/or outputs. For simple graphs -- those with one input and one output of the same type -- see the -filter options. filtergraph is a description of the filter graph, as described in Filtergraph syntax. Input link labels must refer to input streams using the "[file_index:stream_specifier]" syntax (i.e. the same as -map uses). If stream_specifier matches multiple streams, the first one will be used. An unlabeled input will be connected to the first unused input stream of the matching type. Output link labels are referred to with -map. Unlabeled outputs are added to the first output file. Note that with this option it is possible to use only lavfi sources without normal input files. For example, to overlay an image over video ffmpeg -i video.mkv -i image.png -filter_complex '[0:v][1:v]overlay[out]' -map '[out]' out.mkv Here "[0:v]" refers to the first video stream in the first input file, which is linked to the first (main) input of the overlay filter. Similarly the first video stream in the second input is linked to the second (overlay) input of overlay. Assuming there is only one video stream in each input file, we can omit input labels, so the above is equivalent to ffmpeg -i video.mkv -i image.png -filter_complex 'overlay[out]' -map '[out]' out.mkv Furthermore we can omit the output label and the single output from the filter graph will be added to the output file automatically, so we can simply write ffmpeg -i video.mkv -i image.png -filter_complex 'overlay' out.mkv To generate 5 seconds of pure red video using lavfi "color" source: ffmpeg -filter_complex 'color=red' -t 5 out.mkv As a special exception, you can use a bitmap subtitle stream as input: it will be converted into a video with the same size as the largest video in the file, or 720x576 if no video is present. Note that this is an experimental and temporary solution. It will be removed once libavfilter has proper support for subtitles. For example, to hardcode subtitles on top of a DVB-T recording stored in MPEG-TS format, delaying the subtitles by 1 second: ffmpeg -i input.ts -filter_complex \ '[#0x2ef] setpts=PTS+1/TB [sub] ; [#0x2d0] [sub] overlay' \ -sn -map '#0x2dc' output.mkv (0x2d0, 0x2dc and 0x2ef are the MPEG-TS PIDs of respectively the video, audio and subtitles streams; 0:0, 0:3 and 0:7 would have worked too) Preset files A preset file contains a sequence of option=value pairs, one for each line, specifying a sequence of options which would be awkward to specify on the command line. Lines starting with the hash ('#') character are ignored and are used to provide comments. Check the presets directory in the FFmpeg source tree for examples. Preset files are specified with the "vpre", "apre", "spre", and "fpre" options. The "fpre" option takes the filename of the preset instead of a preset name as input and can be used for any kind of codec. For the "vpre", "apre", and "spre" options, the options specified in a preset file are applied to the currently selected codec of the same type as the preset option. The argument passed to the "vpre", "apre", and "spre" preset options identifies the preset file to use according to the following rules: First ffmpeg searches for a file named arg.ffpreset in the directories $FFMPEG_DATADIR (if set), and $HOME/.ffmpeg, and in the datadir defined at configuration time (usually PREFIX/share/ffmpeg) or in a ffpresets folder along the executable on win32, in that order. For example, if the argument is "libvpx-1080p", it will search for the file libvpx-1080p.ffpreset. If no such file is found, then ffmpeg will search for a file named codec_name-arg.ffpreset in the above-mentioned directories, where codec_name is the name of the codec to which the preset file options will be applied. For example, if you select the video codec with "-vcodec libvpx" and use "-vpre 1080p", then it will search for the file libvpx-1080p.ffpreset. TIPS · For streaming at very low bitrate application, use a low frame rate and a small GOP size. This is especially true for RealVideo where the Linux player does not seem to be very fast, so it can miss frames. An example is: ffmpeg -g 3 -r 3 -t 10 -b:v 50k -s qcif -f rv10 /tmp/b.rm · The parameter 'q' which is displayed while encoding is the current quantizer. The value 1 indicates that a very good quality could be achieved. The value 31 indicates the worst quality. If q=31 appears too often, it means that the encoder cannot compress enough to meet your bitrate. You must either increase the bitrate, decrease the frame rate or decrease the frame size. · If your computer is not fast enough, you can speed up the compression at the expense of the compression ratio. You can use '-me zero' to speed up motion estimation, and '-g 0' to disable motion estimation completely (you have only I-frames, which means it is about as good as JPEG compression). · To have very low audio bitrates, reduce the sampling frequency (down to 22050 Hz for MPEG audio, 22050 or 11025 for AC-3). · To have a constant quality (but a variable bitrate), use the option '-qscale n' when 'n' is between 1 (excellent quality) and 31 (worst quality). EXAMPLES Preset files A preset file contains a sequence of option=value pairs, one for each line, specifying a sequence of options which can be specified also on the command line. Lines starting with the hash ('#') character are ignored and are used to provide comments. Empty lines are also ignored. Check the presets directory in the FFmpeg source tree for examples. Preset files are specified with the "pre" option, this option takes a preset name as input. FFmpeg searches for a file named preset_name.avpreset in the directories $AVCONV_DATADIR (if set), and $HOME/.ffmpeg, and in the data directory defined at configuration time (usually $PREFIX/share/ffmpeg) in that order. For example, if the argument is "libx264-max", it will search for the file libx264-max.avpreset. Video and Audio grabbing If you specify the input format and device then ffmpeg can grab video and audio directly. ffmpeg -f oss -i /dev/dsp -f video4linux2 -i /dev/video0 /tmp/out.mpg Or with an ALSA audio source (mono input, card id 1) instead of OSS: ffmpeg -f alsa -ac 1 -i hw:1 -f video4linux2 -i /dev/video0 /tmp/out.mpg Note that you must activate the right video source and channel before launching ffmpeg with any TV viewer such as <http://linux.bytesex.org/xawtv/> by Gerd Knorr. You also have to set the audio recording levels correctly with a standard mixer. X11 grabbing Grab the X11 display with ffmpeg via ffmpeg -f x11grab -s cif -r 25 -i :0.0 /tmp/out.mpg 0.0 is display.screen number of your X11 server, same as the DISPLAY environment variable. ffmpeg -f x11grab -s cif -r 25 -i :0.0+10,20 /tmp/out.mpg 0.0 is display.screen number of your X11 server, same as the DISPLAY environment variable. 10 is the x-offset and 20 the y-offset for the grabbing. Video and Audio file format conversion Any supported file format and protocol can serve as input to ffmpeg: Examples: · You can use YUV files as input: ffmpeg -i /tmp/test%d.Y /tmp/out.mpg It will use the files: /tmp/test0.Y, /tmp/test0.U, /tmp/test0.V, /tmp/test1.Y, /tmp/test1.U, /tmp/test1.V, etc... The Y files use twice the resolution of the U and V files. They are raw files, without header. They can be generated by all decent video decoders. You must specify the size of the image with the -s option if ffmpeg cannot guess it. · You can input from a raw YUV420P file: ffmpeg -i /tmp/test.yuv /tmp/out.avi test.yuv is a file containing raw YUV planar data. Each frame is composed of the Y plane followed by the U and V planes at half vertical and horizontal resolution. · You can output to a raw YUV420P file: ffmpeg -i mydivx.avi hugefile.yuv · You can set several input files and output files: ffmpeg -i /tmp/a.wav -s 640x480 -i /tmp/a.yuv /tmp/a.mpg Converts the audio file a.wav and the raw YUV video file a.yuv to MPEG file a.mpg. · You can also do audio and video conversions at the same time: ffmpeg -i /tmp/a.wav -ar 22050 /tmp/a.mp2 Converts a.wav to MPEG audio at 22050 Hz sample rate. · You can encode to several formats at the same time and define a mapping from input stream to output streams: ffmpeg -i /tmp/a.wav -map 0:a -b:a 64k /tmp/a.mp2 -map 0:a -b:a 128k /tmp/b.mp2 Converts a.wav to a.mp2 at 64 kbits and to b.mp2 at 128 kbits. '-map file:index' specifies which input stream is used for each output stream, in the order of the definition of output streams. · You can transcode decrypted VOBs: ffmpeg -i snatch_1.vob -f avi -c:v mpeg4 -b:v 800k -g 300 -bf 2 -c:a libmp3lame -b:a 128k snatch.avi This is a typical DVD ripping example; the input is a VOB file, the output an AVI file with MPEG-4 video and MP3 audio. Note that in this command we use B-frames so the MPEG-4 stream is DivX5 compatible, and GOP size is 300 which means one intra frame every 10 seconds for 29.97fps input video. Furthermore, the audio stream is MP3-encoded so you need to enable LAME support by passing "--enable-libmp3lame" to configure. The mapping is particularly useful for DVD transcoding to get the desired audio language. NOTE: To see the supported input formats, use "ffmpeg -formats". · You can extract images from a video, or create a video from many images: For extracting images from a video: ffmpeg -i foo.avi -r 1 -s WxH -f image2 foo-%03d.jpeg This will extract one video frame per second from the video and will output them in files named foo-001.jpeg, foo-002.jpeg, etc. Images will be rescaled to fit the new WxH values. If you want to extract just a limited number of frames, you can use the above command in combination with the -vframes or -t option, or in combination with -ss to start extracting from a certain point in time. For creating a video from many images: ffmpeg -f image2 -i foo-%03d.jpeg -r 12 -s WxH foo.avi The syntax "foo-%03d.jpeg" specifies to use a decimal number composed of three digits padded with zeroes to express the sequence number. It is the same syntax supported by the C printf function, but only formats accepting a normal integer are suitable. When importing an image sequence, -i also supports expanding shell- like wildcard patterns (globbing) internally, by selecting the image2-specific "-pattern_type glob" option. For example, for creating a video from filenames matching the glob pattern "foo-*.jpeg": ffmpeg -f image2 -pattern_type glob -i 'foo-*.jpeg' -r 12 -s WxH foo.avi · You can put many streams of the same type in the output: ffmpeg -i test1.avi -i test2.avi -map 0.3 -map 0.2 -map 0.1 -map 0.0 -c copy test12.nut The resulting output file test12.avi will contain first four streams from the input file in reverse order. · To force CBR video output: ffmpeg -i myfile.avi -b 4000k -minrate 4000k -maxrate 4000k -bufsize 1835k out.m2v · The four options lmin, lmax, mblmin and mblmax use 'lambda' units, but you may use the QP2LAMBDA constant to easily convert from 'q' units: ffmpeg -i src.ext -lmax 21*QP2LAMBDA dst.ext SYNTAX When evaluating specific formats, FFmpeg uses internal library parsing functions, shared by the tools. This section documents the syntax of some of these formats. Date The accepted syntax is: [(YYYY-MM-DD|YYYYMMDD)[T|t| ]]((HH:MM:SS[.m...]]])|(HHMMSS[.m...]]]))[Z] now If the value is "now" it takes the current time. Time is local time unless Z is appended, in which case it is interpreted as UTC. If the year-month-day part is not specified it takes the current year-month-day. Time duration The accepted syntax is: [-]HH:MM:SS[.m...] [-]S+[.m...] HH expresses the number of hours, MM the number a of minutes and SS the number of seconds. Video size Specify the size of the sourced video, it may be a string of the form widthxheight, or the name of a size abbreviation. The following abbreviations are recognized: sqcif 128x96 qcif 176x144 cif 352x288 4cif 704x576 16cif 1408x1152 qqvga 160x120 qvga 320x240 vga 640x480 svga 800x600 xga 1024x768 uxga 1600x1200 qxga 2048x1536 sxga 1280x1024 qsxga 2560x2048 hsxga 5120x4096 wvga 852x480 wxga 1366x768 wsxga 1600x1024 wuxga 1920x1200 woxga 2560x1600 wqsxga 3200x2048 wquxga 3840x2400 whsxga 6400x4096 whuxga 7680x4800 cga 320x200 ega 640x350 hd480 852x480 hd720 1280x720 hd1080 1920x1080 Video rate Specify the frame rate of a video, expressed as the number of frames generated per second. It has to be a string in the format frame_rate_num/frame_rate_den, an integer number, a float number or a valid video frame rate abbreviation. The following abbreviations are recognized: ntsc 30000/1001 pal 25/1 qntsc 30000/1 qpal 25/1 sntsc 30000/1 spal 25/1 film 24/1 ntsc-film 24000/1 Ratio A ratio can be expressed as an expression, or in the form numerator:denominator. Note that a ratio with infinite (1/0) or negative value is considered valid, so you should check on the returned value if you want to exclude those values. The undefined value can be expressed using the "0:0" string. Color It can be the name of a color (case insensitive match) or a [0x|#]RRGGBB[AA] sequence, possibly followed by "@" and a string representing the alpha component. The alpha component may be a string composed by "0x" followed by an hexadecimal number or a decimal number between 0.0 and 1.0, which represents the opacity value (0x00/0.0 means completely transparent, 0xff/1.0 completely opaque). If the alpha component is not specified then 0xff is assumed. The string "random" will result in a random color. EXPRESSION EVALUATION When evaluating an arithmetic expression, FFmpeg uses an internal formula evaluator, implemented through the libavutil/eval.h interface. An expression may contain unary, binary operators, constants, and functions. Two expressions expr1 and expr2 can be combined to form another expression "expr1;expr2". expr1 and expr2 are evaluated in turn, and the new expression evaluates to the value of expr2. The following binary operators are available: "+", "-", "*", "/", "^". The following unary operators are available: "+", "-". The following functions are available: sinh(x) Compute hyperbolic sine of x. cosh(x) Compute hyperbolic cosine of x. tanh(x) Compute hyperbolic tangent of x. sin(x) Compute sine of x. cos(x) Compute cosine of x. tan(x) Compute tangent of x. atan(x) Compute arctangent of x. asin(x) Compute arcsine of x. acos(x) Compute arccosine of x. exp(x) Compute exponential of x (with base "e", the Euler's number). log(x) Compute natural logarithm of x. abs(x) Compute absolute value of x. squish(x) Compute expression "1/(1 + exp(4*x))". gauss(x) Compute Gauss function of x, corresponding to "exp(-x*x/2) / sqrt(2*PI)". isinf(x) Return 1.0 if x is +/-INFINITY, 0.0 otherwise. isnan(x) Return 1.0 if x is NAN, 0.0 otherwise. mod(x, y) Compute the remainder of division of x by y. max(x, y) Return the maximum between x and y. min(x, y) Return the maximum between x and y. eq(x, y) Return 1 if x and y are equivalent, 0 otherwise. gte(x, y) Return 1 if x is greater than or equal to y, 0 otherwise. gt(x, y) Return 1 if x is greater than y, 0 otherwise. lte(x, y) Return 1 if x is lesser than or equal to y, 0 otherwise. lt(x, y) Return 1 if x is lesser than y, 0 otherwise. st(var, expr) Allow to store the value of the expression expr in an internal variable. var specifies the number of the variable where to store the value, and it is a value ranging from 0 to 9. The function returns the value stored in the internal variable. Note, Variables are currently not shared between expressions. ld(var) Allow to load the value of the internal variable with number var, which was previously stored with st(var, expr). The function returns the loaded value. while(cond, expr) Evaluate expression expr while the expression cond is non-zero, and returns the value of the last expr evaluation, or NAN if cond was always false. ceil(expr) Round the value of expression expr upwards to the nearest integer. For example, "ceil(1.5)" is "2.0". floor(expr) Round the value of expression expr downwards to the nearest integer. For example, "floor(-1.5)" is "-2.0". trunc(expr) Round the value of expression expr towards zero to the nearest integer. For example, "trunc(-1.5)" is "-1.0". sqrt(expr) Compute the square root of expr. This is equivalent to "(expr)^.5". not(expr) Return 1.0 if expr is zero, 0.0 otherwise. pow(x, y) Compute the power of x elevated y, it is equivalent to "(x)^(y)". random(x) Return a pseudo random value between 0.0 and 1.0. x is the index of the internal variable which will be used to save the seed/state. hypot(x, y) This function is similar to the C function with the same name; it returns "sqrt(x*x + y*y)", the length of the hypotenuse of a right triangle with sides of length x and y, or the distance of the point (x, y) from the origin. gcd(x, y) Return the greatest common divisor of x and y. If both x and y are 0 or either or both are less than zero then behavior is undefined. if(x, y) Evaluate x, and if the result is non-zero return the result of the evaluation of y, return 0 otherwise. ifnot(x, y) Evaluate x, and if the result is zero return the result of the evaluation of y, return 0 otherwise. taylor(expr, x) taylor(expr, x, id) Evaluate a taylor series at x. expr represents the LD(id)-th derivates of f(x) at 0. If id is not specified then 0 is assumed. note, when you have the derivatives at y instead of 0 taylor(expr, x-y) can be used When the series does not converge the results are undefined. root(expr, max) Finds x where f(x)=0 in the interval 0..max. f() must be continuous or the result is undefined. The following constants are available: PI area of the unit disc, approximately 3.14 E exp(1) (Euler's number), approximately 2.718 PHI golden ratio (1+sqrt(5))/2, approximately 1.618 Assuming that an expression is considered "true" if it has a non-zero value, note that: "*" works like AND "+" works like OR and the construct: if A then B else C is equivalent to if(A,B) + ifnot(A,C) In your C code, you can extend the list of unary and binary functions, and define recognized constants, so that they are available for your expressions. The evaluator also recognizes the International System number postfixes. If 'i' is appended after the postfix, powers of 2 are used instead of powers of 10. The 'B' postfix multiplies the value for 8, and can be appended after another postfix or used alone. This allows using for example 'KB', 'MiB', 'G' and 'B' as postfix. Follows the list of available International System postfixes, with indication of the corresponding powers of 10 and of 2. y -24 / -80 z -21 / -70 a -18 / -60 f -15 / -50 p -12 / -40 n -9 / -30 u -6 / -20 m -3 / -10 c -2 d -1 h 2 k 3 / 10 K 3 / 10 M 6 / 20 G 9 / 30 T 12 / 40 P 15 / 40 E 18 / 50 Z 21 / 60 Y 24 / 70 DECODERS Decoders are configured elements in FFmpeg which allow the decoding of multimedia streams. When you configure your FFmpeg build, all the supported native decoders are enabled by default. Decoders requiring an external library must be enabled manually via the corresponding "--enable-lib" option. You can list all available decoders using the configure option "--list-decoders". You can disable all the decoders with the configure option "--disable-decoders" and selectively enable / disable single decoders with the options "--enable-decoder=DECODER" / "--disable-decoder=DECODER". The option "-codecs" of the ff* tools will display the list of enabled decoders. VIDEO DECODERS A description of some of the currently available video decoders follows. rawvideo Raw video decoder. This decoder decodes rawvideo streams. Options top top_field_first Specify the assumed field type of the input video. -1 the video is assumed to be progressive (default) 0 bottom-field-first is assumed 1 top-field-first is assumed AUDIO DECODERS ffwavesynth Internal wave synthetizer. This decoder generates wave patterns according to predefined sequences. Its use is purely internal and the format of the data it accepts is not publicly documented. libcelt libcelt decoder wrapper libcelt allows libavcodec to decode the Xiph CELT ultra-low delay audio codec. Requires the presence of the libcelt headers and library during configuration. You need to explicitly configure the build with "--enable-libcelt". libgsm libgsm decoder wrapper libgsm allows libavcodec to decode the GSM full rate audio codec. Requires the presence of the libgsm headers and library during configuration. You need to explicitly configure the build with "--enable-libgsm". This decoder supports both the ordinary GSM and the Microsoft variant. libilbc libilbc decoder wrapper libilbc allows libavcodec to decode the Internet Low Bitrate Codec (iLBC) audio codec. Requires the presence of the libilbc headers and library during configuration. You need to explicitly configure the build with "--enable-libilbc". Options The following option is supported by the libilbc wrapper. enhance Enable the enhancement of the decoded audio when set to 1. The default value is 0 (disabled). libopencore-amrnb libopencore-amrnb decoder wrapper libopencore-amrnb allows libavcodec to decode the Adaptive Multi-Rate Narrowband audio codec. Using it requires the presence of the libopencore-amrnb headers and library during configuration. You need to explicitly configure the build with "--enable-libopencore-amrnb". An FFmpeg native decoder for AMR-NB exists, so users can decode AMR-NB without this library. libopencore-amrwb libopencore-amrwb decoder wrapper. libopencore-amrwb allows libavcodec to decode the Adaptive Multi-Rate Wideband audio codec. Using it requires the presence of the libopencore- amrwb headers and library during configuration. You need to explicitly configure the build with "--enable-libopencore-amrwb". An FFmpeg native decoder for AMR-WB exists, so users can decode AMR-WB without this library. ENCODERS Encoders are configured elements in FFmpeg which allow the encoding of multimedia streams. When you configure your FFmpeg build, all the supported native encoders are enabled by default. Encoders requiring an external library must be enabled manually via the corresponding "--enable-lib" option. You can list all available encoders using the configure option "--list-encoders". You can disable all the encoders with the configure option "--disable-encoders" and selectively enable / disable single encoders with the options "--enable-encoder=ENCODER" / "--disable-encoder=ENCODER". The option "-codecs" of the ff* tools will display the list of enabled encoders. AUDIO ENCODERS A description of some of the currently available audio encoders follows. ac3 and ac3_fixed AC-3 audio encoders. These encoders implement part of ATSC A/52:2010 and ETSI TS 102 366, as well as the undocumented RealAudio 3 (a.k.a. dnet). The ac3 encoder uses floating-point math, while the ac3_fixed encoder only uses fixed-point integer math. This does not mean that one is always faster, just that one or the other may be better suited to a particular system. The floating-point encoder will generally produce better quality audio for a given bitrate. The ac3_fixed encoder is not the default codec for any of the output formats, so it must be specified explicitly using the option "-acodec ac3_fixed" in order to use it. AC-3 Metadata The AC-3 metadata options are used to set parameters that describe the audio, but in most cases do not affect the audio encoding itself. Some of the options do directly affect or influence the decoding and playback of the resulting bitstream, while others are just for informational purposes. A few of the options will add bits to the output stream that could otherwise be used for audio data, and will thus affect the quality of the output. Those will be indicated accordingly with a note in the option list below. These parameters are described in detail in several publicly-available documents. *<<http://www.atsc.org/cms/standards/a_52-2010.pdf>> *<<http://www.atsc.org/cms/standards/a_54a_with_corr_1.pdf>> *<<http://www.dolby.com/uploadedFiles/zz-_Shared_Assets/English_PDFs/Professional/18_Metadata.Guide.pdf>> *<<http://www.dolby.com/uploadedFiles/zz-_Shared_Assets/English_PDFs/Professional/46_DDEncodingGuidelines.pdf>> Metadata Control Options -per_frame_metadata boolean Allow Per-Frame Metadata. Specifies if the encoder should check for changing metadata for each frame. 0 The metadata values set at initialization will be used for every frame in the stream. (default) 1 Metadata values can be changed before encoding each frame. Downmix Levels -center_mixlev level Center Mix Level. The amount of gain the decoder should apply to the center channel when downmixing to stereo. This field will only be written to the bitstream if a center channel is present. The value is specified as a scale factor. There are 3 valid values: 0.707 Apply -3dB gain 0.595 Apply -4.5dB gain (default) 0.500 Apply -6dB gain -surround_mixlev level Surround Mix Level. The amount of gain the decoder should apply to the surround channel(s) when downmixing to stereo. This field will only be written to the bitstream if one or more surround channels are present. The value is specified as a scale factor. There are 3 valid values: 0.707 Apply -3dB gain 0.500 Apply -6dB gain (default) 0.000 Silence Surround Channel(s) Audio Production Information Audio Production Information is optional information describing the mixing environment. Either none or both of the fields are written to the bitstream. -mixing_level number Mixing Level. Specifies peak sound pressure level (SPL) in the production environment when the mix was mastered. Valid values are 80 to 111, or -1 for unknown or not indicated. The default value is -1, but that value cannot be used if the Audio Production Information is written to the bitstream. Therefore, if the "room_type" option is not the default value, the "mixing_level" option must not be -1. -room_type type Room Type. Describes the equalization used during the final mixing session at the studio or on the dubbing stage. A large room is a dubbing stage with the industry standard X-curve equalization; a small room has flat equalization. This field will not be written to the bitstream if both the "mixing_level" option and the "room_type" option have the default values. 0 notindicated Not Indicated (default) 1 large Large Room 2 small Small Room Other Metadata Options -copyright boolean Copyright Indicator. Specifies whether a copyright exists for this audio. 0 off No Copyright Exists (default) 1 on Copyright Exists -dialnorm value Dialogue Normalization. Indicates how far the average dialogue level of the program is below digital 100% full scale (0 dBFS). This parameter determines a level shift during audio reproduction that sets the average volume of the dialogue to a preset level. The goal is to match volume level between program sources. A value of -31dB will result in no volume level change, relative to the source volume, during audio reproduction. Valid values are whole numbers in the range -31 to -1, with -31 being the default. -dsur_mode mode Dolby Surround Mode. Specifies whether the stereo signal uses Dolby Surround (Pro Logic). This field will only be written to the bitstream if the audio stream is stereo. Using this option does NOT mean the encoder will actually apply Dolby Surround processing. 0 notindicated Not Indicated (default) 1 off Not Dolby Surround Encoded 2 on Dolby Surround Encoded -original boolean Original Bit Stream Indicator. Specifies whether this audio is from the original source and not a copy. 0 off Not Original Source 1 on Original Source (default) Extended Bitstream Information The extended bitstream options are part of the Alternate Bit Stream Syntax as specified in Annex D of the A/52:2010 standard. It is grouped into 2 parts. If any one parameter in a group is specified, all values in that group will be written to the bitstream. Default values are used for those that are written but have not been specified. If the mixing levels are written, the decoder will use these values instead of the ones specified in the "center_mixlev" and "surround_mixlev" options if it supports the Alternate Bit Stream Syntax. Extended Bitstream Information - Part 1 -dmix_mode mode Preferred Stereo Downmix Mode. Allows the user to select either Lt/Rt (Dolby Surround) or Lo/Ro (normal stereo) as the preferred stereo downmix mode. 0 notindicated Not Indicated (default) 1 ltrt Lt/Rt Downmix Preferred 2 loro Lo/Ro Downmix Preferred -ltrt_cmixlev level Lt/Rt Center Mix Level. The amount of gain the decoder should apply to the center channel when downmixing to stereo in Lt/Rt mode. 1.414 Apply +3dB gain 1.189 Apply +1.5dB gain 1.000 Apply 0dB gain 0.841 Apply -1.5dB gain 0.707 Apply -3.0dB gain 0.595 Apply -4.5dB gain (default) 0.500 Apply -6.0dB gain 0.000 Silence Center Channel -ltrt_surmixlev level Lt/Rt Surround Mix Level. The amount of gain the decoder should apply to the surround channel(s) when downmixing to stereo in Lt/Rt mode. 0.841 Apply -1.5dB gain 0.707 Apply -3.0dB gain 0.595 Apply -4.5dB gain 0.500 Apply -6.0dB gain (default) 0.000 Silence Surround Channel(s) -loro_cmixlev level Lo/Ro Center Mix Level. The amount of gain the decoder should apply to the center channel when downmixing to stereo in Lo/Ro mode. 1.414 Apply +3dB gain 1.189 Apply +1.5dB gain 1.000 Apply 0dB gain 0.841 Apply -1.5dB gain 0.707 Apply -3.0dB gain 0.595 Apply -4.5dB gain (default) 0.500 Apply -6.0dB gain 0.000 Silence Center Channel -loro_surmixlev level Lo/Ro Surround Mix Level. The amount of gain the decoder should apply to the surround channel(s) when downmixing to stereo in Lo/Ro mode. 0.841 Apply -1.5dB gain 0.707 Apply -3.0dB gain 0.595 Apply -4.5dB gain 0.500 Apply -6.0dB gain (default) 0.000 Silence Surround Channel(s) Extended Bitstream Information - Part 2 -dsurex_mode mode Dolby Surround EX Mode. Indicates whether the stream uses Dolby Surround EX (7.1 matrixed to 5.1). Using this option does NOT mean the encoder will actually apply Dolby Surround EX processing. 0 notindicated Not Indicated (default) 1 on Dolby Surround EX Off 2 off Dolby Surround EX On -dheadphone_mode mode Dolby Headphone Mode. Indicates whether the stream uses Dolby Headphone encoding (multi-channel matrixed to 2.0 for use with headphones). Using this option does NOT mean the encoder will actually apply Dolby Headphone processing. 0 notindicated Not Indicated (default) 1 on Dolby Headphone Off 2 off Dolby Headphone On -ad_conv_type type A/D Converter Type. Indicates whether the audio has passed through HDCD A/D conversion. 0 standard Standard A/D Converter (default) 1 hdcd HDCD A/D Converter Other AC-3 Encoding Options -stereo_rematrixing boolean Stereo Rematrixing. Enables/Disables use of rematrixing for stereo input. This is an optional AC-3 feature that increases quality by selectively encoding the left/right channels as mid/side. This option is enabled by default, and it is highly recommended that it be left as enabled except for testing purposes. Floating-Point-Only AC-3 Encoding Options These options are only valid for the floating-point encoder and do not exist for the fixed-point encoder due to the corresponding features not being implemented in fixed-point. -channel_coupling boolean Enables/Disables use of channel coupling, which is an optional AC-3 feature that increases quality by combining high frequency information from multiple channels into a single channel. The per- channel high frequency information is sent with less accuracy in both the frequency and time domains. This allows more bits to be used for lower frequencies while preserving enough information to reconstruct the high frequencies. This option is enabled by default for the floating-point encoder and should generally be left as enabled except for testing purposes or to increase encoding speed. -1 auto Selected by Encoder (default) 0 off Disable Channel Coupling 1 on Enable Channel Coupling -cpl_start_band number Coupling Start Band. Sets the channel coupling start band, from 1 to 15. If a value higher than the bandwidth is used, it will be reduced to 1 less than the coupling end band. If auto is used, the start band will be determined by the encoder based on the bit rate, sample rate, and channel layout. This option has no effect if channel coupling is disabled. -1 auto Selected by Encoder (default) libmp3lame LAME (Lame Ain't an MP3 Encoder) MP3 encoder wrapper Requires the presence of the libmp3lame headers and library during configuration. You need to explicitly configure the build with "--enable-libmp3lame". Option Mapping The following options are supported by the libmp3lame wrapper, the LAME- equivalent options follow the FFmpeg ones. FFmpeg : LAME b : b FFmpeg "b" option is expressed in bits/s, lame "bitrate" in kilobits/s. q : V Quality setting for VBR. compression_level : q Algorithm quality. Valid options are integers from 0-9. reservoir : N.A. Enable use of bit reservoir. LAME has this enabled by default. joint_stereo : -m j Enables the the encoder to use (on a frame by frame basis) either L/R stereo or mid/side stereo. libopencore-amrnb OpenCORE Adaptive Multi-Rate Narrowband encoder. Requires the presence of the libopencore-amrnb headers and library during configuration. You need to explicitly configure the build with "--enable-libopencore-amrnb --enable-version3". This is a mono-only encoder. Officially it only supports 8000Hz sample rate, but you can override it by setting strict to unofficial or lower. Options b Set bitrate in bits per second. Only the following bitrates are supported, otherwise libavcodec will round to the nearest valid bitrate. 4750 5150 5900 6700 7400 7950 10200 12200 dtx Allow discontinuous transmission (generate comfort noise) when set to 1. The default value is 0 (disabled). libtwolame TwoLAME MP2 encoder wrapper Requires the presence of the libtwolame headers and library during configuration. You need to explicitly configure the build with "--enable-libtwolame". Options Mapping The following options are supported by the libtwolame wrapper. The TwoLAME-equivalent options follow the FFmpeg ones and are in parentheses. b (b) Set bitrate in bits/s. Note that FFmpeg "b" option is expressed in bits/s, twolame "b" in kilobits/s. The default value is 128k. q (V) Set quality for experimental VBR support. Maximum value range is from -50 to 50, useful range is from -10 to 10. mode (mode) Set MPEG mode. Possible values: auto Choose mode automatically based on the input. This is the default. stereo Stereo joint_stereo Joint stereo dual_channel Dual channel mono Mono psymodel (psyc-mode) Set psychoacoustic model to use in encoding. The argument must be an integer between -1 and 4, inclusive. The higher the value, the better the quality. The default value is 3. energy_levels (energy) Enable energy levels extensions when set to 1. The default value is 0 (disabled). error_protection (protect) Enable CRC error protection when set to 1. The default value is 0 (disabled). copyright (copyright) Set MPEG audio copyright flag when set to 1. The default value is 0 (disabled). original (original) Set MPEG audio original flag when set to 1. The default value is 0 (disabled). libvo-aacenc VisualOn AAC encoder Requires the presence of the libvo-aacenc headers and library during configuration. You need to explicitly configure the build with "--enable-libvo-aacenc --enable-version3". Options The VisualOn AAC encoder only support encoding AAC-LC and up to 2 channels. It is also CBR-only. It is considered to be worse than the native experimental FFmpeg AAC encoder. b Bitrate. libvo-amrwbenc VisualOn Adaptive Multi-Rate Wideband encoder Requires the presence of the libvo-amrwbenc headers and library during configuration. You need to explicitly configure the build with "--enable-libvo-amrwbenc --enable-version3". This is a mono-only encoder. Officially it only supports 16000Hz sample rate, but you can override it by setting strict to unofficial or lower. Options b Set bitrate in bits/s. Only the following bitrates are supported, otherwise libavcodec will round to the nearest valid bitrate. 6600 8850 12650 14250 15850 18250 19850 23050 23850 dtx Allow discontinuous transmission (generate comfort noise) when set to 1. The default value is 0 (disabled). VIDEO ENCODERS A description of some of the currently available video encoders follows. libvpx VP8 format supported through libvpx. Requires the presence of the libvpx headers and library during configuration. You need to explicitly configure the build with "--enable-libvpx". Options Mapping from FFmpeg to libvpx options with conversion notes in parentheses. threads g_threads profile g_profile vb rc_target_bitrate g kf_max_dist keyint_min kf_min_dist qmin rc_min_quantizer qmax rc_max_quantizer bufsize, vb rc_buf_sz "(bufsize * 1000 / vb)" rc_buf_optimal_sz "(bufsize * 1000 / vb * 5 / 6)" rc_init_occupancy, vb rc_buf_initial_sz "(rc_init_occupancy * 1000 / vb)" rc_buffer_aggressivity rc_undershoot_pct skip_threshold rc_dropframe_thresh qcomp rc_2pass_vbr_bias_pct maxrate, vb rc_2pass_vbr_maxsection_pct "(maxrate * 100 / vb)" minrate, vb rc_2pass_vbr_minsection_pct "(minrate * 100 / vb)" minrate, maxrate, vb "VPX_CBR" "(minrate == maxrate == vb)" crf "VPX_CQ", "VP8E_SET_CQ_LEVEL" quality best "VPX_DL_BEST_QUALITY" good "VPX_DL_GOOD_QUALITY" realtime "VPX_DL_REALTIME" speed "VP8E_SET_CPUUSED" nr "VP8E_SET_NOISE_SENSITIVITY" mb_threshold "VP8E_SET_STATIC_THRESHOLD" slices "VP8E_SET_TOKEN_PARTITIONS" max-intra-rate "VP8E_SET_MAX_INTRA_BITRATE_PCT" force_key_frames "VPX_EFLAG_FORCE_KF" Alternate reference frame related vp8flags altref "VP8E_SET_ENABLEAUTOALTREF" arnr_max_frames "VP8E_SET_ARNR_MAXFRAMES" arnr_type "VP8E_SET_ARNR_TYPE" arnr_strength "VP8E_SET_ARNR_STRENGTH" rc_lookahead g_lag_in_frames vp8flags error_resilient g_error_resilient For more information about libvpx see: <http://www.webmproject.org/> libx264 H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10 format supported through libx264. Requires the presence of the libx264 headers and library during configuration. You need to explicitly configure the build with "--enable-libx264". Options preset preset_name Set the encoding preset. tune tune_name Tune the encoding params. fastfirstpass bool Use fast settings when encoding first pass, default value is 1. profile profile_name Set profile restrictions. level level Specify level (as defined by Annex A). Deprecated in favor of x264opts. passlogfile filename Specify filename for 2 pass stats. Deprecated in favor of x264opts (see stats libx264 option). wpredp wpred_type Specify Weighted prediction for P-frames. Deprecated in favor of x264opts (see weightp libx264 option). x264opts options Allow to set any x264 option, see x264 --fullhelp for a list. options is a list of key=value couples separated by ":". For example to specify libx264 encoding options with ffmpeg: ffmpeg -i foo.mpg -vcodec libx264 -x264opts keyint=123:min-keyint=20 -an out.mkv For more information about libx264 and the supported options see: <http://www.videolan.org/developers/x264.html> libxvid Xvid MPEG-4 Part 2 encoder wrapper. This encoder requires the presence of the libxvidcore headers and library during configuration. You need to explicitly configure the build with "--enable-libxvid --enable-gpl". The native "mpeg4" encoder supports the MPEG-4 Part 2 format, so users can encode to this format without this library. Options The following options are supported by the libxvid wrapper. Some of the following options are listed but are not documented, and correspond to shared codec options. The other shared options which are not listed have no effect for the libxvid encoder. b g qmin qmax mpeg_quant threads bf b_qfactor b_qoffset flags Set specific encoding flags. Possible values: mv4 Use four motion vector by macroblock. aic Enable high quality AC prediction. gray Only encode grayscale. gmc Enable the use of global motion compensation (GMC). qpel Enable quarter-pixel motion compensation. cgop Enable closed GOP. global_header Place global headers in extradata instead of every keyframe. trellis me_method Set motion estimation method. Possible values in decreasing order of speed and increasing order of quality: zero Use no motion estimation (default). phods x1 log Enable advanced diamond zonal search for 16x16 blocks and half- pixel refinement for 16x16 blocks. x1 and log are aliases for phods. epzs Enable all of the things described above, plus advanced diamond zonal search for 8x8 blocks, half-pixel refinement for 8x8 blocks, and motion estimation on chroma planes. full Enable all of the things described above, plus extended 16x16 and 8x8 blocks search. mbd Set macroblock decision algorithm. Possible values in the increasing order of quality: simple Use macroblock comparing function algorithm (default). bits Enable rate distortion-based half pixel and quarter pixel refinement for 16x16 blocks. rd Enable all of the things described above, plus rate distortion- based half pixel and quarter pixel refinement for 8x8 blocks, and rate distortion-based search using square pattern. DEMUXERS Demuxers are configured elements in FFmpeg which allow to read the multimedia streams from a particular type of file. When you configure your FFmpeg build, all the supported demuxers are enabled by default. You can list all available ones using the configure option "--list-demuxers". You can disable all the demuxers using the configure option "--disable-demuxers", and selectively enable a single demuxer with the option "--enable-demuxer=DEMUXER", or disable it with the option "--disable-demuxer=DEMUXER". The option "-formats" of the ff* tools will display the list of enabled demuxers. The description of some of the currently available demuxers follows. image2 Image file demuxer. This demuxer reads from a list of image files specified by a pattern. The syntax and meaning of the pattern is specified by the option pattern_type. The pattern may contain a suffix which is used to automatically determine the format of the images contained in the files. The size, the pixel format, and the format of each image must be the same for all the files in the sequence. This demuxer accepts the following options: framerate Set the framerate for the video stream. It defaults to 25. loop If set to 1, loop over the input. Default value is 0. pattern_type Select the pattern type used to interpret the provided filename. pattern_type accepts one of the following values. sequence Select a sequence pattern type, used to specify a sequence of files indexed by sequential numbers. A sequence pattern may contain the string "%d" or "%0Nd", which specifies the position of the characters representing a sequential number in each filename matched by the pattern. If the form "%d0Nd" is used, the string representing the number in each filename is 0-padded and N is the total number of 0-padded digits representing the number. The literal character '%' can be specified in the pattern with the string "%%". If the sequence pattern contains "%d" or "%0Nd", the first filename of the file list specified by the pattern must contain a number inclusively contained between start_number and start_number+start_number_range-1, and all the following numbers must be sequential. For example the pattern "img-%03d.bmp" will match a sequence of filenames of the form img-001.bmp, img-002.bmp, ..., img-010.bmp, etc.; the pattern "i%%m%%g-%d.jpg" will match a sequence of filenames of the form i%m%g-1.jpg, i%m%g-2.jpg, ..., i%m%g-10.jpg, etc. Note that the pattern must not necessarily contain "%d" or "%0Nd", for example to convert a single image file img.jpeg you can employ the command: ffmpeg -i img.jpeg img.png glob Select a glob wildcard pattern type. The pattern is interpreted like a "glob()" pattern. This is only selectable if libavformat was compiled with globbing support. glob_sequence (deprecated, will be removed) Select a mixed glob wildcard/sequence pattern. If your version of libavformat was compiled with globbing support, and the provided pattern contains at least one glob meta character among "%*?[]{}" that is preceded by an unescaped "%", the pattern is interpreted like a "glob()" pattern, otherwise it is interpreted like a sequence pattern. All glob special characters "%*?[]{}" must be prefixed with "%". To escape a literal "%" you shall use "%%". For example the pattern "foo-%*.jpeg" will match all the filenames prefixed by "foo-" and terminating with ".jpeg", and "foo-%?%?%?.jpeg" will match all the filenames prefixed with "foo-", followed by a sequence of three characters, and terminating with ".jpeg". This pattern type is deprecated in favor of glob and sequence. Default value is glob_sequence. pixel_format Set the pixel format of the images to read. If not specified the pixel format is guessed from the first image file in the sequence. start_number Set the index of the file matched by the image file pattern to start to read from. Default value is 0. start_number_range Set the index interval range to check when looking for the first image file in the sequence, starting from start_number. Default value is 5. video_size Set the video size of the images to read. If not specified the video size is guessed from the first image file in the sequence. Examples · Use ffmpeg for creating a video from the images in the file sequence img-001.jpeg, img-002.jpeg, ..., assuming an input frame rate of 10 frames per second: ffmpeg -i 'img-%03d.jpeg' -r 10 out.mkv · As above, but start by reading from a file with index 100 in the sequence: ffmpeg -start_number 100 -i 'img-%03d.jpeg' -r 10 out.mkv · Read images matching the "*.png" glob pattern , that is all the files terminating with the ".png" suffix: ffmpeg -pattern_type glob -i "*.png" -r 10 out.mkv applehttp Apple HTTP Live Streaming demuxer. This demuxer presents all AVStreams from all variant streams. The id field is set to the bitrate variant index number. By setting the discard flags on AVStreams (by pressing 'a' or 'v' in ffplay), the caller can decide which variant streams to actually receive. The total bitrate of the variant that the stream belongs to is available in a metadata key named "variant_bitrate". sbg SBaGen script demuxer. This demuxer reads the script language used by SBaGen <http://uazu.net/sbagen/> to generate binaural beats sessions.  If the script uses either only absolute timestamps (including the script start time) or only relative ones, then its layout is fixed, and the conversion is straightforward. On the other hand, if the script mixes both kind of timestamps, then the NOW reference for relative timestamps will be taken from the current time of day at the time the script is read, and the script layout will be frozen according to that reference. That means that if the script is directly played, the actual times will match the absolute timestamps up to the sound controller's clock accuracy, but if the user somehow pauses the playback or seeks, all times will be shifted accordingly. MUXERS Muxers are configured elements in FFmpeg which allow writing multimedia streams to a particular type of file. When you configure your FFmpeg build, all the supported muxers are enabled by default. You can list all available muxers using the configure option "--list-muxers". You can disable all the muxers with the configure option "--disable-muxers" and selectively enable / disable single muxers with the options "--enable-muxer=MUXER" / "--disable-muxer=MUXER". The option "-formats" of the ff* tools will display the list of enabled muxers. A description of some of the currently available muxers follows. aiff Audio Interchange File Format muxer. It accepts the following options: write_id3v2 Enable ID3v2 tags writing when set to 1. Default is 0 (disabled). id3v2_version Select ID3v2 version to write. Currently only version 3 and 4 (aka. ID3v2.3 and ID3v2.4) are supported. The default is version 4. crc CRC (Cyclic Redundancy Check) testing format. This muxer computes and prints the Adler-32 CRC of all the input audio and video frames. By default audio frames are converted to signed 16-bit raw audio and video frames to raw video before computing the CRC. The output of the muxer consists of a single line of the form: CRC=0xCRC, where CRC is a hexadecimal number 0-padded to 8 digits containing the CRC for all the decoded input frames. For example to compute the CRC of the input, and store it in the file out.crc: ffmpeg -i INPUT -f crc out.crc You can print the CRC to stdout with the command: ffmpeg -i INPUT -f crc - You can select the output format of each frame with ffmpeg by specifying the audio and video codec and format. For example to compute the CRC of the input audio converted to PCM unsigned 8-bit and the input video converted to MPEG-2 video, use the command: ffmpeg -i INPUT -c:a pcm_u8 -c:v mpeg2video -f crc - See also the framecrc muxer. framecrc Per-packet CRC (Cyclic Redundancy Check) testing format. This muxer computes and prints the Adler-32 CRC for each audio and video packet. By default audio frames are converted to signed 16-bit raw audio and video frames to raw video before computing the CRC. The output of the muxer consists of a line for each audio and video packet of the form: <stream_index>, <packet_dts>, <packet_pts>, <packet_duration>, <packet_size>, 0x<CRC> CRC is a hexadecimal number 0-padded to 8 digits containing the CRC of the packet. For example to compute the CRC of the audio and video frames in INPUT, converted to raw audio and video packets, and store it in the file out.crc: ffmpeg -i INPUT -f framecrc out.crc To print the information to stdout, use the command: ffmpeg -i INPUT -f framecrc - With ffmpeg, you can select the output format to which the audio and video frames are encoded before computing the CRC for each packet by specifying the audio and video codec. For example, to compute the CRC of each decoded input audio frame converted to PCM unsigned 8-bit and of each decoded input video frame converted to MPEG-2 video, use the command: ffmpeg -i INPUT -c:a pcm_u8 -c:v mpeg2video -f framecrc - See also the crc muxer. framemd5 Per-packet MD5 testing format. This muxer computes and prints the MD5 hash for each audio and video packet. By default audio frames are converted to signed 16-bit raw audio and video frames to raw video before computing the hash. The output of the muxer consists of a line for each audio and video packet of the form: <stream_index>, <packet_dts>, <packet_pts>, <packet_duration>, <packet_size>, <MD5> MD5 is a hexadecimal number representing the computed MD5 hash for the packet. For example to compute the MD5 of the audio and video frames in INPUT, converted to raw audio and video packets, and store it in the file out.md5: ffmpeg -i INPUT -f framemd5 out.md5 To print the information to stdout, use the command: ffmpeg -i INPUT -f framemd5 - See also the md5 muxer. ico ICO file muxer. Microsoft's icon file format (ICO) has some strict limitations that should be noted: · Size cannot exceed 256 pixels in any dimension · Only BMP and PNG images can be stored · If a BMP image is used, it must be one of the following pixel formats: BMP Bit Depth FFmpeg Pixel Format 1bit pal8 4bit pal8 8bit pal8 16bit rgb555le 24bit bgr24 32bit bgra · If a BMP image is used, it must use the BITMAPINFOHEADER DIB header · If a PNG image is used, it must use the rgba pixel format image2 Image file muxer. The image file muxer writes video frames to image files. The output filenames are specified by a pattern, which can be used to produce sequentially numbered series of files. The pattern may contain the string "%d" or "%0Nd", this string specifies the position of the characters representing a numbering in the filenames. If the form "%0Nd" is used, the string representing the number in each filename is 0-padded to N digits. The literal character '%' can be specified in the pattern with the string "%%". If the pattern contains "%d" or "%0Nd", the first filename of the file list specified will contain the number 1, all the following numbers will be sequential. The pattern may contain a suffix which is used to automatically determine the format of the image files to write. For example the pattern "img-%03d.bmp" will specify a sequence of filenames of the form img-001.bmp, img-002.bmp, ..., img-010.bmp, etc. The pattern "img%%-%d.jpg" will specify a sequence of filenames of the form img%-1.jpg, img%-2.jpg, ..., img%-10.jpg, etc. The following example shows how to use ffmpeg for creating a sequence of files img-001.jpeg, img-002.jpeg, ..., taking one image every second from the input video: ffmpeg -i in.avi -vsync 1 -r 1 -f image2 'img-%03d.jpeg' Note that with ffmpeg, if the format is not specified with the "-f" option and the output filename specifies an image file format, the image2 muxer is automatically selected, so the previous command can be written as: ffmpeg -i in.avi -vsync 1 -r 1 'img-%03d.jpeg' Note also that the pattern must not necessarily contain "%d" or "%0Nd", for example to create a single image file img.jpeg from the input video you can employ the command: ffmpeg -i in.avi -f image2 -frames:v 1 img.jpeg The image muxer supports the .Y.U.V image file format. This format is special in that that each image frame consists of three files, for each of the YUV420P components. To read or write this image file format, specify the name of the '.Y' file. The muxer will automatically open the '.U' and '.V' files as required. md5 MD5 testing format. This muxer computes and prints the MD5 hash of all the input audio and video frames. By default audio frames are converted to signed 16-bit raw audio and video frames to raw video before computing the hash. The output of the muxer consists of a single line of the form: MD5=MD5, where MD5 is a hexadecimal number representing the computed MD5 hash. For example to compute the MD5 hash of the input converted to raw audio and video, and store it in the file out.md5: ffmpeg -i INPUT -f md5 out.md5 You can print the MD5 to stdout with the command: ffmpeg -i INPUT -f md5 - See also the framemd5 muxer. MOV/MP4/ISMV The mov/mp4/ismv muxer supports fragmentation. Normally, a MOV/MP4 file has all the metadata about all packets stored in one location (written at the end of the file, it can be moved to the start for better playback using the qt-faststart tool). A fragmented file consists of a number of fragments, where packets and metadata about these packets are stored together. Writing a fragmented file has the advantage that the file is decodable even if the writing is interrupted (while a normal MOV/MP4 is undecodable if it is not properly finished), and it requires less memory when writing very long files (since writing normal MOV/MP4 files stores info about every single packet in memory until the file is closed). The downside is that it is less compatible with other applications. Fragmentation is enabled by setting one of the AVOptions that define how to cut the file into fragments: -moov_size bytes Reserves space for the moov atom at the beginning of the file instead of placing the moov atom at the end. If the space reserved is insufficient, muxing will fail. -movflags frag_keyframe Start a new fragment at each video keyframe. -frag_duration duration Create fragments that are duration microseconds long. -frag_size size Create fragments that contain up to size bytes of payload data. -movflags frag_custom Allow the caller to manually choose when to cut fragments, by calling "av_write_frame(ctx, NULL)" to write a fragment with the packets written so far. (This is only useful with other applications integrating libavformat, not from ffmpeg.) -min_frag_duration duration Don't create fragments that are shorter than duration microseconds long. If more than one condition is specified, fragments are cut when one of the specified conditions is fulfilled. The exception to this is "-min_frag_duration", which has to be fulfilled for any of the other conditions to apply. Additionally, the way the output file is written can be adjusted through a few other options: -movflags empty_moov Write an initial moov atom directly at the start of the file, without describing any samples in it. Generally, an mdat/moov pair is written at the start of the file, as a normal MOV/MP4 file, containing only a short portion of the file. With this option set, there is no initial mdat atom, and the moov atom only describes the tracks but has a zero duration. Files written with this option set do not work in QuickTime. This option is implicitly set when writing ismv (Smooth Streaming) files. -movflags separate_moof Write a separate moof (movie fragment) atom for each track. Normally, packets for all tracks are written in a moof atom (which is slightly more efficient), but with this option set, the muxer writes one moof/mdat pair for each track, making it easier to separate tracks. This option is implicitly set when writing ismv (Smooth Streaming) files. Smooth Streaming content can be pushed in real time to a publishing point on IIS with this muxer. Example: ffmpeg -re <<normal input/transcoding options>> -movflags isml+frag_keyframe -f ismv http://server/publishingpoint.isml/Streams(Encoder1) mpegts MPEG transport stream muxer. This muxer implements ISO 13818-1 and part of ETSI EN 300 468. The muxer options are: -mpegts_original_network_id number Set the original_network_id (default 0x0001). This is unique identifier of a network in DVB. Its main use is in the unique identification of a service through the path Original_Network_ID, Transport_Stream_ID. -mpegts_transport_stream_id number Set the transport_stream_id (default 0x0001). This identifies a transponder in DVB. -mpegts_service_id number Set the service_id (default 0x0001) also known as program in DVB. -mpegts_pmt_start_pid number Set the first PID for PMT (default 0x1000, max 0x1f00). -mpegts_start_pid number Set the first PID for data packets (default 0x0100, max 0x0f00). The recognized metadata settings in mpegts muxer are "service_provider" and "service_name". If they are not set the default for "service_provider" is "FFmpeg" and the default for "service_name" is "Service01". ffmpeg -i file.mpg -c copy \ -mpegts_original_network_id 0x1122 \ -mpegts_transport_stream_id 0x3344 \ -mpegts_service_id 0x5566 \ -mpegts_pmt_start_pid 0x1500 \ -mpegts_start_pid 0x150 \ -metadata service_provider="Some provider" \ -metadata service_name="Some Channel" \ -y out.ts null Null muxer. This muxer does not generate any output file, it is mainly useful for testing or benchmarking purposes. For example to benchmark decoding with ffmpeg you can use the command: ffmpeg -benchmark -i INPUT -f null out.null Note that the above command does not read or write the out.null file, but specifying the output file is required by the ffmpeg syntax. Alternatively you can write the command as: ffmpeg -benchmark -i INPUT -f null - matroska Matroska container muxer. This muxer implements the matroska and webm container specs. The recognized metadata settings in this muxer are: title=title name Name provided to a single track language=language name Specifies the language of the track in the Matroska languages form stereo_mode=mode Stereo 3D video layout of two views in a single video track mono video is not stereo left_right Both views are arranged side by side, Left-eye view is on the left bottom_top Both views are arranged in top-bottom orientation, Left-eye view is at bottom top_bottom Both views are arranged in top-bottom orientation, Left-eye view is on top checkerboard_rl Each view is arranged in a checkerboard interleaved pattern, Left-eye view being first checkerboard_lr Each view is arranged in a checkerboard interleaved pattern, Right-eye view being first row_interleaved_rl Each view is constituted by a row based interleaving, Right-eye view is first row row_interleaved_lr Each view is constituted by a row based interleaving, Left-eye view is first row col_interleaved_rl Both views are arranged in a column based interleaving manner, Right-eye view is first column col_interleaved_lr Both views are arranged in a column based interleaving manner, Left-eye view is first column anaglyph_cyan_red All frames are in anaglyph format viewable through red-cyan filters right_left Both views are arranged side by side, Right-eye view is on the left anaglyph_green_magenta All frames are in anaglyph format viewable through green-magenta filters block_lr Both eyes laced in one Block, Left-eye view is first block_rl Both eyes laced in one Block, Right-eye view is first For example a 3D WebM clip can be created using the following command line: ffmpeg -i sample_left_right_clip.mpg -an -c:v libvpx -metadata stereo_mode=left_right -y stereo_clip.webm segment, stream_segment, ssegment Basic stream segmenter. The segmenter muxer outputs streams to a number of separate files of nearly fixed duration. Output filename pattern can be set in a fashion similar to image2. "stream_segment" is a variant of the muxer used to write to streaming output formats, i.e. which do not require global headers, and is recommended for outputting e.g. to MPEG transport stream segments. "ssegment" is a shorter alias for "stream_segment". Every segment starts with a video keyframe, if a video stream is present. Note that if you want accurate splitting for a video file, you need to make the input key frames correspond to the exact splitting times expected by the segmenter, or the segment muxer will start the new segment with the key frame found next after the specified start time. The segment muxer works best with a single constant frame rate video. Optionally it can generate a list of the created segments, by setting the option segment_list. The list type is specified by the segment_list_type option. The segment muxer supports the following options: segment_format format Override the inner container format, by default it is guessed by the filename extension. segment_list name Generate also a listfile named name. If not specified no listfile is generated. segment_list_flags flags Set flags affecting the segment list generation. It currently supports the following flags: cache Allow caching (only affects M3U8 list files). live Allow live-friendly file generation. This currently only affects M3U8 lists. In particular, write a fake EXT-X-TARGETDURATION duration field at the top of the file, based on the specified segment_time. Default value is "cache". segment_list_size size Overwrite the listfile once it reaches size entries. If 0 the listfile is never overwritten. Default value is 0. segment_list type type Specify the format for the segment list file. The following values are recognized: flat Generate a flat list for the created segments, one segment per line. csv, ext Generate a list for the created segments, one segment per line, each line matching the format (comma-separated values): <segment_filename>,<segment_start_time>,<segment_end_time> segment_filename is the name of the output file generated by the muxer according to the provided pattern. CSV escaping (according to RFC4180) is applied if required. segment_start_time and segment_end_time specify the segment start and end time expressed in seconds. A list file with the suffix ".csv" or ".ext" will auto-select this format. "ext" is deprecated in favor or "csv". m3u8 Generate an extended M3U8 file, version 4, compliant with <http://tools.ietf.org/id/draft-pantos-http-live-streaming-08.txt>. A list file with the suffix ".m3u8" will auto-select this format. If not specified the type is guessed from the list file name suffix. segment_time time Set segment duration to time. Default value is "2". segment_time_delta delta Specify the accuracy time when selecting the start time for a segment. Default value is "0". When delta is specified a key-frame will start a new segment if its PTS satisfies the relation: PTS >= start_time - time_delta This option is useful when splitting video content, which is always split at GOP boundaries, in case a key frame is found just before the specified split time. In particular may be used in combination with the ffmpeg option force_key_frames. The key frame times specified by force_key_frames may not be set accurately because of rounding issues, with the consequence that a key frame time may result set just before the specified time. For constant frame rate videos a value of 1/2*frame_rate should address the worst case mismatch between the specified time and the time set by force_key_frames. segment_times times Specify a list of split points. times contains a list of comma separated duration specifications, in increasing order. segment_wrap limit Wrap around segment index once it reaches limit. Some examples follow. · To remux the content of file in.mkv to a list of segments out-000.nut, out-001.nut, etc., and write the list of generated segments to out.list: ffmpeg -i in.mkv -codec copy -map 0 -f segment -segment_list out.list out%03d.nut · As the example above, but segment the input file according to the split points specified by the segment_times option: ffmpeg -i in.mkv -codec copy -map 0 -f segment -segment_list out.csv -segment_times 1,2,3,5,8,13,21 out%03d.nut · As the example above, but use the "ffmpeg" force_key_frames option to force key frames in the input at the specified location, together with the segment option segment_time_delta to account for possible roundings operated when setting key frame times. ffmpeg -i in.mkv -force_key_frames 1,2,3,5,8,13,21 -vcodec mpeg4 -acodec pcm_s16le -map 0 \ -f segment -segment_list out.csv -segment_times 1,2,3,5,8,13,21