@anchor{codec-options} @chapter Codec Options @c man begin CODEC OPTIONS libavcodec provides some generic global options, which can be set on all the encoders and decoders. In addition each codec may support so-called private options, which are specific for a given codec. Sometimes, a global option may only affect a specific kind of codec, and may be nonsensical or ignored by another, so you need to be aware of the meaning of the specified options. Also some options are meant only for decoding or encoding. Options may be set by specifying -@var{option} @var{value} in the FFmpeg tools, or by setting the value explicitly in the @code{AVCodecContext} options or using the @file{libavutil/opt.h} API for programmatic use. The list of supported options follow: @table @option @item b @var{integer} (@emph{encoding,audio,video}) Set bitrate in bits/s. Default value is 200K. @item ab @var{integer} (@emph{encoding,audio}) Set audio bitrate (in bits/s). Default value is 128K. @item bt @var{integer} (@emph{encoding,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. @item flags @var{flags} (@emph{decoding/encoding,audio,video,subtitles}) Set generic flags. Possible values: @table @samp @item mv4 Use four motion vector by macroblock (mpeg4). @item qpel Use 1/4 pel motion compensation. @item loop Use loop filter. @item qscale Use fixed qscale. @item pass1 Use internal 2pass ratecontrol in first pass mode. @item pass2 Use internal 2pass ratecontrol in second pass mode. @item gray Only decode/encode grayscale. @item psnr Set error[?] variables during encoding. @item truncated Input bitstream might be randomly truncated. @item drop_changed Don't output frames whose parameters differ from first decoded frame in stream. Error AVERROR_INPUT_CHANGED is returned when a frame is dropped. @item ildct Use interlaced DCT. @item low_delay Force low delay. @item global_header Place global headers in extradata instead of every keyframe. @item bitexact Only write platform-, build- and time-independent data. (except (I)DCT). This ensures that file and data checksums are reproducible and match between platforms. Its primary use is for regression testing. @item aic Apply H263 advanced intra coding / mpeg4 ac prediction. @item ilme Apply interlaced motion estimation. @item cgop Use closed gop. @item output_corrupt Output even potentially corrupted frames. @end table @item time_base @var{rational number} Set codec time base. It is the fundamental unit of time (in seconds) in terms of which frame timestamps are represented. For fixed-fps content, timebase should be @code{1 / frame_rate} and timestamp increments should be identically 1. @item g @var{integer} (@emph{encoding,video}) Set the group of picture (GOP) size. Default value is 12. @item ar @var{integer} (@emph{decoding/encoding,audio}) Set audio sampling rate (in Hz). @item ac @var{integer} (@emph{decoding/encoding,audio}) Set number of audio channels. @item cutoff @var{integer} (@emph{encoding,audio}) Set cutoff bandwidth. (Supported only by selected encoders, see their respective documentation sections.) @item frame_size @var{integer} (@emph{encoding,audio}) Set audio frame size. Each submitted frame except the last must contain exactly frame_size samples per channel. May be 0 when the codec has CODEC_CAP_VARIABLE_FRAME_SIZE set, in that case the frame size is not restricted. It is set by some decoders to indicate constant frame size. @item frame_number @var{integer} Set the frame number. @item delay @var{integer} @item qcomp @var{float} (@emph{encoding,video}) Set video quantizer scale compression (VBR). It is used as a constant in the ratecontrol equation. Recommended range for default rc_eq: 0.0-1.0. @item qblur @var{float} (@emph{encoding,video}) Set video quantizer scale blur (VBR). @item qmin @var{integer} (@emph{encoding,video}) Set min video quantizer scale (VBR). Must be included between -1 and 69, default value is 2. @item qmax @var{integer} (@emph{encoding,video}) Set max video quantizer scale (VBR). Must be included between -1 and 1024, default value is 31. @item qdiff @var{integer} (@emph{encoding,video}) Set max difference between the quantizer scale (VBR). @item bf @var{integer} (@emph{encoding,video}) Set max number of B frames between non-B-frames. Must be an integer between -1 and 16. 0 means that B-frames are disabled. If a value of -1 is used, it will choose an automatic value depending on the encoder. Default value is 0. @item b_qfactor @var{float} (@emph{encoding,video}) Set qp factor between P and B frames. @item codec_tag @var{integer} @item bug @var{flags} (@emph{decoding,video}) Workaround not auto detected encoder bugs. Possible values: @table @samp @item autodetect @item xvid_ilace Xvid interlacing bug (autodetected if fourcc==XVIX) @item ump4 (autodetected if fourcc==UMP4) @item no_padding padding bug (autodetected) @item amv @item qpel_chroma @item std_qpel old standard qpel (autodetected per fourcc/version) @item qpel_chroma2 @item direct_blocksize direct-qpel-blocksize bug (autodetected per fourcc/version) @item edge edge padding bug (autodetected per fourcc/version) @item hpel_chroma @item dc_clip @item ms Workaround various bugs in microsoft broken decoders. @item trunc trancated frames @end table @item strict @var{integer} (@emph{decoding/encoding,audio,video}) Specify how strictly to follow the standards. Possible values: @table @samp @item very strictly conform to an older more strict version of the spec or reference software @item strict strictly conform to all the things in the spec no matter what consequences @item normal @item unofficial allow unofficial extensions @item experimental allow non standardized experimental things, experimental (unfinished/work in progress/not well tested) decoders and encoders. Note: experimental decoders can pose a security risk, do not use this for decoding untrusted input. @end table @item b_qoffset @var{float} (@emph{encoding,video}) Set QP offset between P and B frames. @item err_detect @var{flags} (@emph{decoding,audio,video}) Set error detection flags. Possible values: @table @samp @item crccheck verify embedded CRCs @item bitstream detect bitstream specification deviations @item buffer detect improper bitstream length @item explode abort decoding on minor error detection @item ignore_err ignore decoding errors, and continue decoding. This is useful if you want to analyze the content of a video and thus want everything to be decoded no matter what. This option will not result in a video that is pleasing to watch in case of errors. @item careful consider things that violate the spec and have not been seen in the wild as errors @item compliant consider all spec non compliancies as errors @item aggressive consider things that a sane encoder should not do as an error @end table @item has_b_frames @var{integer} @item block_align @var{integer} @item rc_override_count @var{integer} @item maxrate @var{integer} (@emph{encoding,audio,video}) Set max bitrate tolerance (in bits/s). Requires bufsize to be set. @item minrate @var{integer} (@emph{encoding,audio,video}) Set min bitrate tolerance (in bits/s). Most useful in setting up a CBR encode. It is of little use elsewise. @item bufsize @var{integer} (@emph{encoding,audio,video}) Set ratecontrol buffer size (in bits). @item i_qfactor @var{float} (@emph{encoding,video}) Set QP factor between P and I frames. @item i_qoffset @var{float} (@emph{encoding,video}) Set QP offset between P and I frames. @item dct @var{integer} (@emph{encoding,video}) Set DCT algorithm. Possible values: @table @samp @item auto autoselect a good one (default) @item fastint fast integer @item int accurate integer @item mmx @item altivec @item faan floating point AAN DCT @end table @item lumi_mask @var{float} (@emph{encoding,video}) Compress bright areas stronger than medium ones. @item tcplx_mask @var{float} (@emph{encoding,video}) Set temporal complexity masking. @item scplx_mask @var{float} (@emph{encoding,video}) Set spatial complexity masking. @item p_mask @var{float} (@emph{encoding,video}) Set inter masking. @item dark_mask @var{float} (@emph{encoding,video}) Compress dark areas stronger than medium ones. @item idct @var{integer} (@emph{decoding/encoding,video}) Select IDCT implementation. Possible values: @table @samp @item auto @item int @item simple @item simplemmx @item simpleauto Automatically pick a IDCT compatible with the simple one @item arm @item altivec @item sh4 @item simplearm @item simplearmv5te @item simplearmv6 @item simpleneon @item xvid @item faani floating point AAN IDCT @end table @item slice_count @var{integer} @item ec @var{flags} (@emph{decoding,video}) Set error concealment strategy. Possible values: @table @samp @item guess_mvs iterative motion vector (MV) search (slow) @item deblock use strong deblock filter for damaged MBs @item favor_inter favor predicting from the previous frame instead of the current @end table @item bits_per_coded_sample @var{integer} @item aspect @var{rational number} (@emph{encoding,video}) Set sample aspect ratio. @item sar @var{rational number} (@emph{encoding,video}) Set sample aspect ratio. Alias to @var{aspect}. @item debug @var{flags} (@emph{decoding/encoding,audio,video,subtitles}) Print specific debug info. Possible values: @table @samp @item pict picture info @item rc rate control @item bitstream @item mb_type macroblock (MB) type @item qp per-block quantization parameter (QP) @item dct_coeff @item green_metadata display complexity metadata for the upcoming frame, GoP or for a given duration. @item skip @item startcode @item er error recognition @item mmco memory management control operations (H.264) @item bugs @item buffers picture buffer allocations @item thread_ops threading operations @item nomc skip motion compensation @end table @item cmp @var{integer} (@emph{encoding,video}) Set full pel me compare function. Possible values: @table @samp @item sad sum of absolute differences, fast (default) @item sse sum of squared errors @item satd sum of absolute Hadamard transformed differences @item dct sum of absolute DCT transformed differences @item psnr sum of squared quantization errors (avoid, low quality) @item bit number of bits needed for the block @item rd rate distortion optimal, slow @item zero 0 @item vsad sum of absolute vertical differences @item vsse sum of squared vertical differences @item nsse noise preserving sum of squared differences @item w53 5/3 wavelet, only used in snow @item w97 9/7 wavelet, only used in snow @item dctmax @item chroma @end table @item subcmp @var{integer} (@emph{encoding,video}) Set sub pel me compare function. Possible values: @table @samp @item sad sum of absolute differences, fast (default) @item sse sum of squared errors @item satd sum of absolute Hadamard transformed differences @item dct sum of absolute DCT transformed differences @item psnr sum of squared quantization errors (avoid, low quality) @item bit number of bits needed for the block @item rd rate distortion optimal, slow @item zero 0 @item vsad sum of absolute vertical differences @item vsse sum of squared vertical differences @item nsse noise preserving sum of squared differences @item w53 5/3 wavelet, only used in snow @item w97 9/7 wavelet, only used in snow @item dctmax @item chroma @end table @item mbcmp @var{integer} (@emph{encoding,video}) Set macroblock compare function. Possible values: @table @samp @item sad sum of absolute differences, fast (default) @item sse sum of squared errors @item satd sum of absolute Hadamard transformed differences @item dct sum of absolute DCT transformed differences @item psnr sum of squared quantization errors (avoid, low quality) @item bit number of bits needed for the block @item rd rate distortion optimal, slow @item zero 0 @item vsad sum of absolute vertical differences @item vsse sum of squared vertical differences @item nsse noise preserving sum of squared differences @item w53 5/3 wavelet, only used in snow @item w97 9/7 wavelet, only used in snow @item dctmax @item chroma @end table @item ildctcmp @var{integer} (@emph{encoding,video}) Set interlaced dct compare function. Possible values: @table @samp @item sad sum of absolute differences, fast (default) @item sse sum of squared errors @item satd sum of absolute Hadamard transformed differences @item dct sum of absolute DCT transformed differences @item psnr sum of squared quantization errors (avoid, low quality) @item bit number of bits needed for the block @item rd rate distortion optimal, slow @item zero 0 @item vsad sum of absolute vertical differences @item vsse sum of squared vertical differences @item nsse noise preserving sum of squared differences @item w53 5/3 wavelet, only used in snow @item w97 9/7 wavelet, only used in snow @item dctmax @item chroma @end table @item dia_size @var{integer} (@emph{encoding,video}) Set diamond type & size for motion estimation. @table @samp @item (1024, INT_MAX) full motion estimation(slowest) @item (768, 1024] umh motion estimation @item (512, 768] hex motion estimation @item (256, 512] l2s diamond motion estimation @item [2,256] var diamond motion estimation @item (-1, 2) small diamond motion estimation @item -1 funny diamond motion estimation @item (INT_MIN, -1) sab diamond motion estimation @end table @item last_pred @var{integer} (@emph{encoding,video}) Set amount of motion predictors from the previous frame. @item precmp @var{integer} (@emph{encoding,video}) Set pre motion estimation compare function. Possible values: @table @samp @item sad sum of absolute differences, fast (default) @item sse sum of squared errors @item satd sum of absolute Hadamard transformed differences @item dct sum of absolute DCT transformed differences @item psnr sum of squared quantization errors (avoid, low quality) @item bit number of bits needed for the block @item rd rate distortion optimal, slow @item zero 0 @item vsad sum of absolute vertical differences @item vsse sum of squared vertical differences @item nsse noise preserving sum of squared differences @item w53 5/3 wavelet, only used in snow @item w97 9/7 wavelet, only used in snow @item dctmax @item chroma @end table @item pre_dia_size @var{integer} (@emph{encoding,video}) Set diamond type & size for motion estimation pre-pass. @item subq @var{integer} (@emph{encoding,video}) Set sub pel motion estimation quality. @item me_range @var{integer} (@emph{encoding,video}) Set limit motion vectors range (1023 for DivX player). @item global_quality @var{integer} (@emph{encoding,audio,video}) @item slice_flags @var{integer} @item mbd @var{integer} (@emph{encoding,video}) Set macroblock decision algorithm (high quality mode). Possible values: @table @samp @item simple use mbcmp (default) @item bits use fewest bits @item rd use best rate distortion @end table @item rc_init_occupancy @var{integer} (@emph{encoding,video}) Set number of bits which should be loaded into the rc buffer before decoding starts. @item flags2 @var{flags} (@emph{decoding/encoding,audio,video,subtitles}) Possible values: @table @samp @item fast Allow non spec compliant speedup tricks. @item noout Skip bitstream encoding. @item ignorecrop Ignore cropping information from sps. @item local_header Place global headers at every keyframe instead of in extradata. @item chunks Frame data might be split into multiple chunks. @item showall Show all frames before the first keyframe. @item export_mvs Export motion vectors into frame side-data (see @code{AV_FRAME_DATA_MOTION_VECTORS}) for codecs that support it. See also @file{doc/examples/export_mvs.c}. @item skip_manual Do not skip samples and export skip information as frame side data. @item ass_ro_flush_noop Do not reset ASS ReadOrder field on flush. @item icc_profiles Generate/parse embedded ICC profiles from/to colorimetry tags. @end table @item export_side_data @var{flags} (@emph{decoding/encoding,audio,video,subtitles}) Possible values: @table @samp @item mvs Export motion vectors into frame side-data (see @code{AV_FRAME_DATA_MOTION_VECTORS}) for codecs that support it. See also @file{doc/examples/export_mvs.c}. @item prft Export encoder Producer Reference Time into packet side-data (see @code{AV_PKT_DATA_PRFT}) for codecs that support it. @item venc_params Export video encoding parameters through frame side data (see @code{AV_FRAME_DATA_VIDEO_ENC_PARAMS}) for codecs that support it. At present, those are H.264 and VP9. @item film_grain Export film grain parameters through frame side data (see @code{AV_FRAME_DATA_FILM_GRAIN_PARAMS}). Supported at present by AV1 decoders. @end table @item threads @var{integer} (@emph{decoding/encoding,video}) Set the number of threads to be used, in case the selected codec implementation supports multi-threading. Possible values: @table @samp @item auto, 0 automatically select the number of threads to set @end table Default value is @samp{auto}. @item dc @var{integer} (@emph{encoding,video}) Set intra_dc_precision. @item nssew @var{integer} (@emph{encoding,video}) Set nsse weight. @item skip_top @var{integer} (@emph{decoding,video}) Set number of macroblock rows at the top which are skipped. @item skip_bottom @var{integer} (@emph{decoding,video}) Set number of macroblock rows at the bottom which are skipped. @item profile @var{integer} (@emph{encoding,audio,video}) Set encoder codec profile. Default value is @samp{unknown}. Encoder specific profiles are documented in the relevant encoder documentation. @item level @var{integer} (@emph{encoding,audio,video}) Possible values: @table @samp @item unknown @end table @item lowres @var{integer} (@emph{decoding,audio,video}) Decode at 1= 1/2, 2=1/4, 3=1/8 resolutions. @item mblmin @var{integer} (@emph{encoding,video}) Set min macroblock lagrange factor (VBR). @item mblmax @var{integer} (@emph{encoding,video}) Set max macroblock lagrange factor (VBR). @item skip_loop_filter @var{integer} (@emph{decoding,video}) @item skip_idct @var{integer} (@emph{decoding,video}) @item skip_frame @var{integer} (@emph{decoding,video}) Make decoder discard processing depending on the frame type selected by the option value. @option{skip_loop_filter} skips frame loop filtering, @option{skip_idct} skips frame IDCT/dequantization, @option{skip_frame} skips decoding. Possible values: @table @samp @item none Discard no frame. @item default Discard useless frames like 0-sized frames. @item noref Discard all non-reference frames. @item bidir Discard all bidirectional frames. @item nokey Discard all frames excepts keyframes. @item nointra Discard all frames except I frames. @item all Discard all frames. @end table Default value is @samp{default}. @item bidir_refine @var{integer} (@emph{encoding,video}) Refine the two motion vectors used in bidirectional macroblocks. @item keyint_min @var{integer} (@emph{encoding,video}) Set minimum interval between IDR-frames. @item refs @var{integer} (@emph{encoding,video}) Set reference frames to consider for motion compensation. @item trellis @var{integer} (@emph{encoding,audio,video}) Set rate-distortion optimal quantization. @item mv0_threshold @var{integer} (@emph{encoding,video}) @item compression_level @var{integer} (@emph{encoding,audio,video}) @item bits_per_raw_sample @var{integer} @item channel_layout @var{integer} (@emph{decoding/encoding,audio}) Possible values: @table @samp @end table @item request_channel_layout @var{integer} (@emph{decoding,audio}) Possible values: @table @samp @end table @item rc_max_vbv_use @var{float} (@emph{encoding,video}) @item rc_min_vbv_use @var{float} (@emph{encoding,video}) @item color_primaries @var{integer} (@emph{decoding/encoding,video}) Possible values: @table @samp @item bt709 BT.709 @item bt470m BT.470 M @item bt470bg BT.470 BG @item smpte170m SMPTE 170 M @item smpte240m SMPTE 240 M @item film Film @item bt2020 BT.2020 @item smpte428 @item smpte428_1 SMPTE ST 428-1 @item smpte431 SMPTE 431-2 @item smpte432 SMPTE 432-1 @item jedec-p22 JEDEC P22 @end table @item color_trc @var{integer} (@emph{decoding/encoding,video}) Possible values: @table @samp @item bt709 BT.709 @item gamma22 BT.470 M @item gamma28 BT.470 BG @item smpte170m SMPTE 170 M @item smpte240m SMPTE 240 M @item linear Linear @item log @item log100 Log @item log_sqrt @item log316 Log square root @item iec61966_2_4 @item iec61966-2-4 IEC 61966-2-4 @item bt1361 @item bt1361e BT.1361 @item iec61966_2_1 @item iec61966-2-1 IEC 61966-2-1 @item bt2020_10 @item bt2020_10bit BT.2020 - 10 bit @item bt2020_12 @item bt2020_12bit BT.2020 - 12 bit @item smpte2084 SMPTE ST 2084 @item smpte428 @item smpte428_1 SMPTE ST 428-1 @item arib-std-b67 ARIB STD-B67 @end table @item colorspace @var{integer} (@emph{decoding/encoding,video}) Possible values: @table @samp @item rgb RGB @item bt709 BT.709 @item fcc FCC @item bt470bg BT.470 BG @item smpte170m SMPTE 170 M @item smpte240m SMPTE 240 M @item ycocg YCOCG @item bt2020nc @item bt2020_ncl BT.2020 NCL @item bt2020c @item bt2020_cl BT.2020 CL @item smpte2085 SMPTE 2085 @item chroma-derived-nc Chroma-derived NCL @item chroma-derived-c Chroma-derived CL @item ictcp ICtCp @end table @item color_range @var{integer} (@emph{decoding/encoding,video}) If used as input parameter, it serves as a hint to the decoder, which color_range the input has. Possible values: @table @samp @item tv @item mpeg @item limited MPEG (219*2^(n-8)) @item pc @item jpeg @item full JPEG (2^n-1) @end table @item chroma_sample_location @var{integer} (@emph{decoding/encoding,video}) Possible values: @table @samp @item left @item center @item topleft @item top @item bottomleft @item bottom @end table @item log_level_offset @var{integer} Set the log level offset. @item slices @var{integer} (@emph{encoding,video}) Number of slices, used in parallelized encoding. @item thread_type @var{flags} (@emph{decoding/encoding,video}) Select which multithreading methods to use. Use of @samp{frame} will increase decoding delay by one frame per thread, so clients which cannot provide future frames should not use it. Possible values: @table @samp @item slice Decode more than one part of a single frame at once. Multithreading using slices works only when the video was encoded with slices. @item frame Decode more than one frame at once. @end table Default value is @samp{slice+frame}. @item audio_service_type @var{integer} (@emph{encoding,audio}) Set audio service type. Possible values: @table @samp @item ma Main Audio Service @item ef Effects @item vi Visually Impaired @item hi Hearing Impaired @item di Dialogue @item co Commentary @item em Emergency @item vo Voice Over @item ka Karaoke @end table @item request_sample_fmt @var{sample_fmt} (@emph{decoding,audio}) Set sample format audio decoders should prefer. Default value is @code{none}. @item pkt_timebase @var{rational number} @item sub_charenc @var{encoding} (@emph{decoding,subtitles}) Set the input subtitles character encoding. @item field_order @var{field_order} (@emph{video}) Set/override the field order of the video. Possible values: @table @samp @item progressive Progressive video @item tt Interlaced video, top field coded and displayed first @item bb Interlaced video, bottom field coded and displayed first @item tb Interlaced video, top coded first, bottom displayed first @item bt Interlaced video, bottom coded first, top displayed first @end table @item skip_alpha @var{bool} (@emph{decoding,video}) Set to 1 to disable processing alpha (transparency). This works like the @samp{gray} flag in the @option{flags} option which skips chroma information instead of alpha. Default is 0. @item codec_whitelist @var{list} (@emph{input}) "," separated list of allowed decoders. By default all are allowed. @item dump_separator @var{string} (@emph{input}) Separator used to separate the fields printed on the command line about the Stream parameters. For example, to separate the fields with newlines and indentation: @example ffprobe -dump_separator " " -i ~/videos/matrixbench_mpeg2.mpg @end example @item max_pixels @var{integer} (@emph{decoding/encoding,video}) Maximum number of pixels per image. This value can be used to avoid out of memory failures due to large images. @item apply_cropping @var{bool} (@emph{decoding,video}) Enable cropping if cropping parameters are multiples of the required alignment for the left and top parameters. If the alignment is not met the cropping will be partially applied to maintain alignment. Default is 1 (enabled). Note: The required alignment depends on if @code{AV_CODEC_FLAG_UNALIGNED} is set and the CPU. @code{AV_CODEC_FLAG_UNALIGNED} cannot be changed from the command line. Also hardware decoders will not apply left/top Cropping. @end table @c man end CODEC OPTIONS @ifclear config-writeonly @include decoders.texi @end ifclear @ifclear config-readonly @include encoders.texi @end ifclear