3 @c man begin CODEC OPTIONS
5 libavcodec provides some generic global options, which can be set on
6 all the encoders and decoders. In addition each codec may support
7 so-called private options, which are specific for a given codec.
9 Sometimes, a global option may only affect a specific kind of codec,
10 and may be nonsensical or ignored by another, so you need to be aware
11 of the meaning of the specified options. Also some options are
12 meant only for decoding or encoding.
14 Options may be set by specifying -@var{option} @var{value} in the
15 FFmpeg tools, or by setting the value explicitly in the
16 @code{AVCodecContext} options or using the @file{libavutil/opt.h} API
19 The list of supported options follow:
22 @item b @var{integer} (@emph{encoding,audio,video})
23 Set bitrate in bits/s. Default value is 200K.
25 @item ab @var{integer} (@emph{encoding,audio})
26 Set audio bitrate (in bits/s). Default value is 128K.
28 @item bt @var{integer} (@emph{encoding,video})
29 Set video bitrate tolerance (in bits/s). In 1-pass mode, bitrate
30 tolerance specifies how far ratecontrol is willing to deviate from the
31 target average bitrate value. This is not related to min/max
32 bitrate. Lowering tolerance too much has an adverse effect on quality.
34 @item flags @var{flags} (@emph{decoding/encoding,audio,video,subtitles})
40 Use four motion vector by macroblock (mpeg4).
42 Use 1/4 pel motion compensation.
50 Always try a mb with mv=<0,0>.
54 Use internal 2pass ratecontrol in first pass mode.
56 Use internal 2pass ratecontrol in second pass mode.
58 Only decode/encode grayscale.
62 Set error[?] variables during encoding.
66 Normalize adaptive quantization.
72 Place global headers in extradata instead of every keyframe.
74 Only write platform-, build- and time-independent data. (except (I)DCT).
75 This ensures that file and data checksums are reproducible and match between
76 platforms. Its primary use is for regression testing.
78 Apply H263 advanced intra coding / mpeg4 ac prediction.
80 Deprecated, use mpegvideo private options instead.
82 Deprecated, use mpegvideo private options instead.
84 Apply interlaced motion estimation.
89 @item me_method @var{integer} (@emph{encoding,video})
90 Set motion estimation method.
95 zero motion estimation (fastest)
97 full motion estimation (slowest)
99 EPZS motion estimation (default)
101 esa motion estimation (alias for full)
103 tesa motion estimation
105 dia motion estimation (alias for epzs)
107 log motion estimation
109 phods motion estimation
113 hex motion estimation
115 umh motion estimation
117 iter motion estimation
120 @item extradata_size @var{integer}
123 @item time_base @var{rational number}
126 It is the fundamental unit of time (in seconds) in terms of which
127 frame timestamps are represented. For fixed-fps content, timebase
128 should be @code{1 / frame_rate} and timestamp increments should be
131 @item g @var{integer} (@emph{encoding,video})
132 Set the group of picture (GOP) size. Default value is 12.
134 @item ar @var{integer} (@emph{decoding/encoding,audio})
135 Set audio sampling rate (in Hz).
137 @item ac @var{integer} (@emph{decoding/encoding,audio})
138 Set number of audio channels.
140 @item cutoff @var{integer} (@emph{encoding,audio})
141 Set cutoff bandwidth.
143 @item frame_size @var{integer} (@emph{encoding,audio})
144 Set audio frame size.
146 Each submitted frame except the last must contain exactly frame_size
147 samples per channel. May be 0 when the codec has
148 CODEC_CAP_VARIABLE_FRAME_SIZE set, in that case the frame size is not
149 restricted. It is set by some decoders to indicate constant frame
152 @item frame_number @var{integer}
153 Set the frame number.
155 @item delay @var{integer}
157 @item qcomp @var{float} (@emph{encoding,video})
158 Set video quantizer scale compression (VBR). It is used as a constant
159 in the ratecontrol equation. Recommended range for default rc_eq:
162 @item qblur @var{float} (@emph{encoding,video})
163 Set video quantizer scale blur (VBR).
165 @item qmin @var{integer} (@emph{encoding,video})
166 Set min video quantizer scale (VBR). Must be included between -1 and
167 69, default value is 2.
169 @item qmax @var{integer} (@emph{encoding,video})
170 Set max video quantizer scale (VBR). Must be included between -1 and
171 1024, default value is 31.
173 @item qdiff @var{integer} (@emph{encoding,video})
174 Set max difference between the quantizer scale (VBR).
176 @item bf @var{integer} (@emph{encoding,video})
177 Set max number of B frames between non-B-frames.
179 Must be an integer between -1 and 16. 0 means that B-frames are
180 disabled. If a value of -1 is used, it will choose an automatic value
181 depending on the encoder.
185 @item b_qfactor @var{float} (@emph{encoding,video})
186 Set qp factor between P and B frames.
188 @item rc_strategy @var{integer} (@emph{encoding,video})
189 Set ratecontrol method.
191 @item b_strategy @var{integer} (@emph{encoding,video})
192 Set strategy to choose between I/P/B-frames.
194 @item ps @var{integer} (@emph{encoding,video})
195 Set RTP payload size in bytes.
197 @item mv_bits @var{integer}
198 @item header_bits @var{integer}
199 @item i_tex_bits @var{integer}
200 @item p_tex_bits @var{integer}
201 @item i_count @var{integer}
202 @item p_count @var{integer}
203 @item skip_count @var{integer}
204 @item misc_bits @var{integer}
205 @item frame_bits @var{integer}
206 @item codec_tag @var{integer}
207 @item bug @var{flags} (@emph{decoding,video})
208 Workaround not auto detected encoder bugs.
215 some old lavc generated msmpeg4v3 files (no autodetection)
217 Xvid interlacing bug (autodetected if fourcc==XVIX)
219 (autodetected if fourcc==UMP4)
221 padding bug (autodetected)
225 illegal vlc bug (autodetected per fourcc)
229 old standard qpel (autodetected per fourcc/version)
232 @item direct_blocksize
233 direct-qpel-blocksize bug (autodetected per fourcc/version)
235 edge padding bug (autodetected per fourcc/version)
241 Workaround various bugs in microsoft broken decoders.
246 @item lelim @var{integer} (@emph{encoding,video})
247 Set single coefficient elimination threshold for luminance (negative
248 values also consider DC coefficient).
250 @item celim @var{integer} (@emph{encoding,video})
251 Set single coefficient elimination threshold for chrominance (negative
252 values also consider dc coefficient)
254 @item strict @var{integer} (@emph{decoding/encoding,audio,video})
255 Specify how strictly to follow the standards.
260 strictly conform to a older more strict version of the spec or reference software
262 strictly conform to all the things in the spec no matter what consequences
266 allow unofficial extensions
268 allow non standardized experimental things, experimental
269 (unfinished/work in progress/not well tested) decoders and encoders.
270 Note: experimental decoders can pose a security risk, do not use this for
271 decoding untrusted input.
274 @item b_qoffset @var{float} (@emph{encoding,video})
275 Set QP offset between P and B frames.
277 @item err_detect @var{flags} (@emph{decoding,audio,video})
278 Set error detection flags.
285 detect bitstream specification deviations
287 detect improper bitstream length
289 abort decoding on minor error detection
291 ignore decoding errors, and continue decoding.
292 This is useful if you want to analyze the content of a video and thus want
293 everything to be decoded no matter what. This option will not result in a video
294 that is pleasing to watch in case of errors.
296 consider things that violate the spec and have not been seen in the wild as errors
298 consider all spec non compliancies as errors
300 consider things that a sane encoder should not do as an error
303 @item has_b_frames @var{integer}
305 @item block_align @var{integer}
307 @item mpeg_quant @var{integer} (@emph{encoding,video})
308 Use MPEG quantizers instead of H.263.
310 @item qsquish @var{float} (@emph{encoding,video})
311 How to keep quantizer between qmin and qmax (0 = clip, 1 = use
312 differentiable function).
314 @item rc_qmod_amp @var{float} (@emph{encoding,video})
315 Set experimental quantizer modulation.
317 @item rc_qmod_freq @var{integer} (@emph{encoding,video})
318 Set experimental quantizer modulation.
320 @item rc_override_count @var{integer}
322 @item rc_eq @var{string} (@emph{encoding,video})
323 Set rate control equation. When computing the expression, besides the
324 standard functions defined in the section 'Expression Evaluation', the
325 following functions are available: bits2qp(bits), qp2bits(qp). Also
326 the following constants are available: iTex pTex tex mv fCode iCount
327 mcVar var isI isP isB avgQP qComp avgIITex avgPITex avgPPTex avgBPTex
330 @item maxrate @var{integer} (@emph{encoding,audio,video})
331 Set max bitrate tolerance (in bits/s). Requires bufsize to be set.
333 @item minrate @var{integer} (@emph{encoding,audio,video})
334 Set min bitrate tolerance (in bits/s). Most useful in setting up a CBR
335 encode. It is of little use elsewise.
337 @item bufsize @var{integer} (@emph{encoding,audio,video})
338 Set ratecontrol buffer size (in bits).
340 @item rc_buf_aggressivity @var{float} (@emph{encoding,video})
343 @item i_qfactor @var{float} (@emph{encoding,video})
344 Set QP factor between P and I frames.
346 @item i_qoffset @var{float} (@emph{encoding,video})
347 Set QP offset between P and I frames.
349 @item rc_init_cplx @var{float} (@emph{encoding,video})
350 Set initial complexity for 1-pass encoding.
352 @item dct @var{integer} (@emph{encoding,video})
358 autoselect a good one (default)
368 floating point AAN DCT
371 @item lumi_mask @var{float} (@emph{encoding,video})
372 Compress bright areas stronger than medium ones.
374 @item tcplx_mask @var{float} (@emph{encoding,video})
375 Set temporal complexity masking.
377 @item scplx_mask @var{float} (@emph{encoding,video})
378 Set spatial complexity masking.
380 @item p_mask @var{float} (@emph{encoding,video})
383 @item dark_mask @var{float} (@emph{encoding,video})
384 Compress dark areas stronger than medium ones.
386 @item idct @var{integer} (@emph{decoding/encoding,video})
387 Select IDCT implementation.
400 Automatically pick a IDCT compatible with the simple one
423 floating point AAN IDCT
426 @item slice_count @var{integer}
428 @item ec @var{flags} (@emph{decoding,video})
429 Set error concealment strategy.
434 iterative motion vector (MV) search (slow)
436 use strong deblock filter for damaged MBs
438 favor predicting from the previous frame instead of the current
441 @item bits_per_coded_sample @var{integer}
443 @item pred @var{integer} (@emph{encoding,video})
444 Set prediction method.
456 @item aspect @var{rational number} (@emph{encoding,video})
457 Set sample aspect ratio.
459 @item debug @var{flags} (@emph{decoding/encoding,audio,video,subtitles})
460 Print specific debug info.
473 per-block quantization parameter (QP)
479 display complexity metadata for the upcoming frame, GoP or for a given duration.
490 memory management control operations (H.264)
494 visualize quantization parameter (QP), lower QP are tinted greener
496 visualize block types
498 picture buffer allocations
502 skip motion compensation
505 @item vismv @var{integer} (@emph{decoding,video})
506 Visualize motion vectors (MVs).
508 This option is deprecated, see the codecview filter instead.
513 forward predicted MVs of P-frames
515 forward predicted MVs of B-frames
517 backward predicted MVs of B-frames
520 @item cmp @var{integer} (@emph{encoding,video})
521 Set full pel me compare function.
526 sum of absolute differences, fast (default)
528 sum of squared errors
530 sum of absolute Hadamard transformed differences
532 sum of absolute DCT transformed differences
534 sum of squared quantization errors (avoid, low quality)
536 number of bits needed for the block
538 rate distortion optimal, slow
542 sum of absolute vertical differences
544 sum of squared vertical differences
546 noise preserving sum of squared differences
548 5/3 wavelet, only used in snow
550 9/7 wavelet, only used in snow
557 @item subcmp @var{integer} (@emph{encoding,video})
558 Set sub pel me compare function.
563 sum of absolute differences, fast (default)
565 sum of squared errors
567 sum of absolute Hadamard transformed differences
569 sum of absolute DCT transformed differences
571 sum of squared quantization errors (avoid, low quality)
573 number of bits needed for the block
575 rate distortion optimal, slow
579 sum of absolute vertical differences
581 sum of squared vertical differences
583 noise preserving sum of squared differences
585 5/3 wavelet, only used in snow
587 9/7 wavelet, only used in snow
594 @item mbcmp @var{integer} (@emph{encoding,video})
595 Set macroblock compare function.
600 sum of absolute differences, fast (default)
602 sum of squared errors
604 sum of absolute Hadamard transformed differences
606 sum of absolute DCT transformed differences
608 sum of squared quantization errors (avoid, low quality)
610 number of bits needed for the block
612 rate distortion optimal, slow
616 sum of absolute vertical differences
618 sum of squared vertical differences
620 noise preserving sum of squared differences
622 5/3 wavelet, only used in snow
624 9/7 wavelet, only used in snow
631 @item ildctcmp @var{integer} (@emph{encoding,video})
632 Set interlaced dct compare function.
637 sum of absolute differences, fast (default)
639 sum of squared errors
641 sum of absolute Hadamard transformed differences
643 sum of absolute DCT transformed differences
645 sum of squared quantization errors (avoid, low quality)
647 number of bits needed for the block
649 rate distortion optimal, slow
653 sum of absolute vertical differences
655 sum of squared vertical differences
657 noise preserving sum of squared differences
659 5/3 wavelet, only used in snow
661 9/7 wavelet, only used in snow
668 @item dia_size @var{integer} (@emph{encoding,video})
669 Set diamond type & size for motion estimation.
671 @item last_pred @var{integer} (@emph{encoding,video})
672 Set amount of motion predictors from the previous frame.
674 @item preme @var{integer} (@emph{encoding,video})
675 Set pre motion estimation.
677 @item precmp @var{integer} (@emph{encoding,video})
678 Set pre motion estimation compare function.
683 sum of absolute differences, fast (default)
685 sum of squared errors
687 sum of absolute Hadamard transformed differences
689 sum of absolute DCT transformed differences
691 sum of squared quantization errors (avoid, low quality)
693 number of bits needed for the block
695 rate distortion optimal, slow
699 sum of absolute vertical differences
701 sum of squared vertical differences
703 noise preserving sum of squared differences
705 5/3 wavelet, only used in snow
707 9/7 wavelet, only used in snow
714 @item pre_dia_size @var{integer} (@emph{encoding,video})
715 Set diamond type & size for motion estimation pre-pass.
717 @item subq @var{integer} (@emph{encoding,video})
718 Set sub pel motion estimation quality.
720 @item dtg_active_format @var{integer}
722 @item me_range @var{integer} (@emph{encoding,video})
723 Set limit motion vectors range (1023 for DivX player).
725 @item ibias @var{integer} (@emph{encoding,video})
726 Set intra quant bias.
728 @item pbias @var{integer} (@emph{encoding,video})
729 Set inter quant bias.
731 @item color_table_id @var{integer}
733 @item global_quality @var{integer} (@emph{encoding,audio,video})
735 @item coder @var{integer} (@emph{encoding,video})
740 variable length coder / huffman coder
751 @item context @var{integer} (@emph{encoding,video})
754 @item slice_flags @var{integer}
756 @item xvmc_acceleration @var{integer}
758 @item mbd @var{integer} (@emph{encoding,video})
759 Set macroblock decision algorithm (high quality mode).
768 use best rate distortion
771 @item stream_codec_tag @var{integer}
773 @item sc_threshold @var{integer} (@emph{encoding,video})
774 Set scene change threshold.
776 @item lmin @var{integer} (@emph{encoding,video})
777 Set min lagrange factor (VBR).
779 @item lmax @var{integer} (@emph{encoding,video})
780 Set max lagrange factor (VBR).
782 @item nr @var{integer} (@emph{encoding,video})
785 @item rc_init_occupancy @var{integer} (@emph{encoding,video})
786 Set number of bits which should be loaded into the rc buffer before
789 @item flags2 @var{flags} (@emph{decoding/encoding,audio,video})
794 Allow non spec compliant speedup tricks.
796 Deprecated, use mpegvideo private options instead.
798 Skip bitstream encoding.
800 Ignore cropping information from sps.
802 Place global headers at every keyframe instead of in extradata.
804 Frame data might be split into multiple chunks.
806 Show all frames before the first keyframe.
808 Deprecated, use mpegvideo private options instead.
810 Export motion vectors into frame side-data (see @code{AV_FRAME_DATA_MOTION_VECTORS})
811 for codecs that support it. See also @file{doc/examples/export_mvs.c}.
814 @item error @var{integer} (@emph{encoding,video})
816 @item qns @var{integer} (@emph{encoding,video})
817 Deprecated, use mpegvideo private options instead.
819 @item threads @var{integer} (@emph{decoding/encoding,video})
820 Set the number of threads to be used, in case the selected codec
821 implementation supports multi-threading.
826 automatically select the number of threads to set
829 Default value is @samp{auto}.
831 @item me_threshold @var{integer} (@emph{encoding,video})
832 Set motion estimation threshold.
834 @item mb_threshold @var{integer} (@emph{encoding,video})
835 Set macroblock threshold.
837 @item dc @var{integer} (@emph{encoding,video})
838 Set intra_dc_precision.
840 @item nssew @var{integer} (@emph{encoding,video})
843 @item skip_top @var{integer} (@emph{decoding,video})
844 Set number of macroblock rows at the top which are skipped.
846 @item skip_bottom @var{integer} (@emph{decoding,video})
847 Set number of macroblock rows at the bottom which are skipped.
849 @item profile @var{integer} (@emph{encoding,audio,video})
895 @item level @var{integer} (@emph{encoding,audio,video})
903 @item lowres @var{integer} (@emph{decoding,audio,video})
904 Decode at 1= 1/2, 2=1/4, 3=1/8 resolutions.
906 @item skip_threshold @var{integer} (@emph{encoding,video})
907 Set frame skip threshold.
909 @item skip_factor @var{integer} (@emph{encoding,video})
910 Set frame skip factor.
912 @item skip_exp @var{integer} (@emph{encoding,video})
913 Set frame skip exponent.
914 Negative values behave identical to the corresponding positive ones, except
915 that the score is normalized.
916 Positive values exist primarily for compatibility reasons and are not so useful.
918 @item skipcmp @var{integer} (@emph{encoding,video})
919 Set frame skip compare function.
924 sum of absolute differences, fast (default)
926 sum of squared errors
928 sum of absolute Hadamard transformed differences
930 sum of absolute DCT transformed differences
932 sum of squared quantization errors (avoid, low quality)
934 number of bits needed for the block
936 rate distortion optimal, slow
940 sum of absolute vertical differences
942 sum of squared vertical differences
944 noise preserving sum of squared differences
946 5/3 wavelet, only used in snow
948 9/7 wavelet, only used in snow
955 @item border_mask @var{float} (@emph{encoding,video})
956 Increase the quantizer for macroblocks close to borders.
958 @item mblmin @var{integer} (@emph{encoding,video})
959 Set min macroblock lagrange factor (VBR).
961 @item mblmax @var{integer} (@emph{encoding,video})
962 Set max macroblock lagrange factor (VBR).
964 @item mepc @var{integer} (@emph{encoding,video})
965 Set motion estimation bitrate penalty compensation (1.0 = 256).
967 @item skip_loop_filter @var{integer} (@emph{decoding,video})
968 @item skip_idct @var{integer} (@emph{decoding,video})
969 @item skip_frame @var{integer} (@emph{decoding,video})
971 Make decoder discard processing depending on the frame type selected
974 @option{skip_loop_filter} skips frame loop filtering, @option{skip_idct}
975 skips frame IDCT/dequantization, @option{skip_frame} skips decoding.
983 Discard useless frames like 0-sized frames.
986 Discard all non-reference frames.
989 Discard all bidirectional frames.
992 Discard all frames excepts keyframes.
998 Default value is @samp{default}.
1000 @item bidir_refine @var{integer} (@emph{encoding,video})
1001 Refine the two motion vectors used in bidirectional macroblocks.
1003 @item brd_scale @var{integer} (@emph{encoding,video})
1004 Downscale frames for dynamic B-frame decision.
1006 @item keyint_min @var{integer} (@emph{encoding,video})
1007 Set minimum interval between IDR-frames.
1009 @item refs @var{integer} (@emph{encoding,video})
1010 Set reference frames to consider for motion compensation.
1012 @item chromaoffset @var{integer} (@emph{encoding,video})
1013 Set chroma qp offset from luma.
1015 @item trellis @var{integer} (@emph{encoding,audio,video})
1016 Set rate-distortion optimal quantization.
1018 @item sc_factor @var{integer} (@emph{encoding,video})
1019 Set value multiplied by qscale for each frame and added to
1022 @item mv0_threshold @var{integer} (@emph{encoding,video})
1023 @item b_sensitivity @var{integer} (@emph{encoding,video})
1024 Adjust sensitivity of b_frame_strategy 1.
1026 @item compression_level @var{integer} (@emph{encoding,audio,video})
1027 @item min_prediction_order @var{integer} (@emph{encoding,audio})
1028 @item max_prediction_order @var{integer} (@emph{encoding,audio})
1029 @item timecode_frame_start @var{integer} (@emph{encoding,video})
1030 Set GOP timecode frame start number, in non drop frame format.
1032 @item request_channels @var{integer} (@emph{decoding,audio})
1033 Set desired number of audio channels.
1035 @item bits_per_raw_sample @var{integer}
1036 @item channel_layout @var{integer} (@emph{decoding/encoding,audio})
1041 @item request_channel_layout @var{integer} (@emph{decoding,audio})
1046 @item rc_max_vbv_use @var{float} (@emph{encoding,video})
1047 @item rc_min_vbv_use @var{float} (@emph{encoding,video})
1048 @item ticks_per_frame @var{integer} (@emph{decoding/encoding,audio,video})
1049 @item color_primaries @var{integer} (@emph{decoding/encoding,video})
1050 @item color_trc @var{integer} (@emph{decoding/encoding,video})
1051 @item colorspace @var{integer} (@emph{decoding/encoding,video})
1053 @item color_range @var{integer} (@emph{decoding/encoding,video})
1054 If used as input parameter, it serves as a hint to the decoder, which
1055 color_range the input has.
1057 @item chroma_sample_location @var{integer} (@emph{decoding/encoding,video})
1059 @item log_level_offset @var{integer}
1060 Set the log level offset.
1062 @item slices @var{integer} (@emph{encoding,video})
1063 Number of slices, used in parallelized encoding.
1065 @item thread_type @var{flags} (@emph{decoding/encoding,video})
1066 Select which multithreading methods to use.
1068 Use of @samp{frame} will increase decoding delay by one frame per
1069 thread, so clients which cannot provide future frames should not use
1075 Decode more than one part of a single frame at once.
1077 Multithreading using slices works only when the video was encoded with
1081 Decode more than one frame at once.
1084 Default value is @samp{slice+frame}.
1086 @item audio_service_type @var{integer} (@emph{encoding,audio})
1087 Set audio service type.
1111 @item request_sample_fmt @var{sample_fmt} (@emph{decoding,audio})
1112 Set sample format audio decoders should prefer. Default value is
1115 @item pkt_timebase @var{rational number}
1117 @item sub_charenc @var{encoding} (@emph{decoding,subtitles})
1118 Set the input subtitles character encoding.
1120 @item field_order @var{field_order} (@emph{video})
1121 Set/override the field order of the video.
1127 Interlaced video, top field coded and displayed first
1129 Interlaced video, bottom field coded and displayed first
1131 Interlaced video, top coded first, bottom displayed first
1133 Interlaced video, bottom coded first, top displayed first
1136 @item skip_alpha @var{integer} (@emph{decoding,video})
1137 Set to 1 to disable processing alpha (transparency). This works like the
1138 @samp{gray} flag in the @option{flags} option which skips chroma information
1139 instead of alpha. Default is 0.
1141 @item codec_whitelist @var{list} (@emph{input})
1142 "," separated List of allowed decoders. By default all are allowed.
1144 @item dump_separator @var{string} (@emph{input})
1145 Separator used to separate the fields printed on the command line about the
1147 For example to separate the fields with newlines and indention:
1149 ffprobe -dump_separator "
1150 " -i ~/videos/matrixbench_mpeg2.mpg
1155 @c man end CODEC OPTIONS
1157 @ifclear config-writeonly
1158 @include decoders.texi
1160 @ifclear config-readonly
1161 @include encoders.texi