4 Encoders are configured elements in FFmpeg which allow the encoding of
7 When you configure your FFmpeg build, all the supported native encoders
8 are enabled by default. Encoders requiring an external library must be enabled
9 manually via the corresponding @code{--enable-lib} option. You can list all
10 available encoders using the configure option @code{--list-encoders}.
12 You can disable all the encoders with the configure option
13 @code{--disable-encoders} and selectively enable / disable single encoders
14 with the options @code{--enable-encoder=@var{ENCODER}} /
15 @code{--disable-encoder=@var{ENCODER}}.
17 The option @code{-codecs} of the ff* tools will display the list of
22 @chapter Audio Encoders
23 @c man begin AUDIO ENCODERS
25 A description of some of the currently available audio encoders
31 Advanced Audio Coding (AAC) encoder.
33 This encoder is an experimental FFmpeg-native AAC encoder. Currently only the
34 low complexity (AAC-LC) profile is supported. To use this encoder, you must set
35 @option{strict} option to @samp{experimental} or lower.
37 As this encoder is experimental, unexpected behavior may exist from time to
38 time. For a more stable AAC encoder, see @ref{libvo-aacenc}. However, be warned
39 that it has a worse quality reported by some users.
41 @c Comment this out until somebody writes the respective documentation.
42 @c See also @ref{libfaac}, @ref{libaacplus}, and @ref{libfdk-aac-enc}.
48 Set bit rate in bits/s. Setting this automatically activates constant bit rate
52 Set quality for variable bit rate (VBR) mode. This option is valid only using
53 the @command{ffmpeg} command-line tool. For library interface users, use
54 @option{global_quality}.
57 Set stereo encoding mode. Possible values:
61 Automatically selected by the encoder.
64 Disable middle/side encoding. This is the default.
67 Force middle/side encoding.
71 Set AAC encoder coding method. Possible values:
77 This method is a simplified reimplementation of the method used in FAAC, which
78 sets thresholds proportional to the band energies, and then decreases all the
79 thresholds with quantizer steps to find the appropriate quantization with
80 distortion below threshold band by band.
82 The quality of this method is comparable to the two loop searching method
83 descibed below, but somewhat a little better and slower.
86 Average noise to mask ratio (ANMR) trellis-based solution.
88 This has a theoretic best quality out of all the coding methods, but at the
89 cost of the slowest speed.
92 Two loop searching (TLS) method.
94 This method first sets quantizers depending on band thresholds and then tries
95 to find an optimal combination by adding or subtracting a specific value from
96 all quantizers and adjusting some individual quantizer a little.
98 This method produces similar quality with the FAAC method and is the default.
101 Constant quantizer method.
103 This method sets a constant quantizer for all bands. This is the fastest of all
104 the methods, yet produces the worst quality.
110 @section ac3 and ac3_fixed
114 These encoders implement part of ATSC A/52:2010 and ETSI TS 102 366, as well as
115 the undocumented RealAudio 3 (a.k.a. dnet).
117 The @var{ac3} encoder uses floating-point math, while the @var{ac3_fixed}
118 encoder only uses fixed-point integer math. This does not mean that one is
119 always faster, just that one or the other may be better suited to a
120 particular system. The floating-point encoder will generally produce better
121 quality audio for a given bitrate. The @var{ac3_fixed} encoder is not the
122 default codec for any of the output formats, so it must be specified explicitly
123 using the option @code{-acodec ac3_fixed} in order to use it.
125 @subsection AC-3 Metadata
127 The AC-3 metadata options are used to set parameters that describe the audio,
128 but in most cases do not affect the audio encoding itself. Some of the options
129 do directly affect or influence the decoding and playback of the resulting
130 bitstream, while others are just for informational purposes. A few of the
131 options will add bits to the output stream that could otherwise be used for
132 audio data, and will thus affect the quality of the output. Those will be
133 indicated accordingly with a note in the option list below.
135 These parameters are described in detail in several publicly-available
138 @item @uref{http://www.atsc.org/cms/standards/a_52-2010.pdf,A/52:2010 - Digital Audio Compression (AC-3) (E-AC-3) Standard}
139 @item @uref{http://www.atsc.org/cms/standards/a_54a_with_corr_1.pdf,A/54 - Guide to the Use of the ATSC Digital Television Standard}
140 @item @uref{http://www.dolby.com/uploadedFiles/zz-_Shared_Assets/English_PDFs/Professional/18_Metadata.Guide.pdf,Dolby Metadata Guide}
141 @item @uref{http://www.dolby.com/uploadedFiles/zz-_Shared_Assets/English_PDFs/Professional/46_DDEncodingGuidelines.pdf,Dolby Digital Professional Encoding Guidelines}
144 @subsubsection Metadata Control Options
148 @item -per_frame_metadata @var{boolean}
149 Allow Per-Frame Metadata. Specifies if the encoder should check for changing
150 metadata for each frame.
153 The metadata values set at initialization will be used for every frame in the
156 Metadata values can be changed before encoding each frame.
161 @subsubsection Downmix Levels
165 @item -center_mixlev @var{level}
166 Center Mix Level. The amount of gain the decoder should apply to the center
167 channel when downmixing to stereo. This field will only be written to the
168 bitstream if a center channel is present. The value is specified as a scale
169 factor. There are 3 valid values:
174 Apply -4.5dB gain (default)
179 @item -surround_mixlev @var{level}
180 Surround Mix Level. The amount of gain the decoder should apply to the surround
181 channel(s) when downmixing to stereo. This field will only be written to the
182 bitstream if one or more surround channels are present. The value is specified
183 as a scale factor. There are 3 valid values:
188 Apply -6dB gain (default)
190 Silence Surround Channel(s)
195 @subsubsection Audio Production Information
196 Audio Production Information is optional information describing the mixing
197 environment. Either none or both of the fields are written to the bitstream.
201 @item -mixing_level @var{number}
202 Mixing Level. Specifies peak sound pressure level (SPL) in the production
203 environment when the mix was mastered. Valid values are 80 to 111, or -1 for
204 unknown or not indicated. The default value is -1, but that value cannot be
205 used if the Audio Production Information is written to the bitstream. Therefore,
206 if the @code{room_type} option is not the default value, the @code{mixing_level}
207 option must not be -1.
209 @item -room_type @var{type}
210 Room Type. Describes the equalization used during the final mixing session at
211 the studio or on the dubbing stage. A large room is a dubbing stage with the
212 industry standard X-curve equalization; a small room has flat equalization.
213 This field will not be written to the bitstream if both the @code{mixing_level}
214 option and the @code{room_type} option have the default values.
218 Not Indicated (default)
229 @subsubsection Other Metadata Options
233 @item -copyright @var{boolean}
234 Copyright Indicator. Specifies whether a copyright exists for this audio.
238 No Copyright Exists (default)
244 @item -dialnorm @var{value}
245 Dialogue Normalization. Indicates how far the average dialogue level of the
246 program is below digital 100% full scale (0 dBFS). This parameter determines a
247 level shift during audio reproduction that sets the average volume of the
248 dialogue to a preset level. The goal is to match volume level between program
249 sources. A value of -31dB will result in no volume level change, relative to
250 the source volume, during audio reproduction. Valid values are whole numbers in
251 the range -31 to -1, with -31 being the default.
253 @item -dsur_mode @var{mode}
254 Dolby Surround Mode. Specifies whether the stereo signal uses Dolby Surround
255 (Pro Logic). This field will only be written to the bitstream if the audio
256 stream is stereo. Using this option does @b{NOT} mean the encoder will actually
257 apply Dolby Surround processing.
261 Not Indicated (default)
264 Not Dolby Surround Encoded
267 Dolby Surround Encoded
270 @item -original @var{boolean}
271 Original Bit Stream Indicator. Specifies whether this audio is from the
272 original source and not a copy.
279 Original Source (default)
284 @subsection Extended Bitstream Information
285 The extended bitstream options are part of the Alternate Bit Stream Syntax as
286 specified in Annex D of the A/52:2010 standard. It is grouped into 2 parts.
287 If any one parameter in a group is specified, all values in that group will be
288 written to the bitstream. Default values are used for those that are written
289 but have not been specified. If the mixing levels are written, the decoder
290 will use these values instead of the ones specified in the @code{center_mixlev}
291 and @code{surround_mixlev} options if it supports the Alternate Bit Stream
294 @subsubsection Extended Bitstream Information - Part 1
298 @item -dmix_mode @var{mode}
299 Preferred Stereo Downmix Mode. Allows the user to select either Lt/Rt
300 (Dolby Surround) or Lo/Ro (normal stereo) as the preferred stereo downmix mode.
304 Not Indicated (default)
307 Lt/Rt Downmix Preferred
310 Lo/Ro Downmix Preferred
313 @item -ltrt_cmixlev @var{level}
314 Lt/Rt Center Mix Level. The amount of gain the decoder should apply to the
315 center channel when downmixing to stereo in Lt/Rt mode.
328 Apply -4.5dB gain (default)
332 Silence Center Channel
335 @item -ltrt_surmixlev @var{level}
336 Lt/Rt Surround Mix Level. The amount of gain the decoder should apply to the
337 surround channel(s) when downmixing to stereo in Lt/Rt mode.
346 Apply -6.0dB gain (default)
348 Silence Surround Channel(s)
351 @item -loro_cmixlev @var{level}
352 Lo/Ro Center Mix Level. The amount of gain the decoder should apply to the
353 center channel when downmixing to stereo in Lo/Ro mode.
366 Apply -4.5dB gain (default)
370 Silence Center Channel
373 @item -loro_surmixlev @var{level}
374 Lo/Ro Surround Mix Level. The amount of gain the decoder should apply to the
375 surround channel(s) when downmixing to stereo in Lo/Ro mode.
384 Apply -6.0dB gain (default)
386 Silence Surround Channel(s)
391 @subsubsection Extended Bitstream Information - Part 2
395 @item -dsurex_mode @var{mode}
396 Dolby Surround EX Mode. Indicates whether the stream uses Dolby Surround EX
397 (7.1 matrixed to 5.1). Using this option does @b{NOT} mean the encoder will actually
398 apply Dolby Surround EX processing.
402 Not Indicated (default)
405 Dolby Surround EX Off
411 @item -dheadphone_mode @var{mode}
412 Dolby Headphone Mode. Indicates whether the stream uses Dolby Headphone
413 encoding (multi-channel matrixed to 2.0 for use with headphones). Using this
414 option does @b{NOT} mean the encoder will actually apply Dolby Headphone
419 Not Indicated (default)
428 @item -ad_conv_type @var{type}
429 A/D Converter Type. Indicates whether the audio has passed through HDCD A/D
434 Standard A/D Converter (default)
442 @subsection Other AC-3 Encoding Options
446 @item -stereo_rematrixing @var{boolean}
447 Stereo Rematrixing. Enables/Disables use of rematrixing for stereo input. This
448 is an optional AC-3 feature that increases quality by selectively encoding
449 the left/right channels as mid/side. This option is enabled by default, and it
450 is highly recommended that it be left as enabled except for testing purposes.
454 @subsection Floating-Point-Only AC-3 Encoding Options
456 These options are only valid for the floating-point encoder and do not exist
457 for the fixed-point encoder due to the corresponding features not being
458 implemented in fixed-point.
462 @item -channel_coupling @var{boolean}
463 Enables/Disables use of channel coupling, which is an optional AC-3 feature
464 that increases quality by combining high frequency information from multiple
465 channels into a single channel. The per-channel high frequency information is
466 sent with less accuracy in both the frequency and time domains. This allows
467 more bits to be used for lower frequencies while preserving enough information
468 to reconstruct the high frequencies. This option is enabled by default for the
469 floating-point encoder and should generally be left as enabled except for
470 testing purposes or to increase encoding speed.
474 Selected by Encoder (default)
477 Disable Channel Coupling
480 Enable Channel Coupling
483 @item -cpl_start_band @var{number}
484 Coupling Start Band. Sets the channel coupling start band, from 1 to 15. If a
485 value higher than the bandwidth is used, it will be reduced to 1 less than the
486 coupling end band. If @var{auto} is used, the start band will be determined by
487 the encoder based on the bit rate, sample rate, and channel layout. This option
488 has no effect if channel coupling is disabled.
492 Selected by Encoder (default)
499 LAME (Lame Ain't an MP3 Encoder) MP3 encoder wrapper.
501 Requires the presence of the libmp3lame headers and library during
502 configuration. You need to explicitly configure the build with
503 @code{--enable-libmp3lame}.
507 The following options are supported by the libmp3lame wrapper. The
508 @command{lame}-equivalent of the options are listed in parentheses.
512 Set bitrate expressed in bits/s for CBR. LAME @code{bitrate} is
513 expressed in kilobits/s.
516 Set constant quality setting for VBR. This option is valid only
517 using the @command{ffmpeg} command-line tool. For library interface
518 users, use @option{global_quality}.
520 @item compression_level (@emph{-q})
521 Set algorithm quality. Valid arguments are integers in the 0-9 range,
522 with 0 meaning highest quality but slowest, and 9 meaning fastest
523 while producing the worst quality.
526 Enable use of bit reservoir when set to 1. Default value is 1. LAME
527 has this enabled by default, but can be overriden by use
528 @option{--nores} option.
530 @item joint_stereo (@emph{-m j})
531 Enable the encoder to use (on a frame by frame basis) either L/R
532 stereo or mid/side stereo. Default value is 1.
536 @section libopencore-amrnb
538 OpenCORE Adaptive Multi-Rate Narrowband encoder.
540 Requires the presence of the libopencore-amrnb headers and library during
541 configuration. You need to explicitly configure the build with
542 @code{--enable-libopencore-amrnb --enable-version3}.
544 This is a mono-only encoder. Officially it only supports 8000Hz sample rate,
545 but you can override it by setting @option{strict} to @samp{unofficial} or
553 Set bitrate in bits per second. Only the following bitrates are supported,
554 otherwise libavcodec will round to the nearest valid bitrate.
568 Allow discontinuous transmission (generate comfort noise) when set to 1. The
569 default value is 0 (disabled).
575 TwoLAME MP2 encoder wrapper.
577 Requires the presence of the libtwolame headers and library during
578 configuration. You need to explicitly configure the build with
579 @code{--enable-libtwolame}.
583 The following options are supported by the libtwolame wrapper. The
584 @command{twolame}-equivalent options follow the FFmpeg ones and are in
589 Set bitrate expressed in bits/s for CBR. @command{twolame} @option{b}
590 option is expressed in kilobits/s. Default value is 128k.
593 Set quality for experimental VBR support. Maximum value range is
594 from -50 to 50, useful range is from -10 to 10. The higher the
595 value, the better the quality. This option is valid only using the
596 @command{ffmpeg} command-line tool. For library interface users,
597 use @option{global_quality}.
599 @item mode (@emph{--mode})
600 Set the mode of the resulting audio. Possible values:
604 Choose mode automatically based on the input. This is the default.
615 @item psymodel (@emph{--psyc-mode})
616 Set psychoacoustic model to use in encoding. The argument must be
617 an integer between -1 and 4, inclusive. The higher the value, the
618 better the quality. The default value is 3.
620 @item energy_levels (@emph{--energy})
621 Enable energy levels extensions when set to 1. The default value is
624 @item error_protection (@emph{--protect})
625 Enable CRC error protection when set to 1. The default value is 0
628 @item copyright (@emph{--copyright})
629 Set MPEG audio copyright flag when set to 1. The default value is 0
632 @item original (@emph{--original})
633 Set MPEG audio original flag when set to 1. The default value is 0
638 @anchor{libvo-aacenc}
639 @section libvo-aacenc
641 VisualOn AAC encoder.
643 Requires the presence of the libvo-aacenc headers and library during
644 configuration. You need to explicitly configure the build with
645 @code{--enable-libvo-aacenc --enable-version3}.
647 This encoder is considered to be worse than the
648 @ref{aacenc,,native experimental FFmpeg AAC encoder}, according to
653 The VisualOn AAC encoder only support encoding AAC-LC and up to 2
654 channels. It is also CBR-only.
659 Set bit rate in bits/s.
663 @section libvo-amrwbenc
665 VisualOn Adaptive Multi-Rate Wideband encoder.
667 Requires the presence of the libvo-amrwbenc headers and library during
668 configuration. You need to explicitly configure the build with
669 @code{--enable-libvo-amrwbenc --enable-version3}.
671 This is a mono-only encoder. Officially it only supports 16000Hz sample
672 rate, but you can override it by setting @option{strict} to
673 @samp{unofficial} or lower.
680 Set bitrate in bits/s. Only the following bitrates are supported, otherwise
681 libavcodec will round to the nearest valid bitrate.
696 Allow discontinuous transmission (generate comfort noise) when set to 1. The
697 default value is 0 (disabled).
703 libopus Opus Interactive Audio Codec encoder wrapper.
705 Requires the presence of the libopus headers and library during
706 configuration. You need to explicitly configure the build with
707 @code{--enable-libopus}.
709 @subsection Option Mapping
711 Most libopus options are modeled after the @command{opusenc} utility from
712 opus-tools. The following is an option mapping chart describing options
713 supported by the libopus wrapper, and their @command{opusenc}-equivalent
718 @item b (@emph{bitrate})
719 Set the bit rate in bits/s. FFmpeg's @option{b} option is
720 expressed in bits/s, while @command{opusenc}'s @option{bitrate} in
723 @item vbr (@emph{vbr}, @emph{hard-cbr}, and @emph{cvbr})
724 Set VBR mode. The FFmpeg @option{vbr} option has the following
725 valid arguments, with the their @command{opusenc} equivalent options
729 @item off (@emph{hard-cbr})
730 Use constant bit rate encoding.
732 @item on (@emph{vbr})
733 Use variable bit rate encoding (the default).
735 @item constrained (@emph{cvbr})
736 Use constrained variable bit rate encoding.
739 @item compression_level (@emph{comp})
740 Set encoding algorithm complexity. Valid options are integers in
741 the 0-10 range. 0 gives the fastest encodes but lower quality, while 10
742 gives the highest quality but slowest encoding. The default is 10.
744 @item frame_duration (@emph{framesize})
745 Set maximum frame size, or duration of a frame in milliseconds. The
746 argument must be exactly the following: 2.5, 5, 10, 20, 40, 60. Smaller
747 frame sizes achieve lower latency but less quality at a given bitrate.
748 Sizes greater than 20ms are only interesting at fairly low bitrates.
749 The default of FFmpeg is 10ms, but is 20ms in @command{opusenc}.
751 @item packet_loss (@emph{expect-loss})
752 Set expected packet loss percentage. The default is 0.
754 @item application (N.A.)
755 Set intended application type. Valid options are listed below:
759 Favor improved speech intelligibility.
761 Favor faithfulness to the input (the default).
763 Restrict to only the lowest delay modes.
767 Set cutoff bandwidth in Hz. The argument must be exactly one of the
768 following: 4000, 6000, 8000, 12000, or 20000, corresponding to
769 narrowband, mediumband, wideband, super wideband, and fullband
770 respectively. The default is 0 (cutoff disabled).
776 A wrapper providing WavPack encoding through libwavpack.
778 Only lossless mode using 32-bit integer samples is supported currently.
779 The @option{compression_level} option can be used to control speed vs.
780 compression tradeoff, with the values mapped to libwavpack as follows:
785 Fast mode - corresponding to the wavpack @option{-f} option.
788 Normal (default) settings.
791 High quality - corresponding to the wavpack @option{-h} option.
794 Very high quality - corresponding to the wavpack @option{-hh} option.
797 Same as 3, but with extra processing enabled - corresponding to the wavpack
798 @option{-x} option. I.e. 4 is the same as @option{-x2} and 8 is the same as
803 @c man end AUDIO ENCODERS
805 @chapter Video Encoders
806 @c man begin VIDEO ENCODERS
808 A description of some of the currently available video encoders
813 Theora format supported through libtheora.
815 Requires the presence of the libtheora headers and library during
816 configuration. You need to explicitly configure the build with
817 @code{--enable-libtheora}.
821 The following global options are mapped to internal libtheora options
822 which affect the quality and the bitrate of the encoded stream.
826 Set the video bitrate, only works if the @code{qscale} flag in
827 @option{flags} is not enabled.
830 Used to enable constant quality mode encoding through the
831 @option{qscale} flag, and to enable the @code{pass1} and @code{pass2}
838 Set the global quality in lambda units, only works if the
839 @code{qscale} flag in @option{flags} is enabled. The value is clipped
840 in the [0 - 10*@code{FF_QP2LAMBDA}] range, and then multiplied for 6.3
841 to get a value in the native libtheora range [0-63]. A higher value
842 corresponds to a higher quality.
844 For example, to set maximum constant quality encoding with
847 ffmpeg -i INPUT -flags:v qscale -global_quality:v "10*QP2LAMBDA" -codec:v libtheora OUTPUT.ogg
853 VP8 format supported through libvpx.
855 Requires the presence of the libvpx headers and library during configuration.
856 You need to explicitly configure the build with @code{--enable-libvpx}.
860 Mapping from FFmpeg to libvpx options with conversion notes in parentheses.
887 @code{(bufsize * 1000 / vb)}
890 @code{(bufsize * 1000 / vb * 5 / 6)}
892 @item rc_init_occupancy, vb
894 @code{(rc_init_occupancy * 1000 / vb)}
896 @item rc_buffer_aggressivity
903 rc_2pass_vbr_bias_pct
906 rc_2pass_vbr_maxsection_pct
907 @code{(maxrate * 100 / vb)}
910 rc_2pass_vbr_minsection_pct
911 @code{(minrate * 100 / vb)}
913 @item minrate, maxrate, vb
915 @code{(minrate == maxrate == vb)}
918 @code{VPX_CQ}, @code{VP8E_SET_CQ_LEVEL}
923 @code{VPX_DL_BEST_QUALITY}
925 @code{VPX_DL_GOOD_QUALITY}
927 @code{VPX_DL_REALTIME}
931 @code{VP8E_SET_CPUUSED}
934 @code{VP8E_SET_NOISE_SENSITIVITY}
937 @code{VP8E_SET_STATIC_THRESHOLD}
940 @code{VP8E_SET_TOKEN_PARTITIONS}
943 @code{VP8E_SET_MAX_INTRA_BITRATE_PCT}
945 @item force_key_frames
946 @code{VPX_EFLAG_FORCE_KF}
948 @item Alternate reference frame related
950 @item vp8flags altref
951 @code{VP8E_SET_ENABLEAUTOALTREF}
952 @item @var{arnr_max_frames}
953 @code{VP8E_SET_ARNR_MAXFRAMES}
954 @item @var{arnr_type}
955 @code{VP8E_SET_ARNR_TYPE}
956 @item @var{arnr_strength}
957 @code{VP8E_SET_ARNR_STRENGTH}
958 @item @var{rc_lookahead}
962 @item vp8flags error_resilient
967 For more information about libvpx see:
968 @url{http://www.webmproject.org/}
972 x264 H.264/MPEG-4 AVC encoder wrapper.
974 This encoder requires the presence of the libx264 headers and library
975 during configuration. You need to explicitly configure the build with
976 @code{--enable-libx264}.
978 libx264 supports an impressive number of features, including 8x8 and
979 4x4 adaptive spatial transform, adaptive B-frame placement, CAVLC/CABAC
980 entropy coding, interlacing (MBAFF), lossless mode, psy optimizations
981 for detail retention (adaptive quantization, psy-RD, psy-trellis).
983 Many libx264 encoder options are mapped to FFmpeg global codec
984 options, while unique encoder options are provided through private
985 options. Additionally the @option{x264opts} and @option{x264-params}
986 private options allows to pass a list of key=value tuples as accepted
987 by the libx264 @code{x264_param_parse} function.
989 The x264 project website is at
990 @url{http://www.videolan.org/developers/x264.html}.
994 The following options are supported by the libx264 wrapper. The
995 @command{x264}-equivalent options or values are listed in parentheses
998 To reduce the duplication of documentation, only the private options
999 and some others requiring special attention are documented here. For
1000 the documentation of the undocumented generic options, see
1001 @ref{codec-options,,the Codec Options chapter}.
1003 To get a more accurate and extensive documentation of the libx264
1004 options, invoke the command @command{x264 --full-help} or consult
1005 the libx264 documentation.
1008 @item b (@emph{bitrate})
1009 Set bitrate in bits/s. Note that FFmpeg's @option{b} option is
1010 expressed in bits/s, while @command{x264}'s @option{bitrate} is in
1013 @item bf (@emph{bframes})
1015 @item g (@emph{keyint})
1017 @item qmax (@emph{qpmax})
1019 @item qmin (@emph{qpmin})
1021 @item qdiff (@emph{qpstep})
1023 @item qblur (@emph{qblur})
1025 @item qcomp (@emph{qcomp})
1027 @item refs (@emph{ref})
1029 @item sc_threshold (@emph{scenecut})
1031 @item trellis (@emph{trellis})
1033 @item nr (@emph{nr})
1035 @item me_range (@emph{merange})
1037 @item me_method (@emph{me})
1038 Set motion estimation method. Possible values in the decreasing order
1042 @item dia (@emph{dia})
1043 @item epzs (@emph{dia})
1044 Diamond search with radius 1 (fastest). @samp{epzs} is an alias for
1046 @item hex (@emph{hex})
1047 Hexagonal search with radius 2.
1048 @item umh (@emph{umh})
1049 Uneven multi-hexagon search.
1050 @item esa (@emph{esa})
1052 @item tesa (@emph{tesa})
1053 Hadamard exhaustive search (slowest).
1056 @item subq (@emph{subme})
1058 @item b_strategy (@emph{b-adapt})
1060 @item keyint_min (@emph{min-keyint})
1063 Set entropy encoder. Possible values:
1070 Enable CAVLC and disable CABAC. It generates the same effect as
1071 @command{x264}'s @option{--no-cabac} option.
1075 Set full pixel motion estimation comparation algorithm. Possible values:
1079 Enable chroma in motion estimation.
1082 Ignore chroma in motion estimation. It generates the same effect as
1083 @command{x264}'s @option{--no-chroma-me} option.
1086 @item threads (@emph{threads})
1089 Set multithreading technique. Possible values:
1093 Slice-based multithreading. It generates the same effect as
1094 @command{x264}'s @option{--sliced-threads} option.
1096 Frame-based multithreading.
1100 Set encoding flags. It can be used to disable closed GOP and enable
1101 open GOP by setting it to @code{-cgop}. The result is similar to
1102 the behavior of @command{x264}'s @option{--open-gop} option.
1104 @item rc_init_occupancy (@emph{vbv-init})
1106 @item preset (@emph{preset})
1107 Set the encoding preset.
1109 @item tune (@emph{tune})
1110 Set tuning of the encoding params.
1112 @item profile (@emph{profile})
1113 Set profile restrictions.
1116 Enable fast settings when encoding first pass, when set to 1. When set
1117 to 0, it has the same effect of @command{x264}'s
1118 @option{--slow-firstpass} option.
1120 @item crf (@emph{crf})
1121 Set the quality for constant quality mode.
1123 @item crf_max (@emph{crf-max})
1124 In CRF mode, prevents VBV from lowering quality beyond this point.
1126 @item qp (@emph{qp})
1127 Set constant quantization rate control method parameter.
1129 @item aq-mode (@emph{aq-mode})
1130 Set AQ method. Possible values:
1133 @item none (@emph{0})
1136 @item variance (@emph{1})
1137 Variance AQ (complexity mask).
1139 @item autovariance (@emph{2})
1140 Auto-variance AQ (experimental).
1143 @item aq-strength (@emph{aq-strength})
1144 Set AQ strength, reduce blocking and blurring in flat and textured areas.
1147 Use psychovisual optimizations when set to 1. When set to 0, it has the
1148 same effect as @command{x264}'s @option{--no-psy} option.
1150 @item psy-rd (@emph{psy-rd})
1151 Set strength of psychovisual optimization, in
1152 @var{psy-rd}:@var{psy-trellis} format.
1154 @item rc-lookahead (@emph{rc-lookahead})
1155 Set number of frames to look ahead for frametype and ratecontrol.
1158 Enable weighted prediction for B-frames when set to 1. When set to 0,
1159 it has the same effect as @command{x264}'s @option{--no-weightb} option.
1161 @item weightp (@emph{weightp})
1162 Set weighted prediction method for P-frames. Possible values:
1165 @item none (@emph{0})
1167 @item simple (@emph{1})
1168 Enable only weighted refs
1169 @item smart (@emph{2})
1170 Enable both weighted refs and duplicates
1173 @item ssim (@emph{ssim})
1174 Enable calculation and printing SSIM stats after the encoding.
1176 @item intra-refresh (@emph{intra-refresh})
1177 Enable the use of Periodic Intra Refresh instead of IDR frames when set
1180 @item bluray-compat (@emph{bluray-compat})
1181 Configure the encoder to be compatible with the bluray standard.
1182 It is a shorthand for setting "bluray-compat=1 force-cfr=1".
1184 @item b-bias (@emph{b-bias})
1185 Set the influence on how often B-frames are used.
1187 @item b-pyramid (@emph{b-pyramid})
1188 Set method for keeping of some B-frames as references. Possible values:
1191 @item none (@emph{none})
1193 @item strict (@emph{strict})
1194 Strictly hierarchical pyramid.
1195 @item normal (@emph{normal})
1196 Non-strict (not Blu-ray compatible).
1200 Enable the use of one reference per partition, as opposed to one
1201 reference per macroblock when set to 1. When set to 0, it has the
1202 same effect as @command{x264}'s @option{--no-mixed-refs} option.
1205 Enable adaptive spatial transform (high profile 8x8 transform)
1206 when set to 1. When set to 0, it has the same effect as
1207 @command{x264}'s @option{--no-8x8dct} option.
1210 Enable early SKIP detection on P-frames when set to 1. When set
1211 to 0, it has the same effect as @command{x264}'s
1212 @option{--no-fast-pskip} option.
1214 @item aud (@emph{aud})
1215 Enable use of access unit delimiters when set to 1.
1218 Enable use macroblock tree ratecontrol when set to 1. When set
1219 to 0, it has the same effect as @command{x264}'s
1220 @option{--no-mbtree} option.
1222 @item deblock (@emph{deblock})
1223 Set loop filter parameters, in @var{alpha}:@var{beta} form.
1225 @item cplxblur (@emph{cplxblur})
1226 Set fluctuations reduction in QP (before curve compression).
1228 @item partitions (@emph{partitions})
1229 Set partitions to consider as a comma-separated list of. Possible
1234 8x8 P-frame partition.
1236 4x4 P-frame partition.
1238 4x4 B-frame partition.
1240 8x8 I-frame partition.
1242 4x4 I-frame partition.
1243 (Enabling @samp{p4x4} requires @samp{p8x8} to be enabled. Enabling
1244 @samp{i8x8} requires adaptive spatial transform (@option{8x8dct}
1245 option) to be enabled.)
1246 @item none (@emph{none})
1247 Do not consider any partitions.
1248 @item all (@emph{all})
1249 Consider every partition.
1252 @item direct-pred (@emph{direct})
1253 Set direct MV prediction mode. Possible values:
1256 @item none (@emph{none})
1257 Disable MV prediction.
1258 @item spatial (@emph{spatial})
1259 Enable spatial predicting.
1260 @item temporal (@emph{temporal})
1261 Enable temporal predicting.
1262 @item auto (@emph{auto})
1263 Automatically decided.
1266 @item slice-max-size (@emph{slice-max-size})
1267 Set the limit of the size of each slice in bytes. If not specified
1268 but RTP payload size (@option{ps}) is specified, that is used.
1270 @item stats (@emph{stats})
1271 Set the file name for multi-pass stats.
1273 @item nal-hrd (@emph{nal-hrd})
1274 Set signal HRD information (requires @option{vbv-bufsize} to be set).
1278 @item none (@emph{none})
1279 Disable HRD information signaling.
1280 @item vbr (@emph{vbr})
1282 @item cbr (@emph{cbr})
1283 Constant bit rate (not allowed in MP4 container).
1286 @item x264opts (N.A.)
1287 Set any x264 option, see @command{x264 --fullhelp} for a list.
1289 Argument is a list of @var{key}=@var{value} couples separated by
1290 ":". In @var{filter} and @var{psy-rd} options that use ":" as a separator
1291 themselves, use "," instead. They accept it as well since long ago but this
1292 is kept undocumented for some reason.
1294 For example to specify libx264 encoding options with @command{ffmpeg}:
1296 ffmpeg -i foo.mpg -vcodec libx264 -x264opts keyint=123:min-keyint=20 -an out.mkv
1299 @item x264-params (N.A.)
1300 Override the x264 configuration using a :-separated list of key=value
1303 This option is functionally the same as the @option{x264opts}, but is
1304 duplicated for compability with the Libav fork.
1306 For example to specify libx264 encoding options with @command{ffmpeg}:
1308 ffmpeg -i INPUT -c:v libx264 -x264-params level=30:bframes=0:weightp=0:\
1309 cabac=0:ref=1:vbv-maxrate=768:vbv-bufsize=2000:analyse=all:me=umh:\
1310 no-fast-pskip=1:subq=6:8x8dct=0:trellis=0 OUTPUT
1314 Encoding ffpresets for common usages are provided so they can be used with the
1315 general presets system (e.g. passing the @option{pre} option).
1319 Xvid MPEG-4 Part 2 encoder wrapper.
1321 This encoder requires the presence of the libxvidcore headers and library
1322 during configuration. You need to explicitly configure the build with
1323 @code{--enable-libxvid --enable-gpl}.
1325 The native @code{mpeg4} encoder supports the MPEG-4 Part 2 format, so
1326 users can encode to this format without this library.
1330 The following options are supported by the libxvid wrapper. Some of
1331 the following options are listed but are not documented, and
1332 correspond to shared codec options. See @ref{codec-options,,the Codec
1333 Options chapter} for their documentation. The other shared options
1334 which are not listed have no effect for the libxvid encoder.
1356 Set specific encoding flags. Possible values:
1361 Use four motion vector by macroblock.
1364 Enable high quality AC prediction.
1367 Only encode grayscale.
1370 Enable the use of global motion compensation (GMC).
1373 Enable quarter-pixel motion compensation.
1379 Place global headers in extradata instead of every keyframe.
1386 Set motion estimation method. Possible values in decreasing order of
1387 speed and increasing order of quality:
1391 Use no motion estimation (default).
1396 Enable advanced diamond zonal search for 16x16 blocks and half-pixel
1397 refinement for 16x16 blocks. @samp{x1} and @samp{log} are aliases for
1401 Enable all of the things described above, plus advanced diamond zonal
1402 search for 8x8 blocks, half-pixel refinement for 8x8 blocks, and motion
1403 estimation on chroma planes.
1406 Enable all of the things described above, plus extended 16x16 and 8x8
1411 Set macroblock decision algorithm. Possible values in the increasing
1416 Use macroblock comparing function algorithm (default).
1419 Enable rate distortion-based half pixel and quarter pixel refinement for
1423 Enable all of the things described above, plus rate distortion-based
1424 half pixel and quarter pixel refinement for 8x8 blocks, and rate
1425 distortion-based search using square pattern.
1429 Enable lumi masking adaptive quantization when set to 1. Default is 0
1433 Enable variance adaptive quantization when set to 1. Default is 0
1436 When combined with @option{lumi_aq}, the resulting quality will not
1437 be better than any of the two specified individually. In other
1438 words, the resulting quality will be the worse one of the two
1442 Set structural similarity (SSIM) displaying method. Possible values:
1446 Disable displaying of SSIM information.
1449 Output average SSIM at the end of encoding to stdout. The format of
1450 showing the average SSIM is:
1456 For users who are not familiar with C, %f means a float number, or
1457 a decimal (e.g. 0.939232).
1460 Output both per-frame SSIM data during encoding and average SSIM at
1461 the end of encoding to stdout. The format of per-frame information
1465 SSIM: avg: %1.3f min: %1.3f max: %1.3f
1468 For users who are not familiar with C, %1.3f means a float number
1469 rounded to 3 digits after the dot (e.g. 0.932).
1474 Set SSIM accuracy. Valid options are integers within the range of
1475 0-4, while 0 gives the most accurate result and 4 computes the
1484 @subsection Private options
1487 @item dpi @var{integer}
1488 Set physical density of pixels, in dots per inch, unset by default
1489 @item dpm @var{integer}
1490 Set physical density of pixels, in dots per meter, unset by default
1495 Apple ProRes encoder.
1497 FFmpeg contains 2 ProRes encoders, the prores-aw and prores-ks encoder.
1498 The used encoder can be choosen with the @code{-vcodec} option.
1500 @subsection Private Options for prores-ks
1503 @item profile @var{integer}
1504 Select the ProRes profile to encode
1513 @item quant_mat @var{integer}
1514 Select quantization matrix.
1523 If set to @var{auto}, the matrix matching the profile will be picked.
1524 If not set, the matrix providing the highest quality, @var{default}, will be
1527 @item bits_per_mb @var{integer}
1528 How many bits to allot for coding one macroblock. Different profiles use
1529 between 200 and 2400 bits per macroblock, the maximum is 8000.
1531 @item mbs_per_slice @var{integer}
1532 Number of macroblocks in each slice (1-8); the default value (8)
1533 should be good in almost all situations.
1535 @item vendor @var{string}
1536 Override the 4-byte vendor ID.
1537 A custom vendor ID like @var{apl0} would claim the stream was produced by
1540 @item alpha_bits @var{integer}
1541 Specify number of bits for alpha component.
1542 Possible values are @var{0}, @var{8} and @var{16}.
1543 Use @var{0} to disable alpha plane coding.
1547 @subsection Speed considerations
1549 In the default mode of operation the encoder has to honor frame constraints
1550 (i.e. not produc frames with size bigger than requested) while still making
1551 output picture as good as possible.
1552 A frame containing a lot of small details is harder to compress and the encoder
1553 would spend more time searching for appropriate quantizers for each slice.
1555 Setting a higher @option{bits_per_mb} limit will improve the speed.
1557 For the fastest encoding speed set the @option{qscale} parameter (4 is the
1558 recommended value) and do not set a size constraint.
1560 @c man end VIDEO ENCODERS