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{-encoders} 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 todo @ref{libaacplus}
42 See also @ref{libfdk-aac-enc,,libfdk_aac} and @ref{libfaac}.
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 described 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)
500 FLAC (Free Lossless Audio Codec) Encoder
504 The following options are supported by FFmpeg's flac encoder.
507 @item compression_level
508 Sets the compression level, which chooses defaults for many other options
509 if they are not set explicitly.
512 Sets the size of the frames in samples per channel.
514 @item lpc_coeff_precision
515 Sets the LPC coefficient precision, valid values are from 1 to 15, 15 is the
519 Sets the first stage LPC algorithm
525 fixed LPC coefficients
533 Number of passes to use for Cholesky factorization during LPC analysis
535 @item min_partition_order
536 The minimum partition order
538 @item max_partition_order
539 The maximum partition order
541 @item prediction_order_method
556 The mode is chosen automatically for each frame
558 Chanels are independently coded
564 @item exact_rice_parameters
565 Chooses if rice parameters are calculated exactly or approximately.
566 if set to 1 then they are chosen exactly, which slows the code down slightly and
567 improves compression slightly.
569 @item multi_dim_quant
570 Multi Dimensional Quantization. If set to 1 then a 2nd stage LPC algorithm is
571 applied after the first stage to finetune the coefficients. This is quite slow
572 and slightly improves compression.
579 libfaac AAC (Advanced Audio Coding) encoder wrapper.
581 Requires the presence of the libfaac headers and library during
582 configuration. You need to explicitly configure the build with
583 @code{--enable-libfaac --enable-nonfree}.
585 This encoder is considered to be of higher quality with respect to the
586 @ref{aacenc,,the native experimental FFmpeg AAC encoder}.
588 For more information see the libfaac project at
589 @url{http://www.audiocoding.com/faac.html/}.
593 The following shared FFmpeg codec options are recognized.
595 The following options are supported by the libfaac wrapper. The
596 @command{faac}-equivalent of the options are listed in parentheses.
600 Set bit rate in bits/s for ABR (Average Bit Rate) mode. If the bit rate
601 is not explicitly specified, it is automatically set to a suitable
602 value depending on the selected profile. @command{faac} bitrate is
603 expressed in kilobits/s.
605 Note that libfaac does not support CBR (Constant Bit Rate) but only
606 ABR (Average Bit Rate).
608 If VBR mode is enabled this option is ignored.
611 Set audio sampling rate (in Hz).
614 Set the number of audio channels.
616 @item cutoff (@emph{-C})
617 Set cutoff frequency. If not specified (or explicitly set to 0) it
618 will use a value automatically computed by the library. Default value
624 The following profiles are recognized:
630 Low Complexity AAC (LC)
633 Scalable Sample Rate (SSR)
636 Long Term Prediction (LTP)
639 If not specified it is set to @samp{aac_low}.
642 Set constant quality VBR (Variable Bit Rate) mode.
645 Set quality in VBR mode as an integer number of lambda units.
647 Only relevant when VBR mode is enabled with @code{flags +qscale}. The
648 value is converted to QP units by dividing it by @code{FF_QP2LAMBDA},
649 and used to set the quality value used by libfaac. A reasonable range
650 for the option value in QP units is [10-500], the higher the value the
654 Enable VBR mode when set to a non-negative value, and set constant
655 quality value as a double floating point value in QP units.
657 The value sets the quality value used by libfaac. A reasonable range
658 for the option value is [10-500], the higher the value the higher the
661 This option is valid only using the @command{ffmpeg} command-line
662 tool. For library interface users, use @option{global_quality}.
669 Use @command{ffmpeg} to convert an audio file to ABR 128 kbps AAC in an M4A (MP4)
672 ffmpeg -i input.wav -codec:a libfaac -b:a 128k -output.m4a
676 Use @command{ffmpeg} to convert an audio file to VBR AAC, using the
679 ffmpeg -i input.wav -c:a libfaac -profile:a aac_ltp -q:a 100 output.m4a
683 @anchor{libfdk-aac-enc}
686 libfdk-aac AAC (Advanced Audio Coding) encoder wrapper.
688 The libfdk-aac library is based on the Fraunhofer FDK AAC code from
691 Requires the presence of the libfdk-aac headers and library during
692 configuration. You need to explicitly configure the build with
693 @code{--enable-libfdk-aac}. The library is also incompatible with GPL,
694 so if you allow the use of GPL, you should configure with
695 @code{--enable-gpl --enable-nonfree --enable-libfdk-aac}.
697 This encoder is considered to be of higher quality with respect to
698 both @ref{aacenc,,the native experimental FFmpeg AAC encoder} and
701 VBR encoding, enabled through the @option{vbr} or @option{flags
702 +qscale} options, is experimental and only works with some
703 combinations of parameters.
705 Support for encoding 7.1 audio is only available with libfdk-aac 0.1.3 or
708 For more information see the fdk-aac project at
709 @url{http://sourceforge.net/p/opencore-amr/fdk-aac/}.
713 The following options are mapped on the shared FFmpeg codec options.
717 Set bit rate in bits/s. If the bitrate is not explicitly specified, it
718 is automatically set to a suitable value depending on the selected
721 In case VBR mode is enabled the option is ignored.
724 Set audio sampling rate (in Hz).
727 Set the number of audio channels.
730 Enable fixed quality, VBR (Variable Bit Rate) mode.
731 Note that VBR is implicitly enabled when the @option{vbr} value is
735 Set cutoff frequency. If not specified (or explicitly set to 0) it
736 will use a value automatically computed by the library. Default value
742 The following profiles are recognized:
745 Low Complexity AAC (LC)
748 High Efficiency AAC (HE-AAC)
751 High Efficiency AAC version 2 (HE-AACv2)
757 Enhanced Low Delay AAC (ELD)
760 If not specified it is set to @samp{aac_low}.
763 The following are private options of the libfdk_aac encoder.
767 Enable afterburner feature if set to 1, disabled if set to 0. This
768 improves the quality but also the required processing power.
773 Enable SBR (Spectral Band Replication) for ELD if set to 1, disabled
779 Set SBR/PS signaling style.
781 It can assume one of the following values:
784 choose signaling implicitly (explicit hierarchical by default,
785 implicit if global header is disabled)
788 implicit backwards compatible signaling
791 explicit SBR, implicit PS signaling
793 @item explicit_hierarchical
794 explicit hierarchical signaling
797 Default value is @samp{default}.
800 Output LATM/LOAS encapsulated data if set to 1, disabled if set to 0.
805 Set StreamMuxConfig and PCE repetition period (in frames) for sending
806 in-band configuration buffers within LATM/LOAS transport layer.
808 Must be a 16-bits non-negative integer.
813 Set VBR mode, from 1 to 5. 1 is lowest quality (though still pretty
814 good) and 5 is highest quality. A value of 0 will disable VBR, and CBR
815 (Constant Bit Rate) is enabled.
817 Currently only the @samp{aac_low} profile supports VBR encoding.
819 VBR modes 1-5 correspond to roughly the following average bit rates:
831 about 80-96 kbps/channel
841 Use @command{ffmpeg} to convert an audio file to VBR AAC in an M4A (MP4)
844 ffmpeg -i input.wav -codec:a libfdk_aac -vbr 3 output.m4a
848 Use @command{ffmpeg} to convert an audio file to CBR 64k kbps AAC, using the
849 High-Efficiency AAC profile:
851 ffmpeg -i input.wav -c:a libfdk_aac -profile:a aac_he -b:a 64k output.m4a
858 LAME (Lame Ain't an MP3 Encoder) MP3 encoder wrapper.
860 Requires the presence of the libmp3lame headers and library during
861 configuration. You need to explicitly configure the build with
862 @code{--enable-libmp3lame}.
864 See @ref{libshine} for a fixed-point MP3 encoder, although with a
869 The following options are supported by the libmp3lame wrapper. The
870 @command{lame}-equivalent of the options are listed in parentheses.
874 Set bitrate expressed in bits/s for CBR or ABR. LAME @code{bitrate} is
875 expressed in kilobits/s.
878 Set constant quality setting for VBR. This option is valid only
879 using the @command{ffmpeg} command-line tool. For library interface
880 users, use @option{global_quality}.
882 @item compression_level (@emph{-q})
883 Set algorithm quality. Valid arguments are integers in the 0-9 range,
884 with 0 meaning highest quality but slowest, and 9 meaning fastest
885 while producing the worst quality.
888 Enable use of bit reservoir when set to 1. Default value is 1. LAME
889 has this enabled by default, but can be overridden by use
890 @option{--nores} option.
892 @item joint_stereo (@emph{-m j})
893 Enable the encoder to use (on a frame by frame basis) either L/R
894 stereo or mid/side stereo. Default value is 1.
896 @item abr (@emph{--abr})
897 Enable the encoder to use ABR when set to 1. The @command{lame}
898 @option{--abr} sets the target bitrate, while this options only
899 tells FFmpeg to use ABR still relies on @option{b} to set bitrate.
903 @section libopencore-amrnb
905 OpenCORE Adaptive Multi-Rate Narrowband encoder.
907 Requires the presence of the libopencore-amrnb headers and library during
908 configuration. You need to explicitly configure the build with
909 @code{--enable-libopencore-amrnb --enable-version3}.
911 This is a mono-only encoder. Officially it only supports 8000Hz sample rate,
912 but you can override it by setting @option{strict} to @samp{unofficial} or
920 Set bitrate in bits per second. Only the following bitrates are supported,
921 otherwise libavcodec will round to the nearest valid bitrate.
935 Allow discontinuous transmission (generate comfort noise) when set to 1. The
936 default value is 0 (disabled).
943 Shine Fixed-Point MP3 encoder wrapper.
945 Shine is a fixed-point MP3 encoder. It has a far better performance on
946 platforms without an FPU, e.g. armel CPUs, and some phones and tablets.
947 However, as it is more targeted on performance than quality, it is not on par
948 with LAME and other production-grade encoders quality-wise. Also, according to
949 the project's homepage, this encoder may not be free of bugs as the code was
950 written a long time ago and the project was dead for at least 5 years.
952 This encoder only supports stereo and mono input. This is also CBR-only.
954 The original project (last updated in early 2007) is at
955 @url{http://sourceforge.net/projects/libshine-fxp/}. We only support the
956 updated fork by the Savonet/Liquidsoap project at @url{https://github.com/savonet/shine}.
958 Requires the presence of the libshine headers and library during
959 configuration. You need to explicitly configure the build with
960 @code{--enable-libshine}.
962 See also @ref{libmp3lame}.
966 The following options are supported by the libshine wrapper. The
967 @command{shineenc}-equivalent of the options are listed in parentheses.
971 Set bitrate expressed in bits/s for CBR. @command{shineenc} @option{-b} option
972 is expressed in kilobits/s.
978 TwoLAME MP2 encoder wrapper.
980 Requires the presence of the libtwolame headers and library during
981 configuration. You need to explicitly configure the build with
982 @code{--enable-libtwolame}.
986 The following options are supported by the libtwolame wrapper. The
987 @command{twolame}-equivalent options follow the FFmpeg ones and are in
992 Set bitrate expressed in bits/s for CBR. @command{twolame} @option{b}
993 option is expressed in kilobits/s. Default value is 128k.
996 Set quality for experimental VBR support. Maximum value range is
997 from -50 to 50, useful range is from -10 to 10. The higher the
998 value, the better the quality. This option is valid only using the
999 @command{ffmpeg} command-line tool. For library interface users,
1000 use @option{global_quality}.
1002 @item mode (@emph{--mode})
1003 Set the mode of the resulting audio. Possible values:
1007 Choose mode automatically based on the input. This is the default.
1018 @item psymodel (@emph{--psyc-mode})
1019 Set psychoacoustic model to use in encoding. The argument must be
1020 an integer between -1 and 4, inclusive. The higher the value, the
1021 better the quality. The default value is 3.
1023 @item energy_levels (@emph{--energy})
1024 Enable energy levels extensions when set to 1. The default value is
1027 @item error_protection (@emph{--protect})
1028 Enable CRC error protection when set to 1. The default value is 0
1031 @item copyright (@emph{--copyright})
1032 Set MPEG audio copyright flag when set to 1. The default value is 0
1035 @item original (@emph{--original})
1036 Set MPEG audio original flag when set to 1. The default value is 0
1041 @anchor{libvo-aacenc}
1042 @section libvo-aacenc
1044 VisualOn AAC encoder.
1046 Requires the presence of the libvo-aacenc headers and library during
1047 configuration. You need to explicitly configure the build with
1048 @code{--enable-libvo-aacenc --enable-version3}.
1050 This encoder is considered to be worse than the
1051 @ref{aacenc,,native experimental FFmpeg AAC encoder}, according to
1056 The VisualOn AAC encoder only support encoding AAC-LC and up to 2
1057 channels. It is also CBR-only.
1062 Set bit rate in bits/s.
1066 @section libvo-amrwbenc
1068 VisualOn Adaptive Multi-Rate Wideband encoder.
1070 Requires the presence of the libvo-amrwbenc headers and library during
1071 configuration. You need to explicitly configure the build with
1072 @code{--enable-libvo-amrwbenc --enable-version3}.
1074 This is a mono-only encoder. Officially it only supports 16000Hz sample
1075 rate, but you can override it by setting @option{strict} to
1076 @samp{unofficial} or lower.
1083 Set bitrate in bits/s. Only the following bitrates are supported, otherwise
1084 libavcodec will round to the nearest valid bitrate.
1099 Allow discontinuous transmission (generate comfort noise) when set to 1. The
1100 default value is 0 (disabled).
1106 libopus Opus Interactive Audio Codec encoder wrapper.
1108 Requires the presence of the libopus headers and library during
1109 configuration. You need to explicitly configure the build with
1110 @code{--enable-libopus}.
1112 @subsection Option Mapping
1114 Most libopus options are modelled after the @command{opusenc} utility from
1115 opus-tools. The following is an option mapping chart describing options
1116 supported by the libopus wrapper, and their @command{opusenc}-equivalent
1121 @item b (@emph{bitrate})
1122 Set the bit rate in bits/s. FFmpeg's @option{b} option is
1123 expressed in bits/s, while @command{opusenc}'s @option{bitrate} in
1126 @item vbr (@emph{vbr}, @emph{hard-cbr}, and @emph{cvbr})
1127 Set VBR mode. The FFmpeg @option{vbr} option has the following
1128 valid arguments, with the @command{opusenc} equivalent options
1132 @item off (@emph{hard-cbr})
1133 Use constant bit rate encoding.
1135 @item on (@emph{vbr})
1136 Use variable bit rate encoding (the default).
1138 @item constrained (@emph{cvbr})
1139 Use constrained variable bit rate encoding.
1142 @item compression_level (@emph{comp})
1143 Set encoding algorithm complexity. Valid options are integers in
1144 the 0-10 range. 0 gives the fastest encodes but lower quality, while 10
1145 gives the highest quality but slowest encoding. The default is 10.
1147 @item frame_duration (@emph{framesize})
1148 Set maximum frame size, or duration of a frame in milliseconds. The
1149 argument must be exactly the following: 2.5, 5, 10, 20, 40, 60. Smaller
1150 frame sizes achieve lower latency but less quality at a given bitrate.
1151 Sizes greater than 20ms are only interesting at fairly low bitrates.
1152 The default is 20ms.
1154 @item packet_loss (@emph{expect-loss})
1155 Set expected packet loss percentage. The default is 0.
1157 @item application (N.A.)
1158 Set intended application type. Valid options are listed below:
1162 Favor improved speech intelligibility.
1164 Favor faithfulness to the input (the default).
1166 Restrict to only the lowest delay modes.
1170 Set cutoff bandwidth in Hz. The argument must be exactly one of the
1171 following: 4000, 6000, 8000, 12000, or 20000, corresponding to
1172 narrowband, mediumband, wideband, super wideband, and fullband
1173 respectively. The default is 0 (cutoff disabled).
1179 libvorbis encoder wrapper.
1181 Requires the presence of the libvorbisenc headers and library during
1182 configuration. You need to explicitly configure the build with
1183 @code{--enable-libvorbis}.
1187 The following options are supported by the libvorbis wrapper. The
1188 @command{oggenc}-equivalent of the options are listed in parentheses.
1190 To get a more accurate and extensive documentation of the libvorbis
1191 options, consult the libvorbisenc's and @command{oggenc}'s documentations.
1192 See @url{http://xiph.org/vorbis/},
1193 @url{http://wiki.xiph.org/Vorbis-tools}, and oggenc(1).
1197 Set bitrate expressed in bits/s for ABR. @command{oggenc} @option{-b} is
1198 expressed in kilobits/s.
1201 Set constant quality setting for VBR. The value should be a float
1202 number in the range of -1.0 to 10.0. The higher the value, the better
1203 the quality. The default value is @samp{3.0}.
1205 This option is valid only using the @command{ffmpeg} command-line tool.
1206 For library interface users, use @option{global_quality}.
1208 @item cutoff (@emph{--advanced-encode-option lowpass_frequency=N})
1209 Set cutoff bandwidth in Hz, a value of 0 disables cutoff. @command{oggenc}'s
1210 related option is expressed in kHz. The default value is @samp{0} (cutoff
1213 @item minrate (@emph{-m})
1214 Set minimum bitrate expressed in bits/s. @command{oggenc} @option{-m} is
1215 expressed in kilobits/s.
1217 @item maxrate (@emph{-M})
1218 Set maximum bitrate expressed in bits/s. @command{oggenc} @option{-M} is
1219 expressed in kilobits/s. This only has effect on ABR mode.
1221 @item iblock (@emph{--advanced-encode-option impulse_noisetune=N})
1222 Set noise floor bias for impulse blocks. The value is a float number from
1223 -15.0 to 0.0. A negative bias instructs the encoder to pay special attention
1224 to the crispness of transients in the encoded audio. The tradeoff for better
1225 transient response is a higher bitrate.
1232 A wrapper providing WavPack encoding through libwavpack.
1234 Only lossless mode using 32-bit integer samples is supported currently.
1236 Requires the presence of the libwavpack headers and library during
1237 configuration. You need to explicitly configure the build with
1238 @code{--enable-libwavpack}.
1240 Note that a libavcodec-native encoder for the WavPack codec exists so users can
1241 encode audios with this codec without using this encoder. See @ref{wavpackenc}.
1245 @command{wavpack} command line utility's corresponding options are listed in
1246 parentheses, if any.
1249 @item frame_size (@emph{--blocksize})
1252 @item compression_level
1253 Set speed vs. compression tradeoff. Acceptable arguments are listed below:
1260 Normal (default) settings.
1265 @item 3 (@emph{-hh})
1268 @item 4-8 (@emph{-hh -x}@var{EXTRAPROC})
1269 Same as @samp{3}, but with extra processing enabled.
1271 @samp{4} is the same as @option{-x2} and @samp{8} is the same as @option{-x6}.
1279 WavPack lossless audio encoder.
1281 This is a libavcodec-native WavPack encoder. There is also an encoder based on
1282 libwavpack, but there is virtually no reason to use that encoder.
1284 See also @ref{libwavpack}.
1288 The equivalent options for @command{wavpack} command line utility are listed in
1291 @subsubsection Shared options
1293 The following shared options are effective for this encoder. Only special notes
1294 about this particular encoder will be documented here. For the general meaning
1295 of the options, see @ref{codec-options,,the Codec Options chapter}.
1298 @item frame_size (@emph{--blocksize})
1299 For this encoder, the range for this option is between 128 and 131072. Default
1300 is automatically decided based on sample rate and number of channel.
1302 For the complete formula of calculating default, see
1303 @file{libavcodec/wavpackenc.c}.
1305 @item compression_level (@emph{-f}, @emph{-h}, @emph{-hh}, and @emph{-x})
1306 This option's syntax is consistent with @ref{libwavpack}'s.
1309 @subsubsection Private options
1312 @item joint_stereo (@emph{-j})
1313 Set whether to enable joint stereo. Valid values are:
1317 Force mid/side audio encoding.
1318 @item off (@emph{0})
1319 Force left/right audio encoding.
1321 Let the encoder decide automatically.
1325 Set whether to enable optimization for mono. This option is only effective for
1326 non-mono streams. Available values:
1337 @c man end AUDIO ENCODERS
1339 @chapter Video Encoders
1340 @c man begin VIDEO ENCODERS
1342 A description of some of the currently available video encoders
1345 @section libopenh264
1347 Cisco libopenh264 H.264/MPEG-4 AVC encoder wrapper.
1349 This encoder requires the presence of the libopenh264 headers and
1350 library during configuration. You need to explicitly configure the
1351 build with @code{--enable-libopenh264}. The library is detected using
1352 @command{pkg-config}.
1354 For more information about the library see
1355 @url{http://www.openh264.org}.
1359 The following FFmpeg global options affect the configurations of the
1360 libopenh264 encoder.
1364 Set the bitrate (as a number of bits per second).
1370 Set the max bitrate (as a number of bits per second).
1372 @item flags +global_header
1373 Set global header in the bitstream.
1376 Set the number of slices, used in parallelized encoding. Default value
1377 is 0. This is only used when @option{slice_mode} is set to
1381 Set slice mode. Can assume one of the follwing possible values:
1385 a fixed number of slices
1387 one slice per row of macroblocks
1389 automatic number of slices according to number of thread
1392 Default value is @samp{auto}.
1395 Enable loop filter, if set to 1 (automatically enabled). To disable
1399 Set profile restrictions. If set to the value of @samp{main} enable
1400 CABAC (set the @code{SEncParamExt.iEntropyCodingModeFlag} flag to 1).
1405 The native jpeg 2000 encoder is lossy by default, the @code{-q:v}
1406 option can be used to set the encoding quality. Lossless encoding
1407 can be selected with @code{-pred 1}.
1413 Can be set to either @code{j2k} or @code{jp2} (the default) that
1414 makes it possible to store non-rgb pix_fmts.
1423 @item iterative_dia_size
1424 dia size for the iterative motion estimation
1429 libtheora Theora encoder wrapper.
1431 Requires the presence of the libtheora headers and library during
1432 configuration. You need to explicitly configure the build with
1433 @code{--enable-libtheora}.
1435 For more information about the libtheora project see
1436 @url{http://www.theora.org/}.
1440 The following global options are mapped to internal libtheora options
1441 which affect the quality and the bitrate of the encoded stream.
1445 Set the video bitrate in bit/s for CBR (Constant Bit Rate) mode. In
1446 case VBR (Variable Bit Rate) mode is enabled this option is ignored.
1449 Used to enable constant quality mode (VBR) encoding through the
1450 @option{qscale} flag, and to enable the @code{pass1} and @code{pass2}
1456 @item global_quality
1457 Set the global quality as an integer in lambda units.
1459 Only relevant when VBR mode is enabled with @code{flags +qscale}. The
1460 value is converted to QP units by dividing it by @code{FF_QP2LAMBDA},
1461 clipped in the [0 - 10] range, and then multiplied by 6.3 to get a
1462 value in the native libtheora range [0-63]. A higher value corresponds
1463 to a higher quality.
1466 Enable VBR mode when set to a non-negative value, and set constant
1467 quality value as a double floating point value in QP units.
1469 The value is clipped in the [0-10] range, and then multiplied by 6.3
1470 to get a value in the native libtheora range [0-63].
1472 This option is valid only using the @command{ffmpeg} command-line
1473 tool. For library interface users, use @option{global_quality}.
1476 @subsection Examples
1480 Set maximum constant quality (VBR) encoding with @command{ffmpeg}:
1482 ffmpeg -i INPUT -codec:v libtheora -q:v 10 OUTPUT.ogg
1486 Use @command{ffmpeg} to convert a CBR 1000 kbps Theora video stream:
1488 ffmpeg -i INPUT -codec:v libtheora -b:v 1000k OUTPUT.ogg
1494 VP8/VP9 format supported through libvpx.
1496 Requires the presence of the libvpx headers and library during configuration.
1497 You need to explicitly configure the build with @code{--enable-libvpx}.
1501 The following options are supported by the libvpx wrapper. The
1502 @command{vpxenc}-equivalent options or values are listed in parentheses
1505 To reduce the duplication of documentation, only the private options
1506 and some others requiring special attention are documented here. For
1507 the documentation of the undocumented generic options, see
1508 @ref{codec-options,,the Codec Options chapter}.
1510 To get more documentation of the libvpx options, invoke the command
1511 @command{ffmpeg -h encoder=libvpx}, @command{ffmpeg -h encoder=libvpx-vp9} or
1512 @command{vpxenc --help}. Further information is available in the libvpx API
1517 @item b (@emph{target-bitrate})
1518 Set bitrate in bits/s. Note that FFmpeg's @option{b} option is
1519 expressed in bits/s, while @command{vpxenc}'s @option{target-bitrate} is in
1522 @item g (@emph{kf-max-dist})
1524 @item keyint_min (@emph{kf-min-dist})
1526 @item qmin (@emph{min-q})
1528 @item qmax (@emph{max-q})
1530 @item bufsize (@emph{buf-sz}, @emph{buf-optimal-sz})
1531 Set ratecontrol buffer size (in bits). Note @command{vpxenc}'s options are
1532 specified in milliseconds, the libvpx wrapper converts this value as follows:
1533 @code{buf-sz = bufsize * 1000 / bitrate},
1534 @code{buf-optimal-sz = bufsize * 1000 / bitrate * 5 / 6}.
1536 @item rc_init_occupancy (@emph{buf-initial-sz})
1537 Set number of bits which should be loaded into the rc buffer before decoding
1538 starts. Note @command{vpxenc}'s option is specified in milliseconds, the libvpx
1539 wrapper converts this value as follows:
1540 @code{rc_init_occupancy * 1000 / bitrate}.
1542 @item undershoot-pct
1543 Set datarate undershoot (min) percentage of the target bitrate.
1546 Set datarate overshoot (max) percentage of the target bitrate.
1548 @item skip_threshold (@emph{drop-frame})
1550 @item qcomp (@emph{bias-pct})
1552 @item maxrate (@emph{maxsection-pct})
1553 Set GOP max bitrate in bits/s. Note @command{vpxenc}'s option is specified as a
1554 percentage of the target bitrate, the libvpx wrapper converts this value as
1555 follows: @code{(maxrate * 100 / bitrate)}.
1557 @item minrate (@emph{minsection-pct})
1558 Set GOP min bitrate in bits/s. Note @command{vpxenc}'s option is specified as a
1559 percentage of the target bitrate, the libvpx wrapper converts this value as
1560 follows: @code{(minrate * 100 / bitrate)}.
1562 @item minrate, maxrate, b @emph{end-usage=cbr}
1563 @code{(minrate == maxrate == bitrate)}.
1565 @item crf (@emph{end-usage=cq}, @emph{cq-level})
1567 @item quality, deadline (@emph{deadline})
1570 Use best quality deadline. Poorly named and quite slow, this option should be
1571 avoided as it may give worse quality output than good.
1573 Use good quality deadline. This is a good trade-off between speed and quality
1574 when used with the @option{cpu-used} option.
1576 Use realtime quality deadline.
1579 @item speed, cpu-used (@emph{cpu-used})
1580 Set quality/speed ratio modifier. Higher values speed up the encode at the cost
1583 @item nr (@emph{noise-sensitivity})
1586 Set a change threshold on blocks below which they will be skipped by the
1589 @item slices (@emph{token-parts})
1590 Note that FFmpeg's @option{slices} option gives the total number of partitions,
1591 while @command{vpxenc}'s @option{token-parts} is given as
1592 @code{log2(partitions)}.
1594 @item max-intra-rate
1595 Set maximum I-frame bitrate as a percentage of the target bitrate. A value of 0
1598 @item force_key_frames
1599 @code{VPX_EFLAG_FORCE_KF}
1601 @item Alternate reference frame related
1604 Enable use of alternate reference frames (2-pass only).
1605 @item arnr-max-frames
1606 Set altref noise reduction max frame count.
1608 Set altref noise reduction filter type: backward, forward, centered.
1610 Set altref noise reduction filter strength.
1611 @item rc-lookahead, lag-in-frames (@emph{lag-in-frames})
1612 Set number of frames to look ahead for frametype and ratecontrol.
1615 @item error-resilient
1616 Enable error resiliency features.
1618 @item VP9-specific options
1621 Enable lossless mode.
1623 Set number of tile columns to use. Note this is given as
1624 @code{log2(tile_columns)}. For example, 8 tile columns would be requested by
1625 setting the @option{tile-columns} option to 3.
1627 Set number of tile rows to use. Note this is given as @code{log2(tile_rows)}.
1628 For example, 4 tile rows would be requested by setting the @option{tile-rows}
1630 @item frame-parallel
1631 Enable frame parallel decodability features.
1633 Set adaptive quantization mode (0: off (default), 1: variance 2: complexity, 3:
1635 @item colorspace @emph{color-space}
1636 Set input color space. The VP9 bitstream supports signaling the following
1639 @item @samp{rgb} @emph{sRGB}
1640 @item @samp{bt709} @emph{bt709}
1641 @item @samp{unspecified} @emph{unknown}
1642 @item @samp{bt470bg} @emph{bt601}
1643 @item @samp{smpte170m} @emph{smpte170}
1644 @item @samp{smpte240m} @emph{smpte240}
1645 @item @samp{bt2020_ncl} @emph{bt2020}
1651 For more information about libvpx see:
1652 @url{http://www.webmproject.org/}
1657 libwebp WebP Image encoder wrapper
1659 libwebp is Google's official encoder for WebP images. It can encode in either
1660 lossy or lossless mode. Lossy images are essentially a wrapper around a VP8
1661 frame. Lossless images are a separate codec developed by Google.
1663 @subsection Pixel Format
1665 Currently, libwebp only supports YUV420 for lossy and RGB for lossless due
1666 to limitations of the format and libwebp. Alpha is supported for either mode.
1667 Because of API limitations, if RGB is passed in when encoding lossy or YUV is
1668 passed in for encoding lossless, the pixel format will automatically be
1669 converted using functions from libwebp. This is not ideal and is done only for
1676 @item -lossless @var{boolean}
1677 Enables/Disables use of lossless mode. Default is 0.
1679 @item -compression_level @var{integer}
1680 For lossy, this is a quality/speed tradeoff. Higher values give better quality
1681 for a given size at the cost of increased encoding time. For lossless, this is
1682 a size/speed tradeoff. Higher values give smaller size at the cost of increased
1683 encoding time. More specifically, it controls the number of extra algorithms
1684 and compression tools used, and varies the combination of these tools. This
1685 maps to the @var{method} option in libwebp. The valid range is 0 to 6.
1688 @item -qscale @var{float}
1689 For lossy encoding, this controls image quality, 0 to 100. For lossless
1690 encoding, this controls the effort and time spent at compressing more. The
1691 default value is 75. Note that for usage via libavcodec, this option is called
1692 @var{global_quality} and must be multiplied by @var{FF_QP2LAMBDA}.
1694 @item -preset @var{type}
1695 Configuration preset. This does some automatic settings based on the general
1699 Do not use a preset.
1701 Use the encoder default.
1703 Digital picture, like portrait, inner shot
1705 Outdoor photograph, with natural lighting
1707 Hand or line drawing, with high-contrast details
1709 Small-sized colorful images
1716 @section libx264, libx264rgb
1718 x264 H.264/MPEG-4 AVC encoder wrapper.
1720 This encoder requires the presence of the libx264 headers and library
1721 during configuration. You need to explicitly configure the build with
1722 @code{--enable-libx264}.
1724 libx264 supports an impressive number of features, including 8x8 and
1725 4x4 adaptive spatial transform, adaptive B-frame placement, CAVLC/CABAC
1726 entropy coding, interlacing (MBAFF), lossless mode, psy optimizations
1727 for detail retention (adaptive quantization, psy-RD, psy-trellis).
1729 Many libx264 encoder options are mapped to FFmpeg global codec
1730 options, while unique encoder options are provided through private
1731 options. Additionally the @option{x264opts} and @option{x264-params}
1732 private options allows one to pass a list of key=value tuples as accepted
1733 by the libx264 @code{x264_param_parse} function.
1735 The x264 project website is at
1736 @url{http://www.videolan.org/developers/x264.html}.
1738 The libx264rgb encoder is the same as libx264, except it accepts packed RGB
1739 pixel formats as input instead of YUV.
1741 @subsection Supported Pixel Formats
1743 x264 supports 8- to 10-bit color spaces. The exact bit depth is controlled at
1744 x264's configure time. FFmpeg only supports one bit depth in one particular
1745 build. In other words, it is not possible to build one FFmpeg with multiple
1746 versions of x264 with different bit depths.
1750 The following options are supported by the libx264 wrapper. The
1751 @command{x264}-equivalent options or values are listed in parentheses
1754 To reduce the duplication of documentation, only the private options
1755 and some others requiring special attention are documented here. For
1756 the documentation of the undocumented generic options, see
1757 @ref{codec-options,,the Codec Options chapter}.
1759 To get a more accurate and extensive documentation of the libx264
1760 options, invoke the command @command{x264 --full-help} or consult
1761 the libx264 documentation.
1764 @item b (@emph{bitrate})
1765 Set bitrate in bits/s. Note that FFmpeg's @option{b} option is
1766 expressed in bits/s, while @command{x264}'s @option{bitrate} is in
1769 @item bf (@emph{bframes})
1771 @item g (@emph{keyint})
1773 @item qmin (@emph{qpmin})
1774 Minimum quantizer scale.
1776 @item qmax (@emph{qpmax})
1777 Maximum quantizer scale.
1779 @item qdiff (@emph{qpstep})
1780 Maximum difference between quantizer scales.
1782 @item qblur (@emph{qblur})
1783 Quantizer curve blur
1785 @item qcomp (@emph{qcomp})
1786 Quantizer curve compression factor
1788 @item refs (@emph{ref})
1789 Number of reference frames each P-frame can use. The range is from @var{0-16}.
1791 @item sc_threshold (@emph{scenecut})
1792 Sets the threshold for the scene change detection.
1794 @item trellis (@emph{trellis})
1795 Performs Trellis quantization to increase efficiency. Enabled by default.
1797 @item nr (@emph{nr})
1799 @item me_range (@emph{merange})
1800 Maximum range of the motion search in pixels.
1802 @item me_method (@emph{me})
1803 Set motion estimation method. Possible values in the decreasing order
1807 @item dia (@emph{dia})
1808 @item epzs (@emph{dia})
1809 Diamond search with radius 1 (fastest). @samp{epzs} is an alias for
1811 @item hex (@emph{hex})
1812 Hexagonal search with radius 2.
1813 @item umh (@emph{umh})
1814 Uneven multi-hexagon search.
1815 @item esa (@emph{esa})
1817 @item tesa (@emph{tesa})
1818 Hadamard exhaustive search (slowest).
1821 @item subq (@emph{subme})
1822 Sub-pixel motion estimation method.
1824 @item b_strategy (@emph{b-adapt})
1825 Adaptive B-frame placement decision algorithm. Use only on first-pass.
1827 @item keyint_min (@emph{min-keyint})
1831 Set entropy encoder. Possible values:
1838 Enable CAVLC and disable CABAC. It generates the same effect as
1839 @command{x264}'s @option{--no-cabac} option.
1843 Set full pixel motion estimation comparation algorithm. Possible values:
1847 Enable chroma in motion estimation.
1850 Ignore chroma in motion estimation. It generates the same effect as
1851 @command{x264}'s @option{--no-chroma-me} option.
1854 @item threads (@emph{threads})
1855 Number of encoding threads.
1858 Set multithreading technique. Possible values:
1862 Slice-based multithreading. It generates the same effect as
1863 @command{x264}'s @option{--sliced-threads} option.
1865 Frame-based multithreading.
1869 Set encoding flags. It can be used to disable closed GOP and enable
1870 open GOP by setting it to @code{-cgop}. The result is similar to
1871 the behavior of @command{x264}'s @option{--open-gop} option.
1873 @item rc_init_occupancy (@emph{vbv-init})
1875 @item preset (@emph{preset})
1876 Set the encoding preset.
1878 @item tune (@emph{tune})
1879 Set tuning of the encoding params.
1881 @item profile (@emph{profile})
1882 Set profile restrictions.
1885 Enable fast settings when encoding first pass, when set to 1. When set
1886 to 0, it has the same effect of @command{x264}'s
1887 @option{--slow-firstpass} option.
1889 @item crf (@emph{crf})
1890 Set the quality for constant quality mode.
1892 @item crf_max (@emph{crf-max})
1893 In CRF mode, prevents VBV from lowering quality beyond this point.
1895 @item qp (@emph{qp})
1896 Set constant quantization rate control method parameter.
1898 @item aq-mode (@emph{aq-mode})
1899 Set AQ method. Possible values:
1902 @item none (@emph{0})
1905 @item variance (@emph{1})
1906 Variance AQ (complexity mask).
1908 @item autovariance (@emph{2})
1909 Auto-variance AQ (experimental).
1912 @item aq-strength (@emph{aq-strength})
1913 Set AQ strength, reduce blocking and blurring in flat and textured areas.
1916 Use psychovisual optimizations when set to 1. When set to 0, it has the
1917 same effect as @command{x264}'s @option{--no-psy} option.
1919 @item psy-rd (@emph{psy-rd})
1920 Set strength of psychovisual optimization, in
1921 @var{psy-rd}:@var{psy-trellis} format.
1923 @item rc-lookahead (@emph{rc-lookahead})
1924 Set number of frames to look ahead for frametype and ratecontrol.
1927 Enable weighted prediction for B-frames when set to 1. When set to 0,
1928 it has the same effect as @command{x264}'s @option{--no-weightb} option.
1930 @item weightp (@emph{weightp})
1931 Set weighted prediction method for P-frames. Possible values:
1934 @item none (@emph{0})
1936 @item simple (@emph{1})
1937 Enable only weighted refs
1938 @item smart (@emph{2})
1939 Enable both weighted refs and duplicates
1942 @item ssim (@emph{ssim})
1943 Enable calculation and printing SSIM stats after the encoding.
1945 @item intra-refresh (@emph{intra-refresh})
1946 Enable the use of Periodic Intra Refresh instead of IDR frames when set
1949 @item avcintra-class (@emph{class})
1950 Configure the encoder to generate AVC-Intra.
1951 Valid values are 50,100 and 200
1953 @item bluray-compat (@emph{bluray-compat})
1954 Configure the encoder to be compatible with the bluray standard.
1955 It is a shorthand for setting "bluray-compat=1 force-cfr=1".
1957 @item b-bias (@emph{b-bias})
1958 Set the influence on how often B-frames are used.
1960 @item b-pyramid (@emph{b-pyramid})
1961 Set method for keeping of some B-frames as references. Possible values:
1964 @item none (@emph{none})
1966 @item strict (@emph{strict})
1967 Strictly hierarchical pyramid.
1968 @item normal (@emph{normal})
1969 Non-strict (not Blu-ray compatible).
1973 Enable the use of one reference per partition, as opposed to one
1974 reference per macroblock when set to 1. When set to 0, it has the
1975 same effect as @command{x264}'s @option{--no-mixed-refs} option.
1978 Enable adaptive spatial transform (high profile 8x8 transform)
1979 when set to 1. When set to 0, it has the same effect as
1980 @command{x264}'s @option{--no-8x8dct} option.
1983 Enable early SKIP detection on P-frames when set to 1. When set
1984 to 0, it has the same effect as @command{x264}'s
1985 @option{--no-fast-pskip} option.
1987 @item aud (@emph{aud})
1988 Enable use of access unit delimiters when set to 1.
1991 Enable use macroblock tree ratecontrol when set to 1. When set
1992 to 0, it has the same effect as @command{x264}'s
1993 @option{--no-mbtree} option.
1995 @item deblock (@emph{deblock})
1996 Set loop filter parameters, in @var{alpha}:@var{beta} form.
1998 @item cplxblur (@emph{cplxblur})
1999 Set fluctuations reduction in QP (before curve compression).
2001 @item partitions (@emph{partitions})
2002 Set partitions to consider as a comma-separated list of. Possible
2007 8x8 P-frame partition.
2009 4x4 P-frame partition.
2011 4x4 B-frame partition.
2013 8x8 I-frame partition.
2015 4x4 I-frame partition.
2016 (Enabling @samp{p4x4} requires @samp{p8x8} to be enabled. Enabling
2017 @samp{i8x8} requires adaptive spatial transform (@option{8x8dct}
2018 option) to be enabled.)
2019 @item none (@emph{none})
2020 Do not consider any partitions.
2021 @item all (@emph{all})
2022 Consider every partition.
2025 @item direct-pred (@emph{direct})
2026 Set direct MV prediction mode. Possible values:
2029 @item none (@emph{none})
2030 Disable MV prediction.
2031 @item spatial (@emph{spatial})
2032 Enable spatial predicting.
2033 @item temporal (@emph{temporal})
2034 Enable temporal predicting.
2035 @item auto (@emph{auto})
2036 Automatically decided.
2039 @item slice-max-size (@emph{slice-max-size})
2040 Set the limit of the size of each slice in bytes. If not specified
2041 but RTP payload size (@option{ps}) is specified, that is used.
2043 @item stats (@emph{stats})
2044 Set the file name for multi-pass stats.
2046 @item nal-hrd (@emph{nal-hrd})
2047 Set signal HRD information (requires @option{vbv-bufsize} to be set).
2051 @item none (@emph{none})
2052 Disable HRD information signaling.
2053 @item vbr (@emph{vbr})
2055 @item cbr (@emph{cbr})
2056 Constant bit rate (not allowed in MP4 container).
2059 @item x264opts (N.A.)
2060 Set any x264 option, see @command{x264 --fullhelp} for a list.
2062 Argument is a list of @var{key}=@var{value} couples separated by
2063 ":". In @var{filter} and @var{psy-rd} options that use ":" as a separator
2064 themselves, use "," instead. They accept it as well since long ago but this
2065 is kept undocumented for some reason.
2067 For example to specify libx264 encoding options with @command{ffmpeg}:
2069 ffmpeg -i foo.mpg -vcodec libx264 -x264opts keyint=123:min-keyint=20 -an out.mkv
2072 @item a53cc @var{boolean}
2073 Import closed captions (which must be ATSC compatible format) into output.
2074 Only the mpeg2 and h264 decoders provide these. Default is 0 (off).
2076 @item x264-params (N.A.)
2077 Override the x264 configuration using a :-separated list of key=value
2080 This option is functionally the same as the @option{x264opts}, but is
2081 duplicated for compatibility with the Libav fork.
2083 For example to specify libx264 encoding options with @command{ffmpeg}:
2085 ffmpeg -i INPUT -c:v libx264 -x264-params level=30:bframes=0:weightp=0:\
2086 cabac=0:ref=1:vbv-maxrate=768:vbv-bufsize=2000:analyse=all:me=umh:\
2087 no-fast-pskip=1:subq=6:8x8dct=0:trellis=0 OUTPUT
2091 Encoding ffpresets for common usages are provided so they can be used with the
2092 general presets system (e.g. passing the @option{pre} option).
2096 x265 H.265/HEVC encoder wrapper.
2098 This encoder requires the presence of the libx265 headers and library
2099 during configuration. You need to explicitly configure the build with
2100 @option{--enable-libx265}.
2106 Set the x265 preset.
2109 Set the x265 tune parameter.
2112 Set x265 options using a list of @var{key}=@var{value} couples separated
2113 by ":". See @command{x265 --help} for a list of options.
2115 For example to specify libx265 encoding options with @option{-x265-params}:
2118 ffmpeg -i input -c:v libx265 -x265-params crf=26:psy-rd=1 output.mp4
2124 Xvid MPEG-4 Part 2 encoder wrapper.
2126 This encoder requires the presence of the libxvidcore headers and library
2127 during configuration. You need to explicitly configure the build with
2128 @code{--enable-libxvid --enable-gpl}.
2130 The native @code{mpeg4} encoder supports the MPEG-4 Part 2 format, so
2131 users can encode to this format without this library.
2135 The following options are supported by the libxvid wrapper. Some of
2136 the following options are listed but are not documented, and
2137 correspond to shared codec options. See @ref{codec-options,,the Codec
2138 Options chapter} for their documentation. The other shared options
2139 which are not listed have no effect for the libxvid encoder.
2161 Set specific encoding flags. Possible values:
2166 Use four motion vector by macroblock.
2169 Enable high quality AC prediction.
2172 Only encode grayscale.
2175 Enable the use of global motion compensation (GMC).
2178 Enable quarter-pixel motion compensation.
2184 Place global headers in extradata instead of every keyframe.
2191 Set motion estimation method. Possible values in decreasing order of
2192 speed and increasing order of quality:
2196 Use no motion estimation (default).
2201 Enable advanced diamond zonal search for 16x16 blocks and half-pixel
2202 refinement for 16x16 blocks. @samp{x1} and @samp{log} are aliases for
2206 Enable all of the things described above, plus advanced diamond zonal
2207 search for 8x8 blocks, half-pixel refinement for 8x8 blocks, and motion
2208 estimation on chroma planes.
2211 Enable all of the things described above, plus extended 16x16 and 8x8
2216 Set macroblock decision algorithm. Possible values in the increasing
2221 Use macroblock comparing function algorithm (default).
2224 Enable rate distortion-based half pixel and quarter pixel refinement for
2228 Enable all of the things described above, plus rate distortion-based
2229 half pixel and quarter pixel refinement for 8x8 blocks, and rate
2230 distortion-based search using square pattern.
2234 Enable lumi masking adaptive quantization when set to 1. Default is 0
2238 Enable variance adaptive quantization when set to 1. Default is 0
2241 When combined with @option{lumi_aq}, the resulting quality will not
2242 be better than any of the two specified individually. In other
2243 words, the resulting quality will be the worse one of the two
2247 Set structural similarity (SSIM) displaying method. Possible values:
2251 Disable displaying of SSIM information.
2254 Output average SSIM at the end of encoding to stdout. The format of
2255 showing the average SSIM is:
2261 For users who are not familiar with C, %f means a float number, or
2262 a decimal (e.g. 0.939232).
2265 Output both per-frame SSIM data during encoding and average SSIM at
2266 the end of encoding to stdout. The format of per-frame information
2270 SSIM: avg: %1.3f min: %1.3f max: %1.3f
2273 For users who are not familiar with C, %1.3f means a float number
2274 rounded to 3 digits after the dot (e.g. 0.932).
2279 Set SSIM accuracy. Valid options are integers within the range of
2280 0-4, while 0 gives the most accurate result and 4 computes the
2287 MPEG-2 video encoder.
2292 @item seq_disp_ext @var{integer}
2293 Specifies if the encoder should write a sequence_display_extension to the
2298 Decide automatically to write it or not (this is the default) by checking if
2299 the data to be written is different from the default or unspecified values.
2313 @subsection Private options
2316 @item dpi @var{integer}
2317 Set physical density of pixels, in dots per inch, unset by default
2318 @item dpm @var{integer}
2319 Set physical density of pixels, in dots per meter, unset by default
2324 Apple ProRes encoder.
2326 FFmpeg contains 2 ProRes encoders, the prores-aw and prores-ks encoder.
2327 The used encoder can be chosen with the @code{-vcodec} option.
2329 @subsection Private Options for prores-ks
2332 @item profile @var{integer}
2333 Select the ProRes profile to encode
2342 @item quant_mat @var{integer}
2343 Select quantization matrix.
2352 If set to @var{auto}, the matrix matching the profile will be picked.
2353 If not set, the matrix providing the highest quality, @var{default}, will be
2356 @item bits_per_mb @var{integer}
2357 How many bits to allot for coding one macroblock. Different profiles use
2358 between 200 and 2400 bits per macroblock, the maximum is 8000.
2360 @item mbs_per_slice @var{integer}
2361 Number of macroblocks in each slice (1-8); the default value (8)
2362 should be good in almost all situations.
2364 @item vendor @var{string}
2365 Override the 4-byte vendor ID.
2366 A custom vendor ID like @var{apl0} would claim the stream was produced by
2369 @item alpha_bits @var{integer}
2370 Specify number of bits for alpha component.
2371 Possible values are @var{0}, @var{8} and @var{16}.
2372 Use @var{0} to disable alpha plane coding.
2376 @subsection Speed considerations
2378 In the default mode of operation the encoder has to honor frame constraints
2379 (i.e. not produce frames with size bigger than requested) while still making
2380 output picture as good as possible.
2381 A frame containing a lot of small details is harder to compress and the encoder
2382 would spend more time searching for appropriate quantizers for each slice.
2384 Setting a higher @option{bits_per_mb} limit will improve the speed.
2386 For the fastest encoding speed set the @option{qscale} parameter (4 is the
2387 recommended value) and do not set a size constraint.
2391 Kvazaar H.265/HEVC encoder.
2393 Requires the presence of the libkvazaar headers and library during
2394 configuration. You need to explicitly configure the build with
2395 @option{--enable-libkvazaar}.
2402 Set target video bitrate in bit/s and enable rate control.
2404 @item kvazaar-params
2405 Set kvazaar parameters as a list of @var{name}=@var{value} pairs separated
2406 by commas (,). See kvazaar documentation for a list of options.
2410 @c man end VIDEO ENCODERS
2412 @chapter Subtitles Encoders
2413 @c man begin SUBTITLES ENCODERS
2417 This codec encodes the bitmap subtitle format that is used in DVDs.
2418 Typically they are stored in VOBSUB file pairs (*.idx + *.sub),
2419 and they can also be used in Matroska files.
2425 When set to 1, enable a work-around that makes the number of pixel rows
2426 even in all subtitles. This fixes a problem with some players that
2427 cut off the bottom row if the number is odd. The work-around just adds
2428 a fully transparent row if needed. The overhead is low, typically
2429 one byte per subtitle on average.
2431 By default, this work-around is disabled.
2434 @c man end SUBTITLES ENCODERS