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 the default AAC encoder, natively implemented into FFmpeg. Its
34 quality is on par or better than libfdk_aac at the default bitrate of 128kbps.
35 This encoder also implements more options, profiles and samplerates than
36 other encoders (with only the AAC-HE profile pending to be implemented) so this
37 encoder has become the default and is the recommended choice.
43 Set bit rate in bits/s. Setting this automatically activates constant bit rate
44 (CBR) mode. If this option is unspecified it is set to 128kbps.
47 Set quality for variable bit rate (VBR) mode. This option is valid only using
48 the @command{ffmpeg} command-line tool. For library interface users, use
49 @option{global_quality}.
52 Set cutoff frequency. If unspecified will allow the encoder to dynamically
53 adjust the cutoff to improve clarity on low bitrates.
56 Set AAC encoder coding method. Possible values:
60 Two loop searching (TLS) method.
62 This method first sets quantizers depending on band thresholds and then tries
63 to find an optimal combination by adding or subtracting a specific value from
64 all quantizers and adjusting some individual quantizer a little. Will tune
65 itself based on whether @option{aac_is}, @option{aac_ms} and @option{aac_pns}
69 Average noise to mask ratio (ANMR) trellis-based solution.
71 This is an experimental coder which currently produces a lower quality, is more
72 unstable and is slower than the default twoloop coder but has potential.
73 Currently has no support for the @option{aac_is} or @option{aac_pns} options.
74 Not currently recommended.
77 Constant quantizer method.
79 Uses a cheaper version of twoloop algorithm that doesn't try to do as many
80 clever adjustments. Worse with low bitrates (less than 64kbps), but is better
81 and much faster at higher bitrates.
82 This is the default choice for a coder
87 Sets mid/side coding mode. The default value of "auto" will automatically use
88 M/S with bands which will benefit from such coding. Can be forced for all bands
89 using the value "enable", which is mainly useful for debugging or disabled using
93 Sets intensity stereo coding tool usage. By default, it's enabled and will
94 automatically toggle IS for similar pairs of stereo bands if it's beneficial.
95 Can be disabled for debugging by setting the value to "disable".
98 Uses perceptual noise substitution to replace low entropy high frequency bands
99 with imperceptible white noise during the decoding process. By default, it's
100 enabled, but can be disabled for debugging purposes by using "disable".
103 Enables the use of a multitap FIR filter which spans through the high frequency
104 bands to hide quantization noise during the encoding process and is reverted
105 by the decoder. As well as decreasing unpleasant artifacts in the high range
106 this also reduces the entropy in the high bands and allows for more bits to
107 be used by the mid-low bands. By default it's enabled but can be disabled for
108 debugging by setting the option to "disable".
111 Enables the use of the long term prediction extension which increases coding
112 efficiency in very low bandwidth situations such as encoding of voice or
113 solo piano music by extending constant harmonic peaks in bands throughout
114 frames. This option is implied by profile:a aac_low and is incompatible with
115 aac_pred. Use in conjunction with @option{-ar} to decrease the samplerate.
118 Enables the use of a more traditional style of prediction where the spectral
119 coefficients transmitted are replaced by the difference of the current
120 coefficients minus the previous "predicted" coefficients. In theory and sometimes
121 in practice this can improve quality for low to mid bitrate audio.
122 This option implies the aac_main profile and is incompatible with aac_ltp.
125 Sets the encoding profile, possible values:
129 The default, AAC "Low-complexity" profile. Is the most compatible and produces
133 Equivalent to @code{-profile:a aac_low -aac_pns 0}. PNS was introduced with the
134 MPEG4 specifications.
137 Long term prediction profile, is enabled by and will enable the @option{aac_ltp}
138 option. Introduced in MPEG4.
141 Main-type prediction profile, is enabled by and will enable the @option{aac_pred}
142 option. Introduced in MPEG2.
145 If this option is unspecified it is set to @samp{aac_low}.
148 @section ac3 and ac3_fixed
152 These encoders implement part of ATSC A/52:2010 and ETSI TS 102 366, as well as
153 the undocumented RealAudio 3 (a.k.a. dnet).
155 The @var{ac3} encoder uses floating-point math, while the @var{ac3_fixed}
156 encoder only uses fixed-point integer math. This does not mean that one is
157 always faster, just that one or the other may be better suited to a
158 particular system. The floating-point encoder will generally produce better
159 quality audio for a given bitrate. The @var{ac3_fixed} encoder is not the
160 default codec for any of the output formats, so it must be specified explicitly
161 using the option @code{-acodec ac3_fixed} in order to use it.
163 @subsection AC-3 Metadata
165 The AC-3 metadata options are used to set parameters that describe the audio,
166 but in most cases do not affect the audio encoding itself. Some of the options
167 do directly affect or influence the decoding and playback of the resulting
168 bitstream, while others are just for informational purposes. A few of the
169 options will add bits to the output stream that could otherwise be used for
170 audio data, and will thus affect the quality of the output. Those will be
171 indicated accordingly with a note in the option list below.
173 These parameters are described in detail in several publicly-available
176 @item @uref{http://www.atsc.org/cms/standards/a_52-2010.pdf,A/52:2010 - Digital Audio Compression (AC-3) (E-AC-3) Standard}
177 @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}
178 @item @uref{http://www.dolby.com/uploadedFiles/zz-_Shared_Assets/English_PDFs/Professional/18_Metadata.Guide.pdf,Dolby Metadata Guide}
179 @item @uref{http://www.dolby.com/uploadedFiles/zz-_Shared_Assets/English_PDFs/Professional/46_DDEncodingGuidelines.pdf,Dolby Digital Professional Encoding Guidelines}
182 @subsubsection Metadata Control Options
186 @item -per_frame_metadata @var{boolean}
187 Allow Per-Frame Metadata. Specifies if the encoder should check for changing
188 metadata for each frame.
191 The metadata values set at initialization will be used for every frame in the
194 Metadata values can be changed before encoding each frame.
199 @subsubsection Downmix Levels
203 @item -center_mixlev @var{level}
204 Center Mix Level. The amount of gain the decoder should apply to the center
205 channel when downmixing to stereo. This field will only be written to the
206 bitstream if a center channel is present. The value is specified as a scale
207 factor. There are 3 valid values:
212 Apply -4.5dB gain (default)
217 @item -surround_mixlev @var{level}
218 Surround Mix Level. The amount of gain the decoder should apply to the surround
219 channel(s) when downmixing to stereo. This field will only be written to the
220 bitstream if one or more surround channels are present. The value is specified
221 as a scale factor. There are 3 valid values:
226 Apply -6dB gain (default)
228 Silence Surround Channel(s)
233 @subsubsection Audio Production Information
234 Audio Production Information is optional information describing the mixing
235 environment. Either none or both of the fields are written to the bitstream.
239 @item -mixing_level @var{number}
240 Mixing Level. Specifies peak sound pressure level (SPL) in the production
241 environment when the mix was mastered. Valid values are 80 to 111, or -1 for
242 unknown or not indicated. The default value is -1, but that value cannot be
243 used if the Audio Production Information is written to the bitstream. Therefore,
244 if the @code{room_type} option is not the default value, the @code{mixing_level}
245 option must not be -1.
247 @item -room_type @var{type}
248 Room Type. Describes the equalization used during the final mixing session at
249 the studio or on the dubbing stage. A large room is a dubbing stage with the
250 industry standard X-curve equalization; a small room has flat equalization.
251 This field will not be written to the bitstream if both the @code{mixing_level}
252 option and the @code{room_type} option have the default values.
256 Not Indicated (default)
267 @subsubsection Other Metadata Options
271 @item -copyright @var{boolean}
272 Copyright Indicator. Specifies whether a copyright exists for this audio.
276 No Copyright Exists (default)
282 @item -dialnorm @var{value}
283 Dialogue Normalization. Indicates how far the average dialogue level of the
284 program is below digital 100% full scale (0 dBFS). This parameter determines a
285 level shift during audio reproduction that sets the average volume of the
286 dialogue to a preset level. The goal is to match volume level between program
287 sources. A value of -31dB will result in no volume level change, relative to
288 the source volume, during audio reproduction. Valid values are whole numbers in
289 the range -31 to -1, with -31 being the default.
291 @item -dsur_mode @var{mode}
292 Dolby Surround Mode. Specifies whether the stereo signal uses Dolby Surround
293 (Pro Logic). This field will only be written to the bitstream if the audio
294 stream is stereo. Using this option does @b{NOT} mean the encoder will actually
295 apply Dolby Surround processing.
299 Not Indicated (default)
302 Not Dolby Surround Encoded
305 Dolby Surround Encoded
308 @item -original @var{boolean}
309 Original Bit Stream Indicator. Specifies whether this audio is from the
310 original source and not a copy.
317 Original Source (default)
322 @subsection Extended Bitstream Information
323 The extended bitstream options are part of the Alternate Bit Stream Syntax as
324 specified in Annex D of the A/52:2010 standard. It is grouped into 2 parts.
325 If any one parameter in a group is specified, all values in that group will be
326 written to the bitstream. Default values are used for those that are written
327 but have not been specified. If the mixing levels are written, the decoder
328 will use these values instead of the ones specified in the @code{center_mixlev}
329 and @code{surround_mixlev} options if it supports the Alternate Bit Stream
332 @subsubsection Extended Bitstream Information - Part 1
336 @item -dmix_mode @var{mode}
337 Preferred Stereo Downmix Mode. Allows the user to select either Lt/Rt
338 (Dolby Surround) or Lo/Ro (normal stereo) as the preferred stereo downmix mode.
342 Not Indicated (default)
345 Lt/Rt Downmix Preferred
348 Lo/Ro Downmix Preferred
351 @item -ltrt_cmixlev @var{level}
352 Lt/Rt Center Mix Level. The amount of gain the decoder should apply to the
353 center channel when downmixing to stereo in Lt/Rt mode.
366 Apply -4.5dB gain (default)
370 Silence Center Channel
373 @item -ltrt_surmixlev @var{level}
374 Lt/Rt Surround Mix Level. The amount of gain the decoder should apply to the
375 surround channel(s) when downmixing to stereo in Lt/Rt mode.
384 Apply -6.0dB gain (default)
386 Silence Surround Channel(s)
389 @item -loro_cmixlev @var{level}
390 Lo/Ro Center Mix Level. The amount of gain the decoder should apply to the
391 center channel when downmixing to stereo in Lo/Ro mode.
404 Apply -4.5dB gain (default)
408 Silence Center Channel
411 @item -loro_surmixlev @var{level}
412 Lo/Ro Surround Mix Level. The amount of gain the decoder should apply to the
413 surround channel(s) when downmixing to stereo in Lo/Ro mode.
422 Apply -6.0dB gain (default)
424 Silence Surround Channel(s)
429 @subsubsection Extended Bitstream Information - Part 2
433 @item -dsurex_mode @var{mode}
434 Dolby Surround EX Mode. Indicates whether the stream uses Dolby Surround EX
435 (7.1 matrixed to 5.1). Using this option does @b{NOT} mean the encoder will actually
436 apply Dolby Surround EX processing.
440 Not Indicated (default)
443 Dolby Surround EX Off
449 @item -dheadphone_mode @var{mode}
450 Dolby Headphone Mode. Indicates whether the stream uses Dolby Headphone
451 encoding (multi-channel matrixed to 2.0 for use with headphones). Using this
452 option does @b{NOT} mean the encoder will actually apply Dolby Headphone
457 Not Indicated (default)
466 @item -ad_conv_type @var{type}
467 A/D Converter Type. Indicates whether the audio has passed through HDCD A/D
472 Standard A/D Converter (default)
480 @subsection Other AC-3 Encoding Options
484 @item -stereo_rematrixing @var{boolean}
485 Stereo Rematrixing. Enables/Disables use of rematrixing for stereo input. This
486 is an optional AC-3 feature that increases quality by selectively encoding
487 the left/right channels as mid/side. This option is enabled by default, and it
488 is highly recommended that it be left as enabled except for testing purposes.
490 @item cutoff @var{frequency}
491 Set lowpass cutoff frequency. If unspecified, the encoder selects a default
492 determined by various other encoding parameters.
496 @subsection Floating-Point-Only AC-3 Encoding Options
498 These options are only valid for the floating-point encoder and do not exist
499 for the fixed-point encoder due to the corresponding features not being
500 implemented in fixed-point.
504 @item -channel_coupling @var{boolean}
505 Enables/Disables use of channel coupling, which is an optional AC-3 feature
506 that increases quality by combining high frequency information from multiple
507 channels into a single channel. The per-channel high frequency information is
508 sent with less accuracy in both the frequency and time domains. This allows
509 more bits to be used for lower frequencies while preserving enough information
510 to reconstruct the high frequencies. This option is enabled by default for the
511 floating-point encoder and should generally be left as enabled except for
512 testing purposes or to increase encoding speed.
516 Selected by Encoder (default)
519 Disable Channel Coupling
522 Enable Channel Coupling
525 @item -cpl_start_band @var{number}
526 Coupling Start Band. Sets the channel coupling start band, from 1 to 15. If a
527 value higher than the bandwidth is used, it will be reduced to 1 less than the
528 coupling end band. If @var{auto} is used, the start band will be determined by
529 the encoder based on the bit rate, sample rate, and channel layout. This option
530 has no effect if channel coupling is disabled.
534 Selected by Encoder (default)
542 FLAC (Free Lossless Audio Codec) Encoder
546 The following options are supported by FFmpeg's flac encoder.
549 @item compression_level
550 Sets the compression level, which chooses defaults for many other options
551 if they are not set explicitly. Valid values are from 0 to 12, 5 is the
555 Sets the size of the frames in samples per channel.
557 @item lpc_coeff_precision
558 Sets the LPC coefficient precision, valid values are from 1 to 15, 15 is the
562 Sets the first stage LPC algorithm
568 fixed LPC coefficients
576 Number of passes to use for Cholesky factorization during LPC analysis
578 @item min_partition_order
579 The minimum partition order
581 @item max_partition_order
582 The maximum partition order
584 @item prediction_order_method
599 The mode is chosen automatically for each frame
601 Channels are independently coded
607 @item exact_rice_parameters
608 Chooses if rice parameters are calculated exactly or approximately.
609 if set to 1 then they are chosen exactly, which slows the code down slightly and
610 improves compression slightly.
612 @item multi_dim_quant
613 Multi Dimensional Quantization. If set to 1 then a 2nd stage LPC algorithm is
614 applied after the first stage to finetune the coefficients. This is quite slow
615 and slightly improves compression.
624 This is a native FFmpeg encoder for the Opus format. Currently its in development and
625 only implements the CELT part of the codec. Its quality is usually worse and at best
626 is equal to the libopus encoder.
632 Set bit rate in bits/s. If unspecified it uses the number of channels and the layout
633 to make a good guess.
636 Sets the maximum delay in milliseconds. Lower delays than 20ms will very quickly
640 @anchor{libfdk-aac-enc}
643 libfdk-aac AAC (Advanced Audio Coding) encoder wrapper.
645 The libfdk-aac library is based on the Fraunhofer FDK AAC code from
648 Requires the presence of the libfdk-aac headers and library during
649 configuration. You need to explicitly configure the build with
650 @code{--enable-libfdk-aac}. The library is also incompatible with GPL,
651 so if you allow the use of GPL, you should configure with
652 @code{--enable-gpl --enable-nonfree --enable-libfdk-aac}.
654 This encoder is considered to produce output on par or worse at 128kbps to the
655 @ref{aacenc,,the native FFmpeg AAC encoder} but can often produce better
656 sounding audio at identical or lower bitrates and has support for the
659 VBR encoding, enabled through the @option{vbr} or @option{flags
660 +qscale} options, is experimental and only works with some
661 combinations of parameters.
663 Support for encoding 7.1 audio is only available with libfdk-aac 0.1.3 or
666 For more information see the fdk-aac project at
667 @url{http://sourceforge.net/p/opencore-amr/fdk-aac/}.
671 The following options are mapped on the shared FFmpeg codec options.
675 Set bit rate in bits/s. If the bitrate is not explicitly specified, it
676 is automatically set to a suitable value depending on the selected
679 In case VBR mode is enabled the option is ignored.
682 Set audio sampling rate (in Hz).
685 Set the number of audio channels.
688 Enable fixed quality, VBR (Variable Bit Rate) mode.
689 Note that VBR is implicitly enabled when the @option{vbr} value is
693 Set cutoff frequency. If not specified (or explicitly set to 0) it
694 will use a value automatically computed by the library. Default value
700 The following profiles are recognized:
703 Low Complexity AAC (LC)
706 High Efficiency AAC (HE-AAC)
709 High Efficiency AAC version 2 (HE-AACv2)
715 Enhanced Low Delay AAC (ELD)
718 If not specified it is set to @samp{aac_low}.
721 The following are private options of the libfdk_aac encoder.
725 Enable afterburner feature if set to 1, disabled if set to 0. This
726 improves the quality but also the required processing power.
731 Enable SBR (Spectral Band Replication) for ELD if set to 1, disabled
737 Set SBR/PS signaling style.
739 It can assume one of the following values:
742 choose signaling implicitly (explicit hierarchical by default,
743 implicit if global header is disabled)
746 implicit backwards compatible signaling
749 explicit SBR, implicit PS signaling
751 @item explicit_hierarchical
752 explicit hierarchical signaling
755 Default value is @samp{default}.
758 Output LATM/LOAS encapsulated data if set to 1, disabled if set to 0.
763 Set StreamMuxConfig and PCE repetition period (in frames) for sending
764 in-band configuration buffers within LATM/LOAS transport layer.
766 Must be a 16-bits non-negative integer.
771 Set VBR mode, from 1 to 5. 1 is lowest quality (though still pretty
772 good) and 5 is highest quality. A value of 0 will disable VBR, and CBR
773 (Constant Bit Rate) is enabled.
775 Currently only the @samp{aac_low} profile supports VBR encoding.
777 VBR modes 1-5 correspond to roughly the following average bit rates:
789 about 80-96 kbps/channel
799 Use @command{ffmpeg} to convert an audio file to VBR AAC in an M4A (MP4)
802 ffmpeg -i input.wav -codec:a libfdk_aac -vbr 3 output.m4a
806 Use @command{ffmpeg} to convert an audio file to CBR 64k kbps AAC, using the
807 High-Efficiency AAC profile:
809 ffmpeg -i input.wav -c:a libfdk_aac -profile:a aac_he -b:a 64k output.m4a
816 LAME (Lame Ain't an MP3 Encoder) MP3 encoder wrapper.
818 Requires the presence of the libmp3lame headers and library during
819 configuration. You need to explicitly configure the build with
820 @code{--enable-libmp3lame}.
822 See @ref{libshine} for a fixed-point MP3 encoder, although with a
827 The following options are supported by the libmp3lame wrapper. The
828 @command{lame}-equivalent of the options are listed in parentheses.
832 Set bitrate expressed in bits/s for CBR or ABR. LAME @code{bitrate} is
833 expressed in kilobits/s.
836 Set constant quality setting for VBR. This option is valid only
837 using the @command{ffmpeg} command-line tool. For library interface
838 users, use @option{global_quality}.
840 @item compression_level (@emph{-q})
841 Set algorithm quality. Valid arguments are integers in the 0-9 range,
842 with 0 meaning highest quality but slowest, and 9 meaning fastest
843 while producing the worst quality.
845 @item cutoff (@emph{--lowpass})
846 Set lowpass cutoff frequency. If unspecified, the encoder dynamically
850 Enable use of bit reservoir when set to 1. Default value is 1. LAME
851 has this enabled by default, but can be overridden by use
852 @option{--nores} option.
854 @item joint_stereo (@emph{-m j})
855 Enable the encoder to use (on a frame by frame basis) either L/R
856 stereo or mid/side stereo. Default value is 1.
858 @item abr (@emph{--abr})
859 Enable the encoder to use ABR when set to 1. The @command{lame}
860 @option{--abr} sets the target bitrate, while this options only
861 tells FFmpeg to use ABR still relies on @option{b} to set bitrate.
865 @section libopencore-amrnb
867 OpenCORE Adaptive Multi-Rate Narrowband encoder.
869 Requires the presence of the libopencore-amrnb headers and library during
870 configuration. You need to explicitly configure the build with
871 @code{--enable-libopencore-amrnb --enable-version3}.
873 This is a mono-only encoder. Officially it only supports 8000Hz sample rate,
874 but you can override it by setting @option{strict} to @samp{unofficial} or
882 Set bitrate in bits per second. Only the following bitrates are supported,
883 otherwise libavcodec will round to the nearest valid bitrate.
897 Allow discontinuous transmission (generate comfort noise) when set to 1. The
898 default value is 0 (disabled).
904 libopus Opus Interactive Audio Codec encoder wrapper.
906 Requires the presence of the libopus headers and library during
907 configuration. You need to explicitly configure the build with
908 @code{--enable-libopus}.
910 @subsection Option Mapping
912 Most libopus options are modelled after the @command{opusenc} utility from
913 opus-tools. The following is an option mapping chart describing options
914 supported by the libopus wrapper, and their @command{opusenc}-equivalent
919 @item b (@emph{bitrate})
920 Set the bit rate in bits/s. FFmpeg's @option{b} option is
921 expressed in bits/s, while @command{opusenc}'s @option{bitrate} in
924 @item vbr (@emph{vbr}, @emph{hard-cbr}, and @emph{cvbr})
925 Set VBR mode. The FFmpeg @option{vbr} option has the following
926 valid arguments, with the @command{opusenc} equivalent options
930 @item off (@emph{hard-cbr})
931 Use constant bit rate encoding.
933 @item on (@emph{vbr})
934 Use variable bit rate encoding (the default).
936 @item constrained (@emph{cvbr})
937 Use constrained variable bit rate encoding.
940 @item compression_level (@emph{comp})
941 Set encoding algorithm complexity. Valid options are integers in
942 the 0-10 range. 0 gives the fastest encodes but lower quality, while 10
943 gives the highest quality but slowest encoding. The default is 10.
945 @item frame_duration (@emph{framesize})
946 Set maximum frame size, or duration of a frame in milliseconds. The
947 argument must be exactly the following: 2.5, 5, 10, 20, 40, 60. Smaller
948 frame sizes achieve lower latency but less quality at a given bitrate.
949 Sizes greater than 20ms are only interesting at fairly low bitrates.
952 @item packet_loss (@emph{expect-loss})
953 Set expected packet loss percentage. The default is 0.
955 @item application (N.A.)
956 Set intended application type. Valid options are listed below:
960 Favor improved speech intelligibility.
962 Favor faithfulness to the input (the default).
964 Restrict to only the lowest delay modes.
968 Set cutoff bandwidth in Hz. The argument must be exactly one of the
969 following: 4000, 6000, 8000, 12000, or 20000, corresponding to
970 narrowband, mediumband, wideband, super wideband, and fullband
971 respectively. The default is 0 (cutoff disabled).
973 @item mapping_family (@emph{mapping_family})
974 Set channel mapping family to be used by the encoder. The default value of -1
975 uses mapping family 0 for mono and stereo inputs, and mapping family 1
976 otherwise. The default also disables the surround masking and LFE bandwidth
977 optimzations in libopus, and requires that the input contains 8 channels or
980 Other values include 0 for mono and stereo, 1 for surround sound with masking
981 and LFE bandwidth optimizations, and 255 for independent streams with an
982 unspecified channel layout.
984 @item apply_phase_inv (N.A.) (requires libopus >= 1.2)
985 If set to 0, disables the use of phase inversion for intensity stereo,
986 improving the quality of mono downmixes, but slightly reducing normal stereo
987 quality. The default is 1 (phase inversion enabled).
994 Shine Fixed-Point MP3 encoder wrapper.
996 Shine is a fixed-point MP3 encoder. It has a far better performance on
997 platforms without an FPU, e.g. armel CPUs, and some phones and tablets.
998 However, as it is more targeted on performance than quality, it is not on par
999 with LAME and other production-grade encoders quality-wise. Also, according to
1000 the project's homepage, this encoder may not be free of bugs as the code was
1001 written a long time ago and the project was dead for at least 5 years.
1003 This encoder only supports stereo and mono input. This is also CBR-only.
1005 The original project (last updated in early 2007) is at
1006 @url{http://sourceforge.net/projects/libshine-fxp/}. We only support the
1007 updated fork by the Savonet/Liquidsoap project at @url{https://github.com/savonet/shine}.
1009 Requires the presence of the libshine headers and library during
1010 configuration. You need to explicitly configure the build with
1011 @code{--enable-libshine}.
1013 See also @ref{libmp3lame}.
1017 The following options are supported by the libshine wrapper. The
1018 @command{shineenc}-equivalent of the options are listed in parentheses.
1022 Set bitrate expressed in bits/s for CBR. @command{shineenc} @option{-b} option
1023 is expressed in kilobits/s.
1029 TwoLAME MP2 encoder wrapper.
1031 Requires the presence of the libtwolame headers and library during
1032 configuration. You need to explicitly configure the build with
1033 @code{--enable-libtwolame}.
1037 The following options are supported by the libtwolame wrapper. The
1038 @command{twolame}-equivalent options follow the FFmpeg ones and are in
1043 Set bitrate expressed in bits/s for CBR. @command{twolame} @option{b}
1044 option is expressed in kilobits/s. Default value is 128k.
1047 Set quality for experimental VBR support. Maximum value range is
1048 from -50 to 50, useful range is from -10 to 10. The higher the
1049 value, the better the quality. This option is valid only using the
1050 @command{ffmpeg} command-line tool. For library interface users,
1051 use @option{global_quality}.
1053 @item mode (@emph{--mode})
1054 Set the mode of the resulting audio. Possible values:
1058 Choose mode automatically based on the input. This is the default.
1069 @item psymodel (@emph{--psyc-mode})
1070 Set psychoacoustic model to use in encoding. The argument must be
1071 an integer between -1 and 4, inclusive. The higher the value, the
1072 better the quality. The default value is 3.
1074 @item energy_levels (@emph{--energy})
1075 Enable energy levels extensions when set to 1. The default value is
1078 @item error_protection (@emph{--protect})
1079 Enable CRC error protection when set to 1. The default value is 0
1082 @item copyright (@emph{--copyright})
1083 Set MPEG audio copyright flag when set to 1. The default value is 0
1086 @item original (@emph{--original})
1087 Set MPEG audio original flag when set to 1. The default value is 0
1092 @section libvo-amrwbenc
1094 VisualOn Adaptive Multi-Rate Wideband encoder.
1096 Requires the presence of the libvo-amrwbenc headers and library during
1097 configuration. You need to explicitly configure the build with
1098 @code{--enable-libvo-amrwbenc --enable-version3}.
1100 This is a mono-only encoder. Officially it only supports 16000Hz sample
1101 rate, but you can override it by setting @option{strict} to
1102 @samp{unofficial} or lower.
1109 Set bitrate in bits/s. Only the following bitrates are supported, otherwise
1110 libavcodec will round to the nearest valid bitrate.
1125 Allow discontinuous transmission (generate comfort noise) when set to 1. The
1126 default value is 0 (disabled).
1132 libvorbis encoder wrapper.
1134 Requires the presence of the libvorbisenc headers and library during
1135 configuration. You need to explicitly configure the build with
1136 @code{--enable-libvorbis}.
1140 The following options are supported by the libvorbis wrapper. The
1141 @command{oggenc}-equivalent of the options are listed in parentheses.
1143 To get a more accurate and extensive documentation of the libvorbis
1144 options, consult the libvorbisenc's and @command{oggenc}'s documentations.
1145 See @url{http://xiph.org/vorbis/},
1146 @url{http://wiki.xiph.org/Vorbis-tools}, and oggenc(1).
1150 Set bitrate expressed in bits/s for ABR. @command{oggenc} @option{-b} is
1151 expressed in kilobits/s.
1154 Set constant quality setting for VBR. The value should be a float
1155 number in the range of -1.0 to 10.0. The higher the value, the better
1156 the quality. The default value is @samp{3.0}.
1158 This option is valid only using the @command{ffmpeg} command-line tool.
1159 For library interface users, use @option{global_quality}.
1161 @item cutoff (@emph{--advanced-encode-option lowpass_frequency=N})
1162 Set cutoff bandwidth in Hz, a value of 0 disables cutoff. @command{oggenc}'s
1163 related option is expressed in kHz. The default value is @samp{0} (cutoff
1166 @item minrate (@emph{-m})
1167 Set minimum bitrate expressed in bits/s. @command{oggenc} @option{-m} is
1168 expressed in kilobits/s.
1170 @item maxrate (@emph{-M})
1171 Set maximum bitrate expressed in bits/s. @command{oggenc} @option{-M} is
1172 expressed in kilobits/s. This only has effect on ABR mode.
1174 @item iblock (@emph{--advanced-encode-option impulse_noisetune=N})
1175 Set noise floor bias for impulse blocks. The value is a float number from
1176 -15.0 to 0.0. A negative bias instructs the encoder to pay special attention
1177 to the crispness of transients in the encoded audio. The tradeoff for better
1178 transient response is a higher bitrate.
1185 A wrapper providing WavPack encoding through libwavpack.
1187 Only lossless mode using 32-bit integer samples is supported currently.
1189 Requires the presence of the libwavpack headers and library during
1190 configuration. You need to explicitly configure the build with
1191 @code{--enable-libwavpack}.
1193 Note that a libavcodec-native encoder for the WavPack codec exists so users can
1194 encode audios with this codec without using this encoder. See @ref{wavpackenc}.
1198 @command{wavpack} command line utility's corresponding options are listed in
1199 parentheses, if any.
1202 @item frame_size (@emph{--blocksize})
1205 @item compression_level
1206 Set speed vs. compression tradeoff. Acceptable arguments are listed below:
1213 Normal (default) settings.
1218 @item 3 (@emph{-hh})
1221 @item 4-8 (@emph{-hh -x}@var{EXTRAPROC})
1222 Same as @samp{3}, but with extra processing enabled.
1224 @samp{4} is the same as @option{-x2} and @samp{8} is the same as @option{-x6}.
1232 Motion JPEG encoder.
1238 Set the huffman encoding strategy. Possible values:
1242 Use the default huffman tables. This is the default strategy.
1245 Compute and use optimal huffman tables.
1253 WavPack lossless audio encoder.
1255 This is a libavcodec-native WavPack encoder. There is also an encoder based on
1256 libwavpack, but there is virtually no reason to use that encoder.
1258 See also @ref{libwavpack}.
1262 The equivalent options for @command{wavpack} command line utility are listed in
1265 @subsubsection Shared options
1267 The following shared options are effective for this encoder. Only special notes
1268 about this particular encoder will be documented here. For the general meaning
1269 of the options, see @ref{codec-options,,the Codec Options chapter}.
1272 @item frame_size (@emph{--blocksize})
1273 For this encoder, the range for this option is between 128 and 131072. Default
1274 is automatically decided based on sample rate and number of channel.
1276 For the complete formula of calculating default, see
1277 @file{libavcodec/wavpackenc.c}.
1279 @item compression_level (@emph{-f}, @emph{-h}, @emph{-hh}, and @emph{-x})
1280 This option's syntax is consistent with @ref{libwavpack}'s.
1283 @subsubsection Private options
1286 @item joint_stereo (@emph{-j})
1287 Set whether to enable joint stereo. Valid values are:
1291 Force mid/side audio encoding.
1292 @item off (@emph{0})
1293 Force left/right audio encoding.
1295 Let the encoder decide automatically.
1299 Set whether to enable optimization for mono. This option is only effective for
1300 non-mono streams. Available values:
1311 @c man end AUDIO ENCODERS
1313 @chapter Video Encoders
1314 @c man begin VIDEO ENCODERS
1316 A description of some of the currently available video encoders
1321 Vidvox Hap video encoder.
1326 @item format @var{integer}
1327 Specifies the Hap format to encode.
1335 Default value is @option{hap}.
1337 @item chunks @var{integer}
1338 Specifies the number of chunks to split frames into, between 1 and 64. This
1339 permits multithreaded decoding of large frames, potentially at the cost of
1340 data-rate. The encoder may modify this value to divide frames evenly.
1342 Default value is @var{1}.
1344 @item compressor @var{integer}
1345 Specifies the second-stage compressor to use. If set to @option{none},
1346 @option{chunks} will be limited to 1, as chunked uncompressed frames offer no
1354 Default value is @option{snappy}.
1360 The native jpeg 2000 encoder is lossy by default, the @code{-q:v}
1361 option can be used to set the encoding quality. Lossless encoding
1362 can be selected with @code{-pred 1}.
1368 Can be set to either @code{j2k} or @code{jp2} (the default) that
1369 makes it possible to store non-rgb pix_fmts.
1375 libaom AV1 encoder wrapper.
1377 Requires the presence of the libaom headers and library during
1378 configuration. You need to explicitly configure the build with
1379 @code{--enable-libaom}.
1383 The wrapper supports the following standard libavcodec options:
1388 Set bitrate target in bits/second. By default this will use
1389 variable-bitrate mode. If @option{maxrate} and @option{minrate} are
1390 also set to the same value then it will use constant-bitrate mode,
1391 otherwise if @option{crf} is set as well then it will use
1392 constrained-quality mode.
1395 Set key frame placement. The GOP size sets the maximum distance between
1396 key frames; if zero the output stream will be intra-only. The minimum
1397 distance is ignored unless it is the same as the GOP size, in which case
1398 key frames will always appear at a fixed interval. Not set by default,
1399 so without this option the library has completely free choice about
1400 where to place key frames.
1403 Set minimum/maximum quantisation values. Valid range is from 0 to 63
1404 (warning: this does not match the quantiser values actually used by AV1
1405 - divide by four to map real quantiser values to this range). Defaults
1406 to min/max (no constraint).
1408 @item minrate maxrate bufsize rc_init_occupancy
1409 Set rate control buffering parameters. Not used if not set - defaults
1410 to unconstrained variable bitrate.
1413 Set the number of threads to use while encoding. This may require the
1414 @option{tiles} or @option{row-mt} options to also be set to actually
1415 use the specified number of threads fully. Defaults to the number of
1416 hardware threads supported by the host machine.
1419 Set the encoding profile. Defaults to using the profile which matches
1420 the bit depth and chroma subsampling of the input.
1424 The wrapper also has some specific options:
1429 Set the quality/encoding speed tradeoff. Valid range is from 0 to 8,
1430 higher numbers indicating greater speed and lower quality. The default
1431 value is 1, which will be slow and high quality.
1434 Enable use of alternate reference frames. Defaults to the internal
1435 default of the library.
1437 @item arnr-max-frames (@emph{frames})
1438 Set altref noise reduction max frame count. Default is -1.
1440 @item arnr-strength (@emph{strength})
1441 Set altref noise reduction filter strength. Range is -1 to 6. Default is -1.
1443 @item aq-mode (@emph{aq-mode})
1444 Set adaptive quantization mode. Possible values:
1447 @item none (@emph{0})
1450 @item variance (@emph{1})
1453 @item complexity (@emph{2})
1456 @item cyclic (@emph{3})
1461 Set the maximum number of frames which the encoder may keep in flight
1462 at any one time for lookahead purposes. Defaults to the internal
1463 default of the library.
1465 @item error-resilience
1466 Enable error resilience features:
1469 Improve resilience against losses of whole frames.
1471 Not enabled by default.
1474 Set the quality/size tradeoff for constant-quality (no bitrate target)
1475 and constrained-quality (with maximum bitrate target) modes. Valid
1476 range is 0 to 63, higher numbers indicating lower quality and smaller
1477 output size. Only used if set; by default only the bitrate target is
1481 Set a change threshold on blocks below which they will be skipped by
1482 the encoder. Defined in arbitrary units as a nonnegative integer,
1483 defaulting to zero (no blocks are skipped).
1485 @item drop-threshold
1486 Set a threshold for dropping frames when close to rate control bounds.
1487 Defined as a percentage of the target buffer - when the rate control
1488 buffer falls below this percentage, frames will be dropped until it
1489 has refilled above the threshold. Defaults to zero (no frames are
1492 @item denoise-noise-level (@emph{level})
1493 Amount of noise to be removed for grain synthesis. Grain synthesis is disabled if
1494 this option is not set or set to 0.
1496 @item denoise-block-size (@emph{pixels})
1497 Block size used for denoising for grain synthesis. If not set, AV1 codec
1498 uses the default value of 32.
1500 @item undershoot-pct (@emph{pct})
1501 Set datarate undershoot (min) percentage of the target bitrate. Range is -1 to 100.
1504 @item overshoot-pct (@emph{pct})
1505 Set datarate overshoot (max) percentage of the target bitrate. Range is -1 to 1000.
1508 @item minsection-pct (@emph{pct})
1509 Minimum percentage variation of the GOP bitrate from the target bitrate. If minsection-pct
1510 is not set, the libaomenc wrapper computes it as follows: @code{(minrate * 100 / bitrate)}.
1511 Range is -1 to 100. Default is -1 (unset).
1513 @item maxsection-pct (@emph{pct})
1514 Maximum percentage variation of the GOP bitrate from the target bitrate. If maxsection-pct
1515 is not set, the libaomenc wrapper computes it as follows: @code{(maxrate * 100 / bitrate)}.
1516 Range is -1 to 5000. Default is -1 (unset).
1518 @item frame-parallel (@emph{boolean})
1519 Enable frame parallel decodability features. Default is true.
1522 Set the number of tiles to encode the input video with, as columns x
1523 rows. Larger numbers allow greater parallelism in both encoding and
1524 decoding, but may decrease coding efficiency. Defaults to the minimum
1525 number of tiles required by the size of the input video (this is 1x1
1526 (that is, a single tile) for sizes up to and including 4K).
1528 @item tile-columns tile-rows
1529 Set the number of tiles as log2 of the number of tile rows and columns.
1530 Provided for compatibility with libvpx/VP9.
1532 @item row-mt (Requires libaom >= 1.0.0-759-g90a15f4f2)
1533 Enable row based multi-threading. Disabled by default.
1535 @item enable-cdef (@emph{boolean})
1536 Enable Constrained Directional Enhancement Filter. The libaom-av1
1537 encoder enables CDEF by default.
1539 @item enable-global-motion (@emph{boolean})
1540 Enable the use of global motion for block prediction. Default is true.
1542 @item enable-intrabc (@emph{boolean})
1543 Enable block copy mode for intra block prediction. This mode is
1544 useful for screen content. Default is true.
1550 Kvazaar H.265/HEVC encoder.
1552 Requires the presence of the libkvazaar headers and library during
1553 configuration. You need to explicitly configure the build with
1554 @option{--enable-libkvazaar}.
1561 Set target video bitrate in bit/s and enable rate control.
1563 @item kvazaar-params
1564 Set kvazaar parameters as a list of @var{name}=@var{value} pairs separated
1565 by commas (,). See kvazaar documentation for a list of options.
1569 @section libopenh264
1571 Cisco libopenh264 H.264/MPEG-4 AVC encoder wrapper.
1573 This encoder requires the presence of the libopenh264 headers and
1574 library during configuration. You need to explicitly configure the
1575 build with @code{--enable-libopenh264}. The library is detected using
1576 @command{pkg-config}.
1578 For more information about the library see
1579 @url{http://www.openh264.org}.
1583 The following FFmpeg global options affect the configurations of the
1584 libopenh264 encoder.
1588 Set the bitrate (as a number of bits per second).
1594 Set the max bitrate (as a number of bits per second).
1596 @item flags +global_header
1597 Set global header in the bitstream.
1600 Set the number of slices, used in parallelized encoding. Default value
1601 is 0. This is only used when @option{slice_mode} is set to
1605 Set slice mode. Can assume one of the following possible values:
1609 a fixed number of slices
1611 one slice per row of macroblocks
1613 automatic number of slices according to number of threads
1618 Default value is @samp{auto}.
1621 Enable loop filter, if set to 1 (automatically enabled). To disable
1625 Set profile restrictions. If set to the value of @samp{main} enable
1626 CABAC (set the @code{SEncParamExt.iEntropyCodingModeFlag} flag to 1).
1629 Set maximum NAL size in bytes.
1631 @item allow_skip_frames
1632 Allow skipping frames to hit the target bitrate if set to 1.
1637 libtheora Theora encoder wrapper.
1639 Requires the presence of the libtheora headers and library during
1640 configuration. You need to explicitly configure the build with
1641 @code{--enable-libtheora}.
1643 For more information about the libtheora project see
1644 @url{http://www.theora.org/}.
1648 The following global options are mapped to internal libtheora options
1649 which affect the quality and the bitrate of the encoded stream.
1653 Set the video bitrate in bit/s for CBR (Constant Bit Rate) mode. In
1654 case VBR (Variable Bit Rate) mode is enabled this option is ignored.
1657 Used to enable constant quality mode (VBR) encoding through the
1658 @option{qscale} flag, and to enable the @code{pass1} and @code{pass2}
1664 @item global_quality
1665 Set the global quality as an integer in lambda units.
1667 Only relevant when VBR mode is enabled with @code{flags +qscale}. The
1668 value is converted to QP units by dividing it by @code{FF_QP2LAMBDA},
1669 clipped in the [0 - 10] range, and then multiplied by 6.3 to get a
1670 value in the native libtheora range [0-63]. A higher value corresponds
1671 to a higher quality.
1674 Enable VBR mode when set to a non-negative value, and set constant
1675 quality value as a double floating point value in QP units.
1677 The value is clipped in the [0-10] range, and then multiplied by 6.3
1678 to get a value in the native libtheora range [0-63].
1680 This option is valid only using the @command{ffmpeg} command-line
1681 tool. For library interface users, use @option{global_quality}.
1684 @subsection Examples
1688 Set maximum constant quality (VBR) encoding with @command{ffmpeg}:
1690 ffmpeg -i INPUT -codec:v libtheora -q:v 10 OUTPUT.ogg
1694 Use @command{ffmpeg} to convert a CBR 1000 kbps Theora video stream:
1696 ffmpeg -i INPUT -codec:v libtheora -b:v 1000k OUTPUT.ogg
1702 VP8/VP9 format supported through libvpx.
1704 Requires the presence of the libvpx headers and library during configuration.
1705 You need to explicitly configure the build with @code{--enable-libvpx}.
1709 The following options are supported by the libvpx wrapper. The
1710 @command{vpxenc}-equivalent options or values are listed in parentheses
1713 To reduce the duplication of documentation, only the private options
1714 and some others requiring special attention are documented here. For
1715 the documentation of the undocumented generic options, see
1716 @ref{codec-options,,the Codec Options chapter}.
1718 To get more documentation of the libvpx options, invoke the command
1719 @command{ffmpeg -h encoder=libvpx}, @command{ffmpeg -h encoder=libvpx-vp9} or
1720 @command{vpxenc --help}. Further information is available in the libvpx API
1725 @item b (@emph{target-bitrate})
1726 Set bitrate in bits/s. Note that FFmpeg's @option{b} option is
1727 expressed in bits/s, while @command{vpxenc}'s @option{target-bitrate} is in
1730 @item g (@emph{kf-max-dist})
1732 @item keyint_min (@emph{kf-min-dist})
1734 @item qmin (@emph{min-q})
1736 @item qmax (@emph{max-q})
1738 @item bufsize (@emph{buf-sz}, @emph{buf-optimal-sz})
1739 Set ratecontrol buffer size (in bits). Note @command{vpxenc}'s options are
1740 specified in milliseconds, the libvpx wrapper converts this value as follows:
1741 @code{buf-sz = bufsize * 1000 / bitrate},
1742 @code{buf-optimal-sz = bufsize * 1000 / bitrate * 5 / 6}.
1744 @item rc_init_occupancy (@emph{buf-initial-sz})
1745 Set number of bits which should be loaded into the rc buffer before decoding
1746 starts. Note @command{vpxenc}'s option is specified in milliseconds, the libvpx
1747 wrapper converts this value as follows:
1748 @code{rc_init_occupancy * 1000 / bitrate}.
1750 @item undershoot-pct
1751 Set datarate undershoot (min) percentage of the target bitrate.
1754 Set datarate overshoot (max) percentage of the target bitrate.
1756 @item skip_threshold (@emph{drop-frame})
1758 @item qcomp (@emph{bias-pct})
1760 @item maxrate (@emph{maxsection-pct})
1761 Set GOP max bitrate in bits/s. Note @command{vpxenc}'s option is specified as a
1762 percentage of the target bitrate, the libvpx wrapper converts this value as
1763 follows: @code{(maxrate * 100 / bitrate)}.
1765 @item minrate (@emph{minsection-pct})
1766 Set GOP min bitrate in bits/s. Note @command{vpxenc}'s option is specified as a
1767 percentage of the target bitrate, the libvpx wrapper converts this value as
1768 follows: @code{(minrate * 100 / bitrate)}.
1770 @item minrate, maxrate, b @emph{end-usage=cbr}
1771 @code{(minrate == maxrate == bitrate)}.
1773 @item crf (@emph{end-usage=cq}, @emph{cq-level})
1775 @item tune (@emph{tune})
1777 @item psnr (@emph{psnr})
1778 @item ssim (@emph{ssim})
1781 @item quality, deadline (@emph{deadline})
1784 Use best quality deadline. Poorly named and quite slow, this option should be
1785 avoided as it may give worse quality output than good.
1787 Use good quality deadline. This is a good trade-off between speed and quality
1788 when used with the @option{cpu-used} option.
1790 Use realtime quality deadline.
1793 @item speed, cpu-used (@emph{cpu-used})
1794 Set quality/speed ratio modifier. Higher values speed up the encode at the cost
1797 @item nr (@emph{noise-sensitivity})
1800 Set a change threshold on blocks below which they will be skipped by the
1803 @item slices (@emph{token-parts})
1804 Note that FFmpeg's @option{slices} option gives the total number of partitions,
1805 while @command{vpxenc}'s @option{token-parts} is given as
1806 @code{log2(partitions)}.
1808 @item max-intra-rate
1809 Set maximum I-frame bitrate as a percentage of the target bitrate. A value of 0
1812 @item force_key_frames
1813 @code{VPX_EFLAG_FORCE_KF}
1815 @item Alternate reference frame related
1818 Enable use of alternate reference frames (2-pass only).
1819 Values greater than 1 enable multi-layer alternate reference frames (VP9 only).
1820 @item arnr-maxframes
1821 Set altref noise reduction max frame count.
1823 Set altref noise reduction filter type: backward, forward, centered.
1825 Set altref noise reduction filter strength.
1826 @item rc-lookahead, lag-in-frames (@emph{lag-in-frames})
1827 Set number of frames to look ahead for frametype and ratecontrol.
1830 @item error-resilient
1831 Enable error resiliency features.
1833 @item sharpness @var{integer}
1834 Increase sharpness at the expense of lower PSNR.
1835 The valid range is [0, 7].
1837 @item VP8-specific options
1840 Sets the temporal scalability configuration using a :-separated list of
1841 key=value pairs. For example, to specify temporal scalability parameters
1844 ffmpeg -i INPUT -c:v libvpx -ts-parameters ts_number_layers=3:\
1845 ts_target_bitrate=250000,500000,1000000:ts_rate_decimator=4,2,1:\
1846 ts_periodicity=4:ts_layer_id=0,2,1,2 OUTPUT
1848 Below is a brief explanation of each of the parameters, please
1849 refer to @code{struct vpx_codec_enc_cfg} in @code{vpx/vpx_encoder.h} for more
1852 @item ts_number_layers
1853 Number of temporal coding layers.
1854 @item ts_target_bitrate
1855 Target bitrate for each temporal layer.
1856 @item ts_rate_decimator
1857 Frame rate decimation factor for each temporal layer.
1858 @item ts_periodicity
1859 Length of the sequence defining frame temporal layer membership.
1861 Template defining the membership of frames to temporal layers.
1865 @item VP9-specific options
1868 Enable lossless mode.
1870 Set number of tile columns to use. Note this is given as
1871 @code{log2(tile_columns)}. For example, 8 tile columns would be requested by
1872 setting the @option{tile-columns} option to 3.
1874 Set number of tile rows to use. Note this is given as @code{log2(tile_rows)}.
1875 For example, 4 tile rows would be requested by setting the @option{tile-rows}
1877 @item frame-parallel
1878 Enable frame parallel decodability features.
1880 Set adaptive quantization mode (0: off (default), 1: variance 2: complexity, 3:
1881 cyclic refresh, 4: equator360).
1882 @item colorspace @emph{color-space}
1883 Set input color space. The VP9 bitstream supports signaling the following
1886 @item @samp{rgb} @emph{sRGB}
1887 @item @samp{bt709} @emph{bt709}
1888 @item @samp{unspecified} @emph{unknown}
1889 @item @samp{bt470bg} @emph{bt601}
1890 @item @samp{smpte170m} @emph{smpte170}
1891 @item @samp{smpte240m} @emph{smpte240}
1892 @item @samp{bt2020_ncl} @emph{bt2020}
1894 @item row-mt @var{boolean}
1895 Enable row based multi-threading.
1897 Set content type: default (0), screen (1), film (2).
1898 @item corpus-complexity
1899 Corpus VBR mode is a variant of standard VBR where the complexity distribution
1900 midpoint is passed in rather than calculated for a specific clip or chunk.
1902 The valid range is [0, 10000]. 0 (default) uses standard VBR.
1903 @item enable-tpl @var{boolean}
1904 Enable temporal dependency model.
1909 For more information about libvpx see:
1910 @url{http://www.webmproject.org/}
1914 libwebp WebP Image encoder wrapper
1916 libwebp is Google's official encoder for WebP images. It can encode in either
1917 lossy or lossless mode. Lossy images are essentially a wrapper around a VP8
1918 frame. Lossless images are a separate codec developed by Google.
1920 @subsection Pixel Format
1922 Currently, libwebp only supports YUV420 for lossy and RGB for lossless due
1923 to limitations of the format and libwebp. Alpha is supported for either mode.
1924 Because of API limitations, if RGB is passed in when encoding lossy or YUV is
1925 passed in for encoding lossless, the pixel format will automatically be
1926 converted using functions from libwebp. This is not ideal and is done only for
1933 @item -lossless @var{boolean}
1934 Enables/Disables use of lossless mode. Default is 0.
1936 @item -compression_level @var{integer}
1937 For lossy, this is a quality/speed tradeoff. Higher values give better quality
1938 for a given size at the cost of increased encoding time. For lossless, this is
1939 a size/speed tradeoff. Higher values give smaller size at the cost of increased
1940 encoding time. More specifically, it controls the number of extra algorithms
1941 and compression tools used, and varies the combination of these tools. This
1942 maps to the @var{method} option in libwebp. The valid range is 0 to 6.
1945 @item -qscale @var{float}
1946 For lossy encoding, this controls image quality, 0 to 100. For lossless
1947 encoding, this controls the effort and time spent at compressing more. The
1948 default value is 75. Note that for usage via libavcodec, this option is called
1949 @var{global_quality} and must be multiplied by @var{FF_QP2LAMBDA}.
1951 @item -preset @var{type}
1952 Configuration preset. This does some automatic settings based on the general
1956 Do not use a preset.
1958 Use the encoder default.
1960 Digital picture, like portrait, inner shot
1962 Outdoor photograph, with natural lighting
1964 Hand or line drawing, with high-contrast details
1966 Small-sized colorful images
1973 @section libx264, libx264rgb
1975 x264 H.264/MPEG-4 AVC encoder wrapper.
1977 This encoder requires the presence of the libx264 headers and library
1978 during configuration. You need to explicitly configure the build with
1979 @code{--enable-libx264}.
1981 libx264 supports an impressive number of features, including 8x8 and
1982 4x4 adaptive spatial transform, adaptive B-frame placement, CAVLC/CABAC
1983 entropy coding, interlacing (MBAFF), lossless mode, psy optimizations
1984 for detail retention (adaptive quantization, psy-RD, psy-trellis).
1986 Many libx264 encoder options are mapped to FFmpeg global codec
1987 options, while unique encoder options are provided through private
1988 options. Additionally the @option{x264opts} and @option{x264-params}
1989 private options allows one to pass a list of key=value tuples as accepted
1990 by the libx264 @code{x264_param_parse} function.
1992 The x264 project website is at
1993 @url{http://www.videolan.org/developers/x264.html}.
1995 The libx264rgb encoder is the same as libx264, except it accepts packed RGB
1996 pixel formats as input instead of YUV.
1998 @subsection Supported Pixel Formats
2000 x264 supports 8- to 10-bit color spaces. The exact bit depth is controlled at
2001 x264's configure time. FFmpeg only supports one bit depth in one particular
2002 build. In other words, it is not possible to build one FFmpeg with multiple
2003 versions of x264 with different bit depths.
2007 The following options are supported by the libx264 wrapper. The
2008 @command{x264}-equivalent options or values are listed in parentheses
2011 To reduce the duplication of documentation, only the private options
2012 and some others requiring special attention are documented here. For
2013 the documentation of the undocumented generic options, see
2014 @ref{codec-options,,the Codec Options chapter}.
2016 To get a more accurate and extensive documentation of the libx264
2017 options, invoke the command @command{x264 --fullhelp} or consult
2018 the libx264 documentation.
2021 @item b (@emph{bitrate})
2022 Set bitrate in bits/s. Note that FFmpeg's @option{b} option is
2023 expressed in bits/s, while @command{x264}'s @option{bitrate} is in
2026 @item bf (@emph{bframes})
2028 @item g (@emph{keyint})
2030 @item qmin (@emph{qpmin})
2031 Minimum quantizer scale.
2033 @item qmax (@emph{qpmax})
2034 Maximum quantizer scale.
2036 @item qdiff (@emph{qpstep})
2037 Maximum difference between quantizer scales.
2039 @item qblur (@emph{qblur})
2040 Quantizer curve blur
2042 @item qcomp (@emph{qcomp})
2043 Quantizer curve compression factor
2045 @item refs (@emph{ref})
2046 Number of reference frames each P-frame can use. The range is from @var{0-16}.
2048 @item sc_threshold (@emph{scenecut})
2049 Sets the threshold for the scene change detection.
2051 @item trellis (@emph{trellis})
2052 Performs Trellis quantization to increase efficiency. Enabled by default.
2054 @item nr (@emph{nr})
2056 @item me_range (@emph{merange})
2057 Maximum range of the motion search in pixels.
2059 @item me_method (@emph{me})
2060 Set motion estimation method. Possible values in the decreasing order
2064 @item dia (@emph{dia})
2065 @item epzs (@emph{dia})
2066 Diamond search with radius 1 (fastest). @samp{epzs} is an alias for
2068 @item hex (@emph{hex})
2069 Hexagonal search with radius 2.
2070 @item umh (@emph{umh})
2071 Uneven multi-hexagon search.
2072 @item esa (@emph{esa})
2074 @item tesa (@emph{tesa})
2075 Hadamard exhaustive search (slowest).
2079 Normally, when forcing a I-frame type, the encoder can select any type
2080 of I-frame. This option forces it to choose an IDR-frame.
2082 @item subq (@emph{subme})
2083 Sub-pixel motion estimation method.
2085 @item b_strategy (@emph{b-adapt})
2086 Adaptive B-frame placement decision algorithm. Use only on first-pass.
2088 @item keyint_min (@emph{min-keyint})
2092 Set entropy encoder. Possible values:
2099 Enable CAVLC and disable CABAC. It generates the same effect as
2100 @command{x264}'s @option{--no-cabac} option.
2104 Set full pixel motion estimation comparison algorithm. Possible values:
2108 Enable chroma in motion estimation.
2111 Ignore chroma in motion estimation. It generates the same effect as
2112 @command{x264}'s @option{--no-chroma-me} option.
2115 @item threads (@emph{threads})
2116 Number of encoding threads.
2119 Set multithreading technique. Possible values:
2123 Slice-based multithreading. It generates the same effect as
2124 @command{x264}'s @option{--sliced-threads} option.
2126 Frame-based multithreading.
2130 Set encoding flags. It can be used to disable closed GOP and enable
2131 open GOP by setting it to @code{-cgop}. The result is similar to
2132 the behavior of @command{x264}'s @option{--open-gop} option.
2134 @item rc_init_occupancy (@emph{vbv-init})
2136 @item preset (@emph{preset})
2137 Set the encoding preset.
2139 @item tune (@emph{tune})
2140 Set tuning of the encoding params.
2142 @item profile (@emph{profile})
2143 Set profile restrictions.
2146 Enable fast settings when encoding first pass, when set to 1. When set
2147 to 0, it has the same effect of @command{x264}'s
2148 @option{--slow-firstpass} option.
2150 @item crf (@emph{crf})
2151 Set the quality for constant quality mode.
2153 @item crf_max (@emph{crf-max})
2154 In CRF mode, prevents VBV from lowering quality beyond this point.
2156 @item qp (@emph{qp})
2157 Set constant quantization rate control method parameter.
2159 @item aq-mode (@emph{aq-mode})
2160 Set AQ method. Possible values:
2163 @item none (@emph{0})
2166 @item variance (@emph{1})
2167 Variance AQ (complexity mask).
2169 @item autovariance (@emph{2})
2170 Auto-variance AQ (experimental).
2173 @item aq-strength (@emph{aq-strength})
2174 Set AQ strength, reduce blocking and blurring in flat and textured areas.
2177 Use psychovisual optimizations when set to 1. When set to 0, it has the
2178 same effect as @command{x264}'s @option{--no-psy} option.
2180 @item psy-rd (@emph{psy-rd})
2181 Set strength of psychovisual optimization, in
2182 @var{psy-rd}:@var{psy-trellis} format.
2184 @item rc-lookahead (@emph{rc-lookahead})
2185 Set number of frames to look ahead for frametype and ratecontrol.
2188 Enable weighted prediction for B-frames when set to 1. When set to 0,
2189 it has the same effect as @command{x264}'s @option{--no-weightb} option.
2191 @item weightp (@emph{weightp})
2192 Set weighted prediction method for P-frames. Possible values:
2195 @item none (@emph{0})
2197 @item simple (@emph{1})
2198 Enable only weighted refs
2199 @item smart (@emph{2})
2200 Enable both weighted refs and duplicates
2203 @item ssim (@emph{ssim})
2204 Enable calculation and printing SSIM stats after the encoding.
2206 @item intra-refresh (@emph{intra-refresh})
2207 Enable the use of Periodic Intra Refresh instead of IDR frames when set
2210 @item avcintra-class (@emph{class})
2211 Configure the encoder to generate AVC-Intra.
2212 Valid values are 50,100 and 200
2214 @item bluray-compat (@emph{bluray-compat})
2215 Configure the encoder to be compatible with the bluray standard.
2216 It is a shorthand for setting "bluray-compat=1 force-cfr=1".
2218 @item b-bias (@emph{b-bias})
2219 Set the influence on how often B-frames are used.
2221 @item b-pyramid (@emph{b-pyramid})
2222 Set method for keeping of some B-frames as references. Possible values:
2225 @item none (@emph{none})
2227 @item strict (@emph{strict})
2228 Strictly hierarchical pyramid.
2229 @item normal (@emph{normal})
2230 Non-strict (not Blu-ray compatible).
2234 Enable the use of one reference per partition, as opposed to one
2235 reference per macroblock when set to 1. When set to 0, it has the
2236 same effect as @command{x264}'s @option{--no-mixed-refs} option.
2239 Enable adaptive spatial transform (high profile 8x8 transform)
2240 when set to 1. When set to 0, it has the same effect as
2241 @command{x264}'s @option{--no-8x8dct} option.
2244 Enable early SKIP detection on P-frames when set to 1. When set
2245 to 0, it has the same effect as @command{x264}'s
2246 @option{--no-fast-pskip} option.
2248 @item aud (@emph{aud})
2249 Enable use of access unit delimiters when set to 1.
2252 Enable use macroblock tree ratecontrol when set to 1. When set
2253 to 0, it has the same effect as @command{x264}'s
2254 @option{--no-mbtree} option.
2256 @item deblock (@emph{deblock})
2257 Set loop filter parameters, in @var{alpha}:@var{beta} form.
2259 @item cplxblur (@emph{cplxblur})
2260 Set fluctuations reduction in QP (before curve compression).
2262 @item partitions (@emph{partitions})
2263 Set partitions to consider as a comma-separated list of. Possible
2268 8x8 P-frame partition.
2270 4x4 P-frame partition.
2272 4x4 B-frame partition.
2274 8x8 I-frame partition.
2276 4x4 I-frame partition.
2277 (Enabling @samp{p4x4} requires @samp{p8x8} to be enabled. Enabling
2278 @samp{i8x8} requires adaptive spatial transform (@option{8x8dct}
2279 option) to be enabled.)
2280 @item none (@emph{none})
2281 Do not consider any partitions.
2282 @item all (@emph{all})
2283 Consider every partition.
2286 @item direct-pred (@emph{direct})
2287 Set direct MV prediction mode. Possible values:
2290 @item none (@emph{none})
2291 Disable MV prediction.
2292 @item spatial (@emph{spatial})
2293 Enable spatial predicting.
2294 @item temporal (@emph{temporal})
2295 Enable temporal predicting.
2296 @item auto (@emph{auto})
2297 Automatically decided.
2300 @item slice-max-size (@emph{slice-max-size})
2301 Set the limit of the size of each slice in bytes. If not specified
2302 but RTP payload size (@option{ps}) is specified, that is used.
2304 @item stats (@emph{stats})
2305 Set the file name for multi-pass stats.
2307 @item nal-hrd (@emph{nal-hrd})
2308 Set signal HRD information (requires @option{vbv-bufsize} to be set).
2312 @item none (@emph{none})
2313 Disable HRD information signaling.
2314 @item vbr (@emph{vbr})
2316 @item cbr (@emph{cbr})
2317 Constant bit rate (not allowed in MP4 container).
2320 @item x264opts (N.A.)
2321 Set any x264 option, see @command{x264 --fullhelp} for a list.
2323 Argument is a list of @var{key}=@var{value} couples separated by
2324 ":". In @var{filter} and @var{psy-rd} options that use ":" as a separator
2325 themselves, use "," instead. They accept it as well since long ago but this
2326 is kept undocumented for some reason.
2328 For example to specify libx264 encoding options with @command{ffmpeg}:
2330 ffmpeg -i foo.mpg -c:v libx264 -x264opts keyint=123:min-keyint=20 -an out.mkv
2333 @item a53cc @var{boolean}
2334 Import closed captions (which must be ATSC compatible format) into output.
2335 Only the mpeg2 and h264 decoders provide these. Default is 1 (on).
2337 @item x264-params (N.A.)
2338 Override the x264 configuration using a :-separated list of key=value
2341 This option is functionally the same as the @option{x264opts}, but is
2342 duplicated for compatibility with the Libav fork.
2344 For example to specify libx264 encoding options with @command{ffmpeg}:
2346 ffmpeg -i INPUT -c:v libx264 -x264-params level=30:bframes=0:weightp=0:\
2347 cabac=0:ref=1:vbv-maxrate=768:vbv-bufsize=2000:analyse=all:me=umh:\
2348 no-fast-pskip=1:subq=6:8x8dct=0:trellis=0 OUTPUT
2352 Encoding ffpresets for common usages are provided so they can be used with the
2353 general presets system (e.g. passing the @option{pre} option).
2357 x265 H.265/HEVC encoder wrapper.
2359 This encoder requires the presence of the libx265 headers and library
2360 during configuration. You need to explicitly configure the build with
2361 @option{--enable-libx265}.
2367 Set the x265 preset.
2370 Set the x265 tune parameter.
2373 Set profile restrictions.
2376 Set the quality for constant quality mode.
2379 Normally, when forcing a I-frame type, the encoder can select any type
2380 of I-frame. This option forces it to choose an IDR-frame.
2383 Set x265 options using a list of @var{key}=@var{value} couples separated
2384 by ":". See @command{x265 --help} for a list of options.
2386 For example to specify libx265 encoding options with @option{-x265-params}:
2389 ffmpeg -i input -c:v libx265 -x265-params crf=26:psy-rd=1 output.mp4
2395 xavs2 AVS2-P2/IEEE1857.4 encoder wrapper.
2397 This encoder requires the presence of the libxavs2 headers and library
2398 during configuration. You need to explicitly configure the build with
2399 @option{--enable-libxavs2}.
2401 The following standard libavcodec options are used:
2404 @option{b} / @option{bit_rate}
2406 @option{g} / @option{gop_size}
2408 @option{bf} / @option{max_b_frames}
2411 The encoder also has its own specific options:
2415 @item lcu_row_threads
2416 Set the number of parallel threads for rows from 1 to 8 (default 5).
2419 Set the xavs2 quantization parameter from 1 to 63 (default 34). This is
2420 used to set the initial qp for the first frame.
2423 Set the xavs2 quantization parameter from 1 to 63 (default 34). This is
2424 used to set the qp value under constant-QP mode.
2427 Set the max qp for rate control from 1 to 63 (default 55).
2430 Set the min qp for rate control from 1 to 63 (default 20).
2433 Set the Speed level from 0 to 9 (default 0). Higher is better but slower.
2436 Set the log level from -1 to 3 (default 0). -1: none, 0: error,
2437 1: warning, 2: info, 3: debug.
2440 Set xavs2 options using a list of @var{key}=@var{value} couples separated
2443 For example to specify libxavs2 encoding options with @option{-xavs2-params}:
2446 ffmpeg -i input -c:v libxavs2 -xavs2-params RdoqLevel=0 output.avs2
2452 Xvid MPEG-4 Part 2 encoder wrapper.
2454 This encoder requires the presence of the libxvidcore headers and library
2455 during configuration. You need to explicitly configure the build with
2456 @code{--enable-libxvid --enable-gpl}.
2458 The native @code{mpeg4} encoder supports the MPEG-4 Part 2 format, so
2459 users can encode to this format without this library.
2463 The following options are supported by the libxvid wrapper. Some of
2464 the following options are listed but are not documented, and
2465 correspond to shared codec options. See @ref{codec-options,,the Codec
2466 Options chapter} for their documentation. The other shared options
2467 which are not listed have no effect for the libxvid encoder.
2489 Set specific encoding flags. Possible values:
2494 Use four motion vector by macroblock.
2497 Enable high quality AC prediction.
2500 Only encode grayscale.
2503 Enable the use of global motion compensation (GMC).
2506 Enable quarter-pixel motion compensation.
2512 Place global headers in extradata instead of every keyframe.
2519 Set motion estimation method. Possible values in decreasing order of
2520 speed and increasing order of quality:
2524 Use no motion estimation (default).
2529 Enable advanced diamond zonal search for 16x16 blocks and half-pixel
2530 refinement for 16x16 blocks. @samp{x1} and @samp{log} are aliases for
2534 Enable all of the things described above, plus advanced diamond zonal
2535 search for 8x8 blocks, half-pixel refinement for 8x8 blocks, and motion
2536 estimation on chroma planes.
2539 Enable all of the things described above, plus extended 16x16 and 8x8
2544 Set macroblock decision algorithm. Possible values in the increasing
2549 Use macroblock comparing function algorithm (default).
2552 Enable rate distortion-based half pixel and quarter pixel refinement for
2556 Enable all of the things described above, plus rate distortion-based
2557 half pixel and quarter pixel refinement for 8x8 blocks, and rate
2558 distortion-based search using square pattern.
2562 Enable lumi masking adaptive quantization when set to 1. Default is 0
2566 Enable variance adaptive quantization when set to 1. Default is 0
2569 When combined with @option{lumi_aq}, the resulting quality will not
2570 be better than any of the two specified individually. In other
2571 words, the resulting quality will be the worse one of the two
2575 Set structural similarity (SSIM) displaying method. Possible values:
2579 Disable displaying of SSIM information.
2582 Output average SSIM at the end of encoding to stdout. The format of
2583 showing the average SSIM is:
2589 For users who are not familiar with C, %f means a float number, or
2590 a decimal (e.g. 0.939232).
2593 Output both per-frame SSIM data during encoding and average SSIM at
2594 the end of encoding to stdout. The format of per-frame information
2598 SSIM: avg: %1.3f min: %1.3f max: %1.3f
2601 For users who are not familiar with C, %1.3f means a float number
2602 rounded to 3 digits after the dot (e.g. 0.932).
2607 Set SSIM accuracy. Valid options are integers within the range of
2608 0-4, while 0 gives the most accurate result and 4 computes the
2615 MPEG-2 video encoder.
2620 @item seq_disp_ext @var{integer}
2621 Specifies if the encoder should write a sequence_display_extension to the
2626 Decide automatically to write it or not (this is the default) by checking if
2627 the data to be written is different from the default or unspecified values.
2635 @item video_format @var{integer}
2636 Specifies the video_format written into the sequence display extension
2637 indicating the source of the video pictures. The default is @samp{unspecified},
2638 can be @samp{component}, @samp{pal}, @samp{ntsc}, @samp{secam} or @samp{mac}.
2639 For maximum compatibility, use @samp{component}.
2640 @item a53cc @var{boolean}
2641 Import closed captions (which must be ATSC compatible format) into output.
2649 @subsection Private options
2652 @item dpi @var{integer}
2653 Set physical density of pixels, in dots per inch, unset by default
2654 @item dpm @var{integer}
2655 Set physical density of pixels, in dots per meter, unset by default
2660 Apple ProRes encoder.
2662 FFmpeg contains 2 ProRes encoders, the prores-aw and prores-ks encoder.
2663 The used encoder can be chosen with the @code{-vcodec} option.
2665 @subsection Private Options for prores-ks
2668 @item profile @var{integer}
2669 Select the ProRes profile to encode
2679 @item quant_mat @var{integer}
2680 Select quantization matrix.
2689 If set to @var{auto}, the matrix matching the profile will be picked.
2690 If not set, the matrix providing the highest quality, @var{default}, will be
2693 @item bits_per_mb @var{integer}
2694 How many bits to allot for coding one macroblock. Different profiles use
2695 between 200 and 2400 bits per macroblock, the maximum is 8000.
2697 @item mbs_per_slice @var{integer}
2698 Number of macroblocks in each slice (1-8); the default value (8)
2699 should be good in almost all situations.
2701 @item vendor @var{string}
2702 Override the 4-byte vendor ID.
2703 A custom vendor ID like @var{apl0} would claim the stream was produced by
2706 @item alpha_bits @var{integer}
2707 Specify number of bits for alpha component.
2708 Possible values are @var{0}, @var{8} and @var{16}.
2709 Use @var{0} to disable alpha plane coding.
2713 @subsection Speed considerations
2715 In the default mode of operation the encoder has to honor frame constraints
2716 (i.e. not produce frames with size bigger than requested) while still making
2717 output picture as good as possible.
2718 A frame containing a lot of small details is harder to compress and the encoder
2719 would spend more time searching for appropriate quantizers for each slice.
2721 Setting a higher @option{bits_per_mb} limit will improve the speed.
2723 For the fastest encoding speed set the @option{qscale} parameter (4 is the
2724 recommended value) and do not set a size constraint.
2726 @section QSV encoders
2728 The family of Intel QuickSync Video encoders (MPEG-2, H.264 and HEVC)
2730 The ratecontrol method is selected as follows:
2734 When @option{global_quality} is specified, a quality-based mode is used.
2735 Specifically this means either
2738 @var{CQP} - constant quantizer scale, when the @option{qscale} codec flag is
2739 also set (the @option{-qscale} ffmpeg option).
2742 @var{LA_ICQ} - intelligent constant quality with lookahead, when the
2743 @option{look_ahead} option is also set.
2746 @var{ICQ} -- intelligent constant quality otherwise.
2750 Otherwise, a bitrate-based mode is used. For all of those, you should specify at
2751 least the desired average bitrate with the @option{b} option.
2754 @var{LA} - VBR with lookahead, when the @option{look_ahead} option is specified.
2757 @var{VCM} - video conferencing mode, when the @option{vcm} option is set.
2760 @var{CBR} - constant bitrate, when @option{maxrate} is specified and equal to
2761 the average bitrate.
2764 @var{VBR} - variable bitrate, when @option{maxrate} is specified, but is higher
2765 than the average bitrate.
2768 @var{AVBR} - average VBR mode, when @option{maxrate} is not specified. This mode
2769 is further configured by the @option{avbr_accuracy} and
2770 @option{avbr_convergence} options.
2774 Note that depending on your system, a different mode than the one you specified
2775 may be selected by the encoder. Set the verbosity level to @var{verbose} or
2776 higher to see the actual settings used by the QSV runtime.
2778 Additional libavcodec global options are mapped to MSDK options as follows:
2782 @option{g/gop_size} -> @option{GopPicSize}
2785 @option{bf/max_b_frames}+1 -> @option{GopRefDist}
2788 @option{rc_init_occupancy/rc_initial_buffer_occupancy} ->
2789 @option{InitialDelayInKB}
2792 @option{slices} -> @option{NumSlice}
2795 @option{refs} -> @option{NumRefFrame}
2798 @option{b_strategy/b_frame_strategy} -> @option{BRefType}
2801 @option{cgop/CLOSED_GOP} codec flag -> @option{GopOptFlag}
2804 For the @var{CQP} mode, the @option{i_qfactor/i_qoffset} and
2805 @option{b_qfactor/b_qoffset} set the difference between @var{QPP} and @var{QPI},
2806 and @var{QPP} and @var{QPB} respectively.
2809 Setting the @option{coder} option to the value @var{vlc} will make the H.264
2810 encoder use CAVLC instead of CABAC.
2819 @item iterative_dia_size
2820 dia size for the iterative motion estimation
2823 @section VAAPI encoders
2825 Wrappers for hardware encoders accessible via VAAPI.
2827 These encoders only accept input in VAAPI hardware surfaces. If you have input
2828 in software frames, use the @option{hwupload} filter to upload them to the GPU.
2830 The following standard libavcodec options are used:
2833 @option{g} / @option{gop_size}
2835 @option{bf} / @option{max_b_frames}
2839 If not set, this will be determined automatically from the format of the input
2840 frames and the profiles supported by the driver.
2844 @option{b} / @option{bit_rate}
2846 @option{maxrate} / @option{rc_max_rate}
2848 @option{bufsize} / @option{rc_buffer_size}
2850 @option{rc_init_occupancy} / @option{rc_initial_buffer_occupancy}
2852 @option{compression_level}
2854 Speed / quality tradeoff: higher values are faster / worse quality.
2856 @option{q} / @option{global_quality}
2858 Size / quality tradeoff: higher values are smaller / worse quality.
2864 @option{i_qfactor} / @option{i_quant_factor}
2866 @option{i_qoffset} / @option{i_quant_offset}
2868 @option{b_qfactor} / @option{b_quant_factor}
2870 @option{b_qoffset} / @option{b_quant_offset}
2875 All encoders support the following options:
2878 Some drivers/platforms offer a second encoder for some codecs intended to use
2879 less power than the default encoder; setting this option will attempt to use
2880 that encoder. Note that it may support a reduced feature set, so some other
2881 options may not be available in this mode.
2884 Set the number of normal intra frames between full-refresh (IDR) frames in
2885 open-GOP mode. The intra frames are still IRAPs, but will not include global
2886 headers and may have non-decodable leading pictures.
2889 Set the B-frame reference depth. When set to one (the default), all B-frames
2890 will refer only to P- or I-frames. When set to greater values multiple layers
2891 of B-frames will be present, frames in each layer only referring to frames in
2895 Set the rate control mode to use. A given driver may only support a subset of
2901 Choose the mode automatically based on driver support and the other options.
2902 This is the default.
2910 Intelligent constant-quality.
2912 Quality-defined variable-bitrate.
2914 Average variable bitrate.
2919 Each encoder also has its own specific options:
2923 @option{profile} sets the value of @emph{profile_idc} and the @emph{constraint_set*_flag}s.
2924 @option{level} sets the value of @emph{level_idc}.
2928 Set entropy encoder (default is @emph{cabac}). Possible values:
2941 Include access unit delimiters in the stream (not included by default).
2944 Set SEI message types to include.
2945 Some combination of the following values:
2948 Include a @emph{user_data_unregistered} message containing information about
2951 Include picture timing parameters (@emph{buffering_period} and
2952 @emph{pic_timing} messages).
2953 @item recovery_point
2954 Include recovery points where appropriate (@emph{recovery_point} messages).
2960 @option{profile} and @option{level} set the values of
2961 @emph{general_profile_idc} and @emph{general_level_idc} respectively.
2965 Include access unit delimiters in the stream (not included by default).
2968 Set @emph{general_tier_flag}. This may affect the level chosen for the stream
2969 if it is not explicitly specified.
2972 Set SEI message types to include.
2973 Some combination of the following values:
2976 Include HDR metadata if the input frames have it
2977 (@emph{mastering_display_colour_volume} and @emph{content_light_level}
2984 Only baseline DCT encoding is supported. The encoder always uses the standard
2985 quantisation and huffman tables - @option{global_quality} scales the standard
2986 quantisation table (range 1-100).
2988 For YUV, 4:2:0, 4:2:2 and 4:4:4 subsampling modes are supported. RGB is also
2989 supported, and will create an RGB JPEG.
2993 Include JFIF header in each frame (not included by default).
2995 Include standard huffman tables (on by default). Turning this off will save
2996 a few hundred bytes in each output frame, but may lose compatibility with some
2997 JPEG decoders which don't fully handle MJPEG.
3001 @option{profile} and @option{level} set the value of @emph{profile_and_level_indication}.
3004 B-frames are not supported.
3006 @option{global_quality} sets the @emph{q_idx} used for non-key frames (range 0-127).
3009 @item loop_filter_level
3010 @item loop_filter_sharpness
3011 Manually set the loop filter parameters.
3015 @option{global_quality} sets the @emph{q_idx} used for P-frames (range 0-255).
3018 @item loop_filter_level
3019 @item loop_filter_sharpness
3020 Manually set the loop filter parameters.
3023 B-frames are supported, but the output stream is always in encode order rather than display
3024 order. If B-frames are enabled, it may be necessary to use the @option{vp9_raw_reorder}
3025 bitstream filter to modify the output stream to display frames in the correct order.
3027 Only normal frames are produced - the @option{vp9_superframe} bitstream filter may be
3028 required to produce a stream usable with all decoders.
3034 SMPTE VC-2 (previously BBC Dirac Pro). This codec was primarily aimed at
3035 professional broadcasting but since it supports yuv420, yuv422 and yuv444 at
3036 8 (limited range or full range), 10 or 12 bits, this makes it suitable for
3037 other tasks which require low overhead and low compression (like screen
3045 Sets target video bitrate. Usually that's around 1:6 of the uncompressed
3046 video bitrate (e.g. for 1920x1080 50fps yuv422p10 that's around 400Mbps). Higher
3047 values (close to the uncompressed bitrate) turn on lossless compression mode.
3050 Enables field coding when set (e.g. to tt - top field first) for interlaced
3051 inputs. Should increase compression with interlaced content as it splits the
3052 fields and encodes each separately.
3055 Sets the total amount of wavelet transforms to apply, between 1 and 5 (default).
3056 Lower values reduce compression and quality. Less capable decoders may not be
3057 able to handle values of @option{wavelet_depth} over 3.
3060 Sets the transform type. Currently only @var{5_3} (LeGall) and @var{9_7}
3062 are implemented, with 9_7 being the one with better compression and thus
3067 Sets the slice size for each slice. Larger values result in better compression.
3068 For compatibility with other more limited decoders use @option{slice_width} of
3069 32 and @option{slice_height} of 8.
3072 Sets the undershoot tolerance of the rate control system in percent. This is
3073 to prevent an expensive search from being run.
3076 Sets the quantization matrix preset to use by default or when @option{wavelet_depth}
3081 Uses the default quantization matrix from the specifications, extended with
3082 values for the fifth level. This provides a good balance between keeping detail
3083 and omitting artifacts.
3087 Use a completely zeroed out quantization matrix. This increases PSNR but might
3088 reduce perception. Use in bogus benchmarks.
3092 Reduces detail but attempts to preserve color at extremely low bitrates.
3097 @c man end VIDEO ENCODERS
3099 @chapter Subtitles Encoders
3100 @c man begin SUBTITLES ENCODERS
3104 This codec encodes the bitmap subtitle format that is used in DVDs.
3105 Typically they are stored in VOBSUB file pairs (*.idx + *.sub),
3106 and they can also be used in Matroska files.
3112 When set to 1, enable a work-around that makes the number of pixel rows
3113 even in all subtitles. This fixes a problem with some players that
3114 cut off the bottom row if the number is odd. The work-around just adds
3115 a fully transparent row if needed. The overhead is low, typically
3116 one byte per subtitle on average.
3118 By default, this work-around is disabled.
3121 @c man end SUBTITLES ENCODERS