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 Enable ELDv2 (LD-MPS extension for ELD stereo signals) for ELDv2 if set to 1,
738 disabled if set to 0.
740 Note that option is available when fdk-aac version (AACENCODER_LIB_VL0.AACENCODER_LIB_VL1.AACENCODER_LIB_VL2) > (4.0.0).
745 Set SBR/PS signaling style.
747 It can assume one of the following values:
750 choose signaling implicitly (explicit hierarchical by default,
751 implicit if global header is disabled)
754 implicit backwards compatible signaling
757 explicit SBR, implicit PS signaling
759 @item explicit_hierarchical
760 explicit hierarchical signaling
763 Default value is @samp{default}.
766 Output LATM/LOAS encapsulated data if set to 1, disabled if set to 0.
771 Set StreamMuxConfig and PCE repetition period (in frames) for sending
772 in-band configuration buffers within LATM/LOAS transport layer.
774 Must be a 16-bits non-negative integer.
779 Set VBR mode, from 1 to 5. 1 is lowest quality (though still pretty
780 good) and 5 is highest quality. A value of 0 will disable VBR, and CBR
781 (Constant Bit Rate) is enabled.
783 Currently only the @samp{aac_low} profile supports VBR encoding.
785 VBR modes 1-5 correspond to roughly the following average bit rates:
797 about 80-96 kbps/channel
807 Use @command{ffmpeg} to convert an audio file to VBR AAC in an M4A (MP4)
810 ffmpeg -i input.wav -codec:a libfdk_aac -vbr 3 output.m4a
814 Use @command{ffmpeg} to convert an audio file to CBR 64k kbps AAC, using the
815 High-Efficiency AAC profile:
817 ffmpeg -i input.wav -c:a libfdk_aac -profile:a aac_he -b:a 64k output.m4a
824 LAME (Lame Ain't an MP3 Encoder) MP3 encoder wrapper.
826 Requires the presence of the libmp3lame headers and library during
827 configuration. You need to explicitly configure the build with
828 @code{--enable-libmp3lame}.
830 See @ref{libshine} for a fixed-point MP3 encoder, although with a
835 The following options are supported by the libmp3lame wrapper. The
836 @command{lame}-equivalent of the options are listed in parentheses.
840 Set bitrate expressed in bits/s for CBR or ABR. LAME @code{bitrate} is
841 expressed in kilobits/s.
844 Set constant quality setting for VBR. This option is valid only
845 using the @command{ffmpeg} command-line tool. For library interface
846 users, use @option{global_quality}.
848 @item compression_level (@emph{-q})
849 Set algorithm quality. Valid arguments are integers in the 0-9 range,
850 with 0 meaning highest quality but slowest, and 9 meaning fastest
851 while producing the worst quality.
853 @item cutoff (@emph{--lowpass})
854 Set lowpass cutoff frequency. If unspecified, the encoder dynamically
858 Enable use of bit reservoir when set to 1. Default value is 1. LAME
859 has this enabled by default, but can be overridden by use
860 @option{--nores} option.
862 @item joint_stereo (@emph{-m j})
863 Enable the encoder to use (on a frame by frame basis) either L/R
864 stereo or mid/side stereo. Default value is 1.
866 @item abr (@emph{--abr})
867 Enable the encoder to use ABR when set to 1. The @command{lame}
868 @option{--abr} sets the target bitrate, while this options only
869 tells FFmpeg to use ABR still relies on @option{b} to set bitrate.
873 @section libopencore-amrnb
875 OpenCORE Adaptive Multi-Rate Narrowband encoder.
877 Requires the presence of the libopencore-amrnb headers and library during
878 configuration. You need to explicitly configure the build with
879 @code{--enable-libopencore-amrnb --enable-version3}.
881 This is a mono-only encoder. Officially it only supports 8000Hz sample rate,
882 but you can override it by setting @option{strict} to @samp{unofficial} or
890 Set bitrate in bits per second. Only the following bitrates are supported,
891 otherwise libavcodec will round to the nearest valid bitrate.
905 Allow discontinuous transmission (generate comfort noise) when set to 1. The
906 default value is 0 (disabled).
912 libopus Opus Interactive Audio Codec encoder wrapper.
914 Requires the presence of the libopus headers and library during
915 configuration. You need to explicitly configure the build with
916 @code{--enable-libopus}.
918 @subsection Option Mapping
920 Most libopus options are modelled after the @command{opusenc} utility from
921 opus-tools. The following is an option mapping chart describing options
922 supported by the libopus wrapper, and their @command{opusenc}-equivalent
927 @item b (@emph{bitrate})
928 Set the bit rate in bits/s. FFmpeg's @option{b} option is
929 expressed in bits/s, while @command{opusenc}'s @option{bitrate} in
932 @item vbr (@emph{vbr}, @emph{hard-cbr}, and @emph{cvbr})
933 Set VBR mode. The FFmpeg @option{vbr} option has the following
934 valid arguments, with the @command{opusenc} equivalent options
938 @item off (@emph{hard-cbr})
939 Use constant bit rate encoding.
941 @item on (@emph{vbr})
942 Use variable bit rate encoding (the default).
944 @item constrained (@emph{cvbr})
945 Use constrained variable bit rate encoding.
948 @item compression_level (@emph{comp})
949 Set encoding algorithm complexity. Valid options are integers in
950 the 0-10 range. 0 gives the fastest encodes but lower quality, while 10
951 gives the highest quality but slowest encoding. The default is 10.
953 @item frame_duration (@emph{framesize})
954 Set maximum frame size, or duration of a frame in milliseconds. The
955 argument must be exactly the following: 2.5, 5, 10, 20, 40, 60. Smaller
956 frame sizes achieve lower latency but less quality at a given bitrate.
957 Sizes greater than 20ms are only interesting at fairly low bitrates.
960 @item packet_loss (@emph{expect-loss})
961 Set expected packet loss percentage. The default is 0.
963 @item application (N.A.)
964 Set intended application type. Valid options are listed below:
968 Favor improved speech intelligibility.
970 Favor faithfulness to the input (the default).
972 Restrict to only the lowest delay modes.
976 Set cutoff bandwidth in Hz. The argument must be exactly one of the
977 following: 4000, 6000, 8000, 12000, or 20000, corresponding to
978 narrowband, mediumband, wideband, super wideband, and fullband
979 respectively. The default is 0 (cutoff disabled).
981 @item mapping_family (@emph{mapping_family})
982 Set channel mapping family to be used by the encoder. The default value of -1
983 uses mapping family 0 for mono and stereo inputs, and mapping family 1
984 otherwise. The default also disables the surround masking and LFE bandwidth
985 optimzations in libopus, and requires that the input contains 8 channels or
988 Other values include 0 for mono and stereo, 1 for surround sound with masking
989 and LFE bandwidth optimizations, and 255 for independent streams with an
990 unspecified channel layout.
992 @item apply_phase_inv (N.A.) (requires libopus >= 1.2)
993 If set to 0, disables the use of phase inversion for intensity stereo,
994 improving the quality of mono downmixes, but slightly reducing normal stereo
995 quality. The default is 1 (phase inversion enabled).
1002 Shine Fixed-Point MP3 encoder wrapper.
1004 Shine is a fixed-point MP3 encoder. It has a far better performance on
1005 platforms without an FPU, e.g. armel CPUs, and some phones and tablets.
1006 However, as it is more targeted on performance than quality, it is not on par
1007 with LAME and other production-grade encoders quality-wise. Also, according to
1008 the project's homepage, this encoder may not be free of bugs as the code was
1009 written a long time ago and the project was dead for at least 5 years.
1011 This encoder only supports stereo and mono input. This is also CBR-only.
1013 The original project (last updated in early 2007) is at
1014 @url{http://sourceforge.net/projects/libshine-fxp/}. We only support the
1015 updated fork by the Savonet/Liquidsoap project at @url{https://github.com/savonet/shine}.
1017 Requires the presence of the libshine headers and library during
1018 configuration. You need to explicitly configure the build with
1019 @code{--enable-libshine}.
1021 See also @ref{libmp3lame}.
1025 The following options are supported by the libshine wrapper. The
1026 @command{shineenc}-equivalent of the options are listed in parentheses.
1030 Set bitrate expressed in bits/s for CBR. @command{shineenc} @option{-b} option
1031 is expressed in kilobits/s.
1037 TwoLAME MP2 encoder wrapper.
1039 Requires the presence of the libtwolame headers and library during
1040 configuration. You need to explicitly configure the build with
1041 @code{--enable-libtwolame}.
1045 The following options are supported by the libtwolame wrapper. The
1046 @command{twolame}-equivalent options follow the FFmpeg ones and are in
1051 Set bitrate expressed in bits/s for CBR. @command{twolame} @option{b}
1052 option is expressed in kilobits/s. Default value is 128k.
1055 Set quality for experimental VBR support. Maximum value range is
1056 from -50 to 50, useful range is from -10 to 10. The higher the
1057 value, the better the quality. This option is valid only using the
1058 @command{ffmpeg} command-line tool. For library interface users,
1059 use @option{global_quality}.
1061 @item mode (@emph{--mode})
1062 Set the mode of the resulting audio. Possible values:
1066 Choose mode automatically based on the input. This is the default.
1077 @item psymodel (@emph{--psyc-mode})
1078 Set psychoacoustic model to use in encoding. The argument must be
1079 an integer between -1 and 4, inclusive. The higher the value, the
1080 better the quality. The default value is 3.
1082 @item energy_levels (@emph{--energy})
1083 Enable energy levels extensions when set to 1. The default value is
1086 @item error_protection (@emph{--protect})
1087 Enable CRC error protection when set to 1. The default value is 0
1090 @item copyright (@emph{--copyright})
1091 Set MPEG audio copyright flag when set to 1. The default value is 0
1094 @item original (@emph{--original})
1095 Set MPEG audio original flag when set to 1. The default value is 0
1100 @section libvo-amrwbenc
1102 VisualOn Adaptive Multi-Rate Wideband encoder.
1104 Requires the presence of the libvo-amrwbenc headers and library during
1105 configuration. You need to explicitly configure the build with
1106 @code{--enable-libvo-amrwbenc --enable-version3}.
1108 This is a mono-only encoder. Officially it only supports 16000Hz sample
1109 rate, but you can override it by setting @option{strict} to
1110 @samp{unofficial} or lower.
1117 Set bitrate in bits/s. Only the following bitrates are supported, otherwise
1118 libavcodec will round to the nearest valid bitrate.
1133 Allow discontinuous transmission (generate comfort noise) when set to 1. The
1134 default value is 0 (disabled).
1140 libvorbis encoder wrapper.
1142 Requires the presence of the libvorbisenc headers and library during
1143 configuration. You need to explicitly configure the build with
1144 @code{--enable-libvorbis}.
1148 The following options are supported by the libvorbis wrapper. The
1149 @command{oggenc}-equivalent of the options are listed in parentheses.
1151 To get a more accurate and extensive documentation of the libvorbis
1152 options, consult the libvorbisenc's and @command{oggenc}'s documentations.
1153 See @url{http://xiph.org/vorbis/},
1154 @url{http://wiki.xiph.org/Vorbis-tools}, and oggenc(1).
1158 Set bitrate expressed in bits/s for ABR. @command{oggenc} @option{-b} is
1159 expressed in kilobits/s.
1162 Set constant quality setting for VBR. The value should be a float
1163 number in the range of -1.0 to 10.0. The higher the value, the better
1164 the quality. The default value is @samp{3.0}.
1166 This option is valid only using the @command{ffmpeg} command-line tool.
1167 For library interface users, use @option{global_quality}.
1169 @item cutoff (@emph{--advanced-encode-option lowpass_frequency=N})
1170 Set cutoff bandwidth in Hz, a value of 0 disables cutoff. @command{oggenc}'s
1171 related option is expressed in kHz. The default value is @samp{0} (cutoff
1174 @item minrate (@emph{-m})
1175 Set minimum bitrate expressed in bits/s. @command{oggenc} @option{-m} is
1176 expressed in kilobits/s.
1178 @item maxrate (@emph{-M})
1179 Set maximum bitrate expressed in bits/s. @command{oggenc} @option{-M} is
1180 expressed in kilobits/s. This only has effect on ABR mode.
1182 @item iblock (@emph{--advanced-encode-option impulse_noisetune=N})
1183 Set noise floor bias for impulse blocks. The value is a float number from
1184 -15.0 to 0.0. A negative bias instructs the encoder to pay special attention
1185 to the crispness of transients in the encoded audio. The tradeoff for better
1186 transient response is a higher bitrate.
1193 A wrapper providing WavPack encoding through libwavpack.
1195 Only lossless mode using 32-bit integer samples is supported currently.
1197 Requires the presence of the libwavpack headers and library during
1198 configuration. You need to explicitly configure the build with
1199 @code{--enable-libwavpack}.
1201 Note that a libavcodec-native encoder for the WavPack codec exists so users can
1202 encode audios with this codec without using this encoder. See @ref{wavpackenc}.
1206 @command{wavpack} command line utility's corresponding options are listed in
1207 parentheses, if any.
1210 @item frame_size (@emph{--blocksize})
1213 @item compression_level
1214 Set speed vs. compression tradeoff. Acceptable arguments are listed below:
1221 Normal (default) settings.
1226 @item 3 (@emph{-hh})
1229 @item 4-8 (@emph{-hh -x}@var{EXTRAPROC})
1230 Same as @samp{3}, but with extra processing enabled.
1232 @samp{4} is the same as @option{-x2} and @samp{8} is the same as @option{-x6}.
1240 Motion JPEG encoder.
1246 Set the huffman encoding strategy. Possible values:
1250 Use the default huffman tables. This is the default strategy.
1253 Compute and use optimal huffman tables.
1261 WavPack lossless audio encoder.
1263 This is a libavcodec-native WavPack encoder. There is also an encoder based on
1264 libwavpack, but there is virtually no reason to use that encoder.
1266 See also @ref{libwavpack}.
1270 The equivalent options for @command{wavpack} command line utility are listed in
1273 @subsubsection Shared options
1275 The following shared options are effective for this encoder. Only special notes
1276 about this particular encoder will be documented here. For the general meaning
1277 of the options, see @ref{codec-options,,the Codec Options chapter}.
1280 @item frame_size (@emph{--blocksize})
1281 For this encoder, the range for this option is between 128 and 131072. Default
1282 is automatically decided based on sample rate and number of channel.
1284 For the complete formula of calculating default, see
1285 @file{libavcodec/wavpackenc.c}.
1287 @item compression_level (@emph{-f}, @emph{-h}, @emph{-hh}, and @emph{-x})
1288 This option's syntax is consistent with @ref{libwavpack}'s.
1291 @subsubsection Private options
1294 @item joint_stereo (@emph{-j})
1295 Set whether to enable joint stereo. Valid values are:
1299 Force mid/side audio encoding.
1300 @item off (@emph{0})
1301 Force left/right audio encoding.
1303 Let the encoder decide automatically.
1307 Set whether to enable optimization for mono. This option is only effective for
1308 non-mono streams. Available values:
1319 @c man end AUDIO ENCODERS
1321 @chapter Video Encoders
1322 @c man begin VIDEO ENCODERS
1324 A description of some of the currently available video encoders
1329 Vidvox Hap video encoder.
1334 @item format @var{integer}
1335 Specifies the Hap format to encode.
1343 Default value is @option{hap}.
1345 @item chunks @var{integer}
1346 Specifies the number of chunks to split frames into, between 1 and 64. This
1347 permits multithreaded decoding of large frames, potentially at the cost of
1348 data-rate. The encoder may modify this value to divide frames evenly.
1350 Default value is @var{1}.
1352 @item compressor @var{integer}
1353 Specifies the second-stage compressor to use. If set to @option{none},
1354 @option{chunks} will be limited to 1, as chunked uncompressed frames offer no
1362 Default value is @option{snappy}.
1368 The native jpeg 2000 encoder is lossy by default, the @code{-q:v}
1369 option can be used to set the encoding quality. Lossless encoding
1370 can be selected with @code{-pred 1}.
1376 Can be set to either @code{j2k} or @code{jp2} (the default) that
1377 makes it possible to store non-rgb pix_fmts.
1383 libaom AV1 encoder wrapper.
1385 Requires the presence of the libaom headers and library during
1386 configuration. You need to explicitly configure the build with
1387 @code{--enable-libaom}.
1391 The wrapper supports the following standard libavcodec options:
1396 Set bitrate target in bits/second. By default this will use
1397 variable-bitrate mode. If @option{maxrate} and @option{minrate} are
1398 also set to the same value then it will use constant-bitrate mode,
1399 otherwise if @option{crf} is set as well then it will use
1400 constrained-quality mode.
1403 Set key frame placement. The GOP size sets the maximum distance between
1404 key frames; if zero the output stream will be intra-only. The minimum
1405 distance is ignored unless it is the same as the GOP size, in which case
1406 key frames will always appear at a fixed interval. Not set by default,
1407 so without this option the library has completely free choice about
1408 where to place key frames.
1411 Set minimum/maximum quantisation values. Valid range is from 0 to 63
1412 (warning: this does not match the quantiser values actually used by AV1
1413 - divide by four to map real quantiser values to this range). Defaults
1414 to min/max (no constraint).
1416 @item minrate maxrate bufsize rc_init_occupancy
1417 Set rate control buffering parameters. Not used if not set - defaults
1418 to unconstrained variable bitrate.
1421 Set the number of threads to use while encoding. This may require the
1422 @option{tiles} or @option{row-mt} options to also be set to actually
1423 use the specified number of threads fully. Defaults to the number of
1424 hardware threads supported by the host machine.
1427 Set the encoding profile. Defaults to using the profile which matches
1428 the bit depth and chroma subsampling of the input.
1432 The wrapper also has some specific options:
1437 Set the quality/encoding speed tradeoff. Valid range is from 0 to 8,
1438 higher numbers indicating greater speed and lower quality. The default
1439 value is 1, which will be slow and high quality.
1442 Enable use of alternate reference frames. Defaults to the internal
1443 default of the library.
1445 @item arnr-max-frames (@emph{frames})
1446 Set altref noise reduction max frame count. Default is -1.
1448 @item arnr-strength (@emph{strength})
1449 Set altref noise reduction filter strength. Range is -1 to 6. Default is -1.
1451 @item aq-mode (@emph{aq-mode})
1452 Set adaptive quantization mode. Possible values:
1455 @item none (@emph{0})
1458 @item variance (@emph{1})
1461 @item complexity (@emph{2})
1464 @item cyclic (@emph{3})
1469 Set the maximum number of frames which the encoder may keep in flight
1470 at any one time for lookahead purposes. Defaults to the internal
1471 default of the library.
1473 @item error-resilience
1474 Enable error resilience features:
1477 Improve resilience against losses of whole frames.
1479 Not enabled by default.
1482 Set the quality/size tradeoff for constant-quality (no bitrate target)
1483 and constrained-quality (with maximum bitrate target) modes. Valid
1484 range is 0 to 63, higher numbers indicating lower quality and smaller
1485 output size. Only used if set; by default only the bitrate target is
1489 Set a change threshold on blocks below which they will be skipped by
1490 the encoder. Defined in arbitrary units as a nonnegative integer,
1491 defaulting to zero (no blocks are skipped).
1493 @item drop-threshold
1494 Set a threshold for dropping frames when close to rate control bounds.
1495 Defined as a percentage of the target buffer - when the rate control
1496 buffer falls below this percentage, frames will be dropped until it
1497 has refilled above the threshold. Defaults to zero (no frames are
1500 @item denoise-noise-level (@emph{level})
1501 Amount of noise to be removed for grain synthesis. Grain synthesis is disabled if
1502 this option is not set or set to 0.
1504 @item denoise-block-size (@emph{pixels})
1505 Block size used for denoising for grain synthesis. If not set, AV1 codec
1506 uses the default value of 32.
1508 @item undershoot-pct (@emph{pct})
1509 Set datarate undershoot (min) percentage of the target bitrate. Range is -1 to 100.
1512 @item overshoot-pct (@emph{pct})
1513 Set datarate overshoot (max) percentage of the target bitrate. Range is -1 to 1000.
1516 @item minsection-pct (@emph{pct})
1517 Minimum percentage variation of the GOP bitrate from the target bitrate. If minsection-pct
1518 is not set, the libaomenc wrapper computes it as follows: @code{(minrate * 100 / bitrate)}.
1519 Range is -1 to 100. Default is -1 (unset).
1521 @item maxsection-pct (@emph{pct})
1522 Maximum percentage variation of the GOP bitrate from the target bitrate. If maxsection-pct
1523 is not set, the libaomenc wrapper computes it as follows: @code{(maxrate * 100 / bitrate)}.
1524 Range is -1 to 5000. Default is -1 (unset).
1526 @item frame-parallel (@emph{boolean})
1527 Enable frame parallel decodability features. Default is true.
1530 Set the number of tiles to encode the input video with, as columns x
1531 rows. Larger numbers allow greater parallelism in both encoding and
1532 decoding, but may decrease coding efficiency. Defaults to the minimum
1533 number of tiles required by the size of the input video (this is 1x1
1534 (that is, a single tile) for sizes up to and including 4K).
1536 @item tile-columns tile-rows
1537 Set the number of tiles as log2 of the number of tile rows and columns.
1538 Provided for compatibility with libvpx/VP9.
1540 @item row-mt (Requires libaom >= 1.0.0-759-g90a15f4f2)
1541 Enable row based multi-threading. Disabled by default.
1543 @item enable-cdef (@emph{boolean})
1544 Enable Constrained Directional Enhancement Filter. The libaom-av1
1545 encoder enables CDEF by default.
1547 @item enable-global-motion (@emph{boolean})
1548 Enable the use of global motion for block prediction. Default is true.
1550 @item enable-intrabc (@emph{boolean})
1551 Enable block copy mode for intra block prediction. This mode is
1552 useful for screen content. Default is true.
1558 Kvazaar H.265/HEVC encoder.
1560 Requires the presence of the libkvazaar headers and library during
1561 configuration. You need to explicitly configure the build with
1562 @option{--enable-libkvazaar}.
1569 Set target video bitrate in bit/s and enable rate control.
1571 @item kvazaar-params
1572 Set kvazaar parameters as a list of @var{name}=@var{value} pairs separated
1573 by commas (,). See kvazaar documentation for a list of options.
1577 @section libopenh264
1579 Cisco libopenh264 H.264/MPEG-4 AVC encoder wrapper.
1581 This encoder requires the presence of the libopenh264 headers and
1582 library during configuration. You need to explicitly configure the
1583 build with @code{--enable-libopenh264}. The library is detected using
1584 @command{pkg-config}.
1586 For more information about the library see
1587 @url{http://www.openh264.org}.
1591 The following FFmpeg global options affect the configurations of the
1592 libopenh264 encoder.
1596 Set the bitrate (as a number of bits per second).
1602 Set the max bitrate (as a number of bits per second).
1604 @item flags +global_header
1605 Set global header in the bitstream.
1608 Set the number of slices, used in parallelized encoding. Default value
1609 is 0. This is only used when @option{slice_mode} is set to
1613 Set slice mode. Can assume one of the following possible values:
1617 a fixed number of slices
1619 one slice per row of macroblocks
1621 automatic number of slices according to number of threads
1626 Default value is @samp{auto}.
1629 Enable loop filter, if set to 1 (automatically enabled). To disable
1633 Set profile restrictions. If set to the value of @samp{main} enable
1634 CABAC (set the @code{SEncParamExt.iEntropyCodingModeFlag} flag to 1).
1637 Set maximum NAL size in bytes.
1639 @item allow_skip_frames
1640 Allow skipping frames to hit the target bitrate if set to 1.
1645 libtheora Theora encoder wrapper.
1647 Requires the presence of the libtheora headers and library during
1648 configuration. You need to explicitly configure the build with
1649 @code{--enable-libtheora}.
1651 For more information about the libtheora project see
1652 @url{http://www.theora.org/}.
1656 The following global options are mapped to internal libtheora options
1657 which affect the quality and the bitrate of the encoded stream.
1661 Set the video bitrate in bit/s for CBR (Constant Bit Rate) mode. In
1662 case VBR (Variable Bit Rate) mode is enabled this option is ignored.
1665 Used to enable constant quality mode (VBR) encoding through the
1666 @option{qscale} flag, and to enable the @code{pass1} and @code{pass2}
1672 @item global_quality
1673 Set the global quality as an integer in lambda units.
1675 Only relevant when VBR mode is enabled with @code{flags +qscale}. The
1676 value is converted to QP units by dividing it by @code{FF_QP2LAMBDA},
1677 clipped in the [0 - 10] range, and then multiplied by 6.3 to get a
1678 value in the native libtheora range [0-63]. A higher value corresponds
1679 to a higher quality.
1682 Enable VBR mode when set to a non-negative value, and set constant
1683 quality value as a double floating point value in QP units.
1685 The value is clipped in the [0-10] range, and then multiplied by 6.3
1686 to get a value in the native libtheora range [0-63].
1688 This option is valid only using the @command{ffmpeg} command-line
1689 tool. For library interface users, use @option{global_quality}.
1692 @subsection Examples
1696 Set maximum constant quality (VBR) encoding with @command{ffmpeg}:
1698 ffmpeg -i INPUT -codec:v libtheora -q:v 10 OUTPUT.ogg
1702 Use @command{ffmpeg} to convert a CBR 1000 kbps Theora video stream:
1704 ffmpeg -i INPUT -codec:v libtheora -b:v 1000k OUTPUT.ogg
1710 VP8/VP9 format supported through libvpx.
1712 Requires the presence of the libvpx headers and library during configuration.
1713 You need to explicitly configure the build with @code{--enable-libvpx}.
1717 The following options are supported by the libvpx wrapper. The
1718 @command{vpxenc}-equivalent options or values are listed in parentheses
1721 To reduce the duplication of documentation, only the private options
1722 and some others requiring special attention are documented here. For
1723 the documentation of the undocumented generic options, see
1724 @ref{codec-options,,the Codec Options chapter}.
1726 To get more documentation of the libvpx options, invoke the command
1727 @command{ffmpeg -h encoder=libvpx}, @command{ffmpeg -h encoder=libvpx-vp9} or
1728 @command{vpxenc --help}. Further information is available in the libvpx API
1733 @item b (@emph{target-bitrate})
1734 Set bitrate in bits/s. Note that FFmpeg's @option{b} option is
1735 expressed in bits/s, while @command{vpxenc}'s @option{target-bitrate} is in
1738 @item g (@emph{kf-max-dist})
1740 @item keyint_min (@emph{kf-min-dist})
1742 @item qmin (@emph{min-q})
1744 @item qmax (@emph{max-q})
1746 @item bufsize (@emph{buf-sz}, @emph{buf-optimal-sz})
1747 Set ratecontrol buffer size (in bits). Note @command{vpxenc}'s options are
1748 specified in milliseconds, the libvpx wrapper converts this value as follows:
1749 @code{buf-sz = bufsize * 1000 / bitrate},
1750 @code{buf-optimal-sz = bufsize * 1000 / bitrate * 5 / 6}.
1752 @item rc_init_occupancy (@emph{buf-initial-sz})
1753 Set number of bits which should be loaded into the rc buffer before decoding
1754 starts. Note @command{vpxenc}'s option is specified in milliseconds, the libvpx
1755 wrapper converts this value as follows:
1756 @code{rc_init_occupancy * 1000 / bitrate}.
1758 @item undershoot-pct
1759 Set datarate undershoot (min) percentage of the target bitrate.
1762 Set datarate overshoot (max) percentage of the target bitrate.
1764 @item skip_threshold (@emph{drop-frame})
1766 @item qcomp (@emph{bias-pct})
1768 @item maxrate (@emph{maxsection-pct})
1769 Set GOP max bitrate in bits/s. Note @command{vpxenc}'s option is specified as a
1770 percentage of the target bitrate, the libvpx wrapper converts this value as
1771 follows: @code{(maxrate * 100 / bitrate)}.
1773 @item minrate (@emph{minsection-pct})
1774 Set GOP min bitrate in bits/s. Note @command{vpxenc}'s option is specified as a
1775 percentage of the target bitrate, the libvpx wrapper converts this value as
1776 follows: @code{(minrate * 100 / bitrate)}.
1778 @item minrate, maxrate, b @emph{end-usage=cbr}
1779 @code{(minrate == maxrate == bitrate)}.
1781 @item crf (@emph{end-usage=cq}, @emph{cq-level})
1783 @item tune (@emph{tune})
1785 @item psnr (@emph{psnr})
1786 @item ssim (@emph{ssim})
1789 @item quality, deadline (@emph{deadline})
1792 Use best quality deadline. Poorly named and quite slow, this option should be
1793 avoided as it may give worse quality output than good.
1795 Use good quality deadline. This is a good trade-off between speed and quality
1796 when used with the @option{cpu-used} option.
1798 Use realtime quality deadline.
1801 @item speed, cpu-used (@emph{cpu-used})
1802 Set quality/speed ratio modifier. Higher values speed up the encode at the cost
1805 @item nr (@emph{noise-sensitivity})
1808 Set a change threshold on blocks below which they will be skipped by the
1811 @item slices (@emph{token-parts})
1812 Note that FFmpeg's @option{slices} option gives the total number of partitions,
1813 while @command{vpxenc}'s @option{token-parts} is given as
1814 @code{log2(partitions)}.
1816 @item max-intra-rate
1817 Set maximum I-frame bitrate as a percentage of the target bitrate. A value of 0
1820 @item force_key_frames
1821 @code{VPX_EFLAG_FORCE_KF}
1823 @item Alternate reference frame related
1826 Enable use of alternate reference frames (2-pass only).
1827 Values greater than 1 enable multi-layer alternate reference frames (VP9 only).
1828 @item arnr-maxframes
1829 Set altref noise reduction max frame count.
1831 Set altref noise reduction filter type: backward, forward, centered.
1833 Set altref noise reduction filter strength.
1834 @item rc-lookahead, lag-in-frames (@emph{lag-in-frames})
1835 Set number of frames to look ahead for frametype and ratecontrol.
1838 @item error-resilient
1839 Enable error resiliency features.
1841 @item sharpness @var{integer}
1842 Increase sharpness at the expense of lower PSNR.
1843 The valid range is [0, 7].
1845 @item VP8-specific options
1848 Sets the temporal scalability configuration using a :-separated list of
1849 key=value pairs. For example, to specify temporal scalability parameters
1852 ffmpeg -i INPUT -c:v libvpx -ts-parameters ts_number_layers=3:\
1853 ts_target_bitrate=250000,500000,1000000:ts_rate_decimator=4,2,1:\
1854 ts_periodicity=4:ts_layer_id=0,2,1,2 OUTPUT
1856 Below is a brief explanation of each of the parameters, please
1857 refer to @code{struct vpx_codec_enc_cfg} in @code{vpx/vpx_encoder.h} for more
1860 @item ts_number_layers
1861 Number of temporal coding layers.
1862 @item ts_target_bitrate
1863 Target bitrate for each temporal layer.
1864 @item ts_rate_decimator
1865 Frame rate decimation factor for each temporal layer.
1866 @item ts_periodicity
1867 Length of the sequence defining frame temporal layer membership.
1869 Template defining the membership of frames to temporal layers.
1873 @item VP9-specific options
1876 Enable lossless mode.
1878 Set number of tile columns to use. Note this is given as
1879 @code{log2(tile_columns)}. For example, 8 tile columns would be requested by
1880 setting the @option{tile-columns} option to 3.
1882 Set number of tile rows to use. Note this is given as @code{log2(tile_rows)}.
1883 For example, 4 tile rows would be requested by setting the @option{tile-rows}
1885 @item frame-parallel
1886 Enable frame parallel decodability features.
1888 Set adaptive quantization mode (0: off (default), 1: variance 2: complexity, 3:
1889 cyclic refresh, 4: equator360).
1890 @item colorspace @emph{color-space}
1891 Set input color space. The VP9 bitstream supports signaling the following
1894 @item @samp{rgb} @emph{sRGB}
1895 @item @samp{bt709} @emph{bt709}
1896 @item @samp{unspecified} @emph{unknown}
1897 @item @samp{bt470bg} @emph{bt601}
1898 @item @samp{smpte170m} @emph{smpte170}
1899 @item @samp{smpte240m} @emph{smpte240}
1900 @item @samp{bt2020_ncl} @emph{bt2020}
1902 @item row-mt @var{boolean}
1903 Enable row based multi-threading.
1905 Set content type: default (0), screen (1), film (2).
1906 @item corpus-complexity
1907 Corpus VBR mode is a variant of standard VBR where the complexity distribution
1908 midpoint is passed in rather than calculated for a specific clip or chunk.
1910 The valid range is [0, 10000]. 0 (default) uses standard VBR.
1911 @item enable-tpl @var{boolean}
1912 Enable temporal dependency model.
1917 For more information about libvpx see:
1918 @url{http://www.webmproject.org/}
1922 libwebp WebP Image encoder wrapper
1924 libwebp is Google's official encoder for WebP images. It can encode in either
1925 lossy or lossless mode. Lossy images are essentially a wrapper around a VP8
1926 frame. Lossless images are a separate codec developed by Google.
1928 @subsection Pixel Format
1930 Currently, libwebp only supports YUV420 for lossy and RGB for lossless due
1931 to limitations of the format and libwebp. Alpha is supported for either mode.
1932 Because of API limitations, if RGB is passed in when encoding lossy or YUV is
1933 passed in for encoding lossless, the pixel format will automatically be
1934 converted using functions from libwebp. This is not ideal and is done only for
1941 @item -lossless @var{boolean}
1942 Enables/Disables use of lossless mode. Default is 0.
1944 @item -compression_level @var{integer}
1945 For lossy, this is a quality/speed tradeoff. Higher values give better quality
1946 for a given size at the cost of increased encoding time. For lossless, this is
1947 a size/speed tradeoff. Higher values give smaller size at the cost of increased
1948 encoding time. More specifically, it controls the number of extra algorithms
1949 and compression tools used, and varies the combination of these tools. This
1950 maps to the @var{method} option in libwebp. The valid range is 0 to 6.
1953 @item -qscale @var{float}
1954 For lossy encoding, this controls image quality, 0 to 100. For lossless
1955 encoding, this controls the effort and time spent at compressing more. The
1956 default value is 75. Note that for usage via libavcodec, this option is called
1957 @var{global_quality} and must be multiplied by @var{FF_QP2LAMBDA}.
1959 @item -preset @var{type}
1960 Configuration preset. This does some automatic settings based on the general
1964 Do not use a preset.
1966 Use the encoder default.
1968 Digital picture, like portrait, inner shot
1970 Outdoor photograph, with natural lighting
1972 Hand or line drawing, with high-contrast details
1974 Small-sized colorful images
1981 @section libx264, libx264rgb
1983 x264 H.264/MPEG-4 AVC encoder wrapper.
1985 This encoder requires the presence of the libx264 headers and library
1986 during configuration. You need to explicitly configure the build with
1987 @code{--enable-libx264}.
1989 libx264 supports an impressive number of features, including 8x8 and
1990 4x4 adaptive spatial transform, adaptive B-frame placement, CAVLC/CABAC
1991 entropy coding, interlacing (MBAFF), lossless mode, psy optimizations
1992 for detail retention (adaptive quantization, psy-RD, psy-trellis).
1994 Many libx264 encoder options are mapped to FFmpeg global codec
1995 options, while unique encoder options are provided through private
1996 options. Additionally the @option{x264opts} and @option{x264-params}
1997 private options allows one to pass a list of key=value tuples as accepted
1998 by the libx264 @code{x264_param_parse} function.
2000 The x264 project website is at
2001 @url{http://www.videolan.org/developers/x264.html}.
2003 The libx264rgb encoder is the same as libx264, except it accepts packed RGB
2004 pixel formats as input instead of YUV.
2006 @subsection Supported Pixel Formats
2008 x264 supports 8- to 10-bit color spaces. The exact bit depth is controlled at
2009 x264's configure time. FFmpeg only supports one bit depth in one particular
2010 build. In other words, it is not possible to build one FFmpeg with multiple
2011 versions of x264 with different bit depths.
2015 The following options are supported by the libx264 wrapper. The
2016 @command{x264}-equivalent options or values are listed in parentheses
2019 To reduce the duplication of documentation, only the private options
2020 and some others requiring special attention are documented here. For
2021 the documentation of the undocumented generic options, see
2022 @ref{codec-options,,the Codec Options chapter}.
2024 To get a more accurate and extensive documentation of the libx264
2025 options, invoke the command @command{x264 --fullhelp} or consult
2026 the libx264 documentation.
2029 @item b (@emph{bitrate})
2030 Set bitrate in bits/s. Note that FFmpeg's @option{b} option is
2031 expressed in bits/s, while @command{x264}'s @option{bitrate} is in
2034 @item bf (@emph{bframes})
2036 @item g (@emph{keyint})
2038 @item qmin (@emph{qpmin})
2039 Minimum quantizer scale.
2041 @item qmax (@emph{qpmax})
2042 Maximum quantizer scale.
2044 @item qdiff (@emph{qpstep})
2045 Maximum difference between quantizer scales.
2047 @item qblur (@emph{qblur})
2048 Quantizer curve blur
2050 @item qcomp (@emph{qcomp})
2051 Quantizer curve compression factor
2053 @item refs (@emph{ref})
2054 Number of reference frames each P-frame can use. The range is from @var{0-16}.
2056 @item sc_threshold (@emph{scenecut})
2057 Sets the threshold for the scene change detection.
2059 @item trellis (@emph{trellis})
2060 Performs Trellis quantization to increase efficiency. Enabled by default.
2062 @item nr (@emph{nr})
2064 @item me_range (@emph{merange})
2065 Maximum range of the motion search in pixels.
2067 @item me_method (@emph{me})
2068 Set motion estimation method. Possible values in the decreasing order
2072 @item dia (@emph{dia})
2073 @item epzs (@emph{dia})
2074 Diamond search with radius 1 (fastest). @samp{epzs} is an alias for
2076 @item hex (@emph{hex})
2077 Hexagonal search with radius 2.
2078 @item umh (@emph{umh})
2079 Uneven multi-hexagon search.
2080 @item esa (@emph{esa})
2082 @item tesa (@emph{tesa})
2083 Hadamard exhaustive search (slowest).
2087 Normally, when forcing a I-frame type, the encoder can select any type
2088 of I-frame. This option forces it to choose an IDR-frame.
2090 @item subq (@emph{subme})
2091 Sub-pixel motion estimation method.
2093 @item b_strategy (@emph{b-adapt})
2094 Adaptive B-frame placement decision algorithm. Use only on first-pass.
2096 @item keyint_min (@emph{min-keyint})
2100 Set entropy encoder. Possible values:
2107 Enable CAVLC and disable CABAC. It generates the same effect as
2108 @command{x264}'s @option{--no-cabac} option.
2112 Set full pixel motion estimation comparison algorithm. Possible values:
2116 Enable chroma in motion estimation.
2119 Ignore chroma in motion estimation. It generates the same effect as
2120 @command{x264}'s @option{--no-chroma-me} option.
2123 @item threads (@emph{threads})
2124 Number of encoding threads.
2127 Set multithreading technique. Possible values:
2131 Slice-based multithreading. It generates the same effect as
2132 @command{x264}'s @option{--sliced-threads} option.
2134 Frame-based multithreading.
2138 Set encoding flags. It can be used to disable closed GOP and enable
2139 open GOP by setting it to @code{-cgop}. The result is similar to
2140 the behavior of @command{x264}'s @option{--open-gop} option.
2142 @item rc_init_occupancy (@emph{vbv-init})
2144 @item preset (@emph{preset})
2145 Set the encoding preset.
2147 @item tune (@emph{tune})
2148 Set tuning of the encoding params.
2150 @item profile (@emph{profile})
2151 Set profile restrictions.
2154 Enable fast settings when encoding first pass, when set to 1. When set
2155 to 0, it has the same effect of @command{x264}'s
2156 @option{--slow-firstpass} option.
2158 @item crf (@emph{crf})
2159 Set the quality for constant quality mode.
2161 @item crf_max (@emph{crf-max})
2162 In CRF mode, prevents VBV from lowering quality beyond this point.
2164 @item qp (@emph{qp})
2165 Set constant quantization rate control method parameter.
2167 @item aq-mode (@emph{aq-mode})
2168 Set AQ method. Possible values:
2171 @item none (@emph{0})
2174 @item variance (@emph{1})
2175 Variance AQ (complexity mask).
2177 @item autovariance (@emph{2})
2178 Auto-variance AQ (experimental).
2181 @item aq-strength (@emph{aq-strength})
2182 Set AQ strength, reduce blocking and blurring in flat and textured areas.
2185 Use psychovisual optimizations when set to 1. When set to 0, it has the
2186 same effect as @command{x264}'s @option{--no-psy} option.
2188 @item psy-rd (@emph{psy-rd})
2189 Set strength of psychovisual optimization, in
2190 @var{psy-rd}:@var{psy-trellis} format.
2192 @item rc-lookahead (@emph{rc-lookahead})
2193 Set number of frames to look ahead for frametype and ratecontrol.
2196 Enable weighted prediction for B-frames when set to 1. When set to 0,
2197 it has the same effect as @command{x264}'s @option{--no-weightb} option.
2199 @item weightp (@emph{weightp})
2200 Set weighted prediction method for P-frames. Possible values:
2203 @item none (@emph{0})
2205 @item simple (@emph{1})
2206 Enable only weighted refs
2207 @item smart (@emph{2})
2208 Enable both weighted refs and duplicates
2211 @item ssim (@emph{ssim})
2212 Enable calculation and printing SSIM stats after the encoding.
2214 @item intra-refresh (@emph{intra-refresh})
2215 Enable the use of Periodic Intra Refresh instead of IDR frames when set
2218 @item avcintra-class (@emph{class})
2219 Configure the encoder to generate AVC-Intra.
2220 Valid values are 50,100 and 200
2222 @item bluray-compat (@emph{bluray-compat})
2223 Configure the encoder to be compatible with the bluray standard.
2224 It is a shorthand for setting "bluray-compat=1 force-cfr=1".
2226 @item b-bias (@emph{b-bias})
2227 Set the influence on how often B-frames are used.
2229 @item b-pyramid (@emph{b-pyramid})
2230 Set method for keeping of some B-frames as references. Possible values:
2233 @item none (@emph{none})
2235 @item strict (@emph{strict})
2236 Strictly hierarchical pyramid.
2237 @item normal (@emph{normal})
2238 Non-strict (not Blu-ray compatible).
2242 Enable the use of one reference per partition, as opposed to one
2243 reference per macroblock when set to 1. When set to 0, it has the
2244 same effect as @command{x264}'s @option{--no-mixed-refs} option.
2247 Enable adaptive spatial transform (high profile 8x8 transform)
2248 when set to 1. When set to 0, it has the same effect as
2249 @command{x264}'s @option{--no-8x8dct} option.
2252 Enable early SKIP detection on P-frames when set to 1. When set
2253 to 0, it has the same effect as @command{x264}'s
2254 @option{--no-fast-pskip} option.
2256 @item aud (@emph{aud})
2257 Enable use of access unit delimiters when set to 1.
2260 Enable use macroblock tree ratecontrol when set to 1. When set
2261 to 0, it has the same effect as @command{x264}'s
2262 @option{--no-mbtree} option.
2264 @item deblock (@emph{deblock})
2265 Set loop filter parameters, in @var{alpha}:@var{beta} form.
2267 @item cplxblur (@emph{cplxblur})
2268 Set fluctuations reduction in QP (before curve compression).
2270 @item partitions (@emph{partitions})
2271 Set partitions to consider as a comma-separated list of. Possible
2276 8x8 P-frame partition.
2278 4x4 P-frame partition.
2280 4x4 B-frame partition.
2282 8x8 I-frame partition.
2284 4x4 I-frame partition.
2285 (Enabling @samp{p4x4} requires @samp{p8x8} to be enabled. Enabling
2286 @samp{i8x8} requires adaptive spatial transform (@option{8x8dct}
2287 option) to be enabled.)
2288 @item none (@emph{none})
2289 Do not consider any partitions.
2290 @item all (@emph{all})
2291 Consider every partition.
2294 @item direct-pred (@emph{direct})
2295 Set direct MV prediction mode. Possible values:
2298 @item none (@emph{none})
2299 Disable MV prediction.
2300 @item spatial (@emph{spatial})
2301 Enable spatial predicting.
2302 @item temporal (@emph{temporal})
2303 Enable temporal predicting.
2304 @item auto (@emph{auto})
2305 Automatically decided.
2308 @item slice-max-size (@emph{slice-max-size})
2309 Set the limit of the size of each slice in bytes. If not specified
2310 but RTP payload size (@option{ps}) is specified, that is used.
2312 @item stats (@emph{stats})
2313 Set the file name for multi-pass stats.
2315 @item nal-hrd (@emph{nal-hrd})
2316 Set signal HRD information (requires @option{vbv-bufsize} to be set).
2320 @item none (@emph{none})
2321 Disable HRD information signaling.
2322 @item vbr (@emph{vbr})
2324 @item cbr (@emph{cbr})
2325 Constant bit rate (not allowed in MP4 container).
2328 @item x264opts (N.A.)
2329 Set any x264 option, see @command{x264 --fullhelp} for a list.
2331 Argument is a list of @var{key}=@var{value} couples separated by
2332 ":". In @var{filter} and @var{psy-rd} options that use ":" as a separator
2333 themselves, use "," instead. They accept it as well since long ago but this
2334 is kept undocumented for some reason.
2336 For example to specify libx264 encoding options with @command{ffmpeg}:
2338 ffmpeg -i foo.mpg -c:v libx264 -x264opts keyint=123:min-keyint=20 -an out.mkv
2341 @item a53cc @var{boolean}
2342 Import closed captions (which must be ATSC compatible format) into output.
2343 Only the mpeg2 and h264 decoders provide these. Default is 1 (on).
2345 @item x264-params (N.A.)
2346 Override the x264 configuration using a :-separated list of key=value
2349 This option is functionally the same as the @option{x264opts}, but is
2350 duplicated for compatibility with the Libav fork.
2352 For example to specify libx264 encoding options with @command{ffmpeg}:
2354 ffmpeg -i INPUT -c:v libx264 -x264-params level=30:bframes=0:weightp=0:\
2355 cabac=0:ref=1:vbv-maxrate=768:vbv-bufsize=2000:analyse=all:me=umh:\
2356 no-fast-pskip=1:subq=6:8x8dct=0:trellis=0 OUTPUT
2360 Encoding ffpresets for common usages are provided so they can be used with the
2361 general presets system (e.g. passing the @option{pre} option).
2365 x265 H.265/HEVC encoder wrapper.
2367 This encoder requires the presence of the libx265 headers and library
2368 during configuration. You need to explicitly configure the build with
2369 @option{--enable-libx265}.
2375 Set the x265 preset.
2378 Set the x265 tune parameter.
2381 Set profile restrictions.
2384 Set the quality for constant quality mode.
2387 Normally, when forcing a I-frame type, the encoder can select any type
2388 of I-frame. This option forces it to choose an IDR-frame.
2391 Set x265 options using a list of @var{key}=@var{value} couples separated
2392 by ":". See @command{x265 --help} for a list of options.
2394 For example to specify libx265 encoding options with @option{-x265-params}:
2397 ffmpeg -i input -c:v libx265 -x265-params crf=26:psy-rd=1 output.mp4
2403 xavs2 AVS2-P2/IEEE1857.4 encoder wrapper.
2405 This encoder requires the presence of the libxavs2 headers and library
2406 during configuration. You need to explicitly configure the build with
2407 @option{--enable-libxavs2}.
2409 The following standard libavcodec options are used:
2412 @option{b} / @option{bit_rate}
2414 @option{g} / @option{gop_size}
2416 @option{bf} / @option{max_b_frames}
2419 The encoder also has its own specific options:
2423 @item lcu_row_threads
2424 Set the number of parallel threads for rows from 1 to 8 (default 5).
2427 Set the xavs2 quantization parameter from 1 to 63 (default 34). This is
2428 used to set the initial qp for the first frame.
2431 Set the xavs2 quantization parameter from 1 to 63 (default 34). This is
2432 used to set the qp value under constant-QP mode.
2435 Set the max qp for rate control from 1 to 63 (default 55).
2438 Set the min qp for rate control from 1 to 63 (default 20).
2441 Set the Speed level from 0 to 9 (default 0). Higher is better but slower.
2444 Set the log level from -1 to 3 (default 0). -1: none, 0: error,
2445 1: warning, 2: info, 3: debug.
2448 Set xavs2 options using a list of @var{key}=@var{value} couples separated
2451 For example to specify libxavs2 encoding options with @option{-xavs2-params}:
2454 ffmpeg -i input -c:v libxavs2 -xavs2-params RdoqLevel=0 output.avs2
2460 Xvid MPEG-4 Part 2 encoder wrapper.
2462 This encoder requires the presence of the libxvidcore headers and library
2463 during configuration. You need to explicitly configure the build with
2464 @code{--enable-libxvid --enable-gpl}.
2466 The native @code{mpeg4} encoder supports the MPEG-4 Part 2 format, so
2467 users can encode to this format without this library.
2471 The following options are supported by the libxvid wrapper. Some of
2472 the following options are listed but are not documented, and
2473 correspond to shared codec options. See @ref{codec-options,,the Codec
2474 Options chapter} for their documentation. The other shared options
2475 which are not listed have no effect for the libxvid encoder.
2497 Set specific encoding flags. Possible values:
2502 Use four motion vector by macroblock.
2505 Enable high quality AC prediction.
2508 Only encode grayscale.
2511 Enable the use of global motion compensation (GMC).
2514 Enable quarter-pixel motion compensation.
2520 Place global headers in extradata instead of every keyframe.
2527 Set motion estimation method. Possible values in decreasing order of
2528 speed and increasing order of quality:
2532 Use no motion estimation (default).
2537 Enable advanced diamond zonal search for 16x16 blocks and half-pixel
2538 refinement for 16x16 blocks. @samp{x1} and @samp{log} are aliases for
2542 Enable all of the things described above, plus advanced diamond zonal
2543 search for 8x8 blocks, half-pixel refinement for 8x8 blocks, and motion
2544 estimation on chroma planes.
2547 Enable all of the things described above, plus extended 16x16 and 8x8
2552 Set macroblock decision algorithm. Possible values in the increasing
2557 Use macroblock comparing function algorithm (default).
2560 Enable rate distortion-based half pixel and quarter pixel refinement for
2564 Enable all of the things described above, plus rate distortion-based
2565 half pixel and quarter pixel refinement for 8x8 blocks, and rate
2566 distortion-based search using square pattern.
2570 Enable lumi masking adaptive quantization when set to 1. Default is 0
2574 Enable variance adaptive quantization when set to 1. Default is 0
2577 When combined with @option{lumi_aq}, the resulting quality will not
2578 be better than any of the two specified individually. In other
2579 words, the resulting quality will be the worse one of the two
2583 Set structural similarity (SSIM) displaying method. Possible values:
2587 Disable displaying of SSIM information.
2590 Output average SSIM at the end of encoding to stdout. The format of
2591 showing the average SSIM is:
2597 For users who are not familiar with C, %f means a float number, or
2598 a decimal (e.g. 0.939232).
2601 Output both per-frame SSIM data during encoding and average SSIM at
2602 the end of encoding to stdout. The format of per-frame information
2606 SSIM: avg: %1.3f min: %1.3f max: %1.3f
2609 For users who are not familiar with C, %1.3f means a float number
2610 rounded to 3 digits after the dot (e.g. 0.932).
2615 Set SSIM accuracy. Valid options are integers within the range of
2616 0-4, while 0 gives the most accurate result and 4 computes the
2623 MPEG-2 video encoder.
2628 @item seq_disp_ext @var{integer}
2629 Specifies if the encoder should write a sequence_display_extension to the
2634 Decide automatically to write it or not (this is the default) by checking if
2635 the data to be written is different from the default or unspecified values.
2643 @item video_format @var{integer}
2644 Specifies the video_format written into the sequence display extension
2645 indicating the source of the video pictures. The default is @samp{unspecified},
2646 can be @samp{component}, @samp{pal}, @samp{ntsc}, @samp{secam} or @samp{mac}.
2647 For maximum compatibility, use @samp{component}.
2648 @item a53cc @var{boolean}
2649 Import closed captions (which must be ATSC compatible format) into output.
2657 @subsection Private options
2660 @item dpi @var{integer}
2661 Set physical density of pixels, in dots per inch, unset by default
2662 @item dpm @var{integer}
2663 Set physical density of pixels, in dots per meter, unset by default
2668 Apple ProRes encoder.
2670 FFmpeg contains 2 ProRes encoders, the prores-aw and prores-ks encoder.
2671 The used encoder can be chosen with the @code{-vcodec} option.
2673 @subsection Private Options for prores-ks
2676 @item profile @var{integer}
2677 Select the ProRes profile to encode
2687 @item quant_mat @var{integer}
2688 Select quantization matrix.
2697 If set to @var{auto}, the matrix matching the profile will be picked.
2698 If not set, the matrix providing the highest quality, @var{default}, will be
2701 @item bits_per_mb @var{integer}
2702 How many bits to allot for coding one macroblock. Different profiles use
2703 between 200 and 2400 bits per macroblock, the maximum is 8000.
2705 @item mbs_per_slice @var{integer}
2706 Number of macroblocks in each slice (1-8); the default value (8)
2707 should be good in almost all situations.
2709 @item vendor @var{string}
2710 Override the 4-byte vendor ID.
2711 A custom vendor ID like @var{apl0} would claim the stream was produced by
2714 @item alpha_bits @var{integer}
2715 Specify number of bits for alpha component.
2716 Possible values are @var{0}, @var{8} and @var{16}.
2717 Use @var{0} to disable alpha plane coding.
2721 @subsection Speed considerations
2723 In the default mode of operation the encoder has to honor frame constraints
2724 (i.e. not produce frames with size bigger than requested) while still making
2725 output picture as good as possible.
2726 A frame containing a lot of small details is harder to compress and the encoder
2727 would spend more time searching for appropriate quantizers for each slice.
2729 Setting a higher @option{bits_per_mb} limit will improve the speed.
2731 For the fastest encoding speed set the @option{qscale} parameter (4 is the
2732 recommended value) and do not set a size constraint.
2734 @section QSV encoders
2736 The family of Intel QuickSync Video encoders (MPEG-2, H.264 and HEVC)
2738 The ratecontrol method is selected as follows:
2742 When @option{global_quality} is specified, a quality-based mode is used.
2743 Specifically this means either
2746 @var{CQP} - constant quantizer scale, when the @option{qscale} codec flag is
2747 also set (the @option{-qscale} ffmpeg option).
2750 @var{LA_ICQ} - intelligent constant quality with lookahead, when the
2751 @option{look_ahead} option is also set.
2754 @var{ICQ} -- intelligent constant quality otherwise.
2758 Otherwise, a bitrate-based mode is used. For all of those, you should specify at
2759 least the desired average bitrate with the @option{b} option.
2762 @var{LA} - VBR with lookahead, when the @option{look_ahead} option is specified.
2765 @var{VCM} - video conferencing mode, when the @option{vcm} option is set.
2768 @var{CBR} - constant bitrate, when @option{maxrate} is specified and equal to
2769 the average bitrate.
2772 @var{VBR} - variable bitrate, when @option{maxrate} is specified, but is higher
2773 than the average bitrate.
2776 @var{AVBR} - average VBR mode, when @option{maxrate} is not specified. This mode
2777 is further configured by the @option{avbr_accuracy} and
2778 @option{avbr_convergence} options.
2782 Note that depending on your system, a different mode than the one you specified
2783 may be selected by the encoder. Set the verbosity level to @var{verbose} or
2784 higher to see the actual settings used by the QSV runtime.
2786 Additional libavcodec global options are mapped to MSDK options as follows:
2790 @option{g/gop_size} -> @option{GopPicSize}
2793 @option{bf/max_b_frames}+1 -> @option{GopRefDist}
2796 @option{rc_init_occupancy/rc_initial_buffer_occupancy} ->
2797 @option{InitialDelayInKB}
2800 @option{slices} -> @option{NumSlice}
2803 @option{refs} -> @option{NumRefFrame}
2806 @option{b_strategy/b_frame_strategy} -> @option{BRefType}
2809 @option{cgop/CLOSED_GOP} codec flag -> @option{GopOptFlag}
2812 For the @var{CQP} mode, the @option{i_qfactor/i_qoffset} and
2813 @option{b_qfactor/b_qoffset} set the difference between @var{QPP} and @var{QPI},
2814 and @var{QPP} and @var{QPB} respectively.
2817 Setting the @option{coder} option to the value @var{vlc} will make the H.264
2818 encoder use CAVLC instead of CABAC.
2827 @item iterative_dia_size
2828 dia size for the iterative motion estimation
2831 @section VAAPI encoders
2833 Wrappers for hardware encoders accessible via VAAPI.
2835 These encoders only accept input in VAAPI hardware surfaces. If you have input
2836 in software frames, use the @option{hwupload} filter to upload them to the GPU.
2838 The following standard libavcodec options are used:
2841 @option{g} / @option{gop_size}
2843 @option{bf} / @option{max_b_frames}
2847 If not set, this will be determined automatically from the format of the input
2848 frames and the profiles supported by the driver.
2852 @option{b} / @option{bit_rate}
2854 @option{maxrate} / @option{rc_max_rate}
2856 @option{bufsize} / @option{rc_buffer_size}
2858 @option{rc_init_occupancy} / @option{rc_initial_buffer_occupancy}
2860 @option{compression_level}
2862 Speed / quality tradeoff: higher values are faster / worse quality.
2864 @option{q} / @option{global_quality}
2866 Size / quality tradeoff: higher values are smaller / worse quality.
2872 @option{i_qfactor} / @option{i_quant_factor}
2874 @option{i_qoffset} / @option{i_quant_offset}
2876 @option{b_qfactor} / @option{b_quant_factor}
2878 @option{b_qoffset} / @option{b_quant_offset}
2883 All encoders support the following options:
2886 Some drivers/platforms offer a second encoder for some codecs intended to use
2887 less power than the default encoder; setting this option will attempt to use
2888 that encoder. Note that it may support a reduced feature set, so some other
2889 options may not be available in this mode.
2892 Set the number of normal intra frames between full-refresh (IDR) frames in
2893 open-GOP mode. The intra frames are still IRAPs, but will not include global
2894 headers and may have non-decodable leading pictures.
2897 Set the B-frame reference depth. When set to one (the default), all B-frames
2898 will refer only to P- or I-frames. When set to greater values multiple layers
2899 of B-frames will be present, frames in each layer only referring to frames in
2903 Set the rate control mode to use. A given driver may only support a subset of
2909 Choose the mode automatically based on driver support and the other options.
2910 This is the default.
2918 Intelligent constant-quality.
2920 Quality-defined variable-bitrate.
2922 Average variable bitrate.
2927 Each encoder also has its own specific options:
2931 @option{profile} sets the value of @emph{profile_idc} and the @emph{constraint_set*_flag}s.
2932 @option{level} sets the value of @emph{level_idc}.
2936 Set entropy encoder (default is @emph{cabac}). Possible values:
2949 Include access unit delimiters in the stream (not included by default).
2952 Set SEI message types to include.
2953 Some combination of the following values:
2956 Include a @emph{user_data_unregistered} message containing information about
2959 Include picture timing parameters (@emph{buffering_period} and
2960 @emph{pic_timing} messages).
2961 @item recovery_point
2962 Include recovery points where appropriate (@emph{recovery_point} messages).
2968 @option{profile} and @option{level} set the values of
2969 @emph{general_profile_idc} and @emph{general_level_idc} respectively.
2973 Include access unit delimiters in the stream (not included by default).
2976 Set @emph{general_tier_flag}. This may affect the level chosen for the stream
2977 if it is not explicitly specified.
2980 Set SEI message types to include.
2981 Some combination of the following values:
2984 Include HDR metadata if the input frames have it
2985 (@emph{mastering_display_colour_volume} and @emph{content_light_level}
2992 Only baseline DCT encoding is supported. The encoder always uses the standard
2993 quantisation and huffman tables - @option{global_quality} scales the standard
2994 quantisation table (range 1-100).
2996 For YUV, 4:2:0, 4:2:2 and 4:4:4 subsampling modes are supported. RGB is also
2997 supported, and will create an RGB JPEG.
3001 Include JFIF header in each frame (not included by default).
3003 Include standard huffman tables (on by default). Turning this off will save
3004 a few hundred bytes in each output frame, but may lose compatibility with some
3005 JPEG decoders which don't fully handle MJPEG.
3009 @option{profile} and @option{level} set the value of @emph{profile_and_level_indication}.
3012 B-frames are not supported.
3014 @option{global_quality} sets the @emph{q_idx} used for non-key frames (range 0-127).
3017 @item loop_filter_level
3018 @item loop_filter_sharpness
3019 Manually set the loop filter parameters.
3023 @option{global_quality} sets the @emph{q_idx} used for P-frames (range 0-255).
3026 @item loop_filter_level
3027 @item loop_filter_sharpness
3028 Manually set the loop filter parameters.
3031 B-frames are supported, but the output stream is always in encode order rather than display
3032 order. If B-frames are enabled, it may be necessary to use the @option{vp9_raw_reorder}
3033 bitstream filter to modify the output stream to display frames in the correct order.
3035 Only normal frames are produced - the @option{vp9_superframe} bitstream filter may be
3036 required to produce a stream usable with all decoders.
3042 SMPTE VC-2 (previously BBC Dirac Pro). This codec was primarily aimed at
3043 professional broadcasting but since it supports yuv420, yuv422 and yuv444 at
3044 8 (limited range or full range), 10 or 12 bits, this makes it suitable for
3045 other tasks which require low overhead and low compression (like screen
3053 Sets target video bitrate. Usually that's around 1:6 of the uncompressed
3054 video bitrate (e.g. for 1920x1080 50fps yuv422p10 that's around 400Mbps). Higher
3055 values (close to the uncompressed bitrate) turn on lossless compression mode.
3058 Enables field coding when set (e.g. to tt - top field first) for interlaced
3059 inputs. Should increase compression with interlaced content as it splits the
3060 fields and encodes each separately.
3063 Sets the total amount of wavelet transforms to apply, between 1 and 5 (default).
3064 Lower values reduce compression and quality. Less capable decoders may not be
3065 able to handle values of @option{wavelet_depth} over 3.
3068 Sets the transform type. Currently only @var{5_3} (LeGall) and @var{9_7}
3070 are implemented, with 9_7 being the one with better compression and thus
3075 Sets the slice size for each slice. Larger values result in better compression.
3076 For compatibility with other more limited decoders use @option{slice_width} of
3077 32 and @option{slice_height} of 8.
3080 Sets the undershoot tolerance of the rate control system in percent. This is
3081 to prevent an expensive search from being run.
3084 Sets the quantization matrix preset to use by default or when @option{wavelet_depth}
3089 Uses the default quantization matrix from the specifications, extended with
3090 values for the fifth level. This provides a good balance between keeping detail
3091 and omitting artifacts.
3095 Use a completely zeroed out quantization matrix. This increases PSNR but might
3096 reduce perception. Use in bogus benchmarks.
3100 Reduces detail but attempts to preserve color at extremely low bitrates.
3105 @c man end VIDEO ENCODERS
3107 @chapter Subtitles Encoders
3108 @c man begin SUBTITLES ENCODERS
3112 This codec encodes the bitmap subtitle format that is used in DVDs.
3113 Typically they are stored in VOBSUB file pairs (*.idx + *.sub),
3114 and they can also be used in Matroska files.
3120 When set to 1, enable a work-around that makes the number of pixel rows
3121 even in all subtitles. This fixes a problem with some players that
3122 cut off the bottom row if the number is odd. The work-around just adds
3123 a fully transparent row if needed. The overhead is low, typically
3124 one byte per subtitle on average.
3126 By default, this work-around is disabled.
3129 @c man end SUBTITLES ENCODERS