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.
39 Set bit rate in bits/s. Setting this automatically activates constant bit rate
40 (CBR) mode. If this option is unspecified it is set to 128kbps.
43 Set quality for variable bit rate (VBR) mode. This option is valid only using
44 the @command{ffmpeg} command-line tool. For library interface users, use
45 @option{global_quality}.
48 Set cutoff frequency. If unspecified will allow the encoder to dynamically
49 adjust the cutoff to improve clarity on low bitrates.
52 Set AAC encoder coding method. Possible values:
56 Two loop searching (TLS) method.
58 This method first sets quantizers depending on band thresholds and then tries
59 to find an optimal combination by adding or subtracting a specific value from
60 all quantizers and adjusting some individual quantizer a little. Will tune
61 itself based on whether @option{aac_is}, @option{aac_ms} and @option{aac_pns}
65 Average noise to mask ratio (ANMR) trellis-based solution.
67 This is an experimental coder which currently produces a lower quality, is more
68 unstable and is slower than the default twoloop coder but has potential.
69 Currently has no support for the @option{aac_is} or @option{aac_pns} options.
70 Not currently recommended.
73 Constant quantizer method.
75 Uses a cheaper version of twoloop algorithm that doesn't try to do as many
76 clever adjustments. Worse with low bitrates (less than 64kbps), but is better
77 and much faster at higher bitrates.
78 This is the default choice for a coder
83 Sets mid/side coding mode. The default value of "auto" will automatically use
84 M/S with bands which will benefit from such coding. Can be forced for all bands
85 using the value "enable", which is mainly useful for debugging or disabled using
89 Sets intensity stereo coding tool usage. By default, it's enabled and will
90 automatically toggle IS for similar pairs of stereo bands if it's beneficial.
91 Can be disabled for debugging by setting the value to "disable".
94 Uses perceptual noise substitution to replace low entropy high frequency bands
95 with imperceptible white noise during the decoding process. By default, it's
96 enabled, but can be disabled for debugging purposes by using "disable".
99 Enables the use of a multitap FIR filter which spans through the high frequency
100 bands to hide quantization noise during the encoding process and is reverted
101 by the decoder. As well as decreasing unpleasant artifacts in the high range
102 this also reduces the entropy in the high bands and allows for more bits to
103 be used by the mid-low bands. By default it's enabled but can be disabled for
104 debugging by setting the option to "disable".
107 Enables the use of the long term prediction extension which increases coding
108 efficiency in very low bandwidth situations such as encoding of voice or
109 solo piano music by extending constant harmonic peaks in bands throughout
110 frames. This option is implied by profile:a aac_low and is incompatible with
111 aac_pred. Use in conjunction with @option{-ar} to decrease the samplerate.
114 Enables the use of a more traditional style of prediction where the spectral
115 coefficients transmitted are replaced by the difference of the current
116 coefficients minus the previous "predicted" coefficients. In theory and sometimes
117 in practice this can improve quality for low to mid bitrate audio.
118 This option implies the aac_main profile and is incompatible with aac_ltp.
121 Sets the encoding profile, possible values:
125 The default, AAC "Low-complexity" profile. Is the most compatible and produces
129 Equivalent to @code{-profile:a aac_low -aac_pns 0}. PNS was introduced with the
130 MPEG4 specifications.
133 Long term prediction profile, is enabled by and will enable the @option{aac_ltp}
134 option. Introduced in MPEG4.
137 Main-type prediction profile, is enabled by and will enable the @option{aac_pred}
138 option. Introduced in MPEG2.
141 If this option is unspecified it is set to @samp{aac_low}.
144 @section ac3 and ac3_fixed
148 These encoders implement part of ATSC A/52:2010 and ETSI TS 102 366, as well as
149 the undocumented RealAudio 3 (a.k.a. dnet).
151 The @var{ac3} encoder uses floating-point math, while the @var{ac3_fixed}
152 encoder only uses fixed-point integer math. This does not mean that one is
153 always faster, just that one or the other may be better suited to a
154 particular system. The floating-point encoder will generally produce better
155 quality audio for a given bitrate. The @var{ac3_fixed} encoder is not the
156 default codec for any of the output formats, so it must be specified explicitly
157 using the option @code{-acodec ac3_fixed} in order to use it.
159 @subsection AC-3 Metadata
161 The AC-3 metadata options are used to set parameters that describe the audio,
162 but in most cases do not affect the audio encoding itself. Some of the options
163 do directly affect or influence the decoding and playback of the resulting
164 bitstream, while others are just for informational purposes. A few of the
165 options will add bits to the output stream that could otherwise be used for
166 audio data, and will thus affect the quality of the output. Those will be
167 indicated accordingly with a note in the option list below.
169 These parameters are described in detail in several publicly-available
172 @item @uref{http://www.atsc.org/cms/standards/a_52-2010.pdf,A/52:2010 - Digital Audio Compression (AC-3) (E-AC-3) Standard}
173 @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}
174 @item @uref{http://www.dolby.com/uploadedFiles/zz-_Shared_Assets/English_PDFs/Professional/18_Metadata.Guide.pdf,Dolby Metadata Guide}
175 @item @uref{http://www.dolby.com/uploadedFiles/zz-_Shared_Assets/English_PDFs/Professional/46_DDEncodingGuidelines.pdf,Dolby Digital Professional Encoding Guidelines}
178 @subsubsection Metadata Control Options
182 @item -per_frame_metadata @var{boolean}
183 Allow Per-Frame Metadata. Specifies if the encoder should check for changing
184 metadata for each frame.
187 The metadata values set at initialization will be used for every frame in the
190 Metadata values can be changed before encoding each frame.
195 @subsubsection Downmix Levels
199 @item -center_mixlev @var{level}
200 Center Mix Level. The amount of gain the decoder should apply to the center
201 channel when downmixing to stereo. This field will only be written to the
202 bitstream if a center channel is present. The value is specified as a scale
203 factor. There are 3 valid values:
208 Apply -4.5dB gain (default)
213 @item -surround_mixlev @var{level}
214 Surround Mix Level. The amount of gain the decoder should apply to the surround
215 channel(s) when downmixing to stereo. This field will only be written to the
216 bitstream if one or more surround channels are present. The value is specified
217 as a scale factor. There are 3 valid values:
222 Apply -6dB gain (default)
224 Silence Surround Channel(s)
229 @subsubsection Audio Production Information
230 Audio Production Information is optional information describing the mixing
231 environment. Either none or both of the fields are written to the bitstream.
235 @item -mixing_level @var{number}
236 Mixing Level. Specifies peak sound pressure level (SPL) in the production
237 environment when the mix was mastered. Valid values are 80 to 111, or -1 for
238 unknown or not indicated. The default value is -1, but that value cannot be
239 used if the Audio Production Information is written to the bitstream. Therefore,
240 if the @code{room_type} option is not the default value, the @code{mixing_level}
241 option must not be -1.
243 @item -room_type @var{type}
244 Room Type. Describes the equalization used during the final mixing session at
245 the studio or on the dubbing stage. A large room is a dubbing stage with the
246 industry standard X-curve equalization; a small room has flat equalization.
247 This field will not be written to the bitstream if both the @code{mixing_level}
248 option and the @code{room_type} option have the default values.
252 Not Indicated (default)
263 @subsubsection Other Metadata Options
267 @item -copyright @var{boolean}
268 Copyright Indicator. Specifies whether a copyright exists for this audio.
272 No Copyright Exists (default)
278 @item -dialnorm @var{value}
279 Dialogue Normalization. Indicates how far the average dialogue level of the
280 program is below digital 100% full scale (0 dBFS). This parameter determines a
281 level shift during audio reproduction that sets the average volume of the
282 dialogue to a preset level. The goal is to match volume level between program
283 sources. A value of -31dB will result in no volume level change, relative to
284 the source volume, during audio reproduction. Valid values are whole numbers in
285 the range -31 to -1, with -31 being the default.
287 @item -dsur_mode @var{mode}
288 Dolby Surround Mode. Specifies whether the stereo signal uses Dolby Surround
289 (Pro Logic). This field will only be written to the bitstream if the audio
290 stream is stereo. Using this option does @b{NOT} mean the encoder will actually
291 apply Dolby Surround processing.
295 Not Indicated (default)
298 Not Dolby Surround Encoded
301 Dolby Surround Encoded
304 @item -original @var{boolean}
305 Original Bit Stream Indicator. Specifies whether this audio is from the
306 original source and not a copy.
313 Original Source (default)
318 @subsection Extended Bitstream Information
319 The extended bitstream options are part of the Alternate Bit Stream Syntax as
320 specified in Annex D of the A/52:2010 standard. It is grouped into 2 parts.
321 If any one parameter in a group is specified, all values in that group will be
322 written to the bitstream. Default values are used for those that are written
323 but have not been specified. If the mixing levels are written, the decoder
324 will use these values instead of the ones specified in the @code{center_mixlev}
325 and @code{surround_mixlev} options if it supports the Alternate Bit Stream
328 @subsubsection Extended Bitstream Information - Part 1
332 @item -dmix_mode @var{mode}
333 Preferred Stereo Downmix Mode. Allows the user to select either Lt/Rt
334 (Dolby Surround) or Lo/Ro (normal stereo) as the preferred stereo downmix mode.
338 Not Indicated (default)
341 Lt/Rt Downmix Preferred
344 Lo/Ro Downmix Preferred
347 @item -ltrt_cmixlev @var{level}
348 Lt/Rt Center Mix Level. The amount of gain the decoder should apply to the
349 center channel when downmixing to stereo in Lt/Rt mode.
362 Apply -4.5dB gain (default)
366 Silence Center Channel
369 @item -ltrt_surmixlev @var{level}
370 Lt/Rt Surround Mix Level. The amount of gain the decoder should apply to the
371 surround channel(s) when downmixing to stereo in Lt/Rt mode.
380 Apply -6.0dB gain (default)
382 Silence Surround Channel(s)
385 @item -loro_cmixlev @var{level}
386 Lo/Ro Center Mix Level. The amount of gain the decoder should apply to the
387 center channel when downmixing to stereo in Lo/Ro mode.
400 Apply -4.5dB gain (default)
404 Silence Center Channel
407 @item -loro_surmixlev @var{level}
408 Lo/Ro Surround Mix Level. The amount of gain the decoder should apply to the
409 surround channel(s) when downmixing to stereo in Lo/Ro mode.
418 Apply -6.0dB gain (default)
420 Silence Surround Channel(s)
425 @subsubsection Extended Bitstream Information - Part 2
429 @item -dsurex_mode @var{mode}
430 Dolby Surround EX Mode. Indicates whether the stream uses Dolby Surround EX
431 (7.1 matrixed to 5.1). Using this option does @b{NOT} mean the encoder will actually
432 apply Dolby Surround EX processing.
436 Not Indicated (default)
439 Dolby Surround EX Off
445 @item -dheadphone_mode @var{mode}
446 Dolby Headphone Mode. Indicates whether the stream uses Dolby Headphone
447 encoding (multi-channel matrixed to 2.0 for use with headphones). Using this
448 option does @b{NOT} mean the encoder will actually apply Dolby Headphone
453 Not Indicated (default)
462 @item -ad_conv_type @var{type}
463 A/D Converter Type. Indicates whether the audio has passed through HDCD A/D
468 Standard A/D Converter (default)
476 @subsection Other AC-3 Encoding Options
480 @item -stereo_rematrixing @var{boolean}
481 Stereo Rematrixing. Enables/Disables use of rematrixing for stereo input. This
482 is an optional AC-3 feature that increases quality by selectively encoding
483 the left/right channels as mid/side. This option is enabled by default, and it
484 is highly recommended that it be left as enabled except for testing purposes.
486 @item cutoff @var{frequency}
487 Set lowpass cutoff frequency. If unspecified, the encoder selects a default
488 determined by various other encoding parameters.
492 @subsection Floating-Point-Only AC-3 Encoding Options
494 These options are only valid for the floating-point encoder and do not exist
495 for the fixed-point encoder due to the corresponding features not being
496 implemented in fixed-point.
500 @item -channel_coupling @var{boolean}
501 Enables/Disables use of channel coupling, which is an optional AC-3 feature
502 that increases quality by combining high frequency information from multiple
503 channels into a single channel. The per-channel high frequency information is
504 sent with less accuracy in both the frequency and time domains. This allows
505 more bits to be used for lower frequencies while preserving enough information
506 to reconstruct the high frequencies. This option is enabled by default for the
507 floating-point encoder and should generally be left as enabled except for
508 testing purposes or to increase encoding speed.
512 Selected by Encoder (default)
515 Disable Channel Coupling
518 Enable Channel Coupling
521 @item -cpl_start_band @var{number}
522 Coupling Start Band. Sets the channel coupling start band, from 1 to 15. If a
523 value higher than the bandwidth is used, it will be reduced to 1 less than the
524 coupling end band. If @var{auto} is used, the start band will be determined by
525 the encoder based on the bit rate, sample rate, and channel layout. This option
526 has no effect if channel coupling is disabled.
530 Selected by Encoder (default)
538 FLAC (Free Lossless Audio Codec) Encoder
542 The following options are supported by FFmpeg's flac encoder.
545 @item compression_level
546 Sets the compression level, which chooses defaults for many other options
547 if they are not set explicitly. Valid values are from 0 to 12, 5 is the
551 Sets the size of the frames in samples per channel.
553 @item lpc_coeff_precision
554 Sets the LPC coefficient precision, valid values are from 1 to 15, 15 is the
558 Sets the first stage LPC algorithm
564 fixed LPC coefficients
572 Number of passes to use for Cholesky factorization during LPC analysis
574 @item min_partition_order
575 The minimum partition order
577 @item max_partition_order
578 The maximum partition order
580 @item prediction_order_method
595 The mode is chosen automatically for each frame
597 Channels are independently coded
603 @item exact_rice_parameters
604 Chooses if rice parameters are calculated exactly or approximately.
605 if set to 1 then they are chosen exactly, which slows the code down slightly and
606 improves compression slightly.
608 @item multi_dim_quant
609 Multi Dimensional Quantization. If set to 1 then a 2nd stage LPC algorithm is
610 applied after the first stage to finetune the coefficients. This is quite slow
611 and slightly improves compression.
620 This is a native FFmpeg encoder for the Opus format. Currently its in development and
621 only implements the CELT part of the codec. Its quality is usually worse and at best
622 is equal to the libopus encoder.
628 Set bit rate in bits/s. If unspecified it uses the number of channels and the layout
629 to make a good guess.
632 Sets the maximum delay in milliseconds. Lower delays than 20ms will very quickly
636 @anchor{libfdk-aac-enc}
639 libfdk-aac AAC (Advanced Audio Coding) encoder wrapper.
641 The libfdk-aac library is based on the Fraunhofer FDK AAC code from
644 Requires the presence of the libfdk-aac headers and library during
645 configuration. You need to explicitly configure the build with
646 @code{--enable-libfdk-aac}. The library is also incompatible with GPL,
647 so if you allow the use of GPL, you should configure with
648 @code{--enable-gpl --enable-nonfree --enable-libfdk-aac}.
650 This encoder has support for the AAC-HE profiles.
652 VBR encoding, enabled through the @option{vbr} or @option{flags
653 +qscale} options, is experimental and only works with some
654 combinations of parameters.
656 Support for encoding 7.1 audio is only available with libfdk-aac 0.1.3 or
659 For more information see the fdk-aac project at
660 @url{http://sourceforge.net/p/opencore-amr/fdk-aac/}.
664 The following options are mapped on the shared FFmpeg codec options.
668 Set bit rate in bits/s. If the bitrate is not explicitly specified, it
669 is automatically set to a suitable value depending on the selected
672 In case VBR mode is enabled the option is ignored.
675 Set audio sampling rate (in Hz).
678 Set the number of audio channels.
681 Enable fixed quality, VBR (Variable Bit Rate) mode.
682 Note that VBR is implicitly enabled when the @option{vbr} value is
686 Set cutoff frequency. If not specified (or explicitly set to 0) it
687 will use a value automatically computed by the library. Default value
693 The following profiles are recognized:
696 Low Complexity AAC (LC)
699 High Efficiency AAC (HE-AAC)
702 High Efficiency AAC version 2 (HE-AACv2)
708 Enhanced Low Delay AAC (ELD)
711 If not specified it is set to @samp{aac_low}.
714 The following are private options of the libfdk_aac encoder.
718 Enable afterburner feature if set to 1, disabled if set to 0. This
719 improves the quality but also the required processing power.
724 Enable SBR (Spectral Band Replication) for ELD if set to 1, disabled
730 Enable ELDv2 (LD-MPS extension for ELD stereo signals) for ELDv2 if set to 1,
731 disabled if set to 0.
733 Note that option is available when fdk-aac version (AACENCODER_LIB_VL0.AACENCODER_LIB_VL1.AACENCODER_LIB_VL2) > (4.0.0).
738 Set SBR/PS signaling style.
740 It can assume one of the following values:
743 choose signaling implicitly (explicit hierarchical by default,
744 implicit if global header is disabled)
747 implicit backwards compatible signaling
750 explicit SBR, implicit PS signaling
752 @item explicit_hierarchical
753 explicit hierarchical signaling
756 Default value is @samp{default}.
759 Output LATM/LOAS encapsulated data if set to 1, disabled if set to 0.
764 Set StreamMuxConfig and PCE repetition period (in frames) for sending
765 in-band configuration buffers within LATM/LOAS transport layer.
767 Must be a 16-bits non-negative integer.
772 Set VBR mode, from 1 to 5. 1 is lowest quality (though still pretty
773 good) and 5 is highest quality. A value of 0 will disable VBR, and CBR
774 (Constant Bit Rate) is enabled.
776 Currently only the @samp{aac_low} profile supports VBR encoding.
778 VBR modes 1-5 correspond to roughly the following average bit rates:
790 about 80-96 kbps/channel
800 Use @command{ffmpeg} to convert an audio file to VBR AAC in an M4A (MP4)
803 ffmpeg -i input.wav -codec:a libfdk_aac -vbr 3 output.m4a
807 Use @command{ffmpeg} to convert an audio file to CBR 64k kbps AAC, using the
808 High-Efficiency AAC profile:
810 ffmpeg -i input.wav -c:a libfdk_aac -profile:a aac_he -b:a 64k output.m4a
817 LAME (Lame Ain't an MP3 Encoder) MP3 encoder wrapper.
819 Requires the presence of the libmp3lame headers and library during
820 configuration. You need to explicitly configure the build with
821 @code{--enable-libmp3lame}.
823 See @ref{libshine} for a fixed-point MP3 encoder, although with a
828 The following options are supported by the libmp3lame wrapper. The
829 @command{lame}-equivalent of the options are listed in parentheses.
833 Set bitrate expressed in bits/s for CBR or ABR. LAME @code{bitrate} is
834 expressed in kilobits/s.
837 Set constant quality setting for VBR. This option is valid only
838 using the @command{ffmpeg} command-line tool. For library interface
839 users, use @option{global_quality}.
841 @item compression_level (@emph{-q})
842 Set algorithm quality. Valid arguments are integers in the 0-9 range,
843 with 0 meaning highest quality but slowest, and 9 meaning fastest
844 while producing the worst quality.
846 @item cutoff (@emph{--lowpass})
847 Set lowpass cutoff frequency. If unspecified, the encoder dynamically
851 Enable use of bit reservoir when set to 1. Default value is 1. LAME
852 has this enabled by default, but can be overridden by use
853 @option{--nores} option.
855 @item joint_stereo (@emph{-m j})
856 Enable the encoder to use (on a frame by frame basis) either L/R
857 stereo or mid/side stereo. Default value is 1.
859 @item abr (@emph{--abr})
860 Enable the encoder to use ABR when set to 1. The @command{lame}
861 @option{--abr} sets the target bitrate, while this options only
862 tells FFmpeg to use ABR still relies on @option{b} to set bitrate.
866 @section libopencore-amrnb
868 OpenCORE Adaptive Multi-Rate Narrowband encoder.
870 Requires the presence of the libopencore-amrnb headers and library during
871 configuration. You need to explicitly configure the build with
872 @code{--enable-libopencore-amrnb --enable-version3}.
874 This is a mono-only encoder. Officially it only supports 8000Hz sample rate,
875 but you can override it by setting @option{strict} to @samp{unofficial} or
883 Set bitrate in bits per second. Only the following bitrates are supported,
884 otherwise libavcodec will round to the nearest valid bitrate.
898 Allow discontinuous transmission (generate comfort noise) when set to 1. The
899 default value is 0 (disabled).
905 libopus Opus Interactive Audio Codec encoder wrapper.
907 Requires the presence of the libopus headers and library during
908 configuration. You need to explicitly configure the build with
909 @code{--enable-libopus}.
911 @subsection Option Mapping
913 Most libopus options are modelled after the @command{opusenc} utility from
914 opus-tools. The following is an option mapping chart describing options
915 supported by the libopus wrapper, and their @command{opusenc}-equivalent
920 @item b (@emph{bitrate})
921 Set the bit rate in bits/s. FFmpeg's @option{b} option is
922 expressed in bits/s, while @command{opusenc}'s @option{bitrate} in
925 @item vbr (@emph{vbr}, @emph{hard-cbr}, and @emph{cvbr})
926 Set VBR mode. The FFmpeg @option{vbr} option has the following
927 valid arguments, with the @command{opusenc} equivalent options
931 @item off (@emph{hard-cbr})
932 Use constant bit rate encoding.
934 @item on (@emph{vbr})
935 Use variable bit rate encoding (the default).
937 @item constrained (@emph{cvbr})
938 Use constrained variable bit rate encoding.
941 @item compression_level (@emph{comp})
942 Set encoding algorithm complexity. Valid options are integers in
943 the 0-10 range. 0 gives the fastest encodes but lower quality, while 10
944 gives the highest quality but slowest encoding. The default is 10.
946 @item frame_duration (@emph{framesize})
947 Set maximum frame size, or duration of a frame in milliseconds. The
948 argument must be exactly the following: 2.5, 5, 10, 20, 40, 60. Smaller
949 frame sizes achieve lower latency but less quality at a given bitrate.
950 Sizes greater than 20ms are only interesting at fairly low bitrates.
953 @item packet_loss (@emph{expect-loss})
954 Set expected packet loss percentage. The default is 0.
956 @item application (N.A.)
957 Set intended application type. Valid options are listed below:
961 Favor improved speech intelligibility.
963 Favor faithfulness to the input (the default).
965 Restrict to only the lowest delay modes.
969 Set cutoff bandwidth in Hz. The argument must be exactly one of the
970 following: 4000, 6000, 8000, 12000, or 20000, corresponding to
971 narrowband, mediumband, wideband, super wideband, and fullband
972 respectively. The default is 0 (cutoff disabled).
974 @item mapping_family (@emph{mapping_family})
975 Set channel mapping family to be used by the encoder. The default value of -1
976 uses mapping family 0 for mono and stereo inputs, and mapping family 1
977 otherwise. The default also disables the surround masking and LFE bandwidth
978 optimzations in libopus, and requires that the input contains 8 channels or
981 Other values include 0 for mono and stereo, 1 for surround sound with masking
982 and LFE bandwidth optimizations, and 255 for independent streams with an
983 unspecified channel layout.
985 @item apply_phase_inv (N.A.) (requires libopus >= 1.2)
986 If set to 0, disables the use of phase inversion for intensity stereo,
987 improving the quality of mono downmixes, but slightly reducing normal stereo
988 quality. The default is 1 (phase inversion enabled).
995 Shine Fixed-Point MP3 encoder wrapper.
997 Shine is a fixed-point MP3 encoder. It has a far better performance on
998 platforms without an FPU, e.g. armel CPUs, and some phones and tablets.
999 However, as it is more targeted on performance than quality, it is not on par
1000 with LAME and other production-grade encoders quality-wise. Also, according to
1001 the project's homepage, this encoder may not be free of bugs as the code was
1002 written a long time ago and the project was dead for at least 5 years.
1004 This encoder only supports stereo and mono input. This is also CBR-only.
1006 The original project (last updated in early 2007) is at
1007 @url{http://sourceforge.net/projects/libshine-fxp/}. We only support the
1008 updated fork by the Savonet/Liquidsoap project at @url{https://github.com/savonet/shine}.
1010 Requires the presence of the libshine headers and library during
1011 configuration. You need to explicitly configure the build with
1012 @code{--enable-libshine}.
1014 See also @ref{libmp3lame}.
1018 The following options are supported by the libshine wrapper. The
1019 @command{shineenc}-equivalent of the options are listed in parentheses.
1023 Set bitrate expressed in bits/s for CBR. @command{shineenc} @option{-b} option
1024 is expressed in kilobits/s.
1030 TwoLAME MP2 encoder wrapper.
1032 Requires the presence of the libtwolame headers and library during
1033 configuration. You need to explicitly configure the build with
1034 @code{--enable-libtwolame}.
1038 The following options are supported by the libtwolame wrapper. The
1039 @command{twolame}-equivalent options follow the FFmpeg ones and are in
1044 Set bitrate expressed in bits/s for CBR. @command{twolame} @option{b}
1045 option is expressed in kilobits/s. Default value is 128k.
1048 Set quality for experimental VBR support. Maximum value range is
1049 from -50 to 50, useful range is from -10 to 10. The higher the
1050 value, the better the quality. This option is valid only using the
1051 @command{ffmpeg} command-line tool. For library interface users,
1052 use @option{global_quality}.
1054 @item mode (@emph{--mode})
1055 Set the mode of the resulting audio. Possible values:
1059 Choose mode automatically based on the input. This is the default.
1070 @item psymodel (@emph{--psyc-mode})
1071 Set psychoacoustic model to use in encoding. The argument must be
1072 an integer between -1 and 4, inclusive. The higher the value, the
1073 better the quality. The default value is 3.
1075 @item energy_levels (@emph{--energy})
1076 Enable energy levels extensions when set to 1. The default value is
1079 @item error_protection (@emph{--protect})
1080 Enable CRC error protection when set to 1. The default value is 0
1083 @item copyright (@emph{--copyright})
1084 Set MPEG audio copyright flag when set to 1. The default value is 0
1087 @item original (@emph{--original})
1088 Set MPEG audio original flag when set to 1. The default value is 0
1093 @section libvo-amrwbenc
1095 VisualOn Adaptive Multi-Rate Wideband encoder.
1097 Requires the presence of the libvo-amrwbenc headers and library during
1098 configuration. You need to explicitly configure the build with
1099 @code{--enable-libvo-amrwbenc --enable-version3}.
1101 This is a mono-only encoder. Officially it only supports 16000Hz sample
1102 rate, but you can override it by setting @option{strict} to
1103 @samp{unofficial} or lower.
1110 Set bitrate in bits/s. Only the following bitrates are supported, otherwise
1111 libavcodec will round to the nearest valid bitrate.
1126 Allow discontinuous transmission (generate comfort noise) when set to 1. The
1127 default value is 0 (disabled).
1133 libvorbis encoder wrapper.
1135 Requires the presence of the libvorbisenc headers and library during
1136 configuration. You need to explicitly configure the build with
1137 @code{--enable-libvorbis}.
1141 The following options are supported by the libvorbis wrapper. The
1142 @command{oggenc}-equivalent of the options are listed in parentheses.
1144 To get a more accurate and extensive documentation of the libvorbis
1145 options, consult the libvorbisenc's and @command{oggenc}'s documentations.
1146 See @url{http://xiph.org/vorbis/},
1147 @url{http://wiki.xiph.org/Vorbis-tools}, and oggenc(1).
1151 Set bitrate expressed in bits/s for ABR. @command{oggenc} @option{-b} is
1152 expressed in kilobits/s.
1155 Set constant quality setting for VBR. The value should be a float
1156 number in the range of -1.0 to 10.0. The higher the value, the better
1157 the quality. The default value is @samp{3.0}.
1159 This option is valid only using the @command{ffmpeg} command-line tool.
1160 For library interface users, use @option{global_quality}.
1162 @item cutoff (@emph{--advanced-encode-option lowpass_frequency=N})
1163 Set cutoff bandwidth in Hz, a value of 0 disables cutoff. @command{oggenc}'s
1164 related option is expressed in kHz. The default value is @samp{0} (cutoff
1167 @item minrate (@emph{-m})
1168 Set minimum bitrate expressed in bits/s. @command{oggenc} @option{-m} is
1169 expressed in kilobits/s.
1171 @item maxrate (@emph{-M})
1172 Set maximum bitrate expressed in bits/s. @command{oggenc} @option{-M} is
1173 expressed in kilobits/s. This only has effect on ABR mode.
1175 @item iblock (@emph{--advanced-encode-option impulse_noisetune=N})
1176 Set noise floor bias for impulse blocks. The value is a float number from
1177 -15.0 to 0.0. A negative bias instructs the encoder to pay special attention
1178 to the crispness of transients in the encoded audio. The tradeoff for better
1179 transient response is a higher bitrate.
1186 A wrapper providing WavPack encoding through libwavpack.
1188 Only lossless mode using 32-bit integer samples is supported currently.
1190 Requires the presence of the libwavpack headers and library during
1191 configuration. You need to explicitly configure the build with
1192 @code{--enable-libwavpack}.
1194 Note that a libavcodec-native encoder for the WavPack codec exists so users can
1195 encode audios with this codec without using this encoder. See @ref{wavpackenc}.
1199 @command{wavpack} command line utility's corresponding options are listed in
1200 parentheses, if any.
1203 @item frame_size (@emph{--blocksize})
1206 @item compression_level
1207 Set speed vs. compression tradeoff. Acceptable arguments are listed below:
1214 Normal (default) settings.
1219 @item 3 (@emph{-hh})
1222 @item 4-8 (@emph{-hh -x}@var{EXTRAPROC})
1223 Same as @samp{3}, but with extra processing enabled.
1225 @samp{4} is the same as @option{-x2} and @samp{8} is the same as @option{-x6}.
1233 Motion JPEG encoder.
1239 Set the huffman encoding strategy. Possible values:
1243 Use the default huffman tables. This is the default strategy.
1246 Compute and use optimal huffman tables.
1254 WavPack lossless audio encoder.
1256 This is a libavcodec-native WavPack encoder. There is also an encoder based on
1257 libwavpack, but there is virtually no reason to use that encoder.
1259 See also @ref{libwavpack}.
1263 The equivalent options for @command{wavpack} command line utility are listed in
1266 @subsubsection Shared options
1268 The following shared options are effective for this encoder. Only special notes
1269 about this particular encoder will be documented here. For the general meaning
1270 of the options, see @ref{codec-options,,the Codec Options chapter}.
1273 @item frame_size (@emph{--blocksize})
1274 For this encoder, the range for this option is between 128 and 131072. Default
1275 is automatically decided based on sample rate and number of channel.
1277 For the complete formula of calculating default, see
1278 @file{libavcodec/wavpackenc.c}.
1280 @item compression_level (@emph{-f}, @emph{-h}, @emph{-hh}, and @emph{-x})
1281 This option's syntax is consistent with @ref{libwavpack}'s.
1284 @subsubsection Private options
1287 @item joint_stereo (@emph{-j})
1288 Set whether to enable joint stereo. Valid values are:
1292 Force mid/side audio encoding.
1293 @item off (@emph{0})
1294 Force left/right audio encoding.
1296 Let the encoder decide automatically.
1300 Set whether to enable optimization for mono. This option is only effective for
1301 non-mono streams. Available values:
1312 @c man end AUDIO ENCODERS
1314 @chapter Video Encoders
1315 @c man begin VIDEO ENCODERS
1317 A description of some of the currently available video encoders
1322 Vidvox Hap video encoder.
1327 @item format @var{integer}
1328 Specifies the Hap format to encode.
1336 Default value is @option{hap}.
1338 @item chunks @var{integer}
1339 Specifies the number of chunks to split frames into, between 1 and 64. This
1340 permits multithreaded decoding of large frames, potentially at the cost of
1341 data-rate. The encoder may modify this value to divide frames evenly.
1343 Default value is @var{1}.
1345 @item compressor @var{integer}
1346 Specifies the second-stage compressor to use. If set to @option{none},
1347 @option{chunks} will be limited to 1, as chunked uncompressed frames offer no
1355 Default value is @option{snappy}.
1361 The native jpeg 2000 encoder is lossy by default, the @code{-q:v}
1362 option can be used to set the encoding quality. Lossless encoding
1363 can be selected with @code{-pred 1}.
1369 Can be set to either @code{j2k} or @code{jp2} (the default) that
1370 makes it possible to store non-rgb pix_fmts.
1376 rav1e AV1 encoder wrapper.
1378 Requires the presence of the rav1e headers and library during configuration.
1379 You need to explicitly configure the build with @code{--enable-librav1e}.
1385 Sets the maximum quantizer to use when using bitrate mode.
1388 Sets the minimum quantizer to use when using bitrate mode.
1391 Uses quantizer mode to encode at the given quantizer (0-255).
1394 Selects the speed preset (0-10) to encode with.
1397 Selects how many tiles to encode with.
1400 Selects how many rows of tiles to encode with.
1403 Selects how many columns of tiles to encode with.
1406 Set rav1e options using a list of @var{key}=@var{value} pairs separated
1407 by ":". See @command{rav1e --help} for a list of options.
1409 For example to specify librav1e encoding options with @option{-rav1e-params}:
1412 ffmpeg -i input -c:v librav1e -b:v 500K -rav1e-params speed=5:low_latency=true output.mp4
1419 libaom AV1 encoder wrapper.
1421 Requires the presence of the libaom headers and library during
1422 configuration. You need to explicitly configure the build with
1423 @code{--enable-libaom}.
1427 The wrapper supports the following standard libavcodec options:
1432 Set bitrate target in bits/second. By default this will use
1433 variable-bitrate mode. If @option{maxrate} and @option{minrate} are
1434 also set to the same value then it will use constant-bitrate mode,
1435 otherwise if @option{crf} is set as well then it will use
1436 constrained-quality mode.
1439 Set key frame placement. The GOP size sets the maximum distance between
1440 key frames; if zero the output stream will be intra-only. The minimum
1441 distance is ignored unless it is the same as the GOP size, in which case
1442 key frames will always appear at a fixed interval. Not set by default,
1443 so without this option the library has completely free choice about
1444 where to place key frames.
1447 Set minimum/maximum quantisation values. Valid range is from 0 to 63
1448 (warning: this does not match the quantiser values actually used by AV1
1449 - divide by four to map real quantiser values to this range). Defaults
1450 to min/max (no constraint).
1452 @item minrate maxrate bufsize rc_init_occupancy
1453 Set rate control buffering parameters. Not used if not set - defaults
1454 to unconstrained variable bitrate.
1457 Set the number of threads to use while encoding. This may require the
1458 @option{tiles} or @option{row-mt} options to also be set to actually
1459 use the specified number of threads fully. Defaults to the number of
1460 hardware threads supported by the host machine.
1463 Set the encoding profile. Defaults to using the profile which matches
1464 the bit depth and chroma subsampling of the input.
1468 The wrapper also has some specific options:
1473 Set the quality/encoding speed tradeoff. Valid range is from 0 to 8,
1474 higher numbers indicating greater speed and lower quality. The default
1475 value is 1, which will be slow and high quality.
1478 Enable use of alternate reference frames. Defaults to the internal
1479 default of the library.
1481 @item arnr-max-frames (@emph{frames})
1482 Set altref noise reduction max frame count. Default is -1.
1484 @item arnr-strength (@emph{strength})
1485 Set altref noise reduction filter strength. Range is -1 to 6. Default is -1.
1487 @item aq-mode (@emph{aq-mode})
1488 Set adaptive quantization mode. Possible values:
1491 @item none (@emph{0})
1494 @item variance (@emph{1})
1497 @item complexity (@emph{2})
1500 @item cyclic (@emph{3})
1504 @item tune (@emph{tune})
1505 Set the distortion metric the encoder is tuned with. Default is @code{psnr}.
1508 @item psnr (@emph{0})
1510 @item ssim (@emph{1})
1514 Set the maximum number of frames which the encoder may keep in flight
1515 at any one time for lookahead purposes. Defaults to the internal
1516 default of the library.
1518 @item error-resilience
1519 Enable error resilience features:
1522 Improve resilience against losses of whole frames.
1524 Not enabled by default.
1527 Set the quality/size tradeoff for constant-quality (no bitrate target)
1528 and constrained-quality (with maximum bitrate target) modes. Valid
1529 range is 0 to 63, higher numbers indicating lower quality and smaller
1530 output size. Only used if set; by default only the bitrate target is
1534 Set a change threshold on blocks below which they will be skipped by
1535 the encoder. Defined in arbitrary units as a nonnegative integer,
1536 defaulting to zero (no blocks are skipped).
1538 @item drop-threshold
1539 Set a threshold for dropping frames when close to rate control bounds.
1540 Defined as a percentage of the target buffer - when the rate control
1541 buffer falls below this percentage, frames will be dropped until it
1542 has refilled above the threshold. Defaults to zero (no frames are
1545 @item denoise-noise-level (@emph{level})
1546 Amount of noise to be removed for grain synthesis. Grain synthesis is disabled if
1547 this option is not set or set to 0.
1549 @item denoise-block-size (@emph{pixels})
1550 Block size used for denoising for grain synthesis. If not set, AV1 codec
1551 uses the default value of 32.
1553 @item undershoot-pct (@emph{pct})
1554 Set datarate undershoot (min) percentage of the target bitrate. Range is -1 to 100.
1557 @item overshoot-pct (@emph{pct})
1558 Set datarate overshoot (max) percentage of the target bitrate. Range is -1 to 1000.
1561 @item minsection-pct (@emph{pct})
1562 Minimum percentage variation of the GOP bitrate from the target bitrate. If minsection-pct
1563 is not set, the libaomenc wrapper computes it as follows: @code{(minrate * 100 / bitrate)}.
1564 Range is -1 to 100. Default is -1 (unset).
1566 @item maxsection-pct (@emph{pct})
1567 Maximum percentage variation of the GOP bitrate from the target bitrate. If maxsection-pct
1568 is not set, the libaomenc wrapper computes it as follows: @code{(maxrate * 100 / bitrate)}.
1569 Range is -1 to 5000. Default is -1 (unset).
1571 @item frame-parallel (@emph{boolean})
1572 Enable frame parallel decodability features. Default is true.
1575 Set the number of tiles to encode the input video with, as columns x
1576 rows. Larger numbers allow greater parallelism in both encoding and
1577 decoding, but may decrease coding efficiency. Defaults to the minimum
1578 number of tiles required by the size of the input video (this is 1x1
1579 (that is, a single tile) for sizes up to and including 4K).
1581 @item tile-columns tile-rows
1582 Set the number of tiles as log2 of the number of tile rows and columns.
1583 Provided for compatibility with libvpx/VP9.
1585 @item row-mt (Requires libaom >= 1.0.0-759-g90a15f4f2)
1586 Enable row based multi-threading. Disabled by default.
1588 @item enable-cdef (@emph{boolean})
1589 Enable Constrained Directional Enhancement Filter. The libaom-av1
1590 encoder enables CDEF by default.
1592 @item enable-restoration (@emph{boolean})
1593 Enable Loop Restoration Filter. Default is true for libaom-av1.
1595 @item enable-global-motion (@emph{boolean})
1596 Enable the use of global motion for block prediction. Default is true.
1598 @item enable-intrabc (@emph{boolean})
1599 Enable block copy mode for intra block prediction. This mode is
1600 useful for screen content. Default is true.
1602 @item enable-rect-partitions (@emph{boolean}) (Requires libaom >= v2.0.0)
1603 Enable rectangular partitions. Default is true.
1605 @item enable-1to4-partitions (@emph{boolean}) (Requires libaom >= v2.0.0)
1606 Enable 1:4/4:1 partitions. Default is true.
1608 @item enable-ab-partitions (@emph{boolean}) (Requires libaom >= v2.0.0)
1609 Enable AB shape partitions. Default is true.
1611 @item enable-angle-delta (@emph{boolean}) (Requires libaom >= v2.0.0)
1612 Enable angle delta intra prediction. Default is true.
1614 @item enable-cfl-intra (@emph{boolean}) (Requires libaom >= v2.0.0)
1615 Enable chroma predicted from luma intra prediction. Default is true.
1617 @item enable-filter-intra (@emph{boolean}) (Requires libaom >= v2.0.0)
1618 Enable filter intra predictor. Default is true.
1620 @item enable-intra-edge-filter (@emph{boolean}) (Requires libaom >= v2.0.0)
1621 Enable intra edge filter. Default is true.
1623 @item enable-smooth-intra (@emph{boolean}) (Requires libaom >= v2.0.0)
1624 Enable smooth intra prediction mode. Default is true.
1626 @item enable-paeth-intra (@emph{boolean}) (Requires libaom >= v2.0.0)
1627 Enable paeth predictor in intra prediction. Default is true.
1629 @item enable-palette (@emph{boolean}) (Requires libaom >= v2.0.0)
1630 Enable palette prediction mode. Default is true.
1636 Kvazaar H.265/HEVC encoder.
1638 Requires the presence of the libkvazaar headers and library during
1639 configuration. You need to explicitly configure the build with
1640 @option{--enable-libkvazaar}.
1647 Set target video bitrate in bit/s and enable rate control.
1649 @item kvazaar-params
1650 Set kvazaar parameters as a list of @var{name}=@var{value} pairs separated
1651 by commas (,). See kvazaar documentation for a list of options.
1655 @section libopenh264
1657 Cisco libopenh264 H.264/MPEG-4 AVC encoder wrapper.
1659 This encoder requires the presence of the libopenh264 headers and
1660 library during configuration. You need to explicitly configure the
1661 build with @code{--enable-libopenh264}. The library is detected using
1662 @command{pkg-config}.
1664 For more information about the library see
1665 @url{http://www.openh264.org}.
1669 The following FFmpeg global options affect the configurations of the
1670 libopenh264 encoder.
1674 Set the bitrate (as a number of bits per second).
1680 Set the max bitrate (as a number of bits per second).
1682 @item flags +global_header
1683 Set global header in the bitstream.
1686 Set the number of slices, used in parallelized encoding. Default value
1687 is 0. This is only used when @option{slice_mode} is set to
1691 Set slice mode. Can assume one of the following possible values:
1695 a fixed number of slices
1697 one slice per row of macroblocks
1699 automatic number of slices according to number of threads
1704 Default value is @samp{auto}.
1707 Enable loop filter, if set to 1 (automatically enabled). To disable
1711 Set profile restrictions. If set to the value of @samp{main} enable
1712 CABAC (set the @code{SEncParamExt.iEntropyCodingModeFlag} flag to 1).
1715 Set maximum NAL size in bytes.
1717 @item allow_skip_frames
1718 Allow skipping frames to hit the target bitrate if set to 1.
1723 libtheora Theora encoder wrapper.
1725 Requires the presence of the libtheora headers and library during
1726 configuration. You need to explicitly configure the build with
1727 @code{--enable-libtheora}.
1729 For more information about the libtheora project see
1730 @url{http://www.theora.org/}.
1734 The following global options are mapped to internal libtheora options
1735 which affect the quality and the bitrate of the encoded stream.
1739 Set the video bitrate in bit/s for CBR (Constant Bit Rate) mode. In
1740 case VBR (Variable Bit Rate) mode is enabled this option is ignored.
1743 Used to enable constant quality mode (VBR) encoding through the
1744 @option{qscale} flag, and to enable the @code{pass1} and @code{pass2}
1750 @item global_quality
1751 Set the global quality as an integer in lambda units.
1753 Only relevant when VBR mode is enabled with @code{flags +qscale}. The
1754 value is converted to QP units by dividing it by @code{FF_QP2LAMBDA},
1755 clipped in the [0 - 10] range, and then multiplied by 6.3 to get a
1756 value in the native libtheora range [0-63]. A higher value corresponds
1757 to a higher quality.
1760 Enable VBR mode when set to a non-negative value, and set constant
1761 quality value as a double floating point value in QP units.
1763 The value is clipped in the [0-10] range, and then multiplied by 6.3
1764 to get a value in the native libtheora range [0-63].
1766 This option is valid only using the @command{ffmpeg} command-line
1767 tool. For library interface users, use @option{global_quality}.
1770 @subsection Examples
1774 Set maximum constant quality (VBR) encoding with @command{ffmpeg}:
1776 ffmpeg -i INPUT -codec:v libtheora -q:v 10 OUTPUT.ogg
1780 Use @command{ffmpeg} to convert a CBR 1000 kbps Theora video stream:
1782 ffmpeg -i INPUT -codec:v libtheora -b:v 1000k OUTPUT.ogg
1788 VP8/VP9 format supported through libvpx.
1790 Requires the presence of the libvpx headers and library during configuration.
1791 You need to explicitly configure the build with @code{--enable-libvpx}.
1795 The following options are supported by the libvpx wrapper. The
1796 @command{vpxenc}-equivalent options or values are listed in parentheses
1799 To reduce the duplication of documentation, only the private options
1800 and some others requiring special attention are documented here. For
1801 the documentation of the undocumented generic options, see
1802 @ref{codec-options,,the Codec Options chapter}.
1804 To get more documentation of the libvpx options, invoke the command
1805 @command{ffmpeg -h encoder=libvpx}, @command{ffmpeg -h encoder=libvpx-vp9} or
1806 @command{vpxenc --help}. Further information is available in the libvpx API
1811 @item b (@emph{target-bitrate})
1812 Set bitrate in bits/s. Note that FFmpeg's @option{b} option is
1813 expressed in bits/s, while @command{vpxenc}'s @option{target-bitrate} is in
1816 @item g (@emph{kf-max-dist})
1818 @item keyint_min (@emph{kf-min-dist})
1820 @item qmin (@emph{min-q})
1822 @item qmax (@emph{max-q})
1824 @item bufsize (@emph{buf-sz}, @emph{buf-optimal-sz})
1825 Set ratecontrol buffer size (in bits). Note @command{vpxenc}'s options are
1826 specified in milliseconds, the libvpx wrapper converts this value as follows:
1827 @code{buf-sz = bufsize * 1000 / bitrate},
1828 @code{buf-optimal-sz = bufsize * 1000 / bitrate * 5 / 6}.
1830 @item rc_init_occupancy (@emph{buf-initial-sz})
1831 Set number of bits which should be loaded into the rc buffer before decoding
1832 starts. Note @command{vpxenc}'s option is specified in milliseconds, the libvpx
1833 wrapper converts this value as follows:
1834 @code{rc_init_occupancy * 1000 / bitrate}.
1836 @item undershoot-pct
1837 Set datarate undershoot (min) percentage of the target bitrate.
1840 Set datarate overshoot (max) percentage of the target bitrate.
1842 @item skip_threshold (@emph{drop-frame})
1844 @item qcomp (@emph{bias-pct})
1846 @item maxrate (@emph{maxsection-pct})
1847 Set GOP max bitrate in bits/s. Note @command{vpxenc}'s option is specified as a
1848 percentage of the target bitrate, the libvpx wrapper converts this value as
1849 follows: @code{(maxrate * 100 / bitrate)}.
1851 @item minrate (@emph{minsection-pct})
1852 Set GOP min bitrate in bits/s. Note @command{vpxenc}'s option is specified as a
1853 percentage of the target bitrate, the libvpx wrapper converts this value as
1854 follows: @code{(minrate * 100 / bitrate)}.
1856 @item minrate, maxrate, b @emph{end-usage=cbr}
1857 @code{(minrate == maxrate == bitrate)}.
1859 @item crf (@emph{end-usage=cq}, @emph{cq-level})
1861 @item tune (@emph{tune})
1863 @item psnr (@emph{psnr})
1864 @item ssim (@emph{ssim})
1867 @item quality, deadline (@emph{deadline})
1870 Use best quality deadline. Poorly named and quite slow, this option should be
1871 avoided as it may give worse quality output than good.
1873 Use good quality deadline. This is a good trade-off between speed and quality
1874 when used with the @option{cpu-used} option.
1876 Use realtime quality deadline.
1879 @item speed, cpu-used (@emph{cpu-used})
1880 Set quality/speed ratio modifier. Higher values speed up the encode at the cost
1883 @item nr (@emph{noise-sensitivity})
1886 Set a change threshold on blocks below which they will be skipped by the
1889 @item slices (@emph{token-parts})
1890 Note that FFmpeg's @option{slices} option gives the total number of partitions,
1891 while @command{vpxenc}'s @option{token-parts} is given as
1892 @code{log2(partitions)}.
1894 @item max-intra-rate
1895 Set maximum I-frame bitrate as a percentage of the target bitrate. A value of 0
1898 @item force_key_frames
1899 @code{VPX_EFLAG_FORCE_KF}
1901 @item Alternate reference frame related
1904 Enable use of alternate reference frames (2-pass only).
1905 Values greater than 1 enable multi-layer alternate reference frames (VP9 only).
1906 @item arnr-maxframes
1907 Set altref noise reduction max frame count.
1909 Set altref noise reduction filter type: backward, forward, centered.
1911 Set altref noise reduction filter strength.
1912 @item rc-lookahead, lag-in-frames (@emph{lag-in-frames})
1913 Set number of frames to look ahead for frametype and ratecontrol.
1916 @item error-resilient
1917 Enable error resiliency features.
1919 @item sharpness @var{integer}
1920 Increase sharpness at the expense of lower PSNR.
1921 The valid range is [0, 7].
1924 Sets the temporal scalability configuration using a :-separated list of
1925 key=value pairs. For example, to specify temporal scalability parameters
1928 ffmpeg -i INPUT -c:v libvpx -ts-parameters ts_number_layers=3:\
1929 ts_target_bitrate=250,500,1000:ts_rate_decimator=4,2,1:\
1930 ts_periodicity=4:ts_layer_id=0,2,1,2:ts_layering_mode=3 OUTPUT
1932 Below is a brief explanation of each of the parameters, please
1933 refer to @code{struct vpx_codec_enc_cfg} in @code{vpx/vpx_encoder.h} for more
1936 @item ts_number_layers
1937 Number of temporal coding layers.
1938 @item ts_target_bitrate
1939 Target bitrate for each temporal layer (in kbps).
1940 (bitrate should be inclusive of the lower temporal layer).
1941 @item ts_rate_decimator
1942 Frame rate decimation factor for each temporal layer.
1943 @item ts_periodicity
1944 Length of the sequence defining frame temporal layer membership.
1946 Template defining the membership of frames to temporal layers.
1947 @item ts_layering_mode
1948 (optional) Selecting the temporal structure from a set of pre-defined temporal layering modes.
1949 Currently supports the following options.
1952 No temporal layering flags are provided internally,
1953 relies on flags being passed in using @code{metadata} field in @code{AVFrame}
1954 with following keys.
1957 Sets the flags passed into the encoder to indicate the referencing scheme for
1959 Refer to function @code{vpx_codec_encode} in @code{vpx/vpx_encoder.h} for more
1962 Explicitly sets the temporal id of the current frame to encode.
1965 Two temporal layers. 0-1...
1967 Three temporal layers. 0-2-1-2...; with single reference frame.
1969 Same as option "3", except there is a dependency between
1970 the two temporal layer 2 frames within the temporal period.
1974 @item VP9-specific options
1977 Enable lossless mode.
1979 Set number of tile columns to use. Note this is given as
1980 @code{log2(tile_columns)}. For example, 8 tile columns would be requested by
1981 setting the @option{tile-columns} option to 3.
1983 Set number of tile rows to use. Note this is given as @code{log2(tile_rows)}.
1984 For example, 4 tile rows would be requested by setting the @option{tile-rows}
1986 @item frame-parallel
1987 Enable frame parallel decodability features.
1989 Set adaptive quantization mode (0: off (default), 1: variance 2: complexity, 3:
1990 cyclic refresh, 4: equator360).
1991 @item colorspace @emph{color-space}
1992 Set input color space. The VP9 bitstream supports signaling the following
1995 @item @samp{rgb} @emph{sRGB}
1996 @item @samp{bt709} @emph{bt709}
1997 @item @samp{unspecified} @emph{unknown}
1998 @item @samp{bt470bg} @emph{bt601}
1999 @item @samp{smpte170m} @emph{smpte170}
2000 @item @samp{smpte240m} @emph{smpte240}
2001 @item @samp{bt2020_ncl} @emph{bt2020}
2003 @item row-mt @var{boolean}
2004 Enable row based multi-threading.
2006 Set content type: default (0), screen (1), film (2).
2007 @item corpus-complexity
2008 Corpus VBR mode is a variant of standard VBR where the complexity distribution
2009 midpoint is passed in rather than calculated for a specific clip or chunk.
2011 The valid range is [0, 10000]. 0 (default) uses standard VBR.
2012 @item enable-tpl @var{boolean}
2013 Enable temporal dependency model.
2018 For more information about libvpx see:
2019 @url{http://www.webmproject.org/}
2023 libwebp WebP Image encoder wrapper
2025 libwebp is Google's official encoder for WebP images. It can encode in either
2026 lossy or lossless mode. Lossy images are essentially a wrapper around a VP8
2027 frame. Lossless images are a separate codec developed by Google.
2029 @subsection Pixel Format
2031 Currently, libwebp only supports YUV420 for lossy and RGB for lossless due
2032 to limitations of the format and libwebp. Alpha is supported for either mode.
2033 Because of API limitations, if RGB is passed in when encoding lossy or YUV is
2034 passed in for encoding lossless, the pixel format will automatically be
2035 converted using functions from libwebp. This is not ideal and is done only for
2042 @item -lossless @var{boolean}
2043 Enables/Disables use of lossless mode. Default is 0.
2045 @item -compression_level @var{integer}
2046 For lossy, this is a quality/speed tradeoff. Higher values give better quality
2047 for a given size at the cost of increased encoding time. For lossless, this is
2048 a size/speed tradeoff. Higher values give smaller size at the cost of increased
2049 encoding time. More specifically, it controls the number of extra algorithms
2050 and compression tools used, and varies the combination of these tools. This
2051 maps to the @var{method} option in libwebp. The valid range is 0 to 6.
2054 @item -qscale @var{float}
2055 For lossy encoding, this controls image quality, 0 to 100. For lossless
2056 encoding, this controls the effort and time spent at compressing more. The
2057 default value is 75. Note that for usage via libavcodec, this option is called
2058 @var{global_quality} and must be multiplied by @var{FF_QP2LAMBDA}.
2060 @item -preset @var{type}
2061 Configuration preset. This does some automatic settings based on the general
2065 Do not use a preset.
2067 Use the encoder default.
2069 Digital picture, like portrait, inner shot
2071 Outdoor photograph, with natural lighting
2073 Hand or line drawing, with high-contrast details
2075 Small-sized colorful images
2082 @section libx264, libx264rgb
2084 x264 H.264/MPEG-4 AVC encoder wrapper.
2086 This encoder requires the presence of the libx264 headers and library
2087 during configuration. You need to explicitly configure the build with
2088 @code{--enable-libx264}.
2090 libx264 supports an impressive number of features, including 8x8 and
2091 4x4 adaptive spatial transform, adaptive B-frame placement, CAVLC/CABAC
2092 entropy coding, interlacing (MBAFF), lossless mode, psy optimizations
2093 for detail retention (adaptive quantization, psy-RD, psy-trellis).
2095 Many libx264 encoder options are mapped to FFmpeg global codec
2096 options, while unique encoder options are provided through private
2097 options. Additionally the @option{x264opts} and @option{x264-params}
2098 private options allows one to pass a list of key=value tuples as accepted
2099 by the libx264 @code{x264_param_parse} function.
2101 The x264 project website is at
2102 @url{http://www.videolan.org/developers/x264.html}.
2104 The libx264rgb encoder is the same as libx264, except it accepts packed RGB
2105 pixel formats as input instead of YUV.
2107 @subsection Supported Pixel Formats
2109 x264 supports 8- to 10-bit color spaces. The exact bit depth is controlled at
2110 x264's configure time. FFmpeg only supports one bit depth in one particular
2111 build. In other words, it is not possible to build one FFmpeg with multiple
2112 versions of x264 with different bit depths.
2116 The following options are supported by the libx264 wrapper. The
2117 @command{x264}-equivalent options or values are listed in parentheses
2120 To reduce the duplication of documentation, only the private options
2121 and some others requiring special attention are documented here. For
2122 the documentation of the undocumented generic options, see
2123 @ref{codec-options,,the Codec Options chapter}.
2125 To get a more accurate and extensive documentation of the libx264
2126 options, invoke the command @command{x264 --fullhelp} or consult
2127 the libx264 documentation.
2130 @item b (@emph{bitrate})
2131 Set bitrate in bits/s. Note that FFmpeg's @option{b} option is
2132 expressed in bits/s, while @command{x264}'s @option{bitrate} is in
2135 @item bf (@emph{bframes})
2137 @item g (@emph{keyint})
2139 @item qmin (@emph{qpmin})
2140 Minimum quantizer scale.
2142 @item qmax (@emph{qpmax})
2143 Maximum quantizer scale.
2145 @item qdiff (@emph{qpstep})
2146 Maximum difference between quantizer scales.
2148 @item qblur (@emph{qblur})
2149 Quantizer curve blur
2151 @item qcomp (@emph{qcomp})
2152 Quantizer curve compression factor
2154 @item refs (@emph{ref})
2155 Number of reference frames each P-frame can use. The range is from @var{0-16}.
2157 @item sc_threshold (@emph{scenecut})
2158 Sets the threshold for the scene change detection.
2160 @item trellis (@emph{trellis})
2161 Performs Trellis quantization to increase efficiency. Enabled by default.
2163 @item nr (@emph{nr})
2165 @item me_range (@emph{merange})
2166 Maximum range of the motion search in pixels.
2168 @item me_method (@emph{me})
2169 Set motion estimation method. Possible values in the decreasing order
2173 @item dia (@emph{dia})
2174 @item epzs (@emph{dia})
2175 Diamond search with radius 1 (fastest). @samp{epzs} is an alias for
2177 @item hex (@emph{hex})
2178 Hexagonal search with radius 2.
2179 @item umh (@emph{umh})
2180 Uneven multi-hexagon search.
2181 @item esa (@emph{esa})
2183 @item tesa (@emph{tesa})
2184 Hadamard exhaustive search (slowest).
2188 Normally, when forcing a I-frame type, the encoder can select any type
2189 of I-frame. This option forces it to choose an IDR-frame.
2191 @item subq (@emph{subme})
2192 Sub-pixel motion estimation method.
2194 @item b_strategy (@emph{b-adapt})
2195 Adaptive B-frame placement decision algorithm. Use only on first-pass.
2197 @item keyint_min (@emph{min-keyint})
2201 Set entropy encoder. Possible values:
2208 Enable CAVLC and disable CABAC. It generates the same effect as
2209 @command{x264}'s @option{--no-cabac} option.
2213 Set full pixel motion estimation comparison algorithm. Possible values:
2217 Enable chroma in motion estimation.
2220 Ignore chroma in motion estimation. It generates the same effect as
2221 @command{x264}'s @option{--no-chroma-me} option.
2224 @item threads (@emph{threads})
2225 Number of encoding threads.
2228 Set multithreading technique. Possible values:
2232 Slice-based multithreading. It generates the same effect as
2233 @command{x264}'s @option{--sliced-threads} option.
2235 Frame-based multithreading.
2239 Set encoding flags. It can be used to disable closed GOP and enable
2240 open GOP by setting it to @code{-cgop}. The result is similar to
2241 the behavior of @command{x264}'s @option{--open-gop} option.
2243 @item rc_init_occupancy (@emph{vbv-init})
2245 @item preset (@emph{preset})
2246 Set the encoding preset.
2248 @item tune (@emph{tune})
2249 Set tuning of the encoding params.
2251 @item profile (@emph{profile})
2252 Set profile restrictions.
2255 Enable fast settings when encoding first pass, when set to 1. When set
2256 to 0, it has the same effect of @command{x264}'s
2257 @option{--slow-firstpass} option.
2259 @item crf (@emph{crf})
2260 Set the quality for constant quality mode.
2262 @item crf_max (@emph{crf-max})
2263 In CRF mode, prevents VBV from lowering quality beyond this point.
2265 @item qp (@emph{qp})
2266 Set constant quantization rate control method parameter.
2268 @item aq-mode (@emph{aq-mode})
2269 Set AQ method. Possible values:
2272 @item none (@emph{0})
2275 @item variance (@emph{1})
2276 Variance AQ (complexity mask).
2278 @item autovariance (@emph{2})
2279 Auto-variance AQ (experimental).
2282 @item aq-strength (@emph{aq-strength})
2283 Set AQ strength, reduce blocking and blurring in flat and textured areas.
2286 Use psychovisual optimizations when set to 1. When set to 0, it has the
2287 same effect as @command{x264}'s @option{--no-psy} option.
2289 @item psy-rd (@emph{psy-rd})
2290 Set strength of psychovisual optimization, in
2291 @var{psy-rd}:@var{psy-trellis} format.
2293 @item rc-lookahead (@emph{rc-lookahead})
2294 Set number of frames to look ahead for frametype and ratecontrol.
2297 Enable weighted prediction for B-frames when set to 1. When set to 0,
2298 it has the same effect as @command{x264}'s @option{--no-weightb} option.
2300 @item weightp (@emph{weightp})
2301 Set weighted prediction method for P-frames. Possible values:
2304 @item none (@emph{0})
2306 @item simple (@emph{1})
2307 Enable only weighted refs
2308 @item smart (@emph{2})
2309 Enable both weighted refs and duplicates
2312 @item ssim (@emph{ssim})
2313 Enable calculation and printing SSIM stats after the encoding.
2315 @item intra-refresh (@emph{intra-refresh})
2316 Enable the use of Periodic Intra Refresh instead of IDR frames when set
2319 @item avcintra-class (@emph{class})
2320 Configure the encoder to generate AVC-Intra.
2321 Valid values are 50,100 and 200
2323 @item bluray-compat (@emph{bluray-compat})
2324 Configure the encoder to be compatible with the bluray standard.
2325 It is a shorthand for setting "bluray-compat=1 force-cfr=1".
2327 @item b-bias (@emph{b-bias})
2328 Set the influence on how often B-frames are used.
2330 @item b-pyramid (@emph{b-pyramid})
2331 Set method for keeping of some B-frames as references. Possible values:
2334 @item none (@emph{none})
2336 @item strict (@emph{strict})
2337 Strictly hierarchical pyramid.
2338 @item normal (@emph{normal})
2339 Non-strict (not Blu-ray compatible).
2343 Enable the use of one reference per partition, as opposed to one
2344 reference per macroblock when set to 1. When set to 0, it has the
2345 same effect as @command{x264}'s @option{--no-mixed-refs} option.
2348 Enable adaptive spatial transform (high profile 8x8 transform)
2349 when set to 1. When set to 0, it has the same effect as
2350 @command{x264}'s @option{--no-8x8dct} option.
2353 Enable early SKIP detection on P-frames when set to 1. When set
2354 to 0, it has the same effect as @command{x264}'s
2355 @option{--no-fast-pskip} option.
2357 @item aud (@emph{aud})
2358 Enable use of access unit delimiters when set to 1.
2361 Enable use macroblock tree ratecontrol when set to 1. When set
2362 to 0, it has the same effect as @command{x264}'s
2363 @option{--no-mbtree} option.
2365 @item deblock (@emph{deblock})
2366 Set loop filter parameters, in @var{alpha}:@var{beta} form.
2368 @item cplxblur (@emph{cplxblur})
2369 Set fluctuations reduction in QP (before curve compression).
2371 @item partitions (@emph{partitions})
2372 Set partitions to consider as a comma-separated list of. Possible
2377 8x8 P-frame partition.
2379 4x4 P-frame partition.
2381 4x4 B-frame partition.
2383 8x8 I-frame partition.
2385 4x4 I-frame partition.
2386 (Enabling @samp{p4x4} requires @samp{p8x8} to be enabled. Enabling
2387 @samp{i8x8} requires adaptive spatial transform (@option{8x8dct}
2388 option) to be enabled.)
2389 @item none (@emph{none})
2390 Do not consider any partitions.
2391 @item all (@emph{all})
2392 Consider every partition.
2395 @item direct-pred (@emph{direct})
2396 Set direct MV prediction mode. Possible values:
2399 @item none (@emph{none})
2400 Disable MV prediction.
2401 @item spatial (@emph{spatial})
2402 Enable spatial predicting.
2403 @item temporal (@emph{temporal})
2404 Enable temporal predicting.
2405 @item auto (@emph{auto})
2406 Automatically decided.
2409 @item slice-max-size (@emph{slice-max-size})
2410 Set the limit of the size of each slice in bytes. If not specified
2411 but RTP payload size (@option{ps}) is specified, that is used.
2413 @item stats (@emph{stats})
2414 Set the file name for multi-pass stats.
2416 @item nal-hrd (@emph{nal-hrd})
2417 Set signal HRD information (requires @option{vbv-bufsize} to be set).
2421 @item none (@emph{none})
2422 Disable HRD information signaling.
2423 @item vbr (@emph{vbr})
2425 @item cbr (@emph{cbr})
2426 Constant bit rate (not allowed in MP4 container).
2429 @item x264opts (N.A.)
2430 Set any x264 option, see @command{x264 --fullhelp} for a list.
2432 Argument is a list of @var{key}=@var{value} couples separated by
2433 ":". In @var{filter} and @var{psy-rd} options that use ":" as a separator
2434 themselves, use "," instead. They accept it as well since long ago but this
2435 is kept undocumented for some reason.
2437 For example to specify libx264 encoding options with @command{ffmpeg}:
2439 ffmpeg -i foo.mpg -c:v libx264 -x264opts keyint=123:min-keyint=20 -an out.mkv
2442 @item a53cc @var{boolean}
2443 Import closed captions (which must be ATSC compatible format) into output.
2444 Only the mpeg2 and h264 decoders provide these. Default is 1 (on).
2446 @item x264-params (N.A.)
2447 Override the x264 configuration using a :-separated list of key=value
2450 This option is functionally the same as the @option{x264opts}, but is
2451 duplicated for compatibility with the Libav fork.
2453 For example to specify libx264 encoding options with @command{ffmpeg}:
2455 ffmpeg -i INPUT -c:v libx264 -x264-params level=30:bframes=0:weightp=0:\
2456 cabac=0:ref=1:vbv-maxrate=768:vbv-bufsize=2000:analyse=all:me=umh:\
2457 no-fast-pskip=1:subq=6:8x8dct=0:trellis=0 OUTPUT
2461 Encoding ffpresets for common usages are provided so they can be used with the
2462 general presets system (e.g. passing the @option{pre} option).
2466 x265 H.265/HEVC encoder wrapper.
2468 This encoder requires the presence of the libx265 headers and library
2469 during configuration. You need to explicitly configure the build with
2470 @option{--enable-libx265}.
2476 Sets target video bitrate.
2487 Number of reference frames each P-frame can use. The range is from @var{1-16}.
2490 Set the x265 preset.
2493 Set the x265 tune parameter.
2496 Set profile restrictions.
2499 Set the quality for constant quality mode.
2502 Set constant quantization rate control method parameter.
2505 Minimum quantizer scale.
2508 Maximum quantizer scale.
2511 Maximum difference between quantizer scales.
2514 Quantizer curve blur
2517 Quantizer curve compression factor
2524 Normally, when forcing a I-frame type, the encoder can select any type
2525 of I-frame. This option forces it to choose an IDR-frame.
2528 Set x265 options using a list of @var{key}=@var{value} couples separated
2529 by ":". See @command{x265 --help} for a list of options.
2531 For example to specify libx265 encoding options with @option{-x265-params}:
2534 ffmpeg -i input -c:v libx265 -x265-params crf=26:psy-rd=1 output.mp4
2540 xavs2 AVS2-P2/IEEE1857.4 encoder wrapper.
2542 This encoder requires the presence of the libxavs2 headers and library
2543 during configuration. You need to explicitly configure the build with
2544 @option{--enable-libxavs2}.
2546 The following standard libavcodec options are used:
2549 @option{b} / @option{bit_rate}
2551 @option{g} / @option{gop_size}
2553 @option{bf} / @option{max_b_frames}
2556 The encoder also has its own specific options:
2560 @item lcu_row_threads
2561 Set the number of parallel threads for rows from 1 to 8 (default 5).
2564 Set the xavs2 quantization parameter from 1 to 63 (default 34). This is
2565 used to set the initial qp for the first frame.
2568 Set the xavs2 quantization parameter from 1 to 63 (default 34). This is
2569 used to set the qp value under constant-QP mode.
2572 Set the max qp for rate control from 1 to 63 (default 55).
2575 Set the min qp for rate control from 1 to 63 (default 20).
2578 Set the Speed level from 0 to 9 (default 0). Higher is better but slower.
2581 Set the log level from -1 to 3 (default 0). -1: none, 0: error,
2582 1: warning, 2: info, 3: debug.
2585 Set xavs2 options using a list of @var{key}=@var{value} couples separated
2588 For example to specify libxavs2 encoding options with @option{-xavs2-params}:
2591 ffmpeg -i input -c:v libxavs2 -xavs2-params RdoqLevel=0 output.avs2
2597 Xvid MPEG-4 Part 2 encoder wrapper.
2599 This encoder requires the presence of the libxvidcore headers and library
2600 during configuration. You need to explicitly configure the build with
2601 @code{--enable-libxvid --enable-gpl}.
2603 The native @code{mpeg4} encoder supports the MPEG-4 Part 2 format, so
2604 users can encode to this format without this library.
2608 The following options are supported by the libxvid wrapper. Some of
2609 the following options are listed but are not documented, and
2610 correspond to shared codec options. See @ref{codec-options,,the Codec
2611 Options chapter} for their documentation. The other shared options
2612 which are not listed have no effect for the libxvid encoder.
2634 Set specific encoding flags. Possible values:
2639 Use four motion vector by macroblock.
2642 Enable high quality AC prediction.
2645 Only encode grayscale.
2648 Enable the use of global motion compensation (GMC).
2651 Enable quarter-pixel motion compensation.
2657 Place global headers in extradata instead of every keyframe.
2664 Set motion estimation method. Possible values in decreasing order of
2665 speed and increasing order of quality:
2669 Use no motion estimation (default).
2674 Enable advanced diamond zonal search for 16x16 blocks and half-pixel
2675 refinement for 16x16 blocks. @samp{x1} and @samp{log} are aliases for
2679 Enable all of the things described above, plus advanced diamond zonal
2680 search for 8x8 blocks, half-pixel refinement for 8x8 blocks, and motion
2681 estimation on chroma planes.
2684 Enable all of the things described above, plus extended 16x16 and 8x8
2689 Set macroblock decision algorithm. Possible values in the increasing
2694 Use macroblock comparing function algorithm (default).
2697 Enable rate distortion-based half pixel and quarter pixel refinement for
2701 Enable all of the things described above, plus rate distortion-based
2702 half pixel and quarter pixel refinement for 8x8 blocks, and rate
2703 distortion-based search using square pattern.
2707 Enable lumi masking adaptive quantization when set to 1. Default is 0
2711 Enable variance adaptive quantization when set to 1. Default is 0
2714 When combined with @option{lumi_aq}, the resulting quality will not
2715 be better than any of the two specified individually. In other
2716 words, the resulting quality will be the worse one of the two
2720 Set structural similarity (SSIM) displaying method. Possible values:
2724 Disable displaying of SSIM information.
2727 Output average SSIM at the end of encoding to stdout. The format of
2728 showing the average SSIM is:
2734 For users who are not familiar with C, %f means a float number, or
2735 a decimal (e.g. 0.939232).
2738 Output both per-frame SSIM data during encoding and average SSIM at
2739 the end of encoding to stdout. The format of per-frame information
2743 SSIM: avg: %1.3f min: %1.3f max: %1.3f
2746 For users who are not familiar with C, %1.3f means a float number
2747 rounded to 3 digits after the dot (e.g. 0.932).
2752 Set SSIM accuracy. Valid options are integers within the range of
2753 0-4, while 0 gives the most accurate result and 4 computes the
2758 @section MediaFoundation
2760 This provides wrappers to encoders (both audio and video) in the
2761 MediaFoundation framework. It can access both SW and HW encoders.
2762 Video encoders can take input in either of nv12 or yuv420p form
2763 (some encoders support both, some support only either - in practice,
2764 nv12 is the safer choice, especially among HW encoders).
2768 MPEG-2 video encoder.
2774 Select the mpeg2 profile to encode:
2787 @item seq_disp_ext @var{integer}
2788 Specifies if the encoder should write a sequence_display_extension to the
2793 Decide automatically to write it or not (this is the default) by checking if
2794 the data to be written is different from the default or unspecified values.
2802 @item video_format @var{integer}
2803 Specifies the video_format written into the sequence display extension
2804 indicating the source of the video pictures. The default is @samp{unspecified},
2805 can be @samp{component}, @samp{pal}, @samp{ntsc}, @samp{secam} or @samp{mac}.
2806 For maximum compatibility, use @samp{component}.
2807 @item a53cc @var{boolean}
2808 Import closed captions (which must be ATSC compatible format) into output.
2816 @subsection Private options
2819 @item dpi @var{integer}
2820 Set physical density of pixels, in dots per inch, unset by default
2821 @item dpm @var{integer}
2822 Set physical density of pixels, in dots per meter, unset by default
2827 Apple ProRes encoder.
2829 FFmpeg contains 2 ProRes encoders, the prores-aw and prores-ks encoder.
2830 The used encoder can be chosen with the @code{-vcodec} option.
2832 @subsection Private Options for prores-ks
2835 @item profile @var{integer}
2836 Select the ProRes profile to encode
2846 @item quant_mat @var{integer}
2847 Select quantization matrix.
2856 If set to @var{auto}, the matrix matching the profile will be picked.
2857 If not set, the matrix providing the highest quality, @var{default}, will be
2860 @item bits_per_mb @var{integer}
2861 How many bits to allot for coding one macroblock. Different profiles use
2862 between 200 and 2400 bits per macroblock, the maximum is 8000.
2864 @item mbs_per_slice @var{integer}
2865 Number of macroblocks in each slice (1-8); the default value (8)
2866 should be good in almost all situations.
2868 @item vendor @var{string}
2869 Override the 4-byte vendor ID.
2870 A custom vendor ID like @var{apl0} would claim the stream was produced by
2873 @item alpha_bits @var{integer}
2874 Specify number of bits for alpha component.
2875 Possible values are @var{0}, @var{8} and @var{16}.
2876 Use @var{0} to disable alpha plane coding.
2880 @subsection Speed considerations
2882 In the default mode of operation the encoder has to honor frame constraints
2883 (i.e. not produce frames with size bigger than requested) while still making
2884 output picture as good as possible.
2885 A frame containing a lot of small details is harder to compress and the encoder
2886 would spend more time searching for appropriate quantizers for each slice.
2888 Setting a higher @option{bits_per_mb} limit will improve the speed.
2890 For the fastest encoding speed set the @option{qscale} parameter (4 is the
2891 recommended value) and do not set a size constraint.
2893 @section QSV encoders
2895 The family of Intel QuickSync Video encoders (MPEG-2, H.264, HEVC, JPEG/MJPEG and VP9)
2897 The ratecontrol method is selected as follows:
2901 When @option{global_quality} is specified, a quality-based mode is used.
2902 Specifically this means either
2905 @var{CQP} - constant quantizer scale, when the @option{qscale} codec flag is
2906 also set (the @option{-qscale} ffmpeg option).
2909 @var{LA_ICQ} - intelligent constant quality with lookahead, when the
2910 @option{look_ahead} option is also set.
2913 @var{ICQ} -- intelligent constant quality otherwise.
2917 Otherwise, a bitrate-based mode is used. For all of those, you should specify at
2918 least the desired average bitrate with the @option{b} option.
2921 @var{LA} - VBR with lookahead, when the @option{look_ahead} option is specified.
2924 @var{VCM} - video conferencing mode, when the @option{vcm} option is set.
2927 @var{CBR} - constant bitrate, when @option{maxrate} is specified and equal to
2928 the average bitrate.
2931 @var{VBR} - variable bitrate, when @option{maxrate} is specified, but is higher
2932 than the average bitrate.
2935 @var{AVBR} - average VBR mode, when @option{maxrate} is not specified. This mode
2936 is further configured by the @option{avbr_accuracy} and
2937 @option{avbr_convergence} options.
2941 Note that depending on your system, a different mode than the one you specified
2942 may be selected by the encoder. Set the verbosity level to @var{verbose} or
2943 higher to see the actual settings used by the QSV runtime.
2945 Additional libavcodec global options are mapped to MSDK options as follows:
2949 @option{g/gop_size} -> @option{GopPicSize}
2952 @option{bf/max_b_frames}+1 -> @option{GopRefDist}
2955 @option{rc_init_occupancy/rc_initial_buffer_occupancy} ->
2956 @option{InitialDelayInKB}
2959 @option{slices} -> @option{NumSlice}
2962 @option{refs} -> @option{NumRefFrame}
2965 @option{b_strategy/b_frame_strategy} -> @option{BRefType}
2968 @option{cgop/CLOSED_GOP} codec flag -> @option{GopOptFlag}
2971 For the @var{CQP} mode, the @option{i_qfactor/i_qoffset} and
2972 @option{b_qfactor/b_qoffset} set the difference between @var{QPP} and @var{QPI},
2973 and @var{QPP} and @var{QPB} respectively.
2976 Setting the @option{coder} option to the value @var{vlc} will make the H.264
2977 encoder use CAVLC instead of CABAC.
2986 @item iterative_dia_size
2987 dia size for the iterative motion estimation
2990 @section VAAPI encoders
2992 Wrappers for hardware encoders accessible via VAAPI.
2994 These encoders only accept input in VAAPI hardware surfaces. If you have input
2995 in software frames, use the @option{hwupload} filter to upload them to the GPU.
2997 The following standard libavcodec options are used:
3000 @option{g} / @option{gop_size}
3002 @option{bf} / @option{max_b_frames}
3006 If not set, this will be determined automatically from the format of the input
3007 frames and the profiles supported by the driver.
3011 @option{b} / @option{bit_rate}
3013 @option{maxrate} / @option{rc_max_rate}
3015 @option{bufsize} / @option{rc_buffer_size}
3017 @option{rc_init_occupancy} / @option{rc_initial_buffer_occupancy}
3019 @option{compression_level}
3021 Speed / quality tradeoff: higher values are faster / worse quality.
3023 @option{q} / @option{global_quality}
3025 Size / quality tradeoff: higher values are smaller / worse quality.
3031 @option{i_qfactor} / @option{i_quant_factor}
3033 @option{i_qoffset} / @option{i_quant_offset}
3035 @option{b_qfactor} / @option{b_quant_factor}
3037 @option{b_qoffset} / @option{b_quant_offset}
3042 All encoders support the following options:
3045 Some drivers/platforms offer a second encoder for some codecs intended to use
3046 less power than the default encoder; setting this option will attempt to use
3047 that encoder. Note that it may support a reduced feature set, so some other
3048 options may not be available in this mode.
3051 Set the number of normal intra frames between full-refresh (IDR) frames in
3052 open-GOP mode. The intra frames are still IRAPs, but will not include global
3053 headers and may have non-decodable leading pictures.
3056 Set the B-frame reference depth. When set to one (the default), all B-frames
3057 will refer only to P- or I-frames. When set to greater values multiple layers
3058 of B-frames will be present, frames in each layer only referring to frames in
3062 Set the rate control mode to use. A given driver may only support a subset of
3068 Choose the mode automatically based on driver support and the other options.
3069 This is the default.
3077 Intelligent constant-quality.
3079 Quality-defined variable-bitrate.
3081 Average variable bitrate.
3086 Each encoder also has its own specific options:
3090 @option{profile} sets the value of @emph{profile_idc} and the @emph{constraint_set*_flag}s.
3091 @option{level} sets the value of @emph{level_idc}.
3095 Set entropy encoder (default is @emph{cabac}). Possible values:
3108 Include access unit delimiters in the stream (not included by default).
3111 Set SEI message types to include.
3112 Some combination of the following values:
3115 Include a @emph{user_data_unregistered} message containing information about
3118 Include picture timing parameters (@emph{buffering_period} and
3119 @emph{pic_timing} messages).
3120 @item recovery_point
3121 Include recovery points where appropriate (@emph{recovery_point} messages).
3127 @option{profile} and @option{level} set the values of
3128 @emph{general_profile_idc} and @emph{general_level_idc} respectively.
3132 Include access unit delimiters in the stream (not included by default).
3135 Set @emph{general_tier_flag}. This may affect the level chosen for the stream
3136 if it is not explicitly specified.
3139 Set SEI message types to include.
3140 Some combination of the following values:
3143 Include HDR metadata if the input frames have it
3144 (@emph{mastering_display_colour_volume} and @emph{content_light_level}
3151 Only baseline DCT encoding is supported. The encoder always uses the standard
3152 quantisation and huffman tables - @option{global_quality} scales the standard
3153 quantisation table (range 1-100).
3155 For YUV, 4:2:0, 4:2:2 and 4:4:4 subsampling modes are supported. RGB is also
3156 supported, and will create an RGB JPEG.
3160 Include JFIF header in each frame (not included by default).
3162 Include standard huffman tables (on by default). Turning this off will save
3163 a few hundred bytes in each output frame, but may lose compatibility with some
3164 JPEG decoders which don't fully handle MJPEG.
3168 @option{profile} and @option{level} set the value of @emph{profile_and_level_indication}.
3171 B-frames are not supported.
3173 @option{global_quality} sets the @emph{q_idx} used for non-key frames (range 0-127).
3176 @item loop_filter_level
3177 @item loop_filter_sharpness
3178 Manually set the loop filter parameters.
3182 @option{global_quality} sets the @emph{q_idx} used for P-frames (range 0-255).
3185 @item loop_filter_level
3186 @item loop_filter_sharpness
3187 Manually set the loop filter parameters.
3190 B-frames are supported, but the output stream is always in encode order rather than display
3191 order. If B-frames are enabled, it may be necessary to use the @option{vp9_raw_reorder}
3192 bitstream filter to modify the output stream to display frames in the correct order.
3194 Only normal frames are produced - the @option{vp9_superframe} bitstream filter may be
3195 required to produce a stream usable with all decoders.
3201 SMPTE VC-2 (previously BBC Dirac Pro). This codec was primarily aimed at
3202 professional broadcasting but since it supports yuv420, yuv422 and yuv444 at
3203 8 (limited range or full range), 10 or 12 bits, this makes it suitable for
3204 other tasks which require low overhead and low compression (like screen
3212 Sets target video bitrate. Usually that's around 1:6 of the uncompressed
3213 video bitrate (e.g. for 1920x1080 50fps yuv422p10 that's around 400Mbps). Higher
3214 values (close to the uncompressed bitrate) turn on lossless compression mode.
3217 Enables field coding when set (e.g. to tt - top field first) for interlaced
3218 inputs. Should increase compression with interlaced content as it splits the
3219 fields and encodes each separately.
3222 Sets the total amount of wavelet transforms to apply, between 1 and 5 (default).
3223 Lower values reduce compression and quality. Less capable decoders may not be
3224 able to handle values of @option{wavelet_depth} over 3.
3227 Sets the transform type. Currently only @var{5_3} (LeGall) and @var{9_7}
3229 are implemented, with 9_7 being the one with better compression and thus
3234 Sets the slice size for each slice. Larger values result in better compression.
3235 For compatibility with other more limited decoders use @option{slice_width} of
3236 32 and @option{slice_height} of 8.
3239 Sets the undershoot tolerance of the rate control system in percent. This is
3240 to prevent an expensive search from being run.
3243 Sets the quantization matrix preset to use by default or when @option{wavelet_depth}
3248 Uses the default quantization matrix from the specifications, extended with
3249 values for the fifth level. This provides a good balance between keeping detail
3250 and omitting artifacts.
3254 Use a completely zeroed out quantization matrix. This increases PSNR but might
3255 reduce perception. Use in bogus benchmarks.
3259 Reduces detail but attempts to preserve color at extremely low bitrates.
3264 @c man end VIDEO ENCODERS
3266 @chapter Subtitles Encoders
3267 @c man begin SUBTITLES ENCODERS
3271 This codec encodes the bitmap subtitle format that is used in DVDs.
3272 Typically they are stored in VOBSUB file pairs (*.idx + *.sub),
3273 and they can also be used in Matroska files.
3279 Specify the global palette used by the bitmaps.
3281 The format for this option is a string containing 16 24-bits hexadecimal
3282 numbers (without 0x prefix) separated by commas, for example @code{0d00ee,
3283 ee450d, 101010, eaeaea, 0ce60b, ec14ed, ebff0b, 0d617a, 7b7b7b, d1d1d1,
3284 7b2a0e, 0d950c, 0f007b, cf0dec, cfa80c, 7c127b}.
3287 When set to 1, enable a work-around that makes the number of pixel rows
3288 even in all subtitles. This fixes a problem with some players that
3289 cut off the bottom row if the number is odd. The work-around just adds
3290 a fully transparent row if needed. The overhead is low, typically
3291 one byte per subtitle on average.
3293 By default, this work-around is disabled.
3296 @c man end SUBTITLES ENCODERS