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 rav1e AV1 encoder wrapper.
1385 Requires the presence of the rav1e headers and library during configuration.
1386 You need to explicitly configure the build with @code{--enable-librav1e}.
1392 Sets the maximum quantizer to use when using bitrate mode.
1395 Sets the minimum quantizer to use when using bitrate mode.
1398 Uses quantizer mode to encode at the given quantizer (0-255).
1401 Selects the speed preset (0-10) to encode with.
1404 Selects how many tiles to encode with.
1407 Selects how many rows of tiles to encode with.
1410 Selects how many columns of tiles to encode with.
1413 Set rav1e options using a list of @var{key}=@var{value} pairs separated
1414 by ":". See @command{rav1e --help} for a list of options.
1416 For example to specify librav1e encoding options with @option{-rav1e-params}:
1419 ffmpeg -i input -c:v librav1e -b:v 500K -rav1e-params speed=5:low_latency=true output.mp4
1426 libaom AV1 encoder wrapper.
1428 Requires the presence of the libaom headers and library during
1429 configuration. You need to explicitly configure the build with
1430 @code{--enable-libaom}.
1434 The wrapper supports the following standard libavcodec options:
1439 Set bitrate target in bits/second. By default this will use
1440 variable-bitrate mode. If @option{maxrate} and @option{minrate} are
1441 also set to the same value then it will use constant-bitrate mode,
1442 otherwise if @option{crf} is set as well then it will use
1443 constrained-quality mode.
1446 Set key frame placement. The GOP size sets the maximum distance between
1447 key frames; if zero the output stream will be intra-only. The minimum
1448 distance is ignored unless it is the same as the GOP size, in which case
1449 key frames will always appear at a fixed interval. Not set by default,
1450 so without this option the library has completely free choice about
1451 where to place key frames.
1454 Set minimum/maximum quantisation values. Valid range is from 0 to 63
1455 (warning: this does not match the quantiser values actually used by AV1
1456 - divide by four to map real quantiser values to this range). Defaults
1457 to min/max (no constraint).
1459 @item minrate maxrate bufsize rc_init_occupancy
1460 Set rate control buffering parameters. Not used if not set - defaults
1461 to unconstrained variable bitrate.
1464 Set the number of threads to use while encoding. This may require the
1465 @option{tiles} or @option{row-mt} options to also be set to actually
1466 use the specified number of threads fully. Defaults to the number of
1467 hardware threads supported by the host machine.
1470 Set the encoding profile. Defaults to using the profile which matches
1471 the bit depth and chroma subsampling of the input.
1475 The wrapper also has some specific options:
1480 Set the quality/encoding speed tradeoff. Valid range is from 0 to 8,
1481 higher numbers indicating greater speed and lower quality. The default
1482 value is 1, which will be slow and high quality.
1485 Enable use of alternate reference frames. Defaults to the internal
1486 default of the library.
1488 @item arnr-max-frames (@emph{frames})
1489 Set altref noise reduction max frame count. Default is -1.
1491 @item arnr-strength (@emph{strength})
1492 Set altref noise reduction filter strength. Range is -1 to 6. Default is -1.
1494 @item aq-mode (@emph{aq-mode})
1495 Set adaptive quantization mode. Possible values:
1498 @item none (@emph{0})
1501 @item variance (@emph{1})
1504 @item complexity (@emph{2})
1507 @item cyclic (@emph{3})
1512 Set the maximum number of frames which the encoder may keep in flight
1513 at any one time for lookahead purposes. Defaults to the internal
1514 default of the library.
1516 @item error-resilience
1517 Enable error resilience features:
1520 Improve resilience against losses of whole frames.
1522 Not enabled by default.
1525 Set the quality/size tradeoff for constant-quality (no bitrate target)
1526 and constrained-quality (with maximum bitrate target) modes. Valid
1527 range is 0 to 63, higher numbers indicating lower quality and smaller
1528 output size. Only used if set; by default only the bitrate target is
1532 Set a change threshold on blocks below which they will be skipped by
1533 the encoder. Defined in arbitrary units as a nonnegative integer,
1534 defaulting to zero (no blocks are skipped).
1536 @item drop-threshold
1537 Set a threshold for dropping frames when close to rate control bounds.
1538 Defined as a percentage of the target buffer - when the rate control
1539 buffer falls below this percentage, frames will be dropped until it
1540 has refilled above the threshold. Defaults to zero (no frames are
1543 @item denoise-noise-level (@emph{level})
1544 Amount of noise to be removed for grain synthesis. Grain synthesis is disabled if
1545 this option is not set or set to 0.
1547 @item denoise-block-size (@emph{pixels})
1548 Block size used for denoising for grain synthesis. If not set, AV1 codec
1549 uses the default value of 32.
1551 @item undershoot-pct (@emph{pct})
1552 Set datarate undershoot (min) percentage of the target bitrate. Range is -1 to 100.
1555 @item overshoot-pct (@emph{pct})
1556 Set datarate overshoot (max) percentage of the target bitrate. Range is -1 to 1000.
1559 @item minsection-pct (@emph{pct})
1560 Minimum percentage variation of the GOP bitrate from the target bitrate. If minsection-pct
1561 is not set, the libaomenc wrapper computes it as follows: @code{(minrate * 100 / bitrate)}.
1562 Range is -1 to 100. Default is -1 (unset).
1564 @item maxsection-pct (@emph{pct})
1565 Maximum percentage variation of the GOP bitrate from the target bitrate. If maxsection-pct
1566 is not set, the libaomenc wrapper computes it as follows: @code{(maxrate * 100 / bitrate)}.
1567 Range is -1 to 5000. Default is -1 (unset).
1569 @item frame-parallel (@emph{boolean})
1570 Enable frame parallel decodability features. Default is true.
1573 Set the number of tiles to encode the input video with, as columns x
1574 rows. Larger numbers allow greater parallelism in both encoding and
1575 decoding, but may decrease coding efficiency. Defaults to the minimum
1576 number of tiles required by the size of the input video (this is 1x1
1577 (that is, a single tile) for sizes up to and including 4K).
1579 @item tile-columns tile-rows
1580 Set the number of tiles as log2 of the number of tile rows and columns.
1581 Provided for compatibility with libvpx/VP9.
1583 @item row-mt (Requires libaom >= 1.0.0-759-g90a15f4f2)
1584 Enable row based multi-threading. Disabled by default.
1586 @item enable-cdef (@emph{boolean})
1587 Enable Constrained Directional Enhancement Filter. The libaom-av1
1588 encoder enables CDEF by default.
1590 @item enable-restoration (@emph{boolean})
1591 Enable Loop Restoration Filter. Default is true for libaom-av1.
1593 @item enable-global-motion (@emph{boolean})
1594 Enable the use of global motion for block prediction. Default is true.
1596 @item enable-intrabc (@emph{boolean})
1597 Enable block copy mode for intra block prediction. This mode is
1598 useful for screen content. Default is true.
1604 Kvazaar H.265/HEVC encoder.
1606 Requires the presence of the libkvazaar headers and library during
1607 configuration. You need to explicitly configure the build with
1608 @option{--enable-libkvazaar}.
1615 Set target video bitrate in bit/s and enable rate control.
1617 @item kvazaar-params
1618 Set kvazaar parameters as a list of @var{name}=@var{value} pairs separated
1619 by commas (,). See kvazaar documentation for a list of options.
1623 @section libopenh264
1625 Cisco libopenh264 H.264/MPEG-4 AVC encoder wrapper.
1627 This encoder requires the presence of the libopenh264 headers and
1628 library during configuration. You need to explicitly configure the
1629 build with @code{--enable-libopenh264}. The library is detected using
1630 @command{pkg-config}.
1632 For more information about the library see
1633 @url{http://www.openh264.org}.
1637 The following FFmpeg global options affect the configurations of the
1638 libopenh264 encoder.
1642 Set the bitrate (as a number of bits per second).
1648 Set the max bitrate (as a number of bits per second).
1650 @item flags +global_header
1651 Set global header in the bitstream.
1654 Set the number of slices, used in parallelized encoding. Default value
1655 is 0. This is only used when @option{slice_mode} is set to
1659 Set slice mode. Can assume one of the following possible values:
1663 a fixed number of slices
1665 one slice per row of macroblocks
1667 automatic number of slices according to number of threads
1672 Default value is @samp{auto}.
1675 Enable loop filter, if set to 1 (automatically enabled). To disable
1679 Set profile restrictions. If set to the value of @samp{main} enable
1680 CABAC (set the @code{SEncParamExt.iEntropyCodingModeFlag} flag to 1).
1683 Set maximum NAL size in bytes.
1685 @item allow_skip_frames
1686 Allow skipping frames to hit the target bitrate if set to 1.
1691 libtheora Theora encoder wrapper.
1693 Requires the presence of the libtheora headers and library during
1694 configuration. You need to explicitly configure the build with
1695 @code{--enable-libtheora}.
1697 For more information about the libtheora project see
1698 @url{http://www.theora.org/}.
1702 The following global options are mapped to internal libtheora options
1703 which affect the quality and the bitrate of the encoded stream.
1707 Set the video bitrate in bit/s for CBR (Constant Bit Rate) mode. In
1708 case VBR (Variable Bit Rate) mode is enabled this option is ignored.
1711 Used to enable constant quality mode (VBR) encoding through the
1712 @option{qscale} flag, and to enable the @code{pass1} and @code{pass2}
1718 @item global_quality
1719 Set the global quality as an integer in lambda units.
1721 Only relevant when VBR mode is enabled with @code{flags +qscale}. The
1722 value is converted to QP units by dividing it by @code{FF_QP2LAMBDA},
1723 clipped in the [0 - 10] range, and then multiplied by 6.3 to get a
1724 value in the native libtheora range [0-63]. A higher value corresponds
1725 to a higher quality.
1728 Enable VBR mode when set to a non-negative value, and set constant
1729 quality value as a double floating point value in QP units.
1731 The value is clipped in the [0-10] range, and then multiplied by 6.3
1732 to get a value in the native libtheora range [0-63].
1734 This option is valid only using the @command{ffmpeg} command-line
1735 tool. For library interface users, use @option{global_quality}.
1738 @subsection Examples
1742 Set maximum constant quality (VBR) encoding with @command{ffmpeg}:
1744 ffmpeg -i INPUT -codec:v libtheora -q:v 10 OUTPUT.ogg
1748 Use @command{ffmpeg} to convert a CBR 1000 kbps Theora video stream:
1750 ffmpeg -i INPUT -codec:v libtheora -b:v 1000k OUTPUT.ogg
1756 VP8/VP9 format supported through libvpx.
1758 Requires the presence of the libvpx headers and library during configuration.
1759 You need to explicitly configure the build with @code{--enable-libvpx}.
1763 The following options are supported by the libvpx wrapper. The
1764 @command{vpxenc}-equivalent options or values are listed in parentheses
1767 To reduce the duplication of documentation, only the private options
1768 and some others requiring special attention are documented here. For
1769 the documentation of the undocumented generic options, see
1770 @ref{codec-options,,the Codec Options chapter}.
1772 To get more documentation of the libvpx options, invoke the command
1773 @command{ffmpeg -h encoder=libvpx}, @command{ffmpeg -h encoder=libvpx-vp9} or
1774 @command{vpxenc --help}. Further information is available in the libvpx API
1779 @item b (@emph{target-bitrate})
1780 Set bitrate in bits/s. Note that FFmpeg's @option{b} option is
1781 expressed in bits/s, while @command{vpxenc}'s @option{target-bitrate} is in
1784 @item g (@emph{kf-max-dist})
1786 @item keyint_min (@emph{kf-min-dist})
1788 @item qmin (@emph{min-q})
1790 @item qmax (@emph{max-q})
1792 @item bufsize (@emph{buf-sz}, @emph{buf-optimal-sz})
1793 Set ratecontrol buffer size (in bits). Note @command{vpxenc}'s options are
1794 specified in milliseconds, the libvpx wrapper converts this value as follows:
1795 @code{buf-sz = bufsize * 1000 / bitrate},
1796 @code{buf-optimal-sz = bufsize * 1000 / bitrate * 5 / 6}.
1798 @item rc_init_occupancy (@emph{buf-initial-sz})
1799 Set number of bits which should be loaded into the rc buffer before decoding
1800 starts. Note @command{vpxenc}'s option is specified in milliseconds, the libvpx
1801 wrapper converts this value as follows:
1802 @code{rc_init_occupancy * 1000 / bitrate}.
1804 @item undershoot-pct
1805 Set datarate undershoot (min) percentage of the target bitrate.
1808 Set datarate overshoot (max) percentage of the target bitrate.
1810 @item skip_threshold (@emph{drop-frame})
1812 @item qcomp (@emph{bias-pct})
1814 @item maxrate (@emph{maxsection-pct})
1815 Set GOP max bitrate in bits/s. Note @command{vpxenc}'s option is specified as a
1816 percentage of the target bitrate, the libvpx wrapper converts this value as
1817 follows: @code{(maxrate * 100 / bitrate)}.
1819 @item minrate (@emph{minsection-pct})
1820 Set GOP min bitrate in bits/s. Note @command{vpxenc}'s option is specified as a
1821 percentage of the target bitrate, the libvpx wrapper converts this value as
1822 follows: @code{(minrate * 100 / bitrate)}.
1824 @item minrate, maxrate, b @emph{end-usage=cbr}
1825 @code{(minrate == maxrate == bitrate)}.
1827 @item crf (@emph{end-usage=cq}, @emph{cq-level})
1829 @item tune (@emph{tune})
1831 @item psnr (@emph{psnr})
1832 @item ssim (@emph{ssim})
1835 @item quality, deadline (@emph{deadline})
1838 Use best quality deadline. Poorly named and quite slow, this option should be
1839 avoided as it may give worse quality output than good.
1841 Use good quality deadline. This is a good trade-off between speed and quality
1842 when used with the @option{cpu-used} option.
1844 Use realtime quality deadline.
1847 @item speed, cpu-used (@emph{cpu-used})
1848 Set quality/speed ratio modifier. Higher values speed up the encode at the cost
1851 @item nr (@emph{noise-sensitivity})
1854 Set a change threshold on blocks below which they will be skipped by the
1857 @item slices (@emph{token-parts})
1858 Note that FFmpeg's @option{slices} option gives the total number of partitions,
1859 while @command{vpxenc}'s @option{token-parts} is given as
1860 @code{log2(partitions)}.
1862 @item max-intra-rate
1863 Set maximum I-frame bitrate as a percentage of the target bitrate. A value of 0
1866 @item force_key_frames
1867 @code{VPX_EFLAG_FORCE_KF}
1869 @item Alternate reference frame related
1872 Enable use of alternate reference frames (2-pass only).
1873 Values greater than 1 enable multi-layer alternate reference frames (VP9 only).
1874 @item arnr-maxframes
1875 Set altref noise reduction max frame count.
1877 Set altref noise reduction filter type: backward, forward, centered.
1879 Set altref noise reduction filter strength.
1880 @item rc-lookahead, lag-in-frames (@emph{lag-in-frames})
1881 Set number of frames to look ahead for frametype and ratecontrol.
1884 @item error-resilient
1885 Enable error resiliency features.
1887 @item sharpness @var{integer}
1888 Increase sharpness at the expense of lower PSNR.
1889 The valid range is [0, 7].
1892 Sets the temporal scalability configuration using a :-separated list of
1893 key=value pairs. For example, to specify temporal scalability parameters
1896 ffmpeg -i INPUT -c:v libvpx -ts-parameters ts_number_layers=3:\
1897 ts_target_bitrate=250,500,1000:ts_rate_decimator=4,2,1:\
1898 ts_periodicity=4:ts_layer_id=0,2,1,2:ts_layering_mode=3 OUTPUT
1900 Below is a brief explanation of each of the parameters, please
1901 refer to @code{struct vpx_codec_enc_cfg} in @code{vpx/vpx_encoder.h} for more
1904 @item ts_number_layers
1905 Number of temporal coding layers.
1906 @item ts_target_bitrate
1907 Target bitrate for each temporal layer (in kbps).
1908 (bitrate should be inclusive of the lower temporal layer).
1909 @item ts_rate_decimator
1910 Frame rate decimation factor for each temporal layer.
1911 @item ts_periodicity
1912 Length of the sequence defining frame temporal layer membership.
1914 Template defining the membership of frames to temporal layers.
1915 @item ts_layering_mode
1916 (optional) Selecting the temporal structure from a set of pre-defined temporal layering modes.
1917 Currently supports the following options.
1920 No temporal layering flags are provided internally,
1921 relies on flags being passed in using @code{metadata} field in @code{AVFrame}
1922 with following keys.
1925 Sets the flags passed into the encoder to indicate the referencing scheme for
1927 Refer to function @code{vpx_codec_encode} in @code{vpx/vpx_encoder.h} for more
1930 Explicitly sets the temporal id of the current frame to encode.
1933 Two temporal layers. 0-1...
1935 Three temporal layers. 0-2-1-2...; with single reference frame.
1937 Same as option "3", except there is a dependency between
1938 the two temporal layer 2 frames within the temporal period.
1942 @item VP9-specific options
1945 Enable lossless mode.
1947 Set number of tile columns to use. Note this is given as
1948 @code{log2(tile_columns)}. For example, 8 tile columns would be requested by
1949 setting the @option{tile-columns} option to 3.
1951 Set number of tile rows to use. Note this is given as @code{log2(tile_rows)}.
1952 For example, 4 tile rows would be requested by setting the @option{tile-rows}
1954 @item frame-parallel
1955 Enable frame parallel decodability features.
1957 Set adaptive quantization mode (0: off (default), 1: variance 2: complexity, 3:
1958 cyclic refresh, 4: equator360).
1959 @item colorspace @emph{color-space}
1960 Set input color space. The VP9 bitstream supports signaling the following
1963 @item @samp{rgb} @emph{sRGB}
1964 @item @samp{bt709} @emph{bt709}
1965 @item @samp{unspecified} @emph{unknown}
1966 @item @samp{bt470bg} @emph{bt601}
1967 @item @samp{smpte170m} @emph{smpte170}
1968 @item @samp{smpte240m} @emph{smpte240}
1969 @item @samp{bt2020_ncl} @emph{bt2020}
1971 @item row-mt @var{boolean}
1972 Enable row based multi-threading.
1974 Set content type: default (0), screen (1), film (2).
1975 @item corpus-complexity
1976 Corpus VBR mode is a variant of standard VBR where the complexity distribution
1977 midpoint is passed in rather than calculated for a specific clip or chunk.
1979 The valid range is [0, 10000]. 0 (default) uses standard VBR.
1980 @item enable-tpl @var{boolean}
1981 Enable temporal dependency model.
1986 For more information about libvpx see:
1987 @url{http://www.webmproject.org/}
1991 libwebp WebP Image encoder wrapper
1993 libwebp is Google's official encoder for WebP images. It can encode in either
1994 lossy or lossless mode. Lossy images are essentially a wrapper around a VP8
1995 frame. Lossless images are a separate codec developed by Google.
1997 @subsection Pixel Format
1999 Currently, libwebp only supports YUV420 for lossy and RGB for lossless due
2000 to limitations of the format and libwebp. Alpha is supported for either mode.
2001 Because of API limitations, if RGB is passed in when encoding lossy or YUV is
2002 passed in for encoding lossless, the pixel format will automatically be
2003 converted using functions from libwebp. This is not ideal and is done only for
2010 @item -lossless @var{boolean}
2011 Enables/Disables use of lossless mode. Default is 0.
2013 @item -compression_level @var{integer}
2014 For lossy, this is a quality/speed tradeoff. Higher values give better quality
2015 for a given size at the cost of increased encoding time. For lossless, this is
2016 a size/speed tradeoff. Higher values give smaller size at the cost of increased
2017 encoding time. More specifically, it controls the number of extra algorithms
2018 and compression tools used, and varies the combination of these tools. This
2019 maps to the @var{method} option in libwebp. The valid range is 0 to 6.
2022 @item -qscale @var{float}
2023 For lossy encoding, this controls image quality, 0 to 100. For lossless
2024 encoding, this controls the effort and time spent at compressing more. The
2025 default value is 75. Note that for usage via libavcodec, this option is called
2026 @var{global_quality} and must be multiplied by @var{FF_QP2LAMBDA}.
2028 @item -preset @var{type}
2029 Configuration preset. This does some automatic settings based on the general
2033 Do not use a preset.
2035 Use the encoder default.
2037 Digital picture, like portrait, inner shot
2039 Outdoor photograph, with natural lighting
2041 Hand or line drawing, with high-contrast details
2043 Small-sized colorful images
2050 @section libx264, libx264rgb
2052 x264 H.264/MPEG-4 AVC encoder wrapper.
2054 This encoder requires the presence of the libx264 headers and library
2055 during configuration. You need to explicitly configure the build with
2056 @code{--enable-libx264}.
2058 libx264 supports an impressive number of features, including 8x8 and
2059 4x4 adaptive spatial transform, adaptive B-frame placement, CAVLC/CABAC
2060 entropy coding, interlacing (MBAFF), lossless mode, psy optimizations
2061 for detail retention (adaptive quantization, psy-RD, psy-trellis).
2063 Many libx264 encoder options are mapped to FFmpeg global codec
2064 options, while unique encoder options are provided through private
2065 options. Additionally the @option{x264opts} and @option{x264-params}
2066 private options allows one to pass a list of key=value tuples as accepted
2067 by the libx264 @code{x264_param_parse} function.
2069 The x264 project website is at
2070 @url{http://www.videolan.org/developers/x264.html}.
2072 The libx264rgb encoder is the same as libx264, except it accepts packed RGB
2073 pixel formats as input instead of YUV.
2075 @subsection Supported Pixel Formats
2077 x264 supports 8- to 10-bit color spaces. The exact bit depth is controlled at
2078 x264's configure time. FFmpeg only supports one bit depth in one particular
2079 build. In other words, it is not possible to build one FFmpeg with multiple
2080 versions of x264 with different bit depths.
2084 The following options are supported by the libx264 wrapper. The
2085 @command{x264}-equivalent options or values are listed in parentheses
2088 To reduce the duplication of documentation, only the private options
2089 and some others requiring special attention are documented here. For
2090 the documentation of the undocumented generic options, see
2091 @ref{codec-options,,the Codec Options chapter}.
2093 To get a more accurate and extensive documentation of the libx264
2094 options, invoke the command @command{x264 --fullhelp} or consult
2095 the libx264 documentation.
2098 @item b (@emph{bitrate})
2099 Set bitrate in bits/s. Note that FFmpeg's @option{b} option is
2100 expressed in bits/s, while @command{x264}'s @option{bitrate} is in
2103 @item bf (@emph{bframes})
2105 @item g (@emph{keyint})
2107 @item qmin (@emph{qpmin})
2108 Minimum quantizer scale.
2110 @item qmax (@emph{qpmax})
2111 Maximum quantizer scale.
2113 @item qdiff (@emph{qpstep})
2114 Maximum difference between quantizer scales.
2116 @item qblur (@emph{qblur})
2117 Quantizer curve blur
2119 @item qcomp (@emph{qcomp})
2120 Quantizer curve compression factor
2122 @item refs (@emph{ref})
2123 Number of reference frames each P-frame can use. The range is from @var{0-16}.
2125 @item sc_threshold (@emph{scenecut})
2126 Sets the threshold for the scene change detection.
2128 @item trellis (@emph{trellis})
2129 Performs Trellis quantization to increase efficiency. Enabled by default.
2131 @item nr (@emph{nr})
2133 @item me_range (@emph{merange})
2134 Maximum range of the motion search in pixels.
2136 @item me_method (@emph{me})
2137 Set motion estimation method. Possible values in the decreasing order
2141 @item dia (@emph{dia})
2142 @item epzs (@emph{dia})
2143 Diamond search with radius 1 (fastest). @samp{epzs} is an alias for
2145 @item hex (@emph{hex})
2146 Hexagonal search with radius 2.
2147 @item umh (@emph{umh})
2148 Uneven multi-hexagon search.
2149 @item esa (@emph{esa})
2151 @item tesa (@emph{tesa})
2152 Hadamard exhaustive search (slowest).
2156 Normally, when forcing a I-frame type, the encoder can select any type
2157 of I-frame. This option forces it to choose an IDR-frame.
2159 @item subq (@emph{subme})
2160 Sub-pixel motion estimation method.
2162 @item b_strategy (@emph{b-adapt})
2163 Adaptive B-frame placement decision algorithm. Use only on first-pass.
2165 @item keyint_min (@emph{min-keyint})
2169 Set entropy encoder. Possible values:
2176 Enable CAVLC and disable CABAC. It generates the same effect as
2177 @command{x264}'s @option{--no-cabac} option.
2181 Set full pixel motion estimation comparison algorithm. Possible values:
2185 Enable chroma in motion estimation.
2188 Ignore chroma in motion estimation. It generates the same effect as
2189 @command{x264}'s @option{--no-chroma-me} option.
2192 @item threads (@emph{threads})
2193 Number of encoding threads.
2196 Set multithreading technique. Possible values:
2200 Slice-based multithreading. It generates the same effect as
2201 @command{x264}'s @option{--sliced-threads} option.
2203 Frame-based multithreading.
2207 Set encoding flags. It can be used to disable closed GOP and enable
2208 open GOP by setting it to @code{-cgop}. The result is similar to
2209 the behavior of @command{x264}'s @option{--open-gop} option.
2211 @item rc_init_occupancy (@emph{vbv-init})
2213 @item preset (@emph{preset})
2214 Set the encoding preset.
2216 @item tune (@emph{tune})
2217 Set tuning of the encoding params.
2219 @item profile (@emph{profile})
2220 Set profile restrictions.
2223 Enable fast settings when encoding first pass, when set to 1. When set
2224 to 0, it has the same effect of @command{x264}'s
2225 @option{--slow-firstpass} option.
2227 @item crf (@emph{crf})
2228 Set the quality for constant quality mode.
2230 @item crf_max (@emph{crf-max})
2231 In CRF mode, prevents VBV from lowering quality beyond this point.
2233 @item qp (@emph{qp})
2234 Set constant quantization rate control method parameter.
2236 @item aq-mode (@emph{aq-mode})
2237 Set AQ method. Possible values:
2240 @item none (@emph{0})
2243 @item variance (@emph{1})
2244 Variance AQ (complexity mask).
2246 @item autovariance (@emph{2})
2247 Auto-variance AQ (experimental).
2250 @item aq-strength (@emph{aq-strength})
2251 Set AQ strength, reduce blocking and blurring in flat and textured areas.
2254 Use psychovisual optimizations when set to 1. When set to 0, it has the
2255 same effect as @command{x264}'s @option{--no-psy} option.
2257 @item psy-rd (@emph{psy-rd})
2258 Set strength of psychovisual optimization, in
2259 @var{psy-rd}:@var{psy-trellis} format.
2261 @item rc-lookahead (@emph{rc-lookahead})
2262 Set number of frames to look ahead for frametype and ratecontrol.
2265 Enable weighted prediction for B-frames when set to 1. When set to 0,
2266 it has the same effect as @command{x264}'s @option{--no-weightb} option.
2268 @item weightp (@emph{weightp})
2269 Set weighted prediction method for P-frames. Possible values:
2272 @item none (@emph{0})
2274 @item simple (@emph{1})
2275 Enable only weighted refs
2276 @item smart (@emph{2})
2277 Enable both weighted refs and duplicates
2280 @item ssim (@emph{ssim})
2281 Enable calculation and printing SSIM stats after the encoding.
2283 @item intra-refresh (@emph{intra-refresh})
2284 Enable the use of Periodic Intra Refresh instead of IDR frames when set
2287 @item avcintra-class (@emph{class})
2288 Configure the encoder to generate AVC-Intra.
2289 Valid values are 50,100 and 200
2291 @item bluray-compat (@emph{bluray-compat})
2292 Configure the encoder to be compatible with the bluray standard.
2293 It is a shorthand for setting "bluray-compat=1 force-cfr=1".
2295 @item b-bias (@emph{b-bias})
2296 Set the influence on how often B-frames are used.
2298 @item b-pyramid (@emph{b-pyramid})
2299 Set method for keeping of some B-frames as references. Possible values:
2302 @item none (@emph{none})
2304 @item strict (@emph{strict})
2305 Strictly hierarchical pyramid.
2306 @item normal (@emph{normal})
2307 Non-strict (not Blu-ray compatible).
2311 Enable the use of one reference per partition, as opposed to one
2312 reference per macroblock when set to 1. When set to 0, it has the
2313 same effect as @command{x264}'s @option{--no-mixed-refs} option.
2316 Enable adaptive spatial transform (high profile 8x8 transform)
2317 when set to 1. When set to 0, it has the same effect as
2318 @command{x264}'s @option{--no-8x8dct} option.
2321 Enable early SKIP detection on P-frames when set to 1. When set
2322 to 0, it has the same effect as @command{x264}'s
2323 @option{--no-fast-pskip} option.
2325 @item aud (@emph{aud})
2326 Enable use of access unit delimiters when set to 1.
2329 Enable use macroblock tree ratecontrol when set to 1. When set
2330 to 0, it has the same effect as @command{x264}'s
2331 @option{--no-mbtree} option.
2333 @item deblock (@emph{deblock})
2334 Set loop filter parameters, in @var{alpha}:@var{beta} form.
2336 @item cplxblur (@emph{cplxblur})
2337 Set fluctuations reduction in QP (before curve compression).
2339 @item partitions (@emph{partitions})
2340 Set partitions to consider as a comma-separated list of. Possible
2345 8x8 P-frame partition.
2347 4x4 P-frame partition.
2349 4x4 B-frame partition.
2351 8x8 I-frame partition.
2353 4x4 I-frame partition.
2354 (Enabling @samp{p4x4} requires @samp{p8x8} to be enabled. Enabling
2355 @samp{i8x8} requires adaptive spatial transform (@option{8x8dct}
2356 option) to be enabled.)
2357 @item none (@emph{none})
2358 Do not consider any partitions.
2359 @item all (@emph{all})
2360 Consider every partition.
2363 @item direct-pred (@emph{direct})
2364 Set direct MV prediction mode. Possible values:
2367 @item none (@emph{none})
2368 Disable MV prediction.
2369 @item spatial (@emph{spatial})
2370 Enable spatial predicting.
2371 @item temporal (@emph{temporal})
2372 Enable temporal predicting.
2373 @item auto (@emph{auto})
2374 Automatically decided.
2377 @item slice-max-size (@emph{slice-max-size})
2378 Set the limit of the size of each slice in bytes. If not specified
2379 but RTP payload size (@option{ps}) is specified, that is used.
2381 @item stats (@emph{stats})
2382 Set the file name for multi-pass stats.
2384 @item nal-hrd (@emph{nal-hrd})
2385 Set signal HRD information (requires @option{vbv-bufsize} to be set).
2389 @item none (@emph{none})
2390 Disable HRD information signaling.
2391 @item vbr (@emph{vbr})
2393 @item cbr (@emph{cbr})
2394 Constant bit rate (not allowed in MP4 container).
2397 @item x264opts (N.A.)
2398 Set any x264 option, see @command{x264 --fullhelp} for a list.
2400 Argument is a list of @var{key}=@var{value} couples separated by
2401 ":". In @var{filter} and @var{psy-rd} options that use ":" as a separator
2402 themselves, use "," instead. They accept it as well since long ago but this
2403 is kept undocumented for some reason.
2405 For example to specify libx264 encoding options with @command{ffmpeg}:
2407 ffmpeg -i foo.mpg -c:v libx264 -x264opts keyint=123:min-keyint=20 -an out.mkv
2410 @item a53cc @var{boolean}
2411 Import closed captions (which must be ATSC compatible format) into output.
2412 Only the mpeg2 and h264 decoders provide these. Default is 1 (on).
2414 @item x264-params (N.A.)
2415 Override the x264 configuration using a :-separated list of key=value
2418 This option is functionally the same as the @option{x264opts}, but is
2419 duplicated for compatibility with the Libav fork.
2421 For example to specify libx264 encoding options with @command{ffmpeg}:
2423 ffmpeg -i INPUT -c:v libx264 -x264-params level=30:bframes=0:weightp=0:\
2424 cabac=0:ref=1:vbv-maxrate=768:vbv-bufsize=2000:analyse=all:me=umh:\
2425 no-fast-pskip=1:subq=6:8x8dct=0:trellis=0 OUTPUT
2429 Encoding ffpresets for common usages are provided so they can be used with the
2430 general presets system (e.g. passing the @option{pre} option).
2434 x265 H.265/HEVC encoder wrapper.
2436 This encoder requires the presence of the libx265 headers and library
2437 during configuration. You need to explicitly configure the build with
2438 @option{--enable-libx265}.
2444 Sets target video bitrate.
2455 Number of reference frames each P-frame can use. The range is from @var{1-16}.
2458 Set the x265 preset.
2461 Set the x265 tune parameter.
2464 Set profile restrictions.
2467 Set the quality for constant quality mode.
2470 Set constant quantization rate control method parameter.
2473 Minimum quantizer scale.
2476 Maximum quantizer scale.
2479 Maximum difference between quantizer scales.
2482 Quantizer curve blur
2485 Quantizer curve compression factor
2492 Normally, when forcing a I-frame type, the encoder can select any type
2493 of I-frame. This option forces it to choose an IDR-frame.
2496 Set x265 options using a list of @var{key}=@var{value} couples separated
2497 by ":". See @command{x265 --help} for a list of options.
2499 For example to specify libx265 encoding options with @option{-x265-params}:
2502 ffmpeg -i input -c:v libx265 -x265-params crf=26:psy-rd=1 output.mp4
2508 xavs2 AVS2-P2/IEEE1857.4 encoder wrapper.
2510 This encoder requires the presence of the libxavs2 headers and library
2511 during configuration. You need to explicitly configure the build with
2512 @option{--enable-libxavs2}.
2514 The following standard libavcodec options are used:
2517 @option{b} / @option{bit_rate}
2519 @option{g} / @option{gop_size}
2521 @option{bf} / @option{max_b_frames}
2524 The encoder also has its own specific options:
2528 @item lcu_row_threads
2529 Set the number of parallel threads for rows from 1 to 8 (default 5).
2532 Set the xavs2 quantization parameter from 1 to 63 (default 34). This is
2533 used to set the initial qp for the first frame.
2536 Set the xavs2 quantization parameter from 1 to 63 (default 34). This is
2537 used to set the qp value under constant-QP mode.
2540 Set the max qp for rate control from 1 to 63 (default 55).
2543 Set the min qp for rate control from 1 to 63 (default 20).
2546 Set the Speed level from 0 to 9 (default 0). Higher is better but slower.
2549 Set the log level from -1 to 3 (default 0). -1: none, 0: error,
2550 1: warning, 2: info, 3: debug.
2553 Set xavs2 options using a list of @var{key}=@var{value} couples separated
2556 For example to specify libxavs2 encoding options with @option{-xavs2-params}:
2559 ffmpeg -i input -c:v libxavs2 -xavs2-params RdoqLevel=0 output.avs2
2565 Xvid MPEG-4 Part 2 encoder wrapper.
2567 This encoder requires the presence of the libxvidcore headers and library
2568 during configuration. You need to explicitly configure the build with
2569 @code{--enable-libxvid --enable-gpl}.
2571 The native @code{mpeg4} encoder supports the MPEG-4 Part 2 format, so
2572 users can encode to this format without this library.
2576 The following options are supported by the libxvid wrapper. Some of
2577 the following options are listed but are not documented, and
2578 correspond to shared codec options. See @ref{codec-options,,the Codec
2579 Options chapter} for their documentation. The other shared options
2580 which are not listed have no effect for the libxvid encoder.
2602 Set specific encoding flags. Possible values:
2607 Use four motion vector by macroblock.
2610 Enable high quality AC prediction.
2613 Only encode grayscale.
2616 Enable the use of global motion compensation (GMC).
2619 Enable quarter-pixel motion compensation.
2625 Place global headers in extradata instead of every keyframe.
2632 Set motion estimation method. Possible values in decreasing order of
2633 speed and increasing order of quality:
2637 Use no motion estimation (default).
2642 Enable advanced diamond zonal search for 16x16 blocks and half-pixel
2643 refinement for 16x16 blocks. @samp{x1} and @samp{log} are aliases for
2647 Enable all of the things described above, plus advanced diamond zonal
2648 search for 8x8 blocks, half-pixel refinement for 8x8 blocks, and motion
2649 estimation on chroma planes.
2652 Enable all of the things described above, plus extended 16x16 and 8x8
2657 Set macroblock decision algorithm. Possible values in the increasing
2662 Use macroblock comparing function algorithm (default).
2665 Enable rate distortion-based half pixel and quarter pixel refinement for
2669 Enable all of the things described above, plus rate distortion-based
2670 half pixel and quarter pixel refinement for 8x8 blocks, and rate
2671 distortion-based search using square pattern.
2675 Enable lumi masking adaptive quantization when set to 1. Default is 0
2679 Enable variance adaptive quantization when set to 1. Default is 0
2682 When combined with @option{lumi_aq}, the resulting quality will not
2683 be better than any of the two specified individually. In other
2684 words, the resulting quality will be the worse one of the two
2688 Set structural similarity (SSIM) displaying method. Possible values:
2692 Disable displaying of SSIM information.
2695 Output average SSIM at the end of encoding to stdout. The format of
2696 showing the average SSIM is:
2702 For users who are not familiar with C, %f means a float number, or
2703 a decimal (e.g. 0.939232).
2706 Output both per-frame SSIM data during encoding and average SSIM at
2707 the end of encoding to stdout. The format of per-frame information
2711 SSIM: avg: %1.3f min: %1.3f max: %1.3f
2714 For users who are not familiar with C, %1.3f means a float number
2715 rounded to 3 digits after the dot (e.g. 0.932).
2720 Set SSIM accuracy. Valid options are integers within the range of
2721 0-4, while 0 gives the most accurate result and 4 computes the
2728 MPEG-2 video encoder.
2733 @item seq_disp_ext @var{integer}
2734 Specifies if the encoder should write a sequence_display_extension to the
2739 Decide automatically to write it or not (this is the default) by checking if
2740 the data to be written is different from the default or unspecified values.
2748 @item video_format @var{integer}
2749 Specifies the video_format written into the sequence display extension
2750 indicating the source of the video pictures. The default is @samp{unspecified},
2751 can be @samp{component}, @samp{pal}, @samp{ntsc}, @samp{secam} or @samp{mac}.
2752 For maximum compatibility, use @samp{component}.
2753 @item a53cc @var{boolean}
2754 Import closed captions (which must be ATSC compatible format) into output.
2762 @subsection Private options
2765 @item dpi @var{integer}
2766 Set physical density of pixels, in dots per inch, unset by default
2767 @item dpm @var{integer}
2768 Set physical density of pixels, in dots per meter, unset by default
2773 Apple ProRes encoder.
2775 FFmpeg contains 2 ProRes encoders, the prores-aw and prores-ks encoder.
2776 The used encoder can be chosen with the @code{-vcodec} option.
2778 @subsection Private Options for prores-ks
2781 @item profile @var{integer}
2782 Select the ProRes profile to encode
2792 @item quant_mat @var{integer}
2793 Select quantization matrix.
2802 If set to @var{auto}, the matrix matching the profile will be picked.
2803 If not set, the matrix providing the highest quality, @var{default}, will be
2806 @item bits_per_mb @var{integer}
2807 How many bits to allot for coding one macroblock. Different profiles use
2808 between 200 and 2400 bits per macroblock, the maximum is 8000.
2810 @item mbs_per_slice @var{integer}
2811 Number of macroblocks in each slice (1-8); the default value (8)
2812 should be good in almost all situations.
2814 @item vendor @var{string}
2815 Override the 4-byte vendor ID.
2816 A custom vendor ID like @var{apl0} would claim the stream was produced by
2819 @item alpha_bits @var{integer}
2820 Specify number of bits for alpha component.
2821 Possible values are @var{0}, @var{8} and @var{16}.
2822 Use @var{0} to disable alpha plane coding.
2826 @subsection Speed considerations
2828 In the default mode of operation the encoder has to honor frame constraints
2829 (i.e. not produce frames with size bigger than requested) while still making
2830 output picture as good as possible.
2831 A frame containing a lot of small details is harder to compress and the encoder
2832 would spend more time searching for appropriate quantizers for each slice.
2834 Setting a higher @option{bits_per_mb} limit will improve the speed.
2836 For the fastest encoding speed set the @option{qscale} parameter (4 is the
2837 recommended value) and do not set a size constraint.
2839 @section QSV encoders
2841 The family of Intel QuickSync Video encoders (MPEG-2, H.264, HEVC, JPEG/MJPEG and VP9)
2843 The ratecontrol method is selected as follows:
2847 When @option{global_quality} is specified, a quality-based mode is used.
2848 Specifically this means either
2851 @var{CQP} - constant quantizer scale, when the @option{qscale} codec flag is
2852 also set (the @option{-qscale} ffmpeg option).
2855 @var{LA_ICQ} - intelligent constant quality with lookahead, when the
2856 @option{look_ahead} option is also set.
2859 @var{ICQ} -- intelligent constant quality otherwise.
2863 Otherwise, a bitrate-based mode is used. For all of those, you should specify at
2864 least the desired average bitrate with the @option{b} option.
2867 @var{LA} - VBR with lookahead, when the @option{look_ahead} option is specified.
2870 @var{VCM} - video conferencing mode, when the @option{vcm} option is set.
2873 @var{CBR} - constant bitrate, when @option{maxrate} is specified and equal to
2874 the average bitrate.
2877 @var{VBR} - variable bitrate, when @option{maxrate} is specified, but is higher
2878 than the average bitrate.
2881 @var{AVBR} - average VBR mode, when @option{maxrate} is not specified. This mode
2882 is further configured by the @option{avbr_accuracy} and
2883 @option{avbr_convergence} options.
2887 Note that depending on your system, a different mode than the one you specified
2888 may be selected by the encoder. Set the verbosity level to @var{verbose} or
2889 higher to see the actual settings used by the QSV runtime.
2891 Additional libavcodec global options are mapped to MSDK options as follows:
2895 @option{g/gop_size} -> @option{GopPicSize}
2898 @option{bf/max_b_frames}+1 -> @option{GopRefDist}
2901 @option{rc_init_occupancy/rc_initial_buffer_occupancy} ->
2902 @option{InitialDelayInKB}
2905 @option{slices} -> @option{NumSlice}
2908 @option{refs} -> @option{NumRefFrame}
2911 @option{b_strategy/b_frame_strategy} -> @option{BRefType}
2914 @option{cgop/CLOSED_GOP} codec flag -> @option{GopOptFlag}
2917 For the @var{CQP} mode, the @option{i_qfactor/i_qoffset} and
2918 @option{b_qfactor/b_qoffset} set the difference between @var{QPP} and @var{QPI},
2919 and @var{QPP} and @var{QPB} respectively.
2922 Setting the @option{coder} option to the value @var{vlc} will make the H.264
2923 encoder use CAVLC instead of CABAC.
2932 @item iterative_dia_size
2933 dia size for the iterative motion estimation
2936 @section VAAPI encoders
2938 Wrappers for hardware encoders accessible via VAAPI.
2940 These encoders only accept input in VAAPI hardware surfaces. If you have input
2941 in software frames, use the @option{hwupload} filter to upload them to the GPU.
2943 The following standard libavcodec options are used:
2946 @option{g} / @option{gop_size}
2948 @option{bf} / @option{max_b_frames}
2952 If not set, this will be determined automatically from the format of the input
2953 frames and the profiles supported by the driver.
2957 @option{b} / @option{bit_rate}
2959 @option{maxrate} / @option{rc_max_rate}
2961 @option{bufsize} / @option{rc_buffer_size}
2963 @option{rc_init_occupancy} / @option{rc_initial_buffer_occupancy}
2965 @option{compression_level}
2967 Speed / quality tradeoff: higher values are faster / worse quality.
2969 @option{q} / @option{global_quality}
2971 Size / quality tradeoff: higher values are smaller / worse quality.
2977 @option{i_qfactor} / @option{i_quant_factor}
2979 @option{i_qoffset} / @option{i_quant_offset}
2981 @option{b_qfactor} / @option{b_quant_factor}
2983 @option{b_qoffset} / @option{b_quant_offset}
2988 All encoders support the following options:
2991 Some drivers/platforms offer a second encoder for some codecs intended to use
2992 less power than the default encoder; setting this option will attempt to use
2993 that encoder. Note that it may support a reduced feature set, so some other
2994 options may not be available in this mode.
2997 Set the number of normal intra frames between full-refresh (IDR) frames in
2998 open-GOP mode. The intra frames are still IRAPs, but will not include global
2999 headers and may have non-decodable leading pictures.
3002 Set the B-frame reference depth. When set to one (the default), all B-frames
3003 will refer only to P- or I-frames. When set to greater values multiple layers
3004 of B-frames will be present, frames in each layer only referring to frames in
3008 Set the rate control mode to use. A given driver may only support a subset of
3014 Choose the mode automatically based on driver support and the other options.
3015 This is the default.
3023 Intelligent constant-quality.
3025 Quality-defined variable-bitrate.
3027 Average variable bitrate.
3032 Each encoder also has its own specific options:
3036 @option{profile} sets the value of @emph{profile_idc} and the @emph{constraint_set*_flag}s.
3037 @option{level} sets the value of @emph{level_idc}.
3041 Set entropy encoder (default is @emph{cabac}). Possible values:
3054 Include access unit delimiters in the stream (not included by default).
3057 Set SEI message types to include.
3058 Some combination of the following values:
3061 Include a @emph{user_data_unregistered} message containing information about
3064 Include picture timing parameters (@emph{buffering_period} and
3065 @emph{pic_timing} messages).
3066 @item recovery_point
3067 Include recovery points where appropriate (@emph{recovery_point} messages).
3073 @option{profile} and @option{level} set the values of
3074 @emph{general_profile_idc} and @emph{general_level_idc} respectively.
3078 Include access unit delimiters in the stream (not included by default).
3081 Set @emph{general_tier_flag}. This may affect the level chosen for the stream
3082 if it is not explicitly specified.
3085 Set SEI message types to include.
3086 Some combination of the following values:
3089 Include HDR metadata if the input frames have it
3090 (@emph{mastering_display_colour_volume} and @emph{content_light_level}
3097 Only baseline DCT encoding is supported. The encoder always uses the standard
3098 quantisation and huffman tables - @option{global_quality} scales the standard
3099 quantisation table (range 1-100).
3101 For YUV, 4:2:0, 4:2:2 and 4:4:4 subsampling modes are supported. RGB is also
3102 supported, and will create an RGB JPEG.
3106 Include JFIF header in each frame (not included by default).
3108 Include standard huffman tables (on by default). Turning this off will save
3109 a few hundred bytes in each output frame, but may lose compatibility with some
3110 JPEG decoders which don't fully handle MJPEG.
3114 @option{profile} and @option{level} set the value of @emph{profile_and_level_indication}.
3117 B-frames are not supported.
3119 @option{global_quality} sets the @emph{q_idx} used for non-key frames (range 0-127).
3122 @item loop_filter_level
3123 @item loop_filter_sharpness
3124 Manually set the loop filter parameters.
3128 @option{global_quality} sets the @emph{q_idx} used for P-frames (range 0-255).
3131 @item loop_filter_level
3132 @item loop_filter_sharpness
3133 Manually set the loop filter parameters.
3136 B-frames are supported, but the output stream is always in encode order rather than display
3137 order. If B-frames are enabled, it may be necessary to use the @option{vp9_raw_reorder}
3138 bitstream filter to modify the output stream to display frames in the correct order.
3140 Only normal frames are produced - the @option{vp9_superframe} bitstream filter may be
3141 required to produce a stream usable with all decoders.
3147 SMPTE VC-2 (previously BBC Dirac Pro). This codec was primarily aimed at
3148 professional broadcasting but since it supports yuv420, yuv422 and yuv444 at
3149 8 (limited range or full range), 10 or 12 bits, this makes it suitable for
3150 other tasks which require low overhead and low compression (like screen
3158 Sets target video bitrate. Usually that's around 1:6 of the uncompressed
3159 video bitrate (e.g. for 1920x1080 50fps yuv422p10 that's around 400Mbps). Higher
3160 values (close to the uncompressed bitrate) turn on lossless compression mode.
3163 Enables field coding when set (e.g. to tt - top field first) for interlaced
3164 inputs. Should increase compression with interlaced content as it splits the
3165 fields and encodes each separately.
3168 Sets the total amount of wavelet transforms to apply, between 1 and 5 (default).
3169 Lower values reduce compression and quality. Less capable decoders may not be
3170 able to handle values of @option{wavelet_depth} over 3.
3173 Sets the transform type. Currently only @var{5_3} (LeGall) and @var{9_7}
3175 are implemented, with 9_7 being the one with better compression and thus
3180 Sets the slice size for each slice. Larger values result in better compression.
3181 For compatibility with other more limited decoders use @option{slice_width} of
3182 32 and @option{slice_height} of 8.
3185 Sets the undershoot tolerance of the rate control system in percent. This is
3186 to prevent an expensive search from being run.
3189 Sets the quantization matrix preset to use by default or when @option{wavelet_depth}
3194 Uses the default quantization matrix from the specifications, extended with
3195 values for the fifth level. This provides a good balance between keeping detail
3196 and omitting artifacts.
3200 Use a completely zeroed out quantization matrix. This increases PSNR but might
3201 reduce perception. Use in bogus benchmarks.
3205 Reduces detail but attempts to preserve color at extremely low bitrates.
3210 @c man end VIDEO ENCODERS
3212 @chapter Subtitles Encoders
3213 @c man begin SUBTITLES ENCODERS
3217 This codec encodes the bitmap subtitle format that is used in DVDs.
3218 Typically they are stored in VOBSUB file pairs (*.idx + *.sub),
3219 and they can also be used in Matroska files.
3225 Specify the global palette used by the bitmaps.
3227 The format for this option is a string containing 16 24-bits hexadecimal
3228 numbers (without 0x prefix) separated by commas, for example @code{0d00ee,
3229 ee450d, 101010, eaeaea, 0ce60b, ec14ed, ebff0b, 0d617a, 7b7b7b, d1d1d1,
3230 7b2a0e, 0d950c, 0f007b, cf0dec, cfa80c, 7c127b}.
3233 When set to 1, enable a work-around that makes the number of pixel rows
3234 even in all subtitles. This fixes a problem with some players that
3235 cut off the bottom row if the number is odd. The work-around just adds
3236 a fully transparent row if needed. The overhead is low, typically
3237 one byte per subtitle on average.
3239 By default, this work-around is disabled.
3242 @c man end SUBTITLES ENCODERS