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}
67 This is the default choice for a coder.
70 Average noise to mask ratio (ANMR) trellis-based solution.
72 This is an experimental coder which currently produces a lower quality, is more
73 unstable and is slower than the default twoloop coder but has potential.
74 Currently has no support for the @option{aac_is} or @option{aac_pns} options.
75 Not currently recommended.
78 Constant quantizer method.
80 This method sets a constant quantizer for all bands. This is the fastest of all
81 the methods and has no rate control or support for @option{aac_is} or
88 Sets mid/side coding mode. The default value of "auto" will automatically use
89 M/S with bands which will benefit from such coding. Can be forced for all bands
90 using the value "enable", which is mainly useful for debugging or disabled using
94 Sets intensity stereo coding tool usage. By default, it's enabled and will
95 automatically toggle IS for similar pairs of stereo bands if it's benefitial.
96 Can be disabled for debugging by setting the value to "disable".
99 Uses perceptual noise substitution to replace low entropy high frequency bands
100 with imperceivable white noise during the decoding process. By default, it's
101 enabled, but can be disabled for debugging purposes by using "disable".
104 Enables the use of a multitap FIR filter which spans through the high frequency
105 bands to hide quantization noise during the encoding process and is reverted
106 by the decoder. As well as decreasing unpleasant artifacts in the high range
107 this also reduces the entropy in the high bands and allows for more bits to
108 be used by the mid-low bands. By default it's enabled but can be disabled for
109 debugging by setting the option to "disable".
112 Enables the use of the long term prediction extension which increases coding
113 efficiency in very low bandwidth situations such as encoding of voice or
114 solo piano music by extending constant harmonic peaks in bands throughout
115 frames. This option is implied by profile:a aac_low and is incompatible with
116 aac_pred. Use in conjunction with @option{-ar} to decrease the samplerate.
119 Enables the use of a more traditional style of prediction where the spectral
120 coefficients transmitted are replaced by the difference of the current
121 coefficients minus the previous "predicted" coefficients. In theory and sometimes
122 in practice this can improve quality for low to mid bitrate audio.
123 This option implies the aac_main profile and is incompatible with aac_ltp.
126 Sets the encoding profile, possible values:
130 The default, AAC "Low-complexity" profile. Is the most compatible and produces
134 Equivalent to @code{-profile:a aac_low -aac_pns 0}. PNS was introduced with the
135 MPEG4 specifications.
138 Long term prediction profile, is enabled by and will enable the @option{aac_ltp}
139 option. Introduced in MPEG4.
142 Main-type prediction profile, is enabled by and will enable the @option{aac_pred}
143 option. Introduced in MPEG2.
146 If this option is unspecified it is set to @samp{aac_low}.
149 @section ac3 and ac3_fixed
153 These encoders implement part of ATSC A/52:2010 and ETSI TS 102 366, as well as
154 the undocumented RealAudio 3 (a.k.a. dnet).
156 The @var{ac3} encoder uses floating-point math, while the @var{ac3_fixed}
157 encoder only uses fixed-point integer math. This does not mean that one is
158 always faster, just that one or the other may be better suited to a
159 particular system. The floating-point encoder will generally produce better
160 quality audio for a given bitrate. The @var{ac3_fixed} encoder is not the
161 default codec for any of the output formats, so it must be specified explicitly
162 using the option @code{-acodec ac3_fixed} in order to use it.
164 @subsection AC-3 Metadata
166 The AC-3 metadata options are used to set parameters that describe the audio,
167 but in most cases do not affect the audio encoding itself. Some of the options
168 do directly affect or influence the decoding and playback of the resulting
169 bitstream, while others are just for informational purposes. A few of the
170 options will add bits to the output stream that could otherwise be used for
171 audio data, and will thus affect the quality of the output. Those will be
172 indicated accordingly with a note in the option list below.
174 These parameters are described in detail in several publicly-available
177 @item @uref{http://www.atsc.org/cms/standards/a_52-2010.pdf,A/52:2010 - Digital Audio Compression (AC-3) (E-AC-3) Standard}
178 @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}
179 @item @uref{http://www.dolby.com/uploadedFiles/zz-_Shared_Assets/English_PDFs/Professional/18_Metadata.Guide.pdf,Dolby Metadata Guide}
180 @item @uref{http://www.dolby.com/uploadedFiles/zz-_Shared_Assets/English_PDFs/Professional/46_DDEncodingGuidelines.pdf,Dolby Digital Professional Encoding Guidelines}
183 @subsubsection Metadata Control Options
187 @item -per_frame_metadata @var{boolean}
188 Allow Per-Frame Metadata. Specifies if the encoder should check for changing
189 metadata for each frame.
192 The metadata values set at initialization will be used for every frame in the
195 Metadata values can be changed before encoding each frame.
200 @subsubsection Downmix Levels
204 @item -center_mixlev @var{level}
205 Center Mix Level. The amount of gain the decoder should apply to the center
206 channel when downmixing to stereo. This field will only be written to the
207 bitstream if a center channel is present. The value is specified as a scale
208 factor. There are 3 valid values:
213 Apply -4.5dB gain (default)
218 @item -surround_mixlev @var{level}
219 Surround Mix Level. The amount of gain the decoder should apply to the surround
220 channel(s) when downmixing to stereo. This field will only be written to the
221 bitstream if one or more surround channels are present. The value is specified
222 as a scale factor. There are 3 valid values:
227 Apply -6dB gain (default)
229 Silence Surround Channel(s)
234 @subsubsection Audio Production Information
235 Audio Production Information is optional information describing the mixing
236 environment. Either none or both of the fields are written to the bitstream.
240 @item -mixing_level @var{number}
241 Mixing Level. Specifies peak sound pressure level (SPL) in the production
242 environment when the mix was mastered. Valid values are 80 to 111, or -1 for
243 unknown or not indicated. The default value is -1, but that value cannot be
244 used if the Audio Production Information is written to the bitstream. Therefore,
245 if the @code{room_type} option is not the default value, the @code{mixing_level}
246 option must not be -1.
248 @item -room_type @var{type}
249 Room Type. Describes the equalization used during the final mixing session at
250 the studio or on the dubbing stage. A large room is a dubbing stage with the
251 industry standard X-curve equalization; a small room has flat equalization.
252 This field will not be written to the bitstream if both the @code{mixing_level}
253 option and the @code{room_type} option have the default values.
257 Not Indicated (default)
268 @subsubsection Other Metadata Options
272 @item -copyright @var{boolean}
273 Copyright Indicator. Specifies whether a copyright exists for this audio.
277 No Copyright Exists (default)
283 @item -dialnorm @var{value}
284 Dialogue Normalization. Indicates how far the average dialogue level of the
285 program is below digital 100% full scale (0 dBFS). This parameter determines a
286 level shift during audio reproduction that sets the average volume of the
287 dialogue to a preset level. The goal is to match volume level between program
288 sources. A value of -31dB will result in no volume level change, relative to
289 the source volume, during audio reproduction. Valid values are whole numbers in
290 the range -31 to -1, with -31 being the default.
292 @item -dsur_mode @var{mode}
293 Dolby Surround Mode. Specifies whether the stereo signal uses Dolby Surround
294 (Pro Logic). This field will only be written to the bitstream if the audio
295 stream is stereo. Using this option does @b{NOT} mean the encoder will actually
296 apply Dolby Surround processing.
300 Not Indicated (default)
303 Not Dolby Surround Encoded
306 Dolby Surround Encoded
309 @item -original @var{boolean}
310 Original Bit Stream Indicator. Specifies whether this audio is from the
311 original source and not a copy.
318 Original Source (default)
323 @subsection Extended Bitstream Information
324 The extended bitstream options are part of the Alternate Bit Stream Syntax as
325 specified in Annex D of the A/52:2010 standard. It is grouped into 2 parts.
326 If any one parameter in a group is specified, all values in that group will be
327 written to the bitstream. Default values are used for those that are written
328 but have not been specified. If the mixing levels are written, the decoder
329 will use these values instead of the ones specified in the @code{center_mixlev}
330 and @code{surround_mixlev} options if it supports the Alternate Bit Stream
333 @subsubsection Extended Bitstream Information - Part 1
337 @item -dmix_mode @var{mode}
338 Preferred Stereo Downmix Mode. Allows the user to select either Lt/Rt
339 (Dolby Surround) or Lo/Ro (normal stereo) as the preferred stereo downmix mode.
343 Not Indicated (default)
346 Lt/Rt Downmix Preferred
349 Lo/Ro Downmix Preferred
352 @item -ltrt_cmixlev @var{level}
353 Lt/Rt Center Mix Level. The amount of gain the decoder should apply to the
354 center channel when downmixing to stereo in Lt/Rt mode.
367 Apply -4.5dB gain (default)
371 Silence Center Channel
374 @item -ltrt_surmixlev @var{level}
375 Lt/Rt Surround Mix Level. The amount of gain the decoder should apply to the
376 surround channel(s) when downmixing to stereo in Lt/Rt mode.
385 Apply -6.0dB gain (default)
387 Silence Surround Channel(s)
390 @item -loro_cmixlev @var{level}
391 Lo/Ro Center Mix Level. The amount of gain the decoder should apply to the
392 center channel when downmixing to stereo in Lo/Ro mode.
405 Apply -4.5dB gain (default)
409 Silence Center Channel
412 @item -loro_surmixlev @var{level}
413 Lo/Ro Surround Mix Level. The amount of gain the decoder should apply to the
414 surround channel(s) when downmixing to stereo in Lo/Ro mode.
423 Apply -6.0dB gain (default)
425 Silence Surround Channel(s)
430 @subsubsection Extended Bitstream Information - Part 2
434 @item -dsurex_mode @var{mode}
435 Dolby Surround EX Mode. Indicates whether the stream uses Dolby Surround EX
436 (7.1 matrixed to 5.1). Using this option does @b{NOT} mean the encoder will actually
437 apply Dolby Surround EX processing.
441 Not Indicated (default)
444 Dolby Surround EX Off
450 @item -dheadphone_mode @var{mode}
451 Dolby Headphone Mode. Indicates whether the stream uses Dolby Headphone
452 encoding (multi-channel matrixed to 2.0 for use with headphones). Using this
453 option does @b{NOT} mean the encoder will actually apply Dolby Headphone
458 Not Indicated (default)
467 @item -ad_conv_type @var{type}
468 A/D Converter Type. Indicates whether the audio has passed through HDCD A/D
473 Standard A/D Converter (default)
481 @subsection Other AC-3 Encoding Options
485 @item -stereo_rematrixing @var{boolean}
486 Stereo Rematrixing. Enables/Disables use of rematrixing for stereo input. This
487 is an optional AC-3 feature that increases quality by selectively encoding
488 the left/right channels as mid/side. This option is enabled by default, and it
489 is highly recommended that it be left as enabled except for testing purposes.
493 @subsection Floating-Point-Only AC-3 Encoding Options
495 These options are only valid for the floating-point encoder and do not exist
496 for the fixed-point encoder due to the corresponding features not being
497 implemented in fixed-point.
501 @item -channel_coupling @var{boolean}
502 Enables/Disables use of channel coupling, which is an optional AC-3 feature
503 that increases quality by combining high frequency information from multiple
504 channels into a single channel. The per-channel high frequency information is
505 sent with less accuracy in both the frequency and time domains. This allows
506 more bits to be used for lower frequencies while preserving enough information
507 to reconstruct the high frequencies. This option is enabled by default for the
508 floating-point encoder and should generally be left as enabled except for
509 testing purposes or to increase encoding speed.
513 Selected by Encoder (default)
516 Disable Channel Coupling
519 Enable Channel Coupling
522 @item -cpl_start_band @var{number}
523 Coupling Start Band. Sets the channel coupling start band, from 1 to 15. If a
524 value higher than the bandwidth is used, it will be reduced to 1 less than the
525 coupling end band. If @var{auto} is used, the start band will be determined by
526 the encoder based on the bit rate, sample rate, and channel layout. This option
527 has no effect if channel coupling is disabled.
531 Selected by Encoder (default)
539 FLAC (Free Lossless Audio Codec) Encoder
543 The following options are supported by FFmpeg's flac encoder.
546 @item compression_level
547 Sets the compression level, which chooses defaults for many other options
548 if they are not set explicitly.
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 Chanels 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.
615 @anchor{libfdk-aac-enc}
618 libfdk-aac AAC (Advanced Audio Coding) encoder wrapper.
620 The libfdk-aac library is based on the Fraunhofer FDK AAC code from
623 Requires the presence of the libfdk-aac headers and library during
624 configuration. You need to explicitly configure the build with
625 @code{--enable-libfdk-aac}. The library is also incompatible with GPL,
626 so if you allow the use of GPL, you should configure with
627 @code{--enable-gpl --enable-nonfree --enable-libfdk-aac}.
629 This encoder is considered to produce output on par or worse at 128kbps to the
630 @ref{aacenc,,the native FFmpeg AAC encoder} but can often produce better
631 sounding audio at identical or lower bitrates and has support for the
634 VBR encoding, enabled through the @option{vbr} or @option{flags
635 +qscale} options, is experimental and only works with some
636 combinations of parameters.
638 Support for encoding 7.1 audio is only available with libfdk-aac 0.1.3 or
641 For more information see the fdk-aac project at
642 @url{http://sourceforge.net/p/opencore-amr/fdk-aac/}.
646 The following options are mapped on the shared FFmpeg codec options.
650 Set bit rate in bits/s. If the bitrate is not explicitly specified, it
651 is automatically set to a suitable value depending on the selected
654 In case VBR mode is enabled the option is ignored.
657 Set audio sampling rate (in Hz).
660 Set the number of audio channels.
663 Enable fixed quality, VBR (Variable Bit Rate) mode.
664 Note that VBR is implicitly enabled when the @option{vbr} value is
668 Set cutoff frequency. If not specified (or explicitly set to 0) it
669 will use a value automatically computed by the library. Default value
675 The following profiles are recognized:
678 Low Complexity AAC (LC)
681 High Efficiency AAC (HE-AAC)
684 High Efficiency AAC version 2 (HE-AACv2)
690 Enhanced Low Delay AAC (ELD)
693 If not specified it is set to @samp{aac_low}.
696 The following are private options of the libfdk_aac encoder.
700 Enable afterburner feature if set to 1, disabled if set to 0. This
701 improves the quality but also the required processing power.
706 Enable SBR (Spectral Band Replication) for ELD if set to 1, disabled
712 Set SBR/PS signaling style.
714 It can assume one of the following values:
717 choose signaling implicitly (explicit hierarchical by default,
718 implicit if global header is disabled)
721 implicit backwards compatible signaling
724 explicit SBR, implicit PS signaling
726 @item explicit_hierarchical
727 explicit hierarchical signaling
730 Default value is @samp{default}.
733 Output LATM/LOAS encapsulated data if set to 1, disabled if set to 0.
738 Set StreamMuxConfig and PCE repetition period (in frames) for sending
739 in-band configuration buffers within LATM/LOAS transport layer.
741 Must be a 16-bits non-negative integer.
746 Set VBR mode, from 1 to 5. 1 is lowest quality (though still pretty
747 good) and 5 is highest quality. A value of 0 will disable VBR, and CBR
748 (Constant Bit Rate) is enabled.
750 Currently only the @samp{aac_low} profile supports VBR encoding.
752 VBR modes 1-5 correspond to roughly the following average bit rates:
764 about 80-96 kbps/channel
774 Use @command{ffmpeg} to convert an audio file to VBR AAC in an M4A (MP4)
777 ffmpeg -i input.wav -codec:a libfdk_aac -vbr 3 output.m4a
781 Use @command{ffmpeg} to convert an audio file to CBR 64k kbps AAC, using the
782 High-Efficiency AAC profile:
784 ffmpeg -i input.wav -c:a libfdk_aac -profile:a aac_he -b:a 64k output.m4a
791 LAME (Lame Ain't an MP3 Encoder) MP3 encoder wrapper.
793 Requires the presence of the libmp3lame headers and library during
794 configuration. You need to explicitly configure the build with
795 @code{--enable-libmp3lame}.
797 See @ref{libshine} for a fixed-point MP3 encoder, although with a
802 The following options are supported by the libmp3lame wrapper. The
803 @command{lame}-equivalent of the options are listed in parentheses.
807 Set bitrate expressed in bits/s for CBR or ABR. LAME @code{bitrate} is
808 expressed in kilobits/s.
811 Set constant quality setting for VBR. This option is valid only
812 using the @command{ffmpeg} command-line tool. For library interface
813 users, use @option{global_quality}.
815 @item compression_level (@emph{-q})
816 Set algorithm quality. Valid arguments are integers in the 0-9 range,
817 with 0 meaning highest quality but slowest, and 9 meaning fastest
818 while producing the worst quality.
821 Enable use of bit reservoir when set to 1. Default value is 1. LAME
822 has this enabled by default, but can be overridden by use
823 @option{--nores} option.
825 @item joint_stereo (@emph{-m j})
826 Enable the encoder to use (on a frame by frame basis) either L/R
827 stereo or mid/side stereo. Default value is 1.
829 @item abr (@emph{--abr})
830 Enable the encoder to use ABR when set to 1. The @command{lame}
831 @option{--abr} sets the target bitrate, while this options only
832 tells FFmpeg to use ABR still relies on @option{b} to set bitrate.
836 @section libopencore-amrnb
838 OpenCORE Adaptive Multi-Rate Narrowband encoder.
840 Requires the presence of the libopencore-amrnb headers and library during
841 configuration. You need to explicitly configure the build with
842 @code{--enable-libopencore-amrnb --enable-version3}.
844 This is a mono-only encoder. Officially it only supports 8000Hz sample rate,
845 but you can override it by setting @option{strict} to @samp{unofficial} or
853 Set bitrate in bits per second. Only the following bitrates are supported,
854 otherwise libavcodec will round to the nearest valid bitrate.
868 Allow discontinuous transmission (generate comfort noise) when set to 1. The
869 default value is 0 (disabled).
876 Shine Fixed-Point MP3 encoder wrapper.
878 Shine is a fixed-point MP3 encoder. It has a far better performance on
879 platforms without an FPU, e.g. armel CPUs, and some phones and tablets.
880 However, as it is more targeted on performance than quality, it is not on par
881 with LAME and other production-grade encoders quality-wise. Also, according to
882 the project's homepage, this encoder may not be free of bugs as the code was
883 written a long time ago and the project was dead for at least 5 years.
885 This encoder only supports stereo and mono input. This is also CBR-only.
887 The original project (last updated in early 2007) is at
888 @url{http://sourceforge.net/projects/libshine-fxp/}. We only support the
889 updated fork by the Savonet/Liquidsoap project at @url{https://github.com/savonet/shine}.
891 Requires the presence of the libshine headers and library during
892 configuration. You need to explicitly configure the build with
893 @code{--enable-libshine}.
895 See also @ref{libmp3lame}.
899 The following options are supported by the libshine wrapper. The
900 @command{shineenc}-equivalent of the options are listed in parentheses.
904 Set bitrate expressed in bits/s for CBR. @command{shineenc} @option{-b} option
905 is expressed in kilobits/s.
911 TwoLAME MP2 encoder wrapper.
913 Requires the presence of the libtwolame headers and library during
914 configuration. You need to explicitly configure the build with
915 @code{--enable-libtwolame}.
919 The following options are supported by the libtwolame wrapper. The
920 @command{twolame}-equivalent options follow the FFmpeg ones and are in
925 Set bitrate expressed in bits/s for CBR. @command{twolame} @option{b}
926 option is expressed in kilobits/s. Default value is 128k.
929 Set quality for experimental VBR support. Maximum value range is
930 from -50 to 50, useful range is from -10 to 10. The higher the
931 value, the better the quality. This option is valid only using the
932 @command{ffmpeg} command-line tool. For library interface users,
933 use @option{global_quality}.
935 @item mode (@emph{--mode})
936 Set the mode of the resulting audio. Possible values:
940 Choose mode automatically based on the input. This is the default.
951 @item psymodel (@emph{--psyc-mode})
952 Set psychoacoustic model to use in encoding. The argument must be
953 an integer between -1 and 4, inclusive. The higher the value, the
954 better the quality. The default value is 3.
956 @item energy_levels (@emph{--energy})
957 Enable energy levels extensions when set to 1. The default value is
960 @item error_protection (@emph{--protect})
961 Enable CRC error protection when set to 1. The default value is 0
964 @item copyright (@emph{--copyright})
965 Set MPEG audio copyright flag when set to 1. The default value is 0
968 @item original (@emph{--original})
969 Set MPEG audio original flag when set to 1. The default value is 0
974 @section libvo-amrwbenc
976 VisualOn Adaptive Multi-Rate Wideband encoder.
978 Requires the presence of the libvo-amrwbenc headers and library during
979 configuration. You need to explicitly configure the build with
980 @code{--enable-libvo-amrwbenc --enable-version3}.
982 This is a mono-only encoder. Officially it only supports 16000Hz sample
983 rate, but you can override it by setting @option{strict} to
984 @samp{unofficial} or lower.
991 Set bitrate in bits/s. Only the following bitrates are supported, otherwise
992 libavcodec will round to the nearest valid bitrate.
1007 Allow discontinuous transmission (generate comfort noise) when set to 1. The
1008 default value is 0 (disabled).
1014 libopus Opus Interactive Audio Codec encoder wrapper.
1016 Requires the presence of the libopus headers and library during
1017 configuration. You need to explicitly configure the build with
1018 @code{--enable-libopus}.
1020 @subsection Option Mapping
1022 Most libopus options are modelled after the @command{opusenc} utility from
1023 opus-tools. The following is an option mapping chart describing options
1024 supported by the libopus wrapper, and their @command{opusenc}-equivalent
1029 @item b (@emph{bitrate})
1030 Set the bit rate in bits/s. FFmpeg's @option{b} option is
1031 expressed in bits/s, while @command{opusenc}'s @option{bitrate} in
1034 @item vbr (@emph{vbr}, @emph{hard-cbr}, and @emph{cvbr})
1035 Set VBR mode. The FFmpeg @option{vbr} option has the following
1036 valid arguments, with the @command{opusenc} equivalent options
1040 @item off (@emph{hard-cbr})
1041 Use constant bit rate encoding.
1043 @item on (@emph{vbr})
1044 Use variable bit rate encoding (the default).
1046 @item constrained (@emph{cvbr})
1047 Use constrained variable bit rate encoding.
1050 @item compression_level (@emph{comp})
1051 Set encoding algorithm complexity. Valid options are integers in
1052 the 0-10 range. 0 gives the fastest encodes but lower quality, while 10
1053 gives the highest quality but slowest encoding. The default is 10.
1055 @item frame_duration (@emph{framesize})
1056 Set maximum frame size, or duration of a frame in milliseconds. The
1057 argument must be exactly the following: 2.5, 5, 10, 20, 40, 60. Smaller
1058 frame sizes achieve lower latency but less quality at a given bitrate.
1059 Sizes greater than 20ms are only interesting at fairly low bitrates.
1060 The default is 20ms.
1062 @item packet_loss (@emph{expect-loss})
1063 Set expected packet loss percentage. The default is 0.
1065 @item application (N.A.)
1066 Set intended application type. Valid options are listed below:
1070 Favor improved speech intelligibility.
1072 Favor faithfulness to the input (the default).
1074 Restrict to only the lowest delay modes.
1078 Set cutoff bandwidth in Hz. The argument must be exactly one of the
1079 following: 4000, 6000, 8000, 12000, or 20000, corresponding to
1080 narrowband, mediumband, wideband, super wideband, and fullband
1081 respectively. The default is 0 (cutoff disabled).
1083 @item mapping_family (@emph{mapping_family})
1084 Set channel mapping family to be used by the encoder. The default value of -1
1085 uses mapping family 0 for mono and stereo inputs, and mapping family 1
1086 otherwise. The default also disables the surround masking and LFE bandwidth
1087 optimzations in libopus, and requires that the input contains 8 channels or
1090 Other values include 0 for mono and stereo, 1 for surround sound with masking
1091 and LFE bandwidth optimizations, and 255 for independent streams with an
1092 unspecified channel layout.
1098 libvorbis encoder wrapper.
1100 Requires the presence of the libvorbisenc headers and library during
1101 configuration. You need to explicitly configure the build with
1102 @code{--enable-libvorbis}.
1106 The following options are supported by the libvorbis wrapper. The
1107 @command{oggenc}-equivalent of the options are listed in parentheses.
1109 To get a more accurate and extensive documentation of the libvorbis
1110 options, consult the libvorbisenc's and @command{oggenc}'s documentations.
1111 See @url{http://xiph.org/vorbis/},
1112 @url{http://wiki.xiph.org/Vorbis-tools}, and oggenc(1).
1116 Set bitrate expressed in bits/s for ABR. @command{oggenc} @option{-b} is
1117 expressed in kilobits/s.
1120 Set constant quality setting for VBR. The value should be a float
1121 number in the range of -1.0 to 10.0. The higher the value, the better
1122 the quality. The default value is @samp{3.0}.
1124 This option is valid only using the @command{ffmpeg} command-line tool.
1125 For library interface users, use @option{global_quality}.
1127 @item cutoff (@emph{--advanced-encode-option lowpass_frequency=N})
1128 Set cutoff bandwidth in Hz, a value of 0 disables cutoff. @command{oggenc}'s
1129 related option is expressed in kHz. The default value is @samp{0} (cutoff
1132 @item minrate (@emph{-m})
1133 Set minimum bitrate expressed in bits/s. @command{oggenc} @option{-m} is
1134 expressed in kilobits/s.
1136 @item maxrate (@emph{-M})
1137 Set maximum bitrate expressed in bits/s. @command{oggenc} @option{-M} is
1138 expressed in kilobits/s. This only has effect on ABR mode.
1140 @item iblock (@emph{--advanced-encode-option impulse_noisetune=N})
1141 Set noise floor bias for impulse blocks. The value is a float number from
1142 -15.0 to 0.0. A negative bias instructs the encoder to pay special attention
1143 to the crispness of transients in the encoded audio. The tradeoff for better
1144 transient response is a higher bitrate.
1151 A wrapper providing WavPack encoding through libwavpack.
1153 Only lossless mode using 32-bit integer samples is supported currently.
1155 Requires the presence of the libwavpack headers and library during
1156 configuration. You need to explicitly configure the build with
1157 @code{--enable-libwavpack}.
1159 Note that a libavcodec-native encoder for the WavPack codec exists so users can
1160 encode audios with this codec without using this encoder. See @ref{wavpackenc}.
1164 @command{wavpack} command line utility's corresponding options are listed in
1165 parentheses, if any.
1168 @item frame_size (@emph{--blocksize})
1171 @item compression_level
1172 Set speed vs. compression tradeoff. Acceptable arguments are listed below:
1179 Normal (default) settings.
1184 @item 3 (@emph{-hh})
1187 @item 4-8 (@emph{-hh -x}@var{EXTRAPROC})
1188 Same as @samp{3}, but with extra processing enabled.
1190 @samp{4} is the same as @option{-x2} and @samp{8} is the same as @option{-x6}.
1198 WavPack lossless audio encoder.
1200 This is a libavcodec-native WavPack encoder. There is also an encoder based on
1201 libwavpack, but there is virtually no reason to use that encoder.
1203 See also @ref{libwavpack}.
1207 The equivalent options for @command{wavpack} command line utility are listed in
1210 @subsubsection Shared options
1212 The following shared options are effective for this encoder. Only special notes
1213 about this particular encoder will be documented here. For the general meaning
1214 of the options, see @ref{codec-options,,the Codec Options chapter}.
1217 @item frame_size (@emph{--blocksize})
1218 For this encoder, the range for this option is between 128 and 131072. Default
1219 is automatically decided based on sample rate and number of channel.
1221 For the complete formula of calculating default, see
1222 @file{libavcodec/wavpackenc.c}.
1224 @item compression_level (@emph{-f}, @emph{-h}, @emph{-hh}, and @emph{-x})
1225 This option's syntax is consistent with @ref{libwavpack}'s.
1228 @subsubsection Private options
1231 @item joint_stereo (@emph{-j})
1232 Set whether to enable joint stereo. Valid values are:
1236 Force mid/side audio encoding.
1237 @item off (@emph{0})
1238 Force left/right audio encoding.
1240 Let the encoder decide automatically.
1244 Set whether to enable optimization for mono. This option is only effective for
1245 non-mono streams. Available values:
1256 @c man end AUDIO ENCODERS
1258 @chapter Video Encoders
1259 @c man begin VIDEO ENCODERS
1261 A description of some of the currently available video encoders
1264 @section libopenh264
1266 Cisco libopenh264 H.264/MPEG-4 AVC encoder wrapper.
1268 This encoder requires the presence of the libopenh264 headers and
1269 library during configuration. You need to explicitly configure the
1270 build with @code{--enable-libopenh264}. The library is detected using
1271 @command{pkg-config}.
1273 For more information about the library see
1274 @url{http://www.openh264.org}.
1278 The following FFmpeg global options affect the configurations of the
1279 libopenh264 encoder.
1283 Set the bitrate (as a number of bits per second).
1289 Set the max bitrate (as a number of bits per second).
1291 @item flags +global_header
1292 Set global header in the bitstream.
1295 Set the number of slices, used in parallelized encoding. Default value
1296 is 0. This is only used when @option{slice_mode} is set to
1300 Set slice mode. Can assume one of the following possible values:
1304 a fixed number of slices
1306 one slice per row of macroblocks
1308 automatic number of slices according to number of threads
1313 Default value is @samp{auto}.
1316 Enable loop filter, if set to 1 (automatically enabled). To disable
1320 Set profile restrictions. If set to the value of @samp{main} enable
1321 CABAC (set the @code{SEncParamExt.iEntropyCodingModeFlag} flag to 1).
1324 Set maximum NAL size in bytes.
1326 @item allow_skip_frames
1327 Allow skipping frames to hit the target bitrate if set to 1.
1332 The native jpeg 2000 encoder is lossy by default, the @code{-q:v}
1333 option can be used to set the encoding quality. Lossless encoding
1334 can be selected with @code{-pred 1}.
1340 Can be set to either @code{j2k} or @code{jp2} (the default) that
1341 makes it possible to store non-rgb pix_fmts.
1350 @item iterative_dia_size
1351 dia size for the iterative motion estimation
1356 libtheora Theora encoder wrapper.
1358 Requires the presence of the libtheora headers and library during
1359 configuration. You need to explicitly configure the build with
1360 @code{--enable-libtheora}.
1362 For more information about the libtheora project see
1363 @url{http://www.theora.org/}.
1367 The following global options are mapped to internal libtheora options
1368 which affect the quality and the bitrate of the encoded stream.
1372 Set the video bitrate in bit/s for CBR (Constant Bit Rate) mode. In
1373 case VBR (Variable Bit Rate) mode is enabled this option is ignored.
1376 Used to enable constant quality mode (VBR) encoding through the
1377 @option{qscale} flag, and to enable the @code{pass1} and @code{pass2}
1383 @item global_quality
1384 Set the global quality as an integer in lambda units.
1386 Only relevant when VBR mode is enabled with @code{flags +qscale}. The
1387 value is converted to QP units by dividing it by @code{FF_QP2LAMBDA},
1388 clipped in the [0 - 10] range, and then multiplied by 6.3 to get a
1389 value in the native libtheora range [0-63]. A higher value corresponds
1390 to a higher quality.
1393 Enable VBR mode when set to a non-negative value, and set constant
1394 quality value as a double floating point value in QP units.
1396 The value is clipped in the [0-10] range, and then multiplied by 6.3
1397 to get a value in the native libtheora range [0-63].
1399 This option is valid only using the @command{ffmpeg} command-line
1400 tool. For library interface users, use @option{global_quality}.
1403 @subsection Examples
1407 Set maximum constant quality (VBR) encoding with @command{ffmpeg}:
1409 ffmpeg -i INPUT -codec:v libtheora -q:v 10 OUTPUT.ogg
1413 Use @command{ffmpeg} to convert a CBR 1000 kbps Theora video stream:
1415 ffmpeg -i INPUT -codec:v libtheora -b:v 1000k OUTPUT.ogg
1421 VP8/VP9 format supported through libvpx.
1423 Requires the presence of the libvpx headers and library during configuration.
1424 You need to explicitly configure the build with @code{--enable-libvpx}.
1428 The following options are supported by the libvpx wrapper. The
1429 @command{vpxenc}-equivalent options or values are listed in parentheses
1432 To reduce the duplication of documentation, only the private options
1433 and some others requiring special attention are documented here. For
1434 the documentation of the undocumented generic options, see
1435 @ref{codec-options,,the Codec Options chapter}.
1437 To get more documentation of the libvpx options, invoke the command
1438 @command{ffmpeg -h encoder=libvpx}, @command{ffmpeg -h encoder=libvpx-vp9} or
1439 @command{vpxenc --help}. Further information is available in the libvpx API
1444 @item b (@emph{target-bitrate})
1445 Set bitrate in bits/s. Note that FFmpeg's @option{b} option is
1446 expressed in bits/s, while @command{vpxenc}'s @option{target-bitrate} is in
1449 @item g (@emph{kf-max-dist})
1451 @item keyint_min (@emph{kf-min-dist})
1453 @item qmin (@emph{min-q})
1455 @item qmax (@emph{max-q})
1457 @item bufsize (@emph{buf-sz}, @emph{buf-optimal-sz})
1458 Set ratecontrol buffer size (in bits). Note @command{vpxenc}'s options are
1459 specified in milliseconds, the libvpx wrapper converts this value as follows:
1460 @code{buf-sz = bufsize * 1000 / bitrate},
1461 @code{buf-optimal-sz = bufsize * 1000 / bitrate * 5 / 6}.
1463 @item rc_init_occupancy (@emph{buf-initial-sz})
1464 Set number of bits which should be loaded into the rc buffer before decoding
1465 starts. Note @command{vpxenc}'s option is specified in milliseconds, the libvpx
1466 wrapper converts this value as follows:
1467 @code{rc_init_occupancy * 1000 / bitrate}.
1469 @item undershoot-pct
1470 Set datarate undershoot (min) percentage of the target bitrate.
1473 Set datarate overshoot (max) percentage of the target bitrate.
1475 @item skip_threshold (@emph{drop-frame})
1477 @item qcomp (@emph{bias-pct})
1479 @item maxrate (@emph{maxsection-pct})
1480 Set GOP max bitrate in bits/s. Note @command{vpxenc}'s option is specified as a
1481 percentage of the target bitrate, the libvpx wrapper converts this value as
1482 follows: @code{(maxrate * 100 / bitrate)}.
1484 @item minrate (@emph{minsection-pct})
1485 Set GOP min bitrate in bits/s. Note @command{vpxenc}'s option is specified as a
1486 percentage of the target bitrate, the libvpx wrapper converts this value as
1487 follows: @code{(minrate * 100 / bitrate)}.
1489 @item minrate, maxrate, b @emph{end-usage=cbr}
1490 @code{(minrate == maxrate == bitrate)}.
1492 @item crf (@emph{end-usage=cq}, @emph{cq-level})
1494 @item tune (@emph{tune})
1496 @item psnr (@emph{psnr})
1497 @item ssim (@emph{ssim})
1500 @item quality, deadline (@emph{deadline})
1503 Use best quality deadline. Poorly named and quite slow, this option should be
1504 avoided as it may give worse quality output than good.
1506 Use good quality deadline. This is a good trade-off between speed and quality
1507 when used with the @option{cpu-used} option.
1509 Use realtime quality deadline.
1512 @item speed, cpu-used (@emph{cpu-used})
1513 Set quality/speed ratio modifier. Higher values speed up the encode at the cost
1516 @item nr (@emph{noise-sensitivity})
1519 Set a change threshold on blocks below which they will be skipped by the
1522 @item slices (@emph{token-parts})
1523 Note that FFmpeg's @option{slices} option gives the total number of partitions,
1524 while @command{vpxenc}'s @option{token-parts} is given as
1525 @code{log2(partitions)}.
1527 @item max-intra-rate
1528 Set maximum I-frame bitrate as a percentage of the target bitrate. A value of 0
1531 @item force_key_frames
1532 @code{VPX_EFLAG_FORCE_KF}
1534 @item Alternate reference frame related
1537 Enable use of alternate reference frames (2-pass only).
1538 @item arnr-max-frames
1539 Set altref noise reduction max frame count.
1541 Set altref noise reduction filter type: backward, forward, centered.
1543 Set altref noise reduction filter strength.
1544 @item rc-lookahead, lag-in-frames (@emph{lag-in-frames})
1545 Set number of frames to look ahead for frametype and ratecontrol.
1548 @item error-resilient
1549 Enable error resiliency features.
1551 @item VP9-specific options
1554 Enable lossless mode.
1556 Set number of tile columns to use. Note this is given as
1557 @code{log2(tile_columns)}. For example, 8 tile columns would be requested by
1558 setting the @option{tile-columns} option to 3.
1560 Set number of tile rows to use. Note this is given as @code{log2(tile_rows)}.
1561 For example, 4 tile rows would be requested by setting the @option{tile-rows}
1563 @item frame-parallel
1564 Enable frame parallel decodability features.
1566 Set adaptive quantization mode (0: off (default), 1: variance 2: complexity, 3:
1568 @item colorspace @emph{color-space}
1569 Set input color space. The VP9 bitstream supports signaling the following
1572 @item @samp{rgb} @emph{sRGB}
1573 @item @samp{bt709} @emph{bt709}
1574 @item @samp{unspecified} @emph{unknown}
1575 @item @samp{bt470bg} @emph{bt601}
1576 @item @samp{smpte170m} @emph{smpte170}
1577 @item @samp{smpte240m} @emph{smpte240}
1578 @item @samp{bt2020_ncl} @emph{bt2020}
1584 For more information about libvpx see:
1585 @url{http://www.webmproject.org/}
1590 libwebp WebP Image encoder wrapper
1592 libwebp is Google's official encoder for WebP images. It can encode in either
1593 lossy or lossless mode. Lossy images are essentially a wrapper around a VP8
1594 frame. Lossless images are a separate codec developed by Google.
1596 @subsection Pixel Format
1598 Currently, libwebp only supports YUV420 for lossy and RGB for lossless due
1599 to limitations of the format and libwebp. Alpha is supported for either mode.
1600 Because of API limitations, if RGB is passed in when encoding lossy or YUV is
1601 passed in for encoding lossless, the pixel format will automatically be
1602 converted using functions from libwebp. This is not ideal and is done only for
1609 @item -lossless @var{boolean}
1610 Enables/Disables use of lossless mode. Default is 0.
1612 @item -compression_level @var{integer}
1613 For lossy, this is a quality/speed tradeoff. Higher values give better quality
1614 for a given size at the cost of increased encoding time. For lossless, this is
1615 a size/speed tradeoff. Higher values give smaller size at the cost of increased
1616 encoding time. More specifically, it controls the number of extra algorithms
1617 and compression tools used, and varies the combination of these tools. This
1618 maps to the @var{method} option in libwebp. The valid range is 0 to 6.
1621 @item -qscale @var{float}
1622 For lossy encoding, this controls image quality, 0 to 100. For lossless
1623 encoding, this controls the effort and time spent at compressing more. The
1624 default value is 75. Note that for usage via libavcodec, this option is called
1625 @var{global_quality} and must be multiplied by @var{FF_QP2LAMBDA}.
1627 @item -preset @var{type}
1628 Configuration preset. This does some automatic settings based on the general
1632 Do not use a preset.
1634 Use the encoder default.
1636 Digital picture, like portrait, inner shot
1638 Outdoor photograph, with natural lighting
1640 Hand or line drawing, with high-contrast details
1642 Small-sized colorful images
1649 @section libx264, libx264rgb
1651 x264 H.264/MPEG-4 AVC encoder wrapper.
1653 This encoder requires the presence of the libx264 headers and library
1654 during configuration. You need to explicitly configure the build with
1655 @code{--enable-libx264}.
1657 libx264 supports an impressive number of features, including 8x8 and
1658 4x4 adaptive spatial transform, adaptive B-frame placement, CAVLC/CABAC
1659 entropy coding, interlacing (MBAFF), lossless mode, psy optimizations
1660 for detail retention (adaptive quantization, psy-RD, psy-trellis).
1662 Many libx264 encoder options are mapped to FFmpeg global codec
1663 options, while unique encoder options are provided through private
1664 options. Additionally the @option{x264opts} and @option{x264-params}
1665 private options allows one to pass a list of key=value tuples as accepted
1666 by the libx264 @code{x264_param_parse} function.
1668 The x264 project website is at
1669 @url{http://www.videolan.org/developers/x264.html}.
1671 The libx264rgb encoder is the same as libx264, except it accepts packed RGB
1672 pixel formats as input instead of YUV.
1674 @subsection Supported Pixel Formats
1676 x264 supports 8- to 10-bit color spaces. The exact bit depth is controlled at
1677 x264's configure time. FFmpeg only supports one bit depth in one particular
1678 build. In other words, it is not possible to build one FFmpeg with multiple
1679 versions of x264 with different bit depths.
1683 The following options are supported by the libx264 wrapper. The
1684 @command{x264}-equivalent options or values are listed in parentheses
1687 To reduce the duplication of documentation, only the private options
1688 and some others requiring special attention are documented here. For
1689 the documentation of the undocumented generic options, see
1690 @ref{codec-options,,the Codec Options chapter}.
1692 To get a more accurate and extensive documentation of the libx264
1693 options, invoke the command @command{x264 --full-help} or consult
1694 the libx264 documentation.
1697 @item b (@emph{bitrate})
1698 Set bitrate in bits/s. Note that FFmpeg's @option{b} option is
1699 expressed in bits/s, while @command{x264}'s @option{bitrate} is in
1702 @item bf (@emph{bframes})
1704 @item g (@emph{keyint})
1706 @item qmin (@emph{qpmin})
1707 Minimum quantizer scale.
1709 @item qmax (@emph{qpmax})
1710 Maximum quantizer scale.
1712 @item qdiff (@emph{qpstep})
1713 Maximum difference between quantizer scales.
1715 @item qblur (@emph{qblur})
1716 Quantizer curve blur
1718 @item qcomp (@emph{qcomp})
1719 Quantizer curve compression factor
1721 @item refs (@emph{ref})
1722 Number of reference frames each P-frame can use. The range is from @var{0-16}.
1724 @item sc_threshold (@emph{scenecut})
1725 Sets the threshold for the scene change detection.
1727 @item trellis (@emph{trellis})
1728 Performs Trellis quantization to increase efficiency. Enabled by default.
1730 @item nr (@emph{nr})
1732 @item me_range (@emph{merange})
1733 Maximum range of the motion search in pixels.
1735 @item me_method (@emph{me})
1736 Set motion estimation method. Possible values in the decreasing order
1740 @item dia (@emph{dia})
1741 @item epzs (@emph{dia})
1742 Diamond search with radius 1 (fastest). @samp{epzs} is an alias for
1744 @item hex (@emph{hex})
1745 Hexagonal search with radius 2.
1746 @item umh (@emph{umh})
1747 Uneven multi-hexagon search.
1748 @item esa (@emph{esa})
1750 @item tesa (@emph{tesa})
1751 Hadamard exhaustive search (slowest).
1754 @item subq (@emph{subme})
1755 Sub-pixel motion estimation method.
1757 @item b_strategy (@emph{b-adapt})
1758 Adaptive B-frame placement decision algorithm. Use only on first-pass.
1760 @item keyint_min (@emph{min-keyint})
1764 Set entropy encoder. Possible values:
1771 Enable CAVLC and disable CABAC. It generates the same effect as
1772 @command{x264}'s @option{--no-cabac} option.
1776 Set full pixel motion estimation comparation algorithm. Possible values:
1780 Enable chroma in motion estimation.
1783 Ignore chroma in motion estimation. It generates the same effect as
1784 @command{x264}'s @option{--no-chroma-me} option.
1787 @item threads (@emph{threads})
1788 Number of encoding threads.
1791 Set multithreading technique. Possible values:
1795 Slice-based multithreading. It generates the same effect as
1796 @command{x264}'s @option{--sliced-threads} option.
1798 Frame-based multithreading.
1802 Set encoding flags. It can be used to disable closed GOP and enable
1803 open GOP by setting it to @code{-cgop}. The result is similar to
1804 the behavior of @command{x264}'s @option{--open-gop} option.
1806 @item rc_init_occupancy (@emph{vbv-init})
1808 @item preset (@emph{preset})
1809 Set the encoding preset.
1811 @item tune (@emph{tune})
1812 Set tuning of the encoding params.
1814 @item profile (@emph{profile})
1815 Set profile restrictions.
1818 Enable fast settings when encoding first pass, when set to 1. When set
1819 to 0, it has the same effect of @command{x264}'s
1820 @option{--slow-firstpass} option.
1822 @item crf (@emph{crf})
1823 Set the quality for constant quality mode.
1825 @item crf_max (@emph{crf-max})
1826 In CRF mode, prevents VBV from lowering quality beyond this point.
1828 @item qp (@emph{qp})
1829 Set constant quantization rate control method parameter.
1831 @item aq-mode (@emph{aq-mode})
1832 Set AQ method. Possible values:
1835 @item none (@emph{0})
1838 @item variance (@emph{1})
1839 Variance AQ (complexity mask).
1841 @item autovariance (@emph{2})
1842 Auto-variance AQ (experimental).
1845 @item aq-strength (@emph{aq-strength})
1846 Set AQ strength, reduce blocking and blurring in flat and textured areas.
1849 Use psychovisual optimizations when set to 1. When set to 0, it has the
1850 same effect as @command{x264}'s @option{--no-psy} option.
1852 @item psy-rd (@emph{psy-rd})
1853 Set strength of psychovisual optimization, in
1854 @var{psy-rd}:@var{psy-trellis} format.
1856 @item rc-lookahead (@emph{rc-lookahead})
1857 Set number of frames to look ahead for frametype and ratecontrol.
1860 Enable weighted prediction for B-frames when set to 1. When set to 0,
1861 it has the same effect as @command{x264}'s @option{--no-weightb} option.
1863 @item weightp (@emph{weightp})
1864 Set weighted prediction method for P-frames. Possible values:
1867 @item none (@emph{0})
1869 @item simple (@emph{1})
1870 Enable only weighted refs
1871 @item smart (@emph{2})
1872 Enable both weighted refs and duplicates
1875 @item ssim (@emph{ssim})
1876 Enable calculation and printing SSIM stats after the encoding.
1878 @item intra-refresh (@emph{intra-refresh})
1879 Enable the use of Periodic Intra Refresh instead of IDR frames when set
1882 @item avcintra-class (@emph{class})
1883 Configure the encoder to generate AVC-Intra.
1884 Valid values are 50,100 and 200
1886 @item bluray-compat (@emph{bluray-compat})
1887 Configure the encoder to be compatible with the bluray standard.
1888 It is a shorthand for setting "bluray-compat=1 force-cfr=1".
1890 @item b-bias (@emph{b-bias})
1891 Set the influence on how often B-frames are used.
1893 @item b-pyramid (@emph{b-pyramid})
1894 Set method for keeping of some B-frames as references. Possible values:
1897 @item none (@emph{none})
1899 @item strict (@emph{strict})
1900 Strictly hierarchical pyramid.
1901 @item normal (@emph{normal})
1902 Non-strict (not Blu-ray compatible).
1906 Enable the use of one reference per partition, as opposed to one
1907 reference per macroblock when set to 1. When set to 0, it has the
1908 same effect as @command{x264}'s @option{--no-mixed-refs} option.
1911 Enable adaptive spatial transform (high profile 8x8 transform)
1912 when set to 1. When set to 0, it has the same effect as
1913 @command{x264}'s @option{--no-8x8dct} option.
1916 Enable early SKIP detection on P-frames when set to 1. When set
1917 to 0, it has the same effect as @command{x264}'s
1918 @option{--no-fast-pskip} option.
1920 @item aud (@emph{aud})
1921 Enable use of access unit delimiters when set to 1.
1924 Enable use macroblock tree ratecontrol when set to 1. When set
1925 to 0, it has the same effect as @command{x264}'s
1926 @option{--no-mbtree} option.
1928 @item deblock (@emph{deblock})
1929 Set loop filter parameters, in @var{alpha}:@var{beta} form.
1931 @item cplxblur (@emph{cplxblur})
1932 Set fluctuations reduction in QP (before curve compression).
1934 @item partitions (@emph{partitions})
1935 Set partitions to consider as a comma-separated list of. Possible
1940 8x8 P-frame partition.
1942 4x4 P-frame partition.
1944 4x4 B-frame partition.
1946 8x8 I-frame partition.
1948 4x4 I-frame partition.
1949 (Enabling @samp{p4x4} requires @samp{p8x8} to be enabled. Enabling
1950 @samp{i8x8} requires adaptive spatial transform (@option{8x8dct}
1951 option) to be enabled.)
1952 @item none (@emph{none})
1953 Do not consider any partitions.
1954 @item all (@emph{all})
1955 Consider every partition.
1958 @item direct-pred (@emph{direct})
1959 Set direct MV prediction mode. Possible values:
1962 @item none (@emph{none})
1963 Disable MV prediction.
1964 @item spatial (@emph{spatial})
1965 Enable spatial predicting.
1966 @item temporal (@emph{temporal})
1967 Enable temporal predicting.
1968 @item auto (@emph{auto})
1969 Automatically decided.
1972 @item slice-max-size (@emph{slice-max-size})
1973 Set the limit of the size of each slice in bytes. If not specified
1974 but RTP payload size (@option{ps}) is specified, that is used.
1976 @item stats (@emph{stats})
1977 Set the file name for multi-pass stats.
1979 @item nal-hrd (@emph{nal-hrd})
1980 Set signal HRD information (requires @option{vbv-bufsize} to be set).
1984 @item none (@emph{none})
1985 Disable HRD information signaling.
1986 @item vbr (@emph{vbr})
1988 @item cbr (@emph{cbr})
1989 Constant bit rate (not allowed in MP4 container).
1992 @item x264opts (N.A.)
1993 Set any x264 option, see @command{x264 --fullhelp} for a list.
1995 Argument is a list of @var{key}=@var{value} couples separated by
1996 ":". In @var{filter} and @var{psy-rd} options that use ":" as a separator
1997 themselves, use "," instead. They accept it as well since long ago but this
1998 is kept undocumented for some reason.
2000 For example to specify libx264 encoding options with @command{ffmpeg}:
2002 ffmpeg -i foo.mpg -vcodec libx264 -x264opts keyint=123:min-keyint=20 -an out.mkv
2005 @item a53cc @var{boolean}
2006 Import closed captions (which must be ATSC compatible format) into output.
2007 Only the mpeg2 and h264 decoders provide these. Default is 0 (off).
2009 @item x264-params (N.A.)
2010 Override the x264 configuration using a :-separated list of key=value
2013 This option is functionally the same as the @option{x264opts}, but is
2014 duplicated for compatibility with the Libav fork.
2016 For example to specify libx264 encoding options with @command{ffmpeg}:
2018 ffmpeg -i INPUT -c:v libx264 -x264-params level=30:bframes=0:weightp=0:\
2019 cabac=0:ref=1:vbv-maxrate=768:vbv-bufsize=2000:analyse=all:me=umh:\
2020 no-fast-pskip=1:subq=6:8x8dct=0:trellis=0 OUTPUT
2024 Encoding ffpresets for common usages are provided so they can be used with the
2025 general presets system (e.g. passing the @option{pre} option).
2029 x265 H.265/HEVC encoder wrapper.
2031 This encoder requires the presence of the libx265 headers and library
2032 during configuration. You need to explicitly configure the build with
2033 @option{--enable-libx265}.
2039 Set the x265 preset.
2042 Set the x265 tune parameter.
2045 Set x265 options using a list of @var{key}=@var{value} couples separated
2046 by ":". See @command{x265 --help} for a list of options.
2048 For example to specify libx265 encoding options with @option{-x265-params}:
2051 ffmpeg -i input -c:v libx265 -x265-params crf=26:psy-rd=1 output.mp4
2057 Xvid MPEG-4 Part 2 encoder wrapper.
2059 This encoder requires the presence of the libxvidcore headers and library
2060 during configuration. You need to explicitly configure the build with
2061 @code{--enable-libxvid --enable-gpl}.
2063 The native @code{mpeg4} encoder supports the MPEG-4 Part 2 format, so
2064 users can encode to this format without this library.
2068 The following options are supported by the libxvid wrapper. Some of
2069 the following options are listed but are not documented, and
2070 correspond to shared codec options. See @ref{codec-options,,the Codec
2071 Options chapter} for their documentation. The other shared options
2072 which are not listed have no effect for the libxvid encoder.
2094 Set specific encoding flags. Possible values:
2099 Use four motion vector by macroblock.
2102 Enable high quality AC prediction.
2105 Only encode grayscale.
2108 Enable the use of global motion compensation (GMC).
2111 Enable quarter-pixel motion compensation.
2117 Place global headers in extradata instead of every keyframe.
2124 Set motion estimation method. Possible values in decreasing order of
2125 speed and increasing order of quality:
2129 Use no motion estimation (default).
2134 Enable advanced diamond zonal search for 16x16 blocks and half-pixel
2135 refinement for 16x16 blocks. @samp{x1} and @samp{log} are aliases for
2139 Enable all of the things described above, plus advanced diamond zonal
2140 search for 8x8 blocks, half-pixel refinement for 8x8 blocks, and motion
2141 estimation on chroma planes.
2144 Enable all of the things described above, plus extended 16x16 and 8x8
2149 Set macroblock decision algorithm. Possible values in the increasing
2154 Use macroblock comparing function algorithm (default).
2157 Enable rate distortion-based half pixel and quarter pixel refinement for
2161 Enable all of the things described above, plus rate distortion-based
2162 half pixel and quarter pixel refinement for 8x8 blocks, and rate
2163 distortion-based search using square pattern.
2167 Enable lumi masking adaptive quantization when set to 1. Default is 0
2171 Enable variance adaptive quantization when set to 1. Default is 0
2174 When combined with @option{lumi_aq}, the resulting quality will not
2175 be better than any of the two specified individually. In other
2176 words, the resulting quality will be the worse one of the two
2180 Set structural similarity (SSIM) displaying method. Possible values:
2184 Disable displaying of SSIM information.
2187 Output average SSIM at the end of encoding to stdout. The format of
2188 showing the average SSIM is:
2194 For users who are not familiar with C, %f means a float number, or
2195 a decimal (e.g. 0.939232).
2198 Output both per-frame SSIM data during encoding and average SSIM at
2199 the end of encoding to stdout. The format of per-frame information
2203 SSIM: avg: %1.3f min: %1.3f max: %1.3f
2206 For users who are not familiar with C, %1.3f means a float number
2207 rounded to 3 digits after the dot (e.g. 0.932).
2212 Set SSIM accuracy. Valid options are integers within the range of
2213 0-4, while 0 gives the most accurate result and 4 computes the
2220 MPEG-2 video encoder.
2225 @item seq_disp_ext @var{integer}
2226 Specifies if the encoder should write a sequence_display_extension to the
2231 Decide automatically to write it or not (this is the default) by checking if
2232 the data to be written is different from the default or unspecified values.
2246 @subsection Private options
2249 @item dpi @var{integer}
2250 Set physical density of pixels, in dots per inch, unset by default
2251 @item dpm @var{integer}
2252 Set physical density of pixels, in dots per meter, unset by default
2257 Apple ProRes encoder.
2259 FFmpeg contains 2 ProRes encoders, the prores-aw and prores-ks encoder.
2260 The used encoder can be chosen with the @code{-vcodec} option.
2262 @subsection Private Options for prores-ks
2265 @item profile @var{integer}
2266 Select the ProRes profile to encode
2275 @item quant_mat @var{integer}
2276 Select quantization matrix.
2285 If set to @var{auto}, the matrix matching the profile will be picked.
2286 If not set, the matrix providing the highest quality, @var{default}, will be
2289 @item bits_per_mb @var{integer}
2290 How many bits to allot for coding one macroblock. Different profiles use
2291 between 200 and 2400 bits per macroblock, the maximum is 8000.
2293 @item mbs_per_slice @var{integer}
2294 Number of macroblocks in each slice (1-8); the default value (8)
2295 should be good in almost all situations.
2297 @item vendor @var{string}
2298 Override the 4-byte vendor ID.
2299 A custom vendor ID like @var{apl0} would claim the stream was produced by
2302 @item alpha_bits @var{integer}
2303 Specify number of bits for alpha component.
2304 Possible values are @var{0}, @var{8} and @var{16}.
2305 Use @var{0} to disable alpha plane coding.
2309 @subsection Speed considerations
2311 In the default mode of operation the encoder has to honor frame constraints
2312 (i.e. not produce frames with size bigger than requested) while still making
2313 output picture as good as possible.
2314 A frame containing a lot of small details is harder to compress and the encoder
2315 would spend more time searching for appropriate quantizers for each slice.
2317 Setting a higher @option{bits_per_mb} limit will improve the speed.
2319 For the fastest encoding speed set the @option{qscale} parameter (4 is the
2320 recommended value) and do not set a size constraint.
2324 Kvazaar H.265/HEVC encoder.
2326 Requires the presence of the libkvazaar headers and library during
2327 configuration. You need to explicitly configure the build with
2328 @option{--enable-libkvazaar}.
2335 Set target video bitrate in bit/s and enable rate control.
2337 @item kvazaar-params
2338 Set kvazaar parameters as a list of @var{name}=@var{value} pairs separated
2339 by commas (,). See kvazaar documentation for a list of options.
2343 @section QSV encoders
2345 The family of Intel QuickSync Video encoders (MPEG-2, H.264 and HEVC)
2347 The ratecontrol method is selected as follows:
2351 When @option{global_quality} is specified, a quality-based mode is used.
2352 Specifically this means either
2355 @var{CQP} - constant quantizer scale, when the @option{qscale} codec flag is
2356 also set (the @option{-qscale} ffmpeg option).
2359 @var{LA_ICQ} - intelligent constant quality with lookahead, when the
2360 @option{look_ahead} option is also set.
2363 @var{ICQ} -- intelligent constant quality otherwise.
2367 Otherwise, a bitrate-based mode is used. For all of those, you should specify at
2368 least the desired average bitrate with the @option{b} option.
2371 @var{LA} - VBR with lookahead, when the @option{look_ahead} option is specified.
2374 @var{VCM} - video conferencing mode, when the @option{vcm} option is set.
2377 @var{CBR} - constant bitrate, when @option{maxrate} is specified and equal to
2378 the average bitrate.
2381 @var{VBR} - variable bitrate, when @option{maxrate} is specified, but is higher
2382 than the average bitrate.
2385 @var{AVBR} - average VBR mode, when @option{maxrate} is not specified. This mode
2386 is further configured by the @option{avbr_accuracy} and
2387 @option{avbr_convergence} options.
2391 Note that depending on your system, a different mode than the one you specified
2392 may be selected by the encoder. Set the verbosity level to @var{verbose} or
2393 higher to see the actual settings used by the QSV runtime.
2395 Additional libavcodec global options are mapped to MSDK options as follows:
2399 @option{g/gop_size} -> @option{GopPicSize}
2402 @option{bf/max_b_frames}+1 -> @option{GopRefDist}
2405 @option{rc_init_occupancy/rc_initial_buffer_occupancy} ->
2406 @option{InitialDelayInKB}
2409 @option{slices} -> @option{NumSlice}
2412 @option{refs} -> @option{NumRefFrame}
2415 @option{b_strategy/b_frame_strategy} -> @option{BRefType}
2418 @option{cgop/CLOSED_GOP} codec flag -> @option{GopOptFlag}
2421 For the @var{CQP} mode, the @option{i_qfactor/i_qoffset} and
2422 @option{b_qfactor/b_qoffset} set the difference between @var{QPP} and @var{QPI},
2423 and @var{QPP} and @var{QPB} respectively.
2426 Setting the @option{coder} option to the value @var{vlc} will make the H.264
2427 encoder use CAVLC instead of CABAC.
2433 SMPTE VC-2 (previously BBC Dirac Pro). This codec was primarily aimed at
2434 professional broadcasting but since it supports yuv420, yuv422 and yuv444 at
2435 8 (limited range or full range), 10 or 12 bits, this makes it suitable for
2436 other tasks which require low overhead and low compression (like screen
2444 Sets target video bitrate. Usually that's around 1:6 of the uncompressed
2445 video bitrate (e.g. for 1920x1080 50fps yuv422p10 that's around 400Mbps). Higher
2446 values (close to the uncompressed bitrate) turn on lossless compression mode.
2449 Enables field coding when set (e.g. to tt - top field first) for interlaced
2450 inputs. Should increase compression with interlaced content as it splits the
2451 fields and encodes each separately.
2454 Sets the total amount of wavelet transforms to apply, between 1 and 5 (default).
2455 Lower values reduce compression and quality. Less capable decoders may not be
2456 able to handle values of @option{wavelet_depth} over 3.
2459 Sets the transform type. Currently only @var{5_3} (LeGall) and @var{9_7}
2461 are implemented, with 9_7 being the one with better compression and thus
2466 Sets the slice size for each slice. Larger values result in better compression.
2467 For compatibility with other more limited decoders use @option{slice_width} of
2468 32 and @option{slice_height} of 8.
2471 Sets the undershoot tolerance of the rate control system in percent. This is
2472 to prevent an expensive search from being run.
2475 Sets the quantization matrix preset to use by default or when @option{wavelet_depth}
2480 Uses the default quantization matrix from the specifications, extended with
2481 values for the fifth level. This provides a good balance between keeping detail
2482 and omitting artifacts.
2486 Use a completely zeroed out quantization matrix. This increases PSNR but might
2487 reduce perception. Use in bogus benchmarks.
2491 Reduces detail but attempts to preserve color at extremely low bitrates.
2496 @c man end VIDEO ENCODERS
2498 @chapter Subtitles Encoders
2499 @c man begin SUBTITLES ENCODERS
2503 This codec encodes the bitmap subtitle format that is used in DVDs.
2504 Typically they are stored in VOBSUB file pairs (*.idx + *.sub),
2505 and they can also be used in Matroska files.
2511 When set to 1, enable a work-around that makes the number of pixel rows
2512 even in all subtitles. This fixes a problem with some players that
2513 cut off the bottom row if the number is odd. The work-around just adds
2514 a fully transparent row if needed. The overhead is low, typically
2515 one byte per subtitle on average.
2517 By default, this work-around is disabled.
2520 @c man end SUBTITLES ENCODERS