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.
491 @item cutoff @var{frequency}
492 Set lowpass cutoff frequency. If unspecified, the encoder selects a default
493 determined by various other encoding parameters.
497 @subsection Floating-Point-Only AC-3 Encoding Options
499 These options are only valid for the floating-point encoder and do not exist
500 for the fixed-point encoder due to the corresponding features not being
501 implemented in fixed-point.
505 @item -channel_coupling @var{boolean}
506 Enables/Disables use of channel coupling, which is an optional AC-3 feature
507 that increases quality by combining high frequency information from multiple
508 channels into a single channel. The per-channel high frequency information is
509 sent with less accuracy in both the frequency and time domains. This allows
510 more bits to be used for lower frequencies while preserving enough information
511 to reconstruct the high frequencies. This option is enabled by default for the
512 floating-point encoder and should generally be left as enabled except for
513 testing purposes or to increase encoding speed.
517 Selected by Encoder (default)
520 Disable Channel Coupling
523 Enable Channel Coupling
526 @item -cpl_start_band @var{number}
527 Coupling Start Band. Sets the channel coupling start band, from 1 to 15. If a
528 value higher than the bandwidth is used, it will be reduced to 1 less than the
529 coupling end band. If @var{auto} is used, the start band will be determined by
530 the encoder based on the bit rate, sample rate, and channel layout. This option
531 has no effect if channel coupling is disabled.
535 Selected by Encoder (default)
543 FLAC (Free Lossless Audio Codec) Encoder
547 The following options are supported by FFmpeg's flac encoder.
550 @item compression_level
551 Sets the compression level, which chooses defaults for many other options
552 if they are not set explicitly.
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 Chanels 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.
619 @anchor{libfdk-aac-enc}
622 libfdk-aac AAC (Advanced Audio Coding) encoder wrapper.
624 The libfdk-aac library is based on the Fraunhofer FDK AAC code from
627 Requires the presence of the libfdk-aac headers and library during
628 configuration. You need to explicitly configure the build with
629 @code{--enable-libfdk-aac}. The library is also incompatible with GPL,
630 so if you allow the use of GPL, you should configure with
631 @code{--enable-gpl --enable-nonfree --enable-libfdk-aac}.
633 This encoder is considered to produce output on par or worse at 128kbps to the
634 @ref{aacenc,,the native FFmpeg AAC encoder} but can often produce better
635 sounding audio at identical or lower bitrates and has support for the
638 VBR encoding, enabled through the @option{vbr} or @option{flags
639 +qscale} options, is experimental and only works with some
640 combinations of parameters.
642 Support for encoding 7.1 audio is only available with libfdk-aac 0.1.3 or
645 For more information see the fdk-aac project at
646 @url{http://sourceforge.net/p/opencore-amr/fdk-aac/}.
650 The following options are mapped on the shared FFmpeg codec options.
654 Set bit rate in bits/s. If the bitrate is not explicitly specified, it
655 is automatically set to a suitable value depending on the selected
658 In case VBR mode is enabled the option is ignored.
661 Set audio sampling rate (in Hz).
664 Set the number of audio channels.
667 Enable fixed quality, VBR (Variable Bit Rate) mode.
668 Note that VBR is implicitly enabled when the @option{vbr} value is
672 Set cutoff frequency. If not specified (or explicitly set to 0) it
673 will use a value automatically computed by the library. Default value
679 The following profiles are recognized:
682 Low Complexity AAC (LC)
685 High Efficiency AAC (HE-AAC)
688 High Efficiency AAC version 2 (HE-AACv2)
694 Enhanced Low Delay AAC (ELD)
697 If not specified it is set to @samp{aac_low}.
700 The following are private options of the libfdk_aac encoder.
704 Enable afterburner feature if set to 1, disabled if set to 0. This
705 improves the quality but also the required processing power.
710 Enable SBR (Spectral Band Replication) for ELD if set to 1, disabled
716 Set SBR/PS signaling style.
718 It can assume one of the following values:
721 choose signaling implicitly (explicit hierarchical by default,
722 implicit if global header is disabled)
725 implicit backwards compatible signaling
728 explicit SBR, implicit PS signaling
730 @item explicit_hierarchical
731 explicit hierarchical signaling
734 Default value is @samp{default}.
737 Output LATM/LOAS encapsulated data if set to 1, disabled if set to 0.
742 Set StreamMuxConfig and PCE repetition period (in frames) for sending
743 in-band configuration buffers within LATM/LOAS transport layer.
745 Must be a 16-bits non-negative integer.
750 Set VBR mode, from 1 to 5. 1 is lowest quality (though still pretty
751 good) and 5 is highest quality. A value of 0 will disable VBR, and CBR
752 (Constant Bit Rate) is enabled.
754 Currently only the @samp{aac_low} profile supports VBR encoding.
756 VBR modes 1-5 correspond to roughly the following average bit rates:
768 about 80-96 kbps/channel
778 Use @command{ffmpeg} to convert an audio file to VBR AAC in an M4A (MP4)
781 ffmpeg -i input.wav -codec:a libfdk_aac -vbr 3 output.m4a
785 Use @command{ffmpeg} to convert an audio file to CBR 64k kbps AAC, using the
786 High-Efficiency AAC profile:
788 ffmpeg -i input.wav -c:a libfdk_aac -profile:a aac_he -b:a 64k output.m4a
795 LAME (Lame Ain't an MP3 Encoder) MP3 encoder wrapper.
797 Requires the presence of the libmp3lame headers and library during
798 configuration. You need to explicitly configure the build with
799 @code{--enable-libmp3lame}.
801 See @ref{libshine} for a fixed-point MP3 encoder, although with a
806 The following options are supported by the libmp3lame wrapper. The
807 @command{lame}-equivalent of the options are listed in parentheses.
811 Set bitrate expressed in bits/s for CBR or ABR. LAME @code{bitrate} is
812 expressed in kilobits/s.
815 Set constant quality setting for VBR. This option is valid only
816 using the @command{ffmpeg} command-line tool. For library interface
817 users, use @option{global_quality}.
819 @item compression_level (@emph{-q})
820 Set algorithm quality. Valid arguments are integers in the 0-9 range,
821 with 0 meaning highest quality but slowest, and 9 meaning fastest
822 while producing the worst quality.
824 @item cutoff (@emph{--lowpass})
825 Set lowpass cutoff frequency. If unspecified, the encoder dynamically
829 Enable use of bit reservoir when set to 1. Default value is 1. LAME
830 has this enabled by default, but can be overridden by use
831 @option{--nores} option.
833 @item joint_stereo (@emph{-m j})
834 Enable the encoder to use (on a frame by frame basis) either L/R
835 stereo or mid/side stereo. Default value is 1.
837 @item abr (@emph{--abr})
838 Enable the encoder to use ABR when set to 1. The @command{lame}
839 @option{--abr} sets the target bitrate, while this options only
840 tells FFmpeg to use ABR still relies on @option{b} to set bitrate.
844 @section libopencore-amrnb
846 OpenCORE Adaptive Multi-Rate Narrowband encoder.
848 Requires the presence of the libopencore-amrnb headers and library during
849 configuration. You need to explicitly configure the build with
850 @code{--enable-libopencore-amrnb --enable-version3}.
852 This is a mono-only encoder. Officially it only supports 8000Hz sample rate,
853 but you can override it by setting @option{strict} to @samp{unofficial} or
861 Set bitrate in bits per second. Only the following bitrates are supported,
862 otherwise libavcodec will round to the nearest valid bitrate.
876 Allow discontinuous transmission (generate comfort noise) when set to 1. The
877 default value is 0 (disabled).
883 libopus Opus Interactive Audio Codec encoder wrapper.
885 Requires the presence of the libopus headers and library during
886 configuration. You need to explicitly configure the build with
887 @code{--enable-libopus}.
889 @subsection Option Mapping
891 Most libopus options are modelled after the @command{opusenc} utility from
892 opus-tools. The following is an option mapping chart describing options
893 supported by the libopus wrapper, and their @command{opusenc}-equivalent
898 @item b (@emph{bitrate})
899 Set the bit rate in bits/s. FFmpeg's @option{b} option is
900 expressed in bits/s, while @command{opusenc}'s @option{bitrate} in
903 @item vbr (@emph{vbr}, @emph{hard-cbr}, and @emph{cvbr})
904 Set VBR mode. The FFmpeg @option{vbr} option has the following
905 valid arguments, with the @command{opusenc} equivalent options
909 @item off (@emph{hard-cbr})
910 Use constant bit rate encoding.
912 @item on (@emph{vbr})
913 Use variable bit rate encoding (the default).
915 @item constrained (@emph{cvbr})
916 Use constrained variable bit rate encoding.
919 @item compression_level (@emph{comp})
920 Set encoding algorithm complexity. Valid options are integers in
921 the 0-10 range. 0 gives the fastest encodes but lower quality, while 10
922 gives the highest quality but slowest encoding. The default is 10.
924 @item frame_duration (@emph{framesize})
925 Set maximum frame size, or duration of a frame in milliseconds. The
926 argument must be exactly the following: 2.5, 5, 10, 20, 40, 60. Smaller
927 frame sizes achieve lower latency but less quality at a given bitrate.
928 Sizes greater than 20ms are only interesting at fairly low bitrates.
931 @item packet_loss (@emph{expect-loss})
932 Set expected packet loss percentage. The default is 0.
934 @item application (N.A.)
935 Set intended application type. Valid options are listed below:
939 Favor improved speech intelligibility.
941 Favor faithfulness to the input (the default).
943 Restrict to only the lowest delay modes.
947 Set cutoff bandwidth in Hz. The argument must be exactly one of the
948 following: 4000, 6000, 8000, 12000, or 20000, corresponding to
949 narrowband, mediumband, wideband, super wideband, and fullband
950 respectively. The default is 0 (cutoff disabled).
952 @item mapping_family (@emph{mapping_family})
953 Set channel mapping family to be used by the encoder. The default value of -1
954 uses mapping family 0 for mono and stereo inputs, and mapping family 1
955 otherwise. The default also disables the surround masking and LFE bandwidth
956 optimzations in libopus, and requires that the input contains 8 channels or
959 Other values include 0 for mono and stereo, 1 for surround sound with masking
960 and LFE bandwidth optimizations, and 255 for independent streams with an
961 unspecified channel layout.
968 Shine Fixed-Point MP3 encoder wrapper.
970 Shine is a fixed-point MP3 encoder. It has a far better performance on
971 platforms without an FPU, e.g. armel CPUs, and some phones and tablets.
972 However, as it is more targeted on performance than quality, it is not on par
973 with LAME and other production-grade encoders quality-wise. Also, according to
974 the project's homepage, this encoder may not be free of bugs as the code was
975 written a long time ago and the project was dead for at least 5 years.
977 This encoder only supports stereo and mono input. This is also CBR-only.
979 The original project (last updated in early 2007) is at
980 @url{http://sourceforge.net/projects/libshine-fxp/}. We only support the
981 updated fork by the Savonet/Liquidsoap project at @url{https://github.com/savonet/shine}.
983 Requires the presence of the libshine headers and library during
984 configuration. You need to explicitly configure the build with
985 @code{--enable-libshine}.
987 See also @ref{libmp3lame}.
991 The following options are supported by the libshine wrapper. The
992 @command{shineenc}-equivalent of the options are listed in parentheses.
996 Set bitrate expressed in bits/s for CBR. @command{shineenc} @option{-b} option
997 is expressed in kilobits/s.
1003 TwoLAME MP2 encoder wrapper.
1005 Requires the presence of the libtwolame headers and library during
1006 configuration. You need to explicitly configure the build with
1007 @code{--enable-libtwolame}.
1011 The following options are supported by the libtwolame wrapper. The
1012 @command{twolame}-equivalent options follow the FFmpeg ones and are in
1017 Set bitrate expressed in bits/s for CBR. @command{twolame} @option{b}
1018 option is expressed in kilobits/s. Default value is 128k.
1021 Set quality for experimental VBR support. Maximum value range is
1022 from -50 to 50, useful range is from -10 to 10. The higher the
1023 value, the better the quality. This option is valid only using the
1024 @command{ffmpeg} command-line tool. For library interface users,
1025 use @option{global_quality}.
1027 @item mode (@emph{--mode})
1028 Set the mode of the resulting audio. Possible values:
1032 Choose mode automatically based on the input. This is the default.
1043 @item psymodel (@emph{--psyc-mode})
1044 Set psychoacoustic model to use in encoding. The argument must be
1045 an integer between -1 and 4, inclusive. The higher the value, the
1046 better the quality. The default value is 3.
1048 @item energy_levels (@emph{--energy})
1049 Enable energy levels extensions when set to 1. The default value is
1052 @item error_protection (@emph{--protect})
1053 Enable CRC error protection when set to 1. The default value is 0
1056 @item copyright (@emph{--copyright})
1057 Set MPEG audio copyright flag when set to 1. The default value is 0
1060 @item original (@emph{--original})
1061 Set MPEG audio original flag when set to 1. The default value is 0
1066 @section libvo-amrwbenc
1068 VisualOn Adaptive Multi-Rate Wideband encoder.
1070 Requires the presence of the libvo-amrwbenc headers and library during
1071 configuration. You need to explicitly configure the build with
1072 @code{--enable-libvo-amrwbenc --enable-version3}.
1074 This is a mono-only encoder. Officially it only supports 16000Hz sample
1075 rate, but you can override it by setting @option{strict} to
1076 @samp{unofficial} or lower.
1083 Set bitrate in bits/s. Only the following bitrates are supported, otherwise
1084 libavcodec will round to the nearest valid bitrate.
1099 Allow discontinuous transmission (generate comfort noise) when set to 1. The
1100 default value is 0 (disabled).
1106 libvorbis encoder wrapper.
1108 Requires the presence of the libvorbisenc headers and library during
1109 configuration. You need to explicitly configure the build with
1110 @code{--enable-libvorbis}.
1114 The following options are supported by the libvorbis wrapper. The
1115 @command{oggenc}-equivalent of the options are listed in parentheses.
1117 To get a more accurate and extensive documentation of the libvorbis
1118 options, consult the libvorbisenc's and @command{oggenc}'s documentations.
1119 See @url{http://xiph.org/vorbis/},
1120 @url{http://wiki.xiph.org/Vorbis-tools}, and oggenc(1).
1124 Set bitrate expressed in bits/s for ABR. @command{oggenc} @option{-b} is
1125 expressed in kilobits/s.
1128 Set constant quality setting for VBR. The value should be a float
1129 number in the range of -1.0 to 10.0. The higher the value, the better
1130 the quality. The default value is @samp{3.0}.
1132 This option is valid only using the @command{ffmpeg} command-line tool.
1133 For library interface users, use @option{global_quality}.
1135 @item cutoff (@emph{--advanced-encode-option lowpass_frequency=N})
1136 Set cutoff bandwidth in Hz, a value of 0 disables cutoff. @command{oggenc}'s
1137 related option is expressed in kHz. The default value is @samp{0} (cutoff
1140 @item minrate (@emph{-m})
1141 Set minimum bitrate expressed in bits/s. @command{oggenc} @option{-m} is
1142 expressed in kilobits/s.
1144 @item maxrate (@emph{-M})
1145 Set maximum bitrate expressed in bits/s. @command{oggenc} @option{-M} is
1146 expressed in kilobits/s. This only has effect on ABR mode.
1148 @item iblock (@emph{--advanced-encode-option impulse_noisetune=N})
1149 Set noise floor bias for impulse blocks. The value is a float number from
1150 -15.0 to 0.0. A negative bias instructs the encoder to pay special attention
1151 to the crispness of transients in the encoded audio. The tradeoff for better
1152 transient response is a higher bitrate.
1159 A wrapper providing WavPack encoding through libwavpack.
1161 Only lossless mode using 32-bit integer samples is supported currently.
1163 Requires the presence of the libwavpack headers and library during
1164 configuration. You need to explicitly configure the build with
1165 @code{--enable-libwavpack}.
1167 Note that a libavcodec-native encoder for the WavPack codec exists so users can
1168 encode audios with this codec without using this encoder. See @ref{wavpackenc}.
1172 @command{wavpack} command line utility's corresponding options are listed in
1173 parentheses, if any.
1176 @item frame_size (@emph{--blocksize})
1179 @item compression_level
1180 Set speed vs. compression tradeoff. Acceptable arguments are listed below:
1187 Normal (default) settings.
1192 @item 3 (@emph{-hh})
1195 @item 4-8 (@emph{-hh -x}@var{EXTRAPROC})
1196 Same as @samp{3}, but with extra processing enabled.
1198 @samp{4} is the same as @option{-x2} and @samp{8} is the same as @option{-x6}.
1206 WavPack lossless audio encoder.
1208 This is a libavcodec-native WavPack encoder. There is also an encoder based on
1209 libwavpack, but there is virtually no reason to use that encoder.
1211 See also @ref{libwavpack}.
1215 The equivalent options for @command{wavpack} command line utility are listed in
1218 @subsubsection Shared options
1220 The following shared options are effective for this encoder. Only special notes
1221 about this particular encoder will be documented here. For the general meaning
1222 of the options, see @ref{codec-options,,the Codec Options chapter}.
1225 @item frame_size (@emph{--blocksize})
1226 For this encoder, the range for this option is between 128 and 131072. Default
1227 is automatically decided based on sample rate and number of channel.
1229 For the complete formula of calculating default, see
1230 @file{libavcodec/wavpackenc.c}.
1232 @item compression_level (@emph{-f}, @emph{-h}, @emph{-hh}, and @emph{-x})
1233 This option's syntax is consistent with @ref{libwavpack}'s.
1236 @subsubsection Private options
1239 @item joint_stereo (@emph{-j})
1240 Set whether to enable joint stereo. Valid values are:
1244 Force mid/side audio encoding.
1245 @item off (@emph{0})
1246 Force left/right audio encoding.
1248 Let the encoder decide automatically.
1252 Set whether to enable optimization for mono. This option is only effective for
1253 non-mono streams. Available values:
1264 @c man end AUDIO ENCODERS
1266 @chapter Video Encoders
1267 @c man begin VIDEO ENCODERS
1269 A description of some of the currently available video encoders
1274 Vidvox Hap video encoder.
1279 @item format @var{integer}
1280 Specifies the Hap format to encode.
1288 Default value is @option{hap}.
1290 @item chunks @var{integer}
1291 Specifies the number of chunks to split frames into, between 1 and 64. This
1292 permits multithreaded decoding of large frames, potentially at the cost of
1293 data-rate. The encoder may modify this value to divide frames evenly.
1295 Default value is @var{1}.
1297 @item compressor @var{integer}
1298 Specifies the second-stage compressor to use. If set to @option{none},
1299 @option{chunks} will be limited to 1, as chunked uncompressed frames offer no
1307 Default value is @option{snappy}.
1313 The native jpeg 2000 encoder is lossy by default, the @code{-q:v}
1314 option can be used to set the encoding quality. Lossless encoding
1315 can be selected with @code{-pred 1}.
1321 Can be set to either @code{j2k} or @code{jp2} (the default) that
1322 makes it possible to store non-rgb pix_fmts.
1328 Kvazaar H.265/HEVC encoder.
1330 Requires the presence of the libkvazaar headers and library during
1331 configuration. You need to explicitly configure the build with
1332 @option{--enable-libkvazaar}.
1339 Set target video bitrate in bit/s and enable rate control.
1341 @item kvazaar-params
1342 Set kvazaar parameters as a list of @var{name}=@var{value} pairs separated
1343 by commas (,). See kvazaar documentation for a list of options.
1347 @section libopenh264
1349 Cisco libopenh264 H.264/MPEG-4 AVC encoder wrapper.
1351 This encoder requires the presence of the libopenh264 headers and
1352 library during configuration. You need to explicitly configure the
1353 build with @code{--enable-libopenh264}. The library is detected using
1354 @command{pkg-config}.
1356 For more information about the library see
1357 @url{http://www.openh264.org}.
1361 The following FFmpeg global options affect the configurations of the
1362 libopenh264 encoder.
1366 Set the bitrate (as a number of bits per second).
1372 Set the max bitrate (as a number of bits per second).
1374 @item flags +global_header
1375 Set global header in the bitstream.
1378 Set the number of slices, used in parallelized encoding. Default value
1379 is 0. This is only used when @option{slice_mode} is set to
1383 Set slice mode. Can assume one of the following possible values:
1387 a fixed number of slices
1389 one slice per row of macroblocks
1391 automatic number of slices according to number of threads
1396 Default value is @samp{auto}.
1399 Enable loop filter, if set to 1 (automatically enabled). To disable
1403 Set profile restrictions. If set to the value of @samp{main} enable
1404 CABAC (set the @code{SEncParamExt.iEntropyCodingModeFlag} flag to 1).
1407 Set maximum NAL size in bytes.
1409 @item allow_skip_frames
1410 Allow skipping frames to hit the target bitrate if set to 1.
1415 libtheora Theora encoder wrapper.
1417 Requires the presence of the libtheora headers and library during
1418 configuration. You need to explicitly configure the build with
1419 @code{--enable-libtheora}.
1421 For more information about the libtheora project see
1422 @url{http://www.theora.org/}.
1426 The following global options are mapped to internal libtheora options
1427 which affect the quality and the bitrate of the encoded stream.
1431 Set the video bitrate in bit/s for CBR (Constant Bit Rate) mode. In
1432 case VBR (Variable Bit Rate) mode is enabled this option is ignored.
1435 Used to enable constant quality mode (VBR) encoding through the
1436 @option{qscale} flag, and to enable the @code{pass1} and @code{pass2}
1442 @item global_quality
1443 Set the global quality as an integer in lambda units.
1445 Only relevant when VBR mode is enabled with @code{flags +qscale}. The
1446 value is converted to QP units by dividing it by @code{FF_QP2LAMBDA},
1447 clipped in the [0 - 10] range, and then multiplied by 6.3 to get a
1448 value in the native libtheora range [0-63]. A higher value corresponds
1449 to a higher quality.
1452 Enable VBR mode when set to a non-negative value, and set constant
1453 quality value as a double floating point value in QP units.
1455 The value is clipped in the [0-10] range, and then multiplied by 6.3
1456 to get a value in the native libtheora range [0-63].
1458 This option is valid only using the @command{ffmpeg} command-line
1459 tool. For library interface users, use @option{global_quality}.
1462 @subsection Examples
1466 Set maximum constant quality (VBR) encoding with @command{ffmpeg}:
1468 ffmpeg -i INPUT -codec:v libtheora -q:v 10 OUTPUT.ogg
1472 Use @command{ffmpeg} to convert a CBR 1000 kbps Theora video stream:
1474 ffmpeg -i INPUT -codec:v libtheora -b:v 1000k OUTPUT.ogg
1480 VP8/VP9 format supported through libvpx.
1482 Requires the presence of the libvpx headers and library during configuration.
1483 You need to explicitly configure the build with @code{--enable-libvpx}.
1487 The following options are supported by the libvpx wrapper. The
1488 @command{vpxenc}-equivalent options or values are listed in parentheses
1491 To reduce the duplication of documentation, only the private options
1492 and some others requiring special attention are documented here. For
1493 the documentation of the undocumented generic options, see
1494 @ref{codec-options,,the Codec Options chapter}.
1496 To get more documentation of the libvpx options, invoke the command
1497 @command{ffmpeg -h encoder=libvpx}, @command{ffmpeg -h encoder=libvpx-vp9} or
1498 @command{vpxenc --help}. Further information is available in the libvpx API
1503 @item b (@emph{target-bitrate})
1504 Set bitrate in bits/s. Note that FFmpeg's @option{b} option is
1505 expressed in bits/s, while @command{vpxenc}'s @option{target-bitrate} is in
1508 @item g (@emph{kf-max-dist})
1510 @item keyint_min (@emph{kf-min-dist})
1512 @item qmin (@emph{min-q})
1514 @item qmax (@emph{max-q})
1516 @item bufsize (@emph{buf-sz}, @emph{buf-optimal-sz})
1517 Set ratecontrol buffer size (in bits). Note @command{vpxenc}'s options are
1518 specified in milliseconds, the libvpx wrapper converts this value as follows:
1519 @code{buf-sz = bufsize * 1000 / bitrate},
1520 @code{buf-optimal-sz = bufsize * 1000 / bitrate * 5 / 6}.
1522 @item rc_init_occupancy (@emph{buf-initial-sz})
1523 Set number of bits which should be loaded into the rc buffer before decoding
1524 starts. Note @command{vpxenc}'s option is specified in milliseconds, the libvpx
1525 wrapper converts this value as follows:
1526 @code{rc_init_occupancy * 1000 / bitrate}.
1528 @item undershoot-pct
1529 Set datarate undershoot (min) percentage of the target bitrate.
1532 Set datarate overshoot (max) percentage of the target bitrate.
1534 @item skip_threshold (@emph{drop-frame})
1536 @item qcomp (@emph{bias-pct})
1538 @item maxrate (@emph{maxsection-pct})
1539 Set GOP max bitrate in bits/s. Note @command{vpxenc}'s option is specified as a
1540 percentage of the target bitrate, the libvpx wrapper converts this value as
1541 follows: @code{(maxrate * 100 / bitrate)}.
1543 @item minrate (@emph{minsection-pct})
1544 Set GOP min bitrate in bits/s. Note @command{vpxenc}'s option is specified as a
1545 percentage of the target bitrate, the libvpx wrapper converts this value as
1546 follows: @code{(minrate * 100 / bitrate)}.
1548 @item minrate, maxrate, b @emph{end-usage=cbr}
1549 @code{(minrate == maxrate == bitrate)}.
1551 @item crf (@emph{end-usage=cq}, @emph{cq-level})
1553 @item tune (@emph{tune})
1555 @item psnr (@emph{psnr})
1556 @item ssim (@emph{ssim})
1559 @item quality, deadline (@emph{deadline})
1562 Use best quality deadline. Poorly named and quite slow, this option should be
1563 avoided as it may give worse quality output than good.
1565 Use good quality deadline. This is a good trade-off between speed and quality
1566 when used with the @option{cpu-used} option.
1568 Use realtime quality deadline.
1571 @item speed, cpu-used (@emph{cpu-used})
1572 Set quality/speed ratio modifier. Higher values speed up the encode at the cost
1575 @item nr (@emph{noise-sensitivity})
1578 Set a change threshold on blocks below which they will be skipped by the
1581 @item slices (@emph{token-parts})
1582 Note that FFmpeg's @option{slices} option gives the total number of partitions,
1583 while @command{vpxenc}'s @option{token-parts} is given as
1584 @code{log2(partitions)}.
1586 @item max-intra-rate
1587 Set maximum I-frame bitrate as a percentage of the target bitrate. A value of 0
1590 @item force_key_frames
1591 @code{VPX_EFLAG_FORCE_KF}
1593 @item Alternate reference frame related
1596 Enable use of alternate reference frames (2-pass only).
1597 @item arnr-max-frames
1598 Set altref noise reduction max frame count.
1600 Set altref noise reduction filter type: backward, forward, centered.
1602 Set altref noise reduction filter strength.
1603 @item rc-lookahead, lag-in-frames (@emph{lag-in-frames})
1604 Set number of frames to look ahead for frametype and ratecontrol.
1607 @item error-resilient
1608 Enable error resiliency features.
1610 @item VP9-specific options
1613 Enable lossless mode.
1615 Set number of tile columns to use. Note this is given as
1616 @code{log2(tile_columns)}. For example, 8 tile columns would be requested by
1617 setting the @option{tile-columns} option to 3.
1619 Set number of tile rows to use. Note this is given as @code{log2(tile_rows)}.
1620 For example, 4 tile rows would be requested by setting the @option{tile-rows}
1622 @item frame-parallel
1623 Enable frame parallel decodability features.
1625 Set adaptive quantization mode (0: off (default), 1: variance 2: complexity, 3:
1627 @item colorspace @emph{color-space}
1628 Set input color space. The VP9 bitstream supports signaling the following
1631 @item @samp{rgb} @emph{sRGB}
1632 @item @samp{bt709} @emph{bt709}
1633 @item @samp{unspecified} @emph{unknown}
1634 @item @samp{bt470bg} @emph{bt601}
1635 @item @samp{smpte170m} @emph{smpte170}
1636 @item @samp{smpte240m} @emph{smpte240}
1637 @item @samp{bt2020_ncl} @emph{bt2020}
1643 For more information about libvpx see:
1644 @url{http://www.webmproject.org/}
1648 libwebp WebP Image encoder wrapper
1650 libwebp is Google's official encoder for WebP images. It can encode in either
1651 lossy or lossless mode. Lossy images are essentially a wrapper around a VP8
1652 frame. Lossless images are a separate codec developed by Google.
1654 @subsection Pixel Format
1656 Currently, libwebp only supports YUV420 for lossy and RGB for lossless due
1657 to limitations of the format and libwebp. Alpha is supported for either mode.
1658 Because of API limitations, if RGB is passed in when encoding lossy or YUV is
1659 passed in for encoding lossless, the pixel format will automatically be
1660 converted using functions from libwebp. This is not ideal and is done only for
1667 @item -lossless @var{boolean}
1668 Enables/Disables use of lossless mode. Default is 0.
1670 @item -compression_level @var{integer}
1671 For lossy, this is a quality/speed tradeoff. Higher values give better quality
1672 for a given size at the cost of increased encoding time. For lossless, this is
1673 a size/speed tradeoff. Higher values give smaller size at the cost of increased
1674 encoding time. More specifically, it controls the number of extra algorithms
1675 and compression tools used, and varies the combination of these tools. This
1676 maps to the @var{method} option in libwebp. The valid range is 0 to 6.
1679 @item -qscale @var{float}
1680 For lossy encoding, this controls image quality, 0 to 100. For lossless
1681 encoding, this controls the effort and time spent at compressing more. The
1682 default value is 75. Note that for usage via libavcodec, this option is called
1683 @var{global_quality} and must be multiplied by @var{FF_QP2LAMBDA}.
1685 @item -preset @var{type}
1686 Configuration preset. This does some automatic settings based on the general
1690 Do not use a preset.
1692 Use the encoder default.
1694 Digital picture, like portrait, inner shot
1696 Outdoor photograph, with natural lighting
1698 Hand or line drawing, with high-contrast details
1700 Small-sized colorful images
1707 @section libx264, libx264rgb
1709 x264 H.264/MPEG-4 AVC encoder wrapper.
1711 This encoder requires the presence of the libx264 headers and library
1712 during configuration. You need to explicitly configure the build with
1713 @code{--enable-libx264}.
1715 libx264 supports an impressive number of features, including 8x8 and
1716 4x4 adaptive spatial transform, adaptive B-frame placement, CAVLC/CABAC
1717 entropy coding, interlacing (MBAFF), lossless mode, psy optimizations
1718 for detail retention (adaptive quantization, psy-RD, psy-trellis).
1720 Many libx264 encoder options are mapped to FFmpeg global codec
1721 options, while unique encoder options are provided through private
1722 options. Additionally the @option{x264opts} and @option{x264-params}
1723 private options allows one to pass a list of key=value tuples as accepted
1724 by the libx264 @code{x264_param_parse} function.
1726 The x264 project website is at
1727 @url{http://www.videolan.org/developers/x264.html}.
1729 The libx264rgb encoder is the same as libx264, except it accepts packed RGB
1730 pixel formats as input instead of YUV.
1732 @subsection Supported Pixel Formats
1734 x264 supports 8- to 10-bit color spaces. The exact bit depth is controlled at
1735 x264's configure time. FFmpeg only supports one bit depth in one particular
1736 build. In other words, it is not possible to build one FFmpeg with multiple
1737 versions of x264 with different bit depths.
1741 The following options are supported by the libx264 wrapper. The
1742 @command{x264}-equivalent options or values are listed in parentheses
1745 To reduce the duplication of documentation, only the private options
1746 and some others requiring special attention are documented here. For
1747 the documentation of the undocumented generic options, see
1748 @ref{codec-options,,the Codec Options chapter}.
1750 To get a more accurate and extensive documentation of the libx264
1751 options, invoke the command @command{x264 --full-help} or consult
1752 the libx264 documentation.
1755 @item b (@emph{bitrate})
1756 Set bitrate in bits/s. Note that FFmpeg's @option{b} option is
1757 expressed in bits/s, while @command{x264}'s @option{bitrate} is in
1760 @item bf (@emph{bframes})
1762 @item g (@emph{keyint})
1764 @item qmin (@emph{qpmin})
1765 Minimum quantizer scale.
1767 @item qmax (@emph{qpmax})
1768 Maximum quantizer scale.
1770 @item qdiff (@emph{qpstep})
1771 Maximum difference between quantizer scales.
1773 @item qblur (@emph{qblur})
1774 Quantizer curve blur
1776 @item qcomp (@emph{qcomp})
1777 Quantizer curve compression factor
1779 @item refs (@emph{ref})
1780 Number of reference frames each P-frame can use. The range is from @var{0-16}.
1782 @item sc_threshold (@emph{scenecut})
1783 Sets the threshold for the scene change detection.
1785 @item trellis (@emph{trellis})
1786 Performs Trellis quantization to increase efficiency. Enabled by default.
1788 @item nr (@emph{nr})
1790 @item me_range (@emph{merange})
1791 Maximum range of the motion search in pixels.
1793 @item me_method (@emph{me})
1794 Set motion estimation method. Possible values in the decreasing order
1798 @item dia (@emph{dia})
1799 @item epzs (@emph{dia})
1800 Diamond search with radius 1 (fastest). @samp{epzs} is an alias for
1802 @item hex (@emph{hex})
1803 Hexagonal search with radius 2.
1804 @item umh (@emph{umh})
1805 Uneven multi-hexagon search.
1806 @item esa (@emph{esa})
1808 @item tesa (@emph{tesa})
1809 Hadamard exhaustive search (slowest).
1813 Normally, when forcing a I-frame type, the encoder can select any type
1814 of I-frame. This option forces it to choose an IDR-frame.
1816 @item subq (@emph{subme})
1817 Sub-pixel motion estimation method.
1819 @item b_strategy (@emph{b-adapt})
1820 Adaptive B-frame placement decision algorithm. Use only on first-pass.
1822 @item keyint_min (@emph{min-keyint})
1826 Set entropy encoder. Possible values:
1833 Enable CAVLC and disable CABAC. It generates the same effect as
1834 @command{x264}'s @option{--no-cabac} option.
1838 Set full pixel motion estimation comparison algorithm. Possible values:
1842 Enable chroma in motion estimation.
1845 Ignore chroma in motion estimation. It generates the same effect as
1846 @command{x264}'s @option{--no-chroma-me} option.
1849 @item threads (@emph{threads})
1850 Number of encoding threads.
1853 Set multithreading technique. Possible values:
1857 Slice-based multithreading. It generates the same effect as
1858 @command{x264}'s @option{--sliced-threads} option.
1860 Frame-based multithreading.
1864 Set encoding flags. It can be used to disable closed GOP and enable
1865 open GOP by setting it to @code{-cgop}. The result is similar to
1866 the behavior of @command{x264}'s @option{--open-gop} option.
1868 @item rc_init_occupancy (@emph{vbv-init})
1870 @item preset (@emph{preset})
1871 Set the encoding preset.
1873 @item tune (@emph{tune})
1874 Set tuning of the encoding params.
1876 @item profile (@emph{profile})
1877 Set profile restrictions.
1880 Enable fast settings when encoding first pass, when set to 1. When set
1881 to 0, it has the same effect of @command{x264}'s
1882 @option{--slow-firstpass} option.
1884 @item crf (@emph{crf})
1885 Set the quality for constant quality mode.
1887 @item crf_max (@emph{crf-max})
1888 In CRF mode, prevents VBV from lowering quality beyond this point.
1890 @item qp (@emph{qp})
1891 Set constant quantization rate control method parameter.
1893 @item aq-mode (@emph{aq-mode})
1894 Set AQ method. Possible values:
1897 @item none (@emph{0})
1900 @item variance (@emph{1})
1901 Variance AQ (complexity mask).
1903 @item autovariance (@emph{2})
1904 Auto-variance AQ (experimental).
1907 @item aq-strength (@emph{aq-strength})
1908 Set AQ strength, reduce blocking and blurring in flat and textured areas.
1911 Use psychovisual optimizations when set to 1. When set to 0, it has the
1912 same effect as @command{x264}'s @option{--no-psy} option.
1914 @item psy-rd (@emph{psy-rd})
1915 Set strength of psychovisual optimization, in
1916 @var{psy-rd}:@var{psy-trellis} format.
1918 @item rc-lookahead (@emph{rc-lookahead})
1919 Set number of frames to look ahead for frametype and ratecontrol.
1922 Enable weighted prediction for B-frames when set to 1. When set to 0,
1923 it has the same effect as @command{x264}'s @option{--no-weightb} option.
1925 @item weightp (@emph{weightp})
1926 Set weighted prediction method for P-frames. Possible values:
1929 @item none (@emph{0})
1931 @item simple (@emph{1})
1932 Enable only weighted refs
1933 @item smart (@emph{2})
1934 Enable both weighted refs and duplicates
1937 @item ssim (@emph{ssim})
1938 Enable calculation and printing SSIM stats after the encoding.
1940 @item intra-refresh (@emph{intra-refresh})
1941 Enable the use of Periodic Intra Refresh instead of IDR frames when set
1944 @item avcintra-class (@emph{class})
1945 Configure the encoder to generate AVC-Intra.
1946 Valid values are 50,100 and 200
1948 @item bluray-compat (@emph{bluray-compat})
1949 Configure the encoder to be compatible with the bluray standard.
1950 It is a shorthand for setting "bluray-compat=1 force-cfr=1".
1952 @item b-bias (@emph{b-bias})
1953 Set the influence on how often B-frames are used.
1955 @item b-pyramid (@emph{b-pyramid})
1956 Set method for keeping of some B-frames as references. Possible values:
1959 @item none (@emph{none})
1961 @item strict (@emph{strict})
1962 Strictly hierarchical pyramid.
1963 @item normal (@emph{normal})
1964 Non-strict (not Blu-ray compatible).
1968 Enable the use of one reference per partition, as opposed to one
1969 reference per macroblock when set to 1. When set to 0, it has the
1970 same effect as @command{x264}'s @option{--no-mixed-refs} option.
1973 Enable adaptive spatial transform (high profile 8x8 transform)
1974 when set to 1. When set to 0, it has the same effect as
1975 @command{x264}'s @option{--no-8x8dct} option.
1978 Enable early SKIP detection on P-frames when set to 1. When set
1979 to 0, it has the same effect as @command{x264}'s
1980 @option{--no-fast-pskip} option.
1982 @item aud (@emph{aud})
1983 Enable use of access unit delimiters when set to 1.
1986 Enable use macroblock tree ratecontrol when set to 1. When set
1987 to 0, it has the same effect as @command{x264}'s
1988 @option{--no-mbtree} option.
1990 @item deblock (@emph{deblock})
1991 Set loop filter parameters, in @var{alpha}:@var{beta} form.
1993 @item cplxblur (@emph{cplxblur})
1994 Set fluctuations reduction in QP (before curve compression).
1996 @item partitions (@emph{partitions})
1997 Set partitions to consider as a comma-separated list of. Possible
2002 8x8 P-frame partition.
2004 4x4 P-frame partition.
2006 4x4 B-frame partition.
2008 8x8 I-frame partition.
2010 4x4 I-frame partition.
2011 (Enabling @samp{p4x4} requires @samp{p8x8} to be enabled. Enabling
2012 @samp{i8x8} requires adaptive spatial transform (@option{8x8dct}
2013 option) to be enabled.)
2014 @item none (@emph{none})
2015 Do not consider any partitions.
2016 @item all (@emph{all})
2017 Consider every partition.
2020 @item direct-pred (@emph{direct})
2021 Set direct MV prediction mode. Possible values:
2024 @item none (@emph{none})
2025 Disable MV prediction.
2026 @item spatial (@emph{spatial})
2027 Enable spatial predicting.
2028 @item temporal (@emph{temporal})
2029 Enable temporal predicting.
2030 @item auto (@emph{auto})
2031 Automatically decided.
2034 @item slice-max-size (@emph{slice-max-size})
2035 Set the limit of the size of each slice in bytes. If not specified
2036 but RTP payload size (@option{ps}) is specified, that is used.
2038 @item stats (@emph{stats})
2039 Set the file name for multi-pass stats.
2041 @item nal-hrd (@emph{nal-hrd})
2042 Set signal HRD information (requires @option{vbv-bufsize} to be set).
2046 @item none (@emph{none})
2047 Disable HRD information signaling.
2048 @item vbr (@emph{vbr})
2050 @item cbr (@emph{cbr})
2051 Constant bit rate (not allowed in MP4 container).
2054 @item x264opts (N.A.)
2055 Set any x264 option, see @command{x264 --fullhelp} for a list.
2057 Argument is a list of @var{key}=@var{value} couples separated by
2058 ":". In @var{filter} and @var{psy-rd} options that use ":" as a separator
2059 themselves, use "," instead. They accept it as well since long ago but this
2060 is kept undocumented for some reason.
2062 For example to specify libx264 encoding options with @command{ffmpeg}:
2064 ffmpeg -i foo.mpg -vcodec libx264 -x264opts keyint=123:min-keyint=20 -an out.mkv
2067 @item a53cc @var{boolean}
2068 Import closed captions (which must be ATSC compatible format) into output.
2069 Only the mpeg2 and h264 decoders provide these. Default is 1 (on).
2071 @item x264-params (N.A.)
2072 Override the x264 configuration using a :-separated list of key=value
2075 This option is functionally the same as the @option{x264opts}, but is
2076 duplicated for compatibility with the Libav fork.
2078 For example to specify libx264 encoding options with @command{ffmpeg}:
2080 ffmpeg -i INPUT -c:v libx264 -x264-params level=30:bframes=0:weightp=0:\
2081 cabac=0:ref=1:vbv-maxrate=768:vbv-bufsize=2000:analyse=all:me=umh:\
2082 no-fast-pskip=1:subq=6:8x8dct=0:trellis=0 OUTPUT
2086 Encoding ffpresets for common usages are provided so they can be used with the
2087 general presets system (e.g. passing the @option{pre} option).
2091 x265 H.265/HEVC encoder wrapper.
2093 This encoder requires the presence of the libx265 headers and library
2094 during configuration. You need to explicitly configure the build with
2095 @option{--enable-libx265}.
2101 Set the x265 preset.
2104 Set the x265 tune parameter.
2107 Normally, when forcing a I-frame type, the encoder can select any type
2108 of I-frame. This option forces it to choose an IDR-frame.
2111 Set x265 options using a list of @var{key}=@var{value} couples separated
2112 by ":". See @command{x265 --help} for a list of options.
2114 For example to specify libx265 encoding options with @option{-x265-params}:
2117 ffmpeg -i input -c:v libx265 -x265-params crf=26:psy-rd=1 output.mp4
2123 Xvid MPEG-4 Part 2 encoder wrapper.
2125 This encoder requires the presence of the libxvidcore headers and library
2126 during configuration. You need to explicitly configure the build with
2127 @code{--enable-libxvid --enable-gpl}.
2129 The native @code{mpeg4} encoder supports the MPEG-4 Part 2 format, so
2130 users can encode to this format without this library.
2134 The following options are supported by the libxvid wrapper. Some of
2135 the following options are listed but are not documented, and
2136 correspond to shared codec options. See @ref{codec-options,,the Codec
2137 Options chapter} for their documentation. The other shared options
2138 which are not listed have no effect for the libxvid encoder.
2160 Set specific encoding flags. Possible values:
2165 Use four motion vector by macroblock.
2168 Enable high quality AC prediction.
2171 Only encode grayscale.
2174 Enable the use of global motion compensation (GMC).
2177 Enable quarter-pixel motion compensation.
2183 Place global headers in extradata instead of every keyframe.
2190 Set motion estimation method. Possible values in decreasing order of
2191 speed and increasing order of quality:
2195 Use no motion estimation (default).
2200 Enable advanced diamond zonal search for 16x16 blocks and half-pixel
2201 refinement for 16x16 blocks. @samp{x1} and @samp{log} are aliases for
2205 Enable all of the things described above, plus advanced diamond zonal
2206 search for 8x8 blocks, half-pixel refinement for 8x8 blocks, and motion
2207 estimation on chroma planes.
2210 Enable all of the things described above, plus extended 16x16 and 8x8
2215 Set macroblock decision algorithm. Possible values in the increasing
2220 Use macroblock comparing function algorithm (default).
2223 Enable rate distortion-based half pixel and quarter pixel refinement for
2227 Enable all of the things described above, plus rate distortion-based
2228 half pixel and quarter pixel refinement for 8x8 blocks, and rate
2229 distortion-based search using square pattern.
2233 Enable lumi masking adaptive quantization when set to 1. Default is 0
2237 Enable variance adaptive quantization when set to 1. Default is 0
2240 When combined with @option{lumi_aq}, the resulting quality will not
2241 be better than any of the two specified individually. In other
2242 words, the resulting quality will be the worse one of the two
2246 Set structural similarity (SSIM) displaying method. Possible values:
2250 Disable displaying of SSIM information.
2253 Output average SSIM at the end of encoding to stdout. The format of
2254 showing the average SSIM is:
2260 For users who are not familiar with C, %f means a float number, or
2261 a decimal (e.g. 0.939232).
2264 Output both per-frame SSIM data during encoding and average SSIM at
2265 the end of encoding to stdout. The format of per-frame information
2269 SSIM: avg: %1.3f min: %1.3f max: %1.3f
2272 For users who are not familiar with C, %1.3f means a float number
2273 rounded to 3 digits after the dot (e.g. 0.932).
2278 Set SSIM accuracy. Valid options are integers within the range of
2279 0-4, while 0 gives the most accurate result and 4 computes the
2286 MPEG-2 video encoder.
2291 @item seq_disp_ext @var{integer}
2292 Specifies if the encoder should write a sequence_display_extension to the
2297 Decide automatically to write it or not (this is the default) by checking if
2298 the data to be written is different from the default or unspecified values.
2312 @subsection Private options
2315 @item dpi @var{integer}
2316 Set physical density of pixels, in dots per inch, unset by default
2317 @item dpm @var{integer}
2318 Set physical density of pixels, in dots per meter, unset by default
2323 Apple ProRes encoder.
2325 FFmpeg contains 2 ProRes encoders, the prores-aw and prores-ks encoder.
2326 The used encoder can be chosen with the @code{-vcodec} option.
2328 @subsection Private Options for prores-ks
2331 @item profile @var{integer}
2332 Select the ProRes profile to encode
2341 @item quant_mat @var{integer}
2342 Select quantization matrix.
2351 If set to @var{auto}, the matrix matching the profile will be picked.
2352 If not set, the matrix providing the highest quality, @var{default}, will be
2355 @item bits_per_mb @var{integer}
2356 How many bits to allot for coding one macroblock. Different profiles use
2357 between 200 and 2400 bits per macroblock, the maximum is 8000.
2359 @item mbs_per_slice @var{integer}
2360 Number of macroblocks in each slice (1-8); the default value (8)
2361 should be good in almost all situations.
2363 @item vendor @var{string}
2364 Override the 4-byte vendor ID.
2365 A custom vendor ID like @var{apl0} would claim the stream was produced by
2368 @item alpha_bits @var{integer}
2369 Specify number of bits for alpha component.
2370 Possible values are @var{0}, @var{8} and @var{16}.
2371 Use @var{0} to disable alpha plane coding.
2375 @subsection Speed considerations
2377 In the default mode of operation the encoder has to honor frame constraints
2378 (i.e. not produce frames with size bigger than requested) while still making
2379 output picture as good as possible.
2380 A frame containing a lot of small details is harder to compress and the encoder
2381 would spend more time searching for appropriate quantizers for each slice.
2383 Setting a higher @option{bits_per_mb} limit will improve the speed.
2385 For the fastest encoding speed set the @option{qscale} parameter (4 is the
2386 recommended value) and do not set a size constraint.
2388 @section QSV encoders
2390 The family of Intel QuickSync Video encoders (MPEG-2, H.264 and HEVC)
2392 The ratecontrol method is selected as follows:
2396 When @option{global_quality} is specified, a quality-based mode is used.
2397 Specifically this means either
2400 @var{CQP} - constant quantizer scale, when the @option{qscale} codec flag is
2401 also set (the @option{-qscale} ffmpeg option).
2404 @var{LA_ICQ} - intelligent constant quality with lookahead, when the
2405 @option{look_ahead} option is also set.
2408 @var{ICQ} -- intelligent constant quality otherwise.
2412 Otherwise, a bitrate-based mode is used. For all of those, you should specify at
2413 least the desired average bitrate with the @option{b} option.
2416 @var{LA} - VBR with lookahead, when the @option{look_ahead} option is specified.
2419 @var{VCM} - video conferencing mode, when the @option{vcm} option is set.
2422 @var{CBR} - constant bitrate, when @option{maxrate} is specified and equal to
2423 the average bitrate.
2426 @var{VBR} - variable bitrate, when @option{maxrate} is specified, but is higher
2427 than the average bitrate.
2430 @var{AVBR} - average VBR mode, when @option{maxrate} is not specified. This mode
2431 is further configured by the @option{avbr_accuracy} and
2432 @option{avbr_convergence} options.
2436 Note that depending on your system, a different mode than the one you specified
2437 may be selected by the encoder. Set the verbosity level to @var{verbose} or
2438 higher to see the actual settings used by the QSV runtime.
2440 Additional libavcodec global options are mapped to MSDK options as follows:
2444 @option{g/gop_size} -> @option{GopPicSize}
2447 @option{bf/max_b_frames}+1 -> @option{GopRefDist}
2450 @option{rc_init_occupancy/rc_initial_buffer_occupancy} ->
2451 @option{InitialDelayInKB}
2454 @option{slices} -> @option{NumSlice}
2457 @option{refs} -> @option{NumRefFrame}
2460 @option{b_strategy/b_frame_strategy} -> @option{BRefType}
2463 @option{cgop/CLOSED_GOP} codec flag -> @option{GopOptFlag}
2466 For the @var{CQP} mode, the @option{i_qfactor/i_qoffset} and
2467 @option{b_qfactor/b_qoffset} set the difference between @var{QPP} and @var{QPI},
2468 and @var{QPP} and @var{QPB} respectively.
2471 Setting the @option{coder} option to the value @var{vlc} will make the H.264
2472 encoder use CAVLC instead of CABAC.
2481 @item iterative_dia_size
2482 dia size for the iterative motion estimation
2487 SMPTE VC-2 (previously BBC Dirac Pro). This codec was primarily aimed at
2488 professional broadcasting but since it supports yuv420, yuv422 and yuv444 at
2489 8 (limited range or full range), 10 or 12 bits, this makes it suitable for
2490 other tasks which require low overhead and low compression (like screen
2498 Sets target video bitrate. Usually that's around 1:6 of the uncompressed
2499 video bitrate (e.g. for 1920x1080 50fps yuv422p10 that's around 400Mbps). Higher
2500 values (close to the uncompressed bitrate) turn on lossless compression mode.
2503 Enables field coding when set (e.g. to tt - top field first) for interlaced
2504 inputs. Should increase compression with interlaced content as it splits the
2505 fields and encodes each separately.
2508 Sets the total amount of wavelet transforms to apply, between 1 and 5 (default).
2509 Lower values reduce compression and quality. Less capable decoders may not be
2510 able to handle values of @option{wavelet_depth} over 3.
2513 Sets the transform type. Currently only @var{5_3} (LeGall) and @var{9_7}
2515 are implemented, with 9_7 being the one with better compression and thus
2520 Sets the slice size for each slice. Larger values result in better compression.
2521 For compatibility with other more limited decoders use @option{slice_width} of
2522 32 and @option{slice_height} of 8.
2525 Sets the undershoot tolerance of the rate control system in percent. This is
2526 to prevent an expensive search from being run.
2529 Sets the quantization matrix preset to use by default or when @option{wavelet_depth}
2534 Uses the default quantization matrix from the specifications, extended with
2535 values for the fifth level. This provides a good balance between keeping detail
2536 and omitting artifacts.
2540 Use a completely zeroed out quantization matrix. This increases PSNR but might
2541 reduce perception. Use in bogus benchmarks.
2545 Reduces detail but attempts to preserve color at extremely low bitrates.
2550 @c man end VIDEO ENCODERS
2552 @chapter Subtitles Encoders
2553 @c man begin SUBTITLES ENCODERS
2557 This codec encodes the bitmap subtitle format that is used in DVDs.
2558 Typically they are stored in VOBSUB file pairs (*.idx + *.sub),
2559 and they can also be used in Matroska files.
2565 When set to 1, enable a work-around that makes the number of pixel rows
2566 even in all subtitles. This fixes a problem with some players that
2567 cut off the bottom row if the number is odd. The work-around just adds
2568 a fully transparent row if needed. The overhead is low, typically
2569 one byte per subtitle on average.
2571 By default, this work-around is disabled.
2574 @c man end SUBTITLES ENCODERS