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.
618 libfaac AAC (Advanced Audio Coding) encoder wrapper.
620 This encoder is of much lower quality and is more unstable than any other AAC
621 encoders, so it's highly recommended to instead use other encoders, like
622 @ref{aacenc,,the native FFmpeg AAC encoder}.
624 This encoder also requires the presence of the libfaac headers and library
625 during configuration. You need to explicitly configure the build with
626 @code{--enable-libfaac --enable-nonfree}.
630 The following shared FFmpeg codec options are recognized.
632 The following options are supported by the libfaac wrapper. The
633 @command{faac}-equivalent of the options are listed in parentheses.
637 Set bit rate in bits/s for ABR (Average Bit Rate) mode. If the bit rate
638 is not explicitly specified, it is automatically set to a suitable
639 value depending on the selected profile. @command{faac} bitrate is
640 expressed in kilobits/s.
642 Note that libfaac does not support CBR (Constant Bit Rate) but only
643 ABR (Average Bit Rate).
645 If VBR mode is enabled this option is ignored.
648 Set audio sampling rate (in Hz).
651 Set the number of audio channels.
653 @item cutoff (@emph{-C})
654 Set cutoff frequency. If not specified (or explicitly set to 0) it
655 will use a value automatically computed by the library. Default value
661 The following profiles are recognized:
667 Low Complexity AAC (LC)
670 Scalable Sample Rate (SSR)
673 Long Term Prediction (LTP)
676 If not specified it is set to @samp{aac_low}.
679 Set constant quality VBR (Variable Bit Rate) mode.
682 Set quality in VBR mode as an integer number of lambda units.
684 Only relevant when VBR mode is enabled with @code{flags +qscale}. The
685 value is converted to QP units by dividing it by @code{FF_QP2LAMBDA},
686 and used to set the quality value used by libfaac. A reasonable range
687 for the option value in QP units is [10-500], the higher the value the
691 Enable VBR mode when set to a non-negative value, and set constant
692 quality value as a double floating point value in QP units.
694 The value sets the quality value used by libfaac. A reasonable range
695 for the option value is [10-500], the higher the value the higher the
698 This option is valid only using the @command{ffmpeg} command-line
699 tool. For library interface users, use @option{global_quality}.
706 Use @command{ffmpeg} to convert an audio file to ABR 128 kbps AAC in an M4A (MP4)
709 ffmpeg -i input.wav -codec:a libfaac -b:a 128k -output.m4a
713 Use @command{ffmpeg} to convert an audio file to VBR AAC, using the
716 ffmpeg -i input.wav -c:a libfaac -profile:a aac_ltp -q:a 100 output.m4a
720 @anchor{libfdk-aac-enc}
723 libfdk-aac AAC (Advanced Audio Coding) encoder wrapper.
725 The libfdk-aac library is based on the Fraunhofer FDK AAC code from
728 Requires the presence of the libfdk-aac headers and library during
729 configuration. You need to explicitly configure the build with
730 @code{--enable-libfdk-aac}. The library is also incompatible with GPL,
731 so if you allow the use of GPL, you should configure with
732 @code{--enable-gpl --enable-nonfree --enable-libfdk-aac}.
734 This encoder is considered to produce output on par or worse at 128kbps to the
735 @ref{aacenc,,the native FFmpeg AAC encoder} but can often produce better
736 sounding audio at identical or lower bitrates and has support for the
739 VBR encoding, enabled through the @option{vbr} or @option{flags
740 +qscale} options, is experimental and only works with some
741 combinations of parameters.
743 Support for encoding 7.1 audio is only available with libfdk-aac 0.1.3 or
746 For more information see the fdk-aac project at
747 @url{http://sourceforge.net/p/opencore-amr/fdk-aac/}.
751 The following options are mapped on the shared FFmpeg codec options.
755 Set bit rate in bits/s. If the bitrate is not explicitly specified, it
756 is automatically set to a suitable value depending on the selected
759 In case VBR mode is enabled the option is ignored.
762 Set audio sampling rate (in Hz).
765 Set the number of audio channels.
768 Enable fixed quality, VBR (Variable Bit Rate) mode.
769 Note that VBR is implicitly enabled when the @option{vbr} value is
773 Set cutoff frequency. If not specified (or explicitly set to 0) it
774 will use a value automatically computed by the library. Default value
780 The following profiles are recognized:
783 Low Complexity AAC (LC)
786 High Efficiency AAC (HE-AAC)
789 High Efficiency AAC version 2 (HE-AACv2)
795 Enhanced Low Delay AAC (ELD)
798 If not specified it is set to @samp{aac_low}.
801 The following are private options of the libfdk_aac encoder.
805 Enable afterburner feature if set to 1, disabled if set to 0. This
806 improves the quality but also the required processing power.
811 Enable SBR (Spectral Band Replication) for ELD if set to 1, disabled
817 Set SBR/PS signaling style.
819 It can assume one of the following values:
822 choose signaling implicitly (explicit hierarchical by default,
823 implicit if global header is disabled)
826 implicit backwards compatible signaling
829 explicit SBR, implicit PS signaling
831 @item explicit_hierarchical
832 explicit hierarchical signaling
835 Default value is @samp{default}.
838 Output LATM/LOAS encapsulated data if set to 1, disabled if set to 0.
843 Set StreamMuxConfig and PCE repetition period (in frames) for sending
844 in-band configuration buffers within LATM/LOAS transport layer.
846 Must be a 16-bits non-negative integer.
851 Set VBR mode, from 1 to 5. 1 is lowest quality (though still pretty
852 good) and 5 is highest quality. A value of 0 will disable VBR, and CBR
853 (Constant Bit Rate) is enabled.
855 Currently only the @samp{aac_low} profile supports VBR encoding.
857 VBR modes 1-5 correspond to roughly the following average bit rates:
869 about 80-96 kbps/channel
879 Use @command{ffmpeg} to convert an audio file to VBR AAC in an M4A (MP4)
882 ffmpeg -i input.wav -codec:a libfdk_aac -vbr 3 output.m4a
886 Use @command{ffmpeg} to convert an audio file to CBR 64k kbps AAC, using the
887 High-Efficiency AAC profile:
889 ffmpeg -i input.wav -c:a libfdk_aac -profile:a aac_he -b:a 64k output.m4a
896 LAME (Lame Ain't an MP3 Encoder) MP3 encoder wrapper.
898 Requires the presence of the libmp3lame headers and library during
899 configuration. You need to explicitly configure the build with
900 @code{--enable-libmp3lame}.
902 See @ref{libshine} for a fixed-point MP3 encoder, although with a
907 The following options are supported by the libmp3lame wrapper. The
908 @command{lame}-equivalent of the options are listed in parentheses.
912 Set bitrate expressed in bits/s for CBR or ABR. LAME @code{bitrate} is
913 expressed in kilobits/s.
916 Set constant quality setting for VBR. This option is valid only
917 using the @command{ffmpeg} command-line tool. For library interface
918 users, use @option{global_quality}.
920 @item compression_level (@emph{-q})
921 Set algorithm quality. Valid arguments are integers in the 0-9 range,
922 with 0 meaning highest quality but slowest, and 9 meaning fastest
923 while producing the worst quality.
926 Enable use of bit reservoir when set to 1. Default value is 1. LAME
927 has this enabled by default, but can be overridden by use
928 @option{--nores} option.
930 @item joint_stereo (@emph{-m j})
931 Enable the encoder to use (on a frame by frame basis) either L/R
932 stereo or mid/side stereo. Default value is 1.
934 @item abr (@emph{--abr})
935 Enable the encoder to use ABR when set to 1. The @command{lame}
936 @option{--abr} sets the target bitrate, while this options only
937 tells FFmpeg to use ABR still relies on @option{b} to set bitrate.
941 @section libopencore-amrnb
943 OpenCORE Adaptive Multi-Rate Narrowband encoder.
945 Requires the presence of the libopencore-amrnb headers and library during
946 configuration. You need to explicitly configure the build with
947 @code{--enable-libopencore-amrnb --enable-version3}.
949 This is a mono-only encoder. Officially it only supports 8000Hz sample rate,
950 but you can override it by setting @option{strict} to @samp{unofficial} or
958 Set bitrate in bits per second. Only the following bitrates are supported,
959 otherwise libavcodec will round to the nearest valid bitrate.
973 Allow discontinuous transmission (generate comfort noise) when set to 1. The
974 default value is 0 (disabled).
981 Shine Fixed-Point MP3 encoder wrapper.
983 Shine is a fixed-point MP3 encoder. It has a far better performance on
984 platforms without an FPU, e.g. armel CPUs, and some phones and tablets.
985 However, as it is more targeted on performance than quality, it is not on par
986 with LAME and other production-grade encoders quality-wise. Also, according to
987 the project's homepage, this encoder may not be free of bugs as the code was
988 written a long time ago and the project was dead for at least 5 years.
990 This encoder only supports stereo and mono input. This is also CBR-only.
992 The original project (last updated in early 2007) is at
993 @url{http://sourceforge.net/projects/libshine-fxp/}. We only support the
994 updated fork by the Savonet/Liquidsoap project at @url{https://github.com/savonet/shine}.
996 Requires the presence of the libshine headers and library during
997 configuration. You need to explicitly configure the build with
998 @code{--enable-libshine}.
1000 See also @ref{libmp3lame}.
1004 The following options are supported by the libshine wrapper. The
1005 @command{shineenc}-equivalent of the options are listed in parentheses.
1009 Set bitrate expressed in bits/s for CBR. @command{shineenc} @option{-b} option
1010 is expressed in kilobits/s.
1016 TwoLAME MP2 encoder wrapper.
1018 Requires the presence of the libtwolame headers and library during
1019 configuration. You need to explicitly configure the build with
1020 @code{--enable-libtwolame}.
1024 The following options are supported by the libtwolame wrapper. The
1025 @command{twolame}-equivalent options follow the FFmpeg ones and are in
1030 Set bitrate expressed in bits/s for CBR. @command{twolame} @option{b}
1031 option is expressed in kilobits/s. Default value is 128k.
1034 Set quality for experimental VBR support. Maximum value range is
1035 from -50 to 50, useful range is from -10 to 10. The higher the
1036 value, the better the quality. This option is valid only using the
1037 @command{ffmpeg} command-line tool. For library interface users,
1038 use @option{global_quality}.
1040 @item mode (@emph{--mode})
1041 Set the mode of the resulting audio. Possible values:
1045 Choose mode automatically based on the input. This is the default.
1056 @item psymodel (@emph{--psyc-mode})
1057 Set psychoacoustic model to use in encoding. The argument must be
1058 an integer between -1 and 4, inclusive. The higher the value, the
1059 better the quality. The default value is 3.
1061 @item energy_levels (@emph{--energy})
1062 Enable energy levels extensions when set to 1. The default value is
1065 @item error_protection (@emph{--protect})
1066 Enable CRC error protection when set to 1. The default value is 0
1069 @item copyright (@emph{--copyright})
1070 Set MPEG audio copyright flag when set to 1. The default value is 0
1073 @item original (@emph{--original})
1074 Set MPEG audio original flag when set to 1. The default value is 0
1079 @section libvo-amrwbenc
1081 VisualOn Adaptive Multi-Rate Wideband encoder.
1083 Requires the presence of the libvo-amrwbenc headers and library during
1084 configuration. You need to explicitly configure the build with
1085 @code{--enable-libvo-amrwbenc --enable-version3}.
1087 This is a mono-only encoder. Officially it only supports 16000Hz sample
1088 rate, but you can override it by setting @option{strict} to
1089 @samp{unofficial} or lower.
1096 Set bitrate in bits/s. Only the following bitrates are supported, otherwise
1097 libavcodec will round to the nearest valid bitrate.
1112 Allow discontinuous transmission (generate comfort noise) when set to 1. The
1113 default value is 0 (disabled).
1119 libopus Opus Interactive Audio Codec encoder wrapper.
1121 Requires the presence of the libopus headers and library during
1122 configuration. You need to explicitly configure the build with
1123 @code{--enable-libopus}.
1125 @subsection Option Mapping
1127 Most libopus options are modelled after the @command{opusenc} utility from
1128 opus-tools. The following is an option mapping chart describing options
1129 supported by the libopus wrapper, and their @command{opusenc}-equivalent
1134 @item b (@emph{bitrate})
1135 Set the bit rate in bits/s. FFmpeg's @option{b} option is
1136 expressed in bits/s, while @command{opusenc}'s @option{bitrate} in
1139 @item vbr (@emph{vbr}, @emph{hard-cbr}, and @emph{cvbr})
1140 Set VBR mode. The FFmpeg @option{vbr} option has the following
1141 valid arguments, with the @command{opusenc} equivalent options
1145 @item off (@emph{hard-cbr})
1146 Use constant bit rate encoding.
1148 @item on (@emph{vbr})
1149 Use variable bit rate encoding (the default).
1151 @item constrained (@emph{cvbr})
1152 Use constrained variable bit rate encoding.
1155 @item compression_level (@emph{comp})
1156 Set encoding algorithm complexity. Valid options are integers in
1157 the 0-10 range. 0 gives the fastest encodes but lower quality, while 10
1158 gives the highest quality but slowest encoding. The default is 10.
1160 @item frame_duration (@emph{framesize})
1161 Set maximum frame size, or duration of a frame in milliseconds. The
1162 argument must be exactly the following: 2.5, 5, 10, 20, 40, 60. Smaller
1163 frame sizes achieve lower latency but less quality at a given bitrate.
1164 Sizes greater than 20ms are only interesting at fairly low bitrates.
1165 The default is 20ms.
1167 @item packet_loss (@emph{expect-loss})
1168 Set expected packet loss percentage. The default is 0.
1170 @item application (N.A.)
1171 Set intended application type. Valid options are listed below:
1175 Favor improved speech intelligibility.
1177 Favor faithfulness to the input (the default).
1179 Restrict to only the lowest delay modes.
1183 Set cutoff bandwidth in Hz. The argument must be exactly one of the
1184 following: 4000, 6000, 8000, 12000, or 20000, corresponding to
1185 narrowband, mediumband, wideband, super wideband, and fullband
1186 respectively. The default is 0 (cutoff disabled).
1188 @item mapping_family (@emph{mapping_family})
1189 Set channel mapping family to be used by the encoder. The default value of -1
1190 uses mapping family 0 for mono and stereo inputs, and mapping family 1
1191 otherwise. The default also disables the surround masking and LFE bandwidth
1192 optimzations in libopus, and requires that the input contains 8 channels or
1195 Other values include 0 for mono and stereo, 1 for surround sound with masking
1196 and LFE bandwidth optimizations, and 255 for independent streams with an
1197 unspecified channel layout.
1203 libvorbis encoder wrapper.
1205 Requires the presence of the libvorbisenc headers and library during
1206 configuration. You need to explicitly configure the build with
1207 @code{--enable-libvorbis}.
1211 The following options are supported by the libvorbis wrapper. The
1212 @command{oggenc}-equivalent of the options are listed in parentheses.
1214 To get a more accurate and extensive documentation of the libvorbis
1215 options, consult the libvorbisenc's and @command{oggenc}'s documentations.
1216 See @url{http://xiph.org/vorbis/},
1217 @url{http://wiki.xiph.org/Vorbis-tools}, and oggenc(1).
1221 Set bitrate expressed in bits/s for ABR. @command{oggenc} @option{-b} is
1222 expressed in kilobits/s.
1225 Set constant quality setting for VBR. The value should be a float
1226 number in the range of -1.0 to 10.0. The higher the value, the better
1227 the quality. The default value is @samp{3.0}.
1229 This option is valid only using the @command{ffmpeg} command-line tool.
1230 For library interface users, use @option{global_quality}.
1232 @item cutoff (@emph{--advanced-encode-option lowpass_frequency=N})
1233 Set cutoff bandwidth in Hz, a value of 0 disables cutoff. @command{oggenc}'s
1234 related option is expressed in kHz. The default value is @samp{0} (cutoff
1237 @item minrate (@emph{-m})
1238 Set minimum bitrate expressed in bits/s. @command{oggenc} @option{-m} is
1239 expressed in kilobits/s.
1241 @item maxrate (@emph{-M})
1242 Set maximum bitrate expressed in bits/s. @command{oggenc} @option{-M} is
1243 expressed in kilobits/s. This only has effect on ABR mode.
1245 @item iblock (@emph{--advanced-encode-option impulse_noisetune=N})
1246 Set noise floor bias for impulse blocks. The value is a float number from
1247 -15.0 to 0.0. A negative bias instructs the encoder to pay special attention
1248 to the crispness of transients in the encoded audio. The tradeoff for better
1249 transient response is a higher bitrate.
1256 A wrapper providing WavPack encoding through libwavpack.
1258 Only lossless mode using 32-bit integer samples is supported currently.
1260 Requires the presence of the libwavpack headers and library during
1261 configuration. You need to explicitly configure the build with
1262 @code{--enable-libwavpack}.
1264 Note that a libavcodec-native encoder for the WavPack codec exists so users can
1265 encode audios with this codec without using this encoder. See @ref{wavpackenc}.
1269 @command{wavpack} command line utility's corresponding options are listed in
1270 parentheses, if any.
1273 @item frame_size (@emph{--blocksize})
1276 @item compression_level
1277 Set speed vs. compression tradeoff. Acceptable arguments are listed below:
1284 Normal (default) settings.
1289 @item 3 (@emph{-hh})
1292 @item 4-8 (@emph{-hh -x}@var{EXTRAPROC})
1293 Same as @samp{3}, but with extra processing enabled.
1295 @samp{4} is the same as @option{-x2} and @samp{8} is the same as @option{-x6}.
1303 WavPack lossless audio encoder.
1305 This is a libavcodec-native WavPack encoder. There is also an encoder based on
1306 libwavpack, but there is virtually no reason to use that encoder.
1308 See also @ref{libwavpack}.
1312 The equivalent options for @command{wavpack} command line utility are listed in
1315 @subsubsection Shared options
1317 The following shared options are effective for this encoder. Only special notes
1318 about this particular encoder will be documented here. For the general meaning
1319 of the options, see @ref{codec-options,,the Codec Options chapter}.
1322 @item frame_size (@emph{--blocksize})
1323 For this encoder, the range for this option is between 128 and 131072. Default
1324 is automatically decided based on sample rate and number of channel.
1326 For the complete formula of calculating default, see
1327 @file{libavcodec/wavpackenc.c}.
1329 @item compression_level (@emph{-f}, @emph{-h}, @emph{-hh}, and @emph{-x})
1330 This option's syntax is consistent with @ref{libwavpack}'s.
1333 @subsubsection Private options
1336 @item joint_stereo (@emph{-j})
1337 Set whether to enable joint stereo. Valid values are:
1341 Force mid/side audio encoding.
1342 @item off (@emph{0})
1343 Force left/right audio encoding.
1345 Let the encoder decide automatically.
1349 Set whether to enable optimization for mono. This option is only effective for
1350 non-mono streams. Available values:
1361 @c man end AUDIO ENCODERS
1363 @chapter Video Encoders
1364 @c man begin VIDEO ENCODERS
1366 A description of some of the currently available video encoders
1369 @section libopenh264
1371 Cisco libopenh264 H.264/MPEG-4 AVC encoder wrapper.
1373 This encoder requires the presence of the libopenh264 headers and
1374 library during configuration. You need to explicitly configure the
1375 build with @code{--enable-libopenh264}. The library is detected using
1376 @command{pkg-config}.
1378 For more information about the library see
1379 @url{http://www.openh264.org}.
1383 The following FFmpeg global options affect the configurations of the
1384 libopenh264 encoder.
1388 Set the bitrate (as a number of bits per second).
1394 Set the max bitrate (as a number of bits per second).
1396 @item flags +global_header
1397 Set global header in the bitstream.
1400 Set the number of slices, used in parallelized encoding. Default value
1401 is 0. This is only used when @option{slice_mode} is set to
1405 Set slice mode. Can assume one of the following possible values:
1409 a fixed number of slices
1411 one slice per row of macroblocks
1413 automatic number of slices according to number of threads
1418 Default value is @samp{auto}.
1421 Enable loop filter, if set to 1 (automatically enabled). To disable
1425 Set profile restrictions. If set to the value of @samp{main} enable
1426 CABAC (set the @code{SEncParamExt.iEntropyCodingModeFlag} flag to 1).
1429 Set maximum NAL size in bytes.
1431 @item allow_skip_frames
1432 Allow skipping frames to hit the target bitrate if set to 1.
1437 The native jpeg 2000 encoder is lossy by default, the @code{-q:v}
1438 option can be used to set the encoding quality. Lossless encoding
1439 can be selected with @code{-pred 1}.
1445 Can be set to either @code{j2k} or @code{jp2} (the default) that
1446 makes it possible to store non-rgb pix_fmts.
1455 @item iterative_dia_size
1456 dia size for the iterative motion estimation
1461 libtheora Theora encoder wrapper.
1463 Requires the presence of the libtheora headers and library during
1464 configuration. You need to explicitly configure the build with
1465 @code{--enable-libtheora}.
1467 For more information about the libtheora project see
1468 @url{http://www.theora.org/}.
1472 The following global options are mapped to internal libtheora options
1473 which affect the quality and the bitrate of the encoded stream.
1477 Set the video bitrate in bit/s for CBR (Constant Bit Rate) mode. In
1478 case VBR (Variable Bit Rate) mode is enabled this option is ignored.
1481 Used to enable constant quality mode (VBR) encoding through the
1482 @option{qscale} flag, and to enable the @code{pass1} and @code{pass2}
1488 @item global_quality
1489 Set the global quality as an integer in lambda units.
1491 Only relevant when VBR mode is enabled with @code{flags +qscale}. The
1492 value is converted to QP units by dividing it by @code{FF_QP2LAMBDA},
1493 clipped in the [0 - 10] range, and then multiplied by 6.3 to get a
1494 value in the native libtheora range [0-63]. A higher value corresponds
1495 to a higher quality.
1498 Enable VBR mode when set to a non-negative value, and set constant
1499 quality value as a double floating point value in QP units.
1501 The value is clipped in the [0-10] range, and then multiplied by 6.3
1502 to get a value in the native libtheora range [0-63].
1504 This option is valid only using the @command{ffmpeg} command-line
1505 tool. For library interface users, use @option{global_quality}.
1508 @subsection Examples
1512 Set maximum constant quality (VBR) encoding with @command{ffmpeg}:
1514 ffmpeg -i INPUT -codec:v libtheora -q:v 10 OUTPUT.ogg
1518 Use @command{ffmpeg} to convert a CBR 1000 kbps Theora video stream:
1520 ffmpeg -i INPUT -codec:v libtheora -b:v 1000k OUTPUT.ogg
1526 VP8/VP9 format supported through libvpx.
1528 Requires the presence of the libvpx headers and library during configuration.
1529 You need to explicitly configure the build with @code{--enable-libvpx}.
1533 The following options are supported by the libvpx wrapper. The
1534 @command{vpxenc}-equivalent options or values are listed in parentheses
1537 To reduce the duplication of documentation, only the private options
1538 and some others requiring special attention are documented here. For
1539 the documentation of the undocumented generic options, see
1540 @ref{codec-options,,the Codec Options chapter}.
1542 To get more documentation of the libvpx options, invoke the command
1543 @command{ffmpeg -h encoder=libvpx}, @command{ffmpeg -h encoder=libvpx-vp9} or
1544 @command{vpxenc --help}. Further information is available in the libvpx API
1549 @item b (@emph{target-bitrate})
1550 Set bitrate in bits/s. Note that FFmpeg's @option{b} option is
1551 expressed in bits/s, while @command{vpxenc}'s @option{target-bitrate} is in
1554 @item g (@emph{kf-max-dist})
1556 @item keyint_min (@emph{kf-min-dist})
1558 @item qmin (@emph{min-q})
1560 @item qmax (@emph{max-q})
1562 @item bufsize (@emph{buf-sz}, @emph{buf-optimal-sz})
1563 Set ratecontrol buffer size (in bits). Note @command{vpxenc}'s options are
1564 specified in milliseconds, the libvpx wrapper converts this value as follows:
1565 @code{buf-sz = bufsize * 1000 / bitrate},
1566 @code{buf-optimal-sz = bufsize * 1000 / bitrate * 5 / 6}.
1568 @item rc_init_occupancy (@emph{buf-initial-sz})
1569 Set number of bits which should be loaded into the rc buffer before decoding
1570 starts. Note @command{vpxenc}'s option is specified in milliseconds, the libvpx
1571 wrapper converts this value as follows:
1572 @code{rc_init_occupancy * 1000 / bitrate}.
1574 @item undershoot-pct
1575 Set datarate undershoot (min) percentage of the target bitrate.
1578 Set datarate overshoot (max) percentage of the target bitrate.
1580 @item skip_threshold (@emph{drop-frame})
1582 @item qcomp (@emph{bias-pct})
1584 @item maxrate (@emph{maxsection-pct})
1585 Set GOP max bitrate in bits/s. Note @command{vpxenc}'s option is specified as a
1586 percentage of the target bitrate, the libvpx wrapper converts this value as
1587 follows: @code{(maxrate * 100 / bitrate)}.
1589 @item minrate (@emph{minsection-pct})
1590 Set GOP min bitrate in bits/s. Note @command{vpxenc}'s option is specified as a
1591 percentage of the target bitrate, the libvpx wrapper converts this value as
1592 follows: @code{(minrate * 100 / bitrate)}.
1594 @item minrate, maxrate, b @emph{end-usage=cbr}
1595 @code{(minrate == maxrate == bitrate)}.
1597 @item crf (@emph{end-usage=cq}, @emph{cq-level})
1599 @item tune (@emph{tune})
1601 @item psnr (@emph{psnr})
1602 @item ssim (@emph{ssim})
1605 @item quality, deadline (@emph{deadline})
1608 Use best quality deadline. Poorly named and quite slow, this option should be
1609 avoided as it may give worse quality output than good.
1611 Use good quality deadline. This is a good trade-off between speed and quality
1612 when used with the @option{cpu-used} option.
1614 Use realtime quality deadline.
1617 @item speed, cpu-used (@emph{cpu-used})
1618 Set quality/speed ratio modifier. Higher values speed up the encode at the cost
1621 @item nr (@emph{noise-sensitivity})
1624 Set a change threshold on blocks below which they will be skipped by the
1627 @item slices (@emph{token-parts})
1628 Note that FFmpeg's @option{slices} option gives the total number of partitions,
1629 while @command{vpxenc}'s @option{token-parts} is given as
1630 @code{log2(partitions)}.
1632 @item max-intra-rate
1633 Set maximum I-frame bitrate as a percentage of the target bitrate. A value of 0
1636 @item force_key_frames
1637 @code{VPX_EFLAG_FORCE_KF}
1639 @item Alternate reference frame related
1642 Enable use of alternate reference frames (2-pass only).
1643 @item arnr-max-frames
1644 Set altref noise reduction max frame count.
1646 Set altref noise reduction filter type: backward, forward, centered.
1648 Set altref noise reduction filter strength.
1649 @item rc-lookahead, lag-in-frames (@emph{lag-in-frames})
1650 Set number of frames to look ahead for frametype and ratecontrol.
1653 @item error-resilient
1654 Enable error resiliency features.
1656 @item VP9-specific options
1659 Enable lossless mode.
1661 Set number of tile columns to use. Note this is given as
1662 @code{log2(tile_columns)}. For example, 8 tile columns would be requested by
1663 setting the @option{tile-columns} option to 3.
1665 Set number of tile rows to use. Note this is given as @code{log2(tile_rows)}.
1666 For example, 4 tile rows would be requested by setting the @option{tile-rows}
1668 @item frame-parallel
1669 Enable frame parallel decodability features.
1671 Set adaptive quantization mode (0: off (default), 1: variance 2: complexity, 3:
1673 @item colorspace @emph{color-space}
1674 Set input color space. The VP9 bitstream supports signaling the following
1677 @item @samp{rgb} @emph{sRGB}
1678 @item @samp{bt709} @emph{bt709}
1679 @item @samp{unspecified} @emph{unknown}
1680 @item @samp{bt470bg} @emph{bt601}
1681 @item @samp{smpte170m} @emph{smpte170}
1682 @item @samp{smpte240m} @emph{smpte240}
1683 @item @samp{bt2020_ncl} @emph{bt2020}
1689 For more information about libvpx see:
1690 @url{http://www.webmproject.org/}
1695 libwebp WebP Image encoder wrapper
1697 libwebp is Google's official encoder for WebP images. It can encode in either
1698 lossy or lossless mode. Lossy images are essentially a wrapper around a VP8
1699 frame. Lossless images are a separate codec developed by Google.
1701 @subsection Pixel Format
1703 Currently, libwebp only supports YUV420 for lossy and RGB for lossless due
1704 to limitations of the format and libwebp. Alpha is supported for either mode.
1705 Because of API limitations, if RGB is passed in when encoding lossy or YUV is
1706 passed in for encoding lossless, the pixel format will automatically be
1707 converted using functions from libwebp. This is not ideal and is done only for
1714 @item -lossless @var{boolean}
1715 Enables/Disables use of lossless mode. Default is 0.
1717 @item -compression_level @var{integer}
1718 For lossy, this is a quality/speed tradeoff. Higher values give better quality
1719 for a given size at the cost of increased encoding time. For lossless, this is
1720 a size/speed tradeoff. Higher values give smaller size at the cost of increased
1721 encoding time. More specifically, it controls the number of extra algorithms
1722 and compression tools used, and varies the combination of these tools. This
1723 maps to the @var{method} option in libwebp. The valid range is 0 to 6.
1726 @item -qscale @var{float}
1727 For lossy encoding, this controls image quality, 0 to 100. For lossless
1728 encoding, this controls the effort and time spent at compressing more. The
1729 default value is 75. Note that for usage via libavcodec, this option is called
1730 @var{global_quality} and must be multiplied by @var{FF_QP2LAMBDA}.
1732 @item -preset @var{type}
1733 Configuration preset. This does some automatic settings based on the general
1737 Do not use a preset.
1739 Use the encoder default.
1741 Digital picture, like portrait, inner shot
1743 Outdoor photograph, with natural lighting
1745 Hand or line drawing, with high-contrast details
1747 Small-sized colorful images
1754 @section libx264, libx264rgb
1756 x264 H.264/MPEG-4 AVC encoder wrapper.
1758 This encoder requires the presence of the libx264 headers and library
1759 during configuration. You need to explicitly configure the build with
1760 @code{--enable-libx264}.
1762 libx264 supports an impressive number of features, including 8x8 and
1763 4x4 adaptive spatial transform, adaptive B-frame placement, CAVLC/CABAC
1764 entropy coding, interlacing (MBAFF), lossless mode, psy optimizations
1765 for detail retention (adaptive quantization, psy-RD, psy-trellis).
1767 Many libx264 encoder options are mapped to FFmpeg global codec
1768 options, while unique encoder options are provided through private
1769 options. Additionally the @option{x264opts} and @option{x264-params}
1770 private options allows one to pass a list of key=value tuples as accepted
1771 by the libx264 @code{x264_param_parse} function.
1773 The x264 project website is at
1774 @url{http://www.videolan.org/developers/x264.html}.
1776 The libx264rgb encoder is the same as libx264, except it accepts packed RGB
1777 pixel formats as input instead of YUV.
1779 @subsection Supported Pixel Formats
1781 x264 supports 8- to 10-bit color spaces. The exact bit depth is controlled at
1782 x264's configure time. FFmpeg only supports one bit depth in one particular
1783 build. In other words, it is not possible to build one FFmpeg with multiple
1784 versions of x264 with different bit depths.
1788 The following options are supported by the libx264 wrapper. The
1789 @command{x264}-equivalent options or values are listed in parentheses
1792 To reduce the duplication of documentation, only the private options
1793 and some others requiring special attention are documented here. For
1794 the documentation of the undocumented generic options, see
1795 @ref{codec-options,,the Codec Options chapter}.
1797 To get a more accurate and extensive documentation of the libx264
1798 options, invoke the command @command{x264 --full-help} or consult
1799 the libx264 documentation.
1802 @item b (@emph{bitrate})
1803 Set bitrate in bits/s. Note that FFmpeg's @option{b} option is
1804 expressed in bits/s, while @command{x264}'s @option{bitrate} is in
1807 @item bf (@emph{bframes})
1809 @item g (@emph{keyint})
1811 @item qmin (@emph{qpmin})
1812 Minimum quantizer scale.
1814 @item qmax (@emph{qpmax})
1815 Maximum quantizer scale.
1817 @item qdiff (@emph{qpstep})
1818 Maximum difference between quantizer scales.
1820 @item qblur (@emph{qblur})
1821 Quantizer curve blur
1823 @item qcomp (@emph{qcomp})
1824 Quantizer curve compression factor
1826 @item refs (@emph{ref})
1827 Number of reference frames each P-frame can use. The range is from @var{0-16}.
1829 @item sc_threshold (@emph{scenecut})
1830 Sets the threshold for the scene change detection.
1832 @item trellis (@emph{trellis})
1833 Performs Trellis quantization to increase efficiency. Enabled by default.
1835 @item nr (@emph{nr})
1837 @item me_range (@emph{merange})
1838 Maximum range of the motion search in pixels.
1840 @item me_method (@emph{me})
1841 Set motion estimation method. Possible values in the decreasing order
1845 @item dia (@emph{dia})
1846 @item epzs (@emph{dia})
1847 Diamond search with radius 1 (fastest). @samp{epzs} is an alias for
1849 @item hex (@emph{hex})
1850 Hexagonal search with radius 2.
1851 @item umh (@emph{umh})
1852 Uneven multi-hexagon search.
1853 @item esa (@emph{esa})
1855 @item tesa (@emph{tesa})
1856 Hadamard exhaustive search (slowest).
1859 @item subq (@emph{subme})
1860 Sub-pixel motion estimation method.
1862 @item b_strategy (@emph{b-adapt})
1863 Adaptive B-frame placement decision algorithm. Use only on first-pass.
1865 @item keyint_min (@emph{min-keyint})
1869 Set entropy encoder. Possible values:
1876 Enable CAVLC and disable CABAC. It generates the same effect as
1877 @command{x264}'s @option{--no-cabac} option.
1881 Set full pixel motion estimation comparation algorithm. Possible values:
1885 Enable chroma in motion estimation.
1888 Ignore chroma in motion estimation. It generates the same effect as
1889 @command{x264}'s @option{--no-chroma-me} option.
1892 @item threads (@emph{threads})
1893 Number of encoding threads.
1896 Set multithreading technique. Possible values:
1900 Slice-based multithreading. It generates the same effect as
1901 @command{x264}'s @option{--sliced-threads} option.
1903 Frame-based multithreading.
1907 Set encoding flags. It can be used to disable closed GOP and enable
1908 open GOP by setting it to @code{-cgop}. The result is similar to
1909 the behavior of @command{x264}'s @option{--open-gop} option.
1911 @item rc_init_occupancy (@emph{vbv-init})
1913 @item preset (@emph{preset})
1914 Set the encoding preset.
1916 @item tune (@emph{tune})
1917 Set tuning of the encoding params.
1919 @item profile (@emph{profile})
1920 Set profile restrictions.
1923 Enable fast settings when encoding first pass, when set to 1. When set
1924 to 0, it has the same effect of @command{x264}'s
1925 @option{--slow-firstpass} option.
1927 @item crf (@emph{crf})
1928 Set the quality for constant quality mode.
1930 @item crf_max (@emph{crf-max})
1931 In CRF mode, prevents VBV from lowering quality beyond this point.
1933 @item qp (@emph{qp})
1934 Set constant quantization rate control method parameter.
1936 @item aq-mode (@emph{aq-mode})
1937 Set AQ method. Possible values:
1940 @item none (@emph{0})
1943 @item variance (@emph{1})
1944 Variance AQ (complexity mask).
1946 @item autovariance (@emph{2})
1947 Auto-variance AQ (experimental).
1950 @item aq-strength (@emph{aq-strength})
1951 Set AQ strength, reduce blocking and blurring in flat and textured areas.
1954 Use psychovisual optimizations when set to 1. When set to 0, it has the
1955 same effect as @command{x264}'s @option{--no-psy} option.
1957 @item psy-rd (@emph{psy-rd})
1958 Set strength of psychovisual optimization, in
1959 @var{psy-rd}:@var{psy-trellis} format.
1961 @item rc-lookahead (@emph{rc-lookahead})
1962 Set number of frames to look ahead for frametype and ratecontrol.
1965 Enable weighted prediction for B-frames when set to 1. When set to 0,
1966 it has the same effect as @command{x264}'s @option{--no-weightb} option.
1968 @item weightp (@emph{weightp})
1969 Set weighted prediction method for P-frames. Possible values:
1972 @item none (@emph{0})
1974 @item simple (@emph{1})
1975 Enable only weighted refs
1976 @item smart (@emph{2})
1977 Enable both weighted refs and duplicates
1980 @item ssim (@emph{ssim})
1981 Enable calculation and printing SSIM stats after the encoding.
1983 @item intra-refresh (@emph{intra-refresh})
1984 Enable the use of Periodic Intra Refresh instead of IDR frames when set
1987 @item avcintra-class (@emph{class})
1988 Configure the encoder to generate AVC-Intra.
1989 Valid values are 50,100 and 200
1991 @item bluray-compat (@emph{bluray-compat})
1992 Configure the encoder to be compatible with the bluray standard.
1993 It is a shorthand for setting "bluray-compat=1 force-cfr=1".
1995 @item b-bias (@emph{b-bias})
1996 Set the influence on how often B-frames are used.
1998 @item b-pyramid (@emph{b-pyramid})
1999 Set method for keeping of some B-frames as references. Possible values:
2002 @item none (@emph{none})
2004 @item strict (@emph{strict})
2005 Strictly hierarchical pyramid.
2006 @item normal (@emph{normal})
2007 Non-strict (not Blu-ray compatible).
2011 Enable the use of one reference per partition, as opposed to one
2012 reference per macroblock when set to 1. When set to 0, it has the
2013 same effect as @command{x264}'s @option{--no-mixed-refs} option.
2016 Enable adaptive spatial transform (high profile 8x8 transform)
2017 when set to 1. When set to 0, it has the same effect as
2018 @command{x264}'s @option{--no-8x8dct} option.
2021 Enable early SKIP detection on P-frames when set to 1. When set
2022 to 0, it has the same effect as @command{x264}'s
2023 @option{--no-fast-pskip} option.
2025 @item aud (@emph{aud})
2026 Enable use of access unit delimiters when set to 1.
2029 Enable use macroblock tree ratecontrol when set to 1. When set
2030 to 0, it has the same effect as @command{x264}'s
2031 @option{--no-mbtree} option.
2033 @item deblock (@emph{deblock})
2034 Set loop filter parameters, in @var{alpha}:@var{beta} form.
2036 @item cplxblur (@emph{cplxblur})
2037 Set fluctuations reduction in QP (before curve compression).
2039 @item partitions (@emph{partitions})
2040 Set partitions to consider as a comma-separated list of. Possible
2045 8x8 P-frame partition.
2047 4x4 P-frame partition.
2049 4x4 B-frame partition.
2051 8x8 I-frame partition.
2053 4x4 I-frame partition.
2054 (Enabling @samp{p4x4} requires @samp{p8x8} to be enabled. Enabling
2055 @samp{i8x8} requires adaptive spatial transform (@option{8x8dct}
2056 option) to be enabled.)
2057 @item none (@emph{none})
2058 Do not consider any partitions.
2059 @item all (@emph{all})
2060 Consider every partition.
2063 @item direct-pred (@emph{direct})
2064 Set direct MV prediction mode. Possible values:
2067 @item none (@emph{none})
2068 Disable MV prediction.
2069 @item spatial (@emph{spatial})
2070 Enable spatial predicting.
2071 @item temporal (@emph{temporal})
2072 Enable temporal predicting.
2073 @item auto (@emph{auto})
2074 Automatically decided.
2077 @item slice-max-size (@emph{slice-max-size})
2078 Set the limit of the size of each slice in bytes. If not specified
2079 but RTP payload size (@option{ps}) is specified, that is used.
2081 @item stats (@emph{stats})
2082 Set the file name for multi-pass stats.
2084 @item nal-hrd (@emph{nal-hrd})
2085 Set signal HRD information (requires @option{vbv-bufsize} to be set).
2089 @item none (@emph{none})
2090 Disable HRD information signaling.
2091 @item vbr (@emph{vbr})
2093 @item cbr (@emph{cbr})
2094 Constant bit rate (not allowed in MP4 container).
2097 @item x264opts (N.A.)
2098 Set any x264 option, see @command{x264 --fullhelp} for a list.
2100 Argument is a list of @var{key}=@var{value} couples separated by
2101 ":". In @var{filter} and @var{psy-rd} options that use ":" as a separator
2102 themselves, use "," instead. They accept it as well since long ago but this
2103 is kept undocumented for some reason.
2105 For example to specify libx264 encoding options with @command{ffmpeg}:
2107 ffmpeg -i foo.mpg -vcodec libx264 -x264opts keyint=123:min-keyint=20 -an out.mkv
2110 @item a53cc @var{boolean}
2111 Import closed captions (which must be ATSC compatible format) into output.
2112 Only the mpeg2 and h264 decoders provide these. Default is 0 (off).
2114 @item x264-params (N.A.)
2115 Override the x264 configuration using a :-separated list of key=value
2118 This option is functionally the same as the @option{x264opts}, but is
2119 duplicated for compatibility with the Libav fork.
2121 For example to specify libx264 encoding options with @command{ffmpeg}:
2123 ffmpeg -i INPUT -c:v libx264 -x264-params level=30:bframes=0:weightp=0:\
2124 cabac=0:ref=1:vbv-maxrate=768:vbv-bufsize=2000:analyse=all:me=umh:\
2125 no-fast-pskip=1:subq=6:8x8dct=0:trellis=0 OUTPUT
2129 Encoding ffpresets for common usages are provided so they can be used with the
2130 general presets system (e.g. passing the @option{pre} option).
2134 x265 H.265/HEVC encoder wrapper.
2136 This encoder requires the presence of the libx265 headers and library
2137 during configuration. You need to explicitly configure the build with
2138 @option{--enable-libx265}.
2144 Set the x265 preset.
2147 Set the x265 tune parameter.
2150 Set x265 options using a list of @var{key}=@var{value} couples separated
2151 by ":". See @command{x265 --help} for a list of options.
2153 For example to specify libx265 encoding options with @option{-x265-params}:
2156 ffmpeg -i input -c:v libx265 -x265-params crf=26:psy-rd=1 output.mp4
2162 Xvid MPEG-4 Part 2 encoder wrapper.
2164 This encoder requires the presence of the libxvidcore headers and library
2165 during configuration. You need to explicitly configure the build with
2166 @code{--enable-libxvid --enable-gpl}.
2168 The native @code{mpeg4} encoder supports the MPEG-4 Part 2 format, so
2169 users can encode to this format without this library.
2173 The following options are supported by the libxvid wrapper. Some of
2174 the following options are listed but are not documented, and
2175 correspond to shared codec options. See @ref{codec-options,,the Codec
2176 Options chapter} for their documentation. The other shared options
2177 which are not listed have no effect for the libxvid encoder.
2199 Set specific encoding flags. Possible values:
2204 Use four motion vector by macroblock.
2207 Enable high quality AC prediction.
2210 Only encode grayscale.
2213 Enable the use of global motion compensation (GMC).
2216 Enable quarter-pixel motion compensation.
2222 Place global headers in extradata instead of every keyframe.
2229 Set motion estimation method. Possible values in decreasing order of
2230 speed and increasing order of quality:
2234 Use no motion estimation (default).
2239 Enable advanced diamond zonal search for 16x16 blocks and half-pixel
2240 refinement for 16x16 blocks. @samp{x1} and @samp{log} are aliases for
2244 Enable all of the things described above, plus advanced diamond zonal
2245 search for 8x8 blocks, half-pixel refinement for 8x8 blocks, and motion
2246 estimation on chroma planes.
2249 Enable all of the things described above, plus extended 16x16 and 8x8
2254 Set macroblock decision algorithm. Possible values in the increasing
2259 Use macroblock comparing function algorithm (default).
2262 Enable rate distortion-based half pixel and quarter pixel refinement for
2266 Enable all of the things described above, plus rate distortion-based
2267 half pixel and quarter pixel refinement for 8x8 blocks, and rate
2268 distortion-based search using square pattern.
2272 Enable lumi masking adaptive quantization when set to 1. Default is 0
2276 Enable variance adaptive quantization when set to 1. Default is 0
2279 When combined with @option{lumi_aq}, the resulting quality will not
2280 be better than any of the two specified individually. In other
2281 words, the resulting quality will be the worse one of the two
2285 Set structural similarity (SSIM) displaying method. Possible values:
2289 Disable displaying of SSIM information.
2292 Output average SSIM at the end of encoding to stdout. The format of
2293 showing the average SSIM is:
2299 For users who are not familiar with C, %f means a float number, or
2300 a decimal (e.g. 0.939232).
2303 Output both per-frame SSIM data during encoding and average SSIM at
2304 the end of encoding to stdout. The format of per-frame information
2308 SSIM: avg: %1.3f min: %1.3f max: %1.3f
2311 For users who are not familiar with C, %1.3f means a float number
2312 rounded to 3 digits after the dot (e.g. 0.932).
2317 Set SSIM accuracy. Valid options are integers within the range of
2318 0-4, while 0 gives the most accurate result and 4 computes the
2325 MPEG-2 video encoder.
2330 @item seq_disp_ext @var{integer}
2331 Specifies if the encoder should write a sequence_display_extension to the
2336 Decide automatically to write it or not (this is the default) by checking if
2337 the data to be written is different from the default or unspecified values.
2351 @subsection Private options
2354 @item dpi @var{integer}
2355 Set physical density of pixels, in dots per inch, unset by default
2356 @item dpm @var{integer}
2357 Set physical density of pixels, in dots per meter, unset by default
2362 Apple ProRes encoder.
2364 FFmpeg contains 2 ProRes encoders, the prores-aw and prores-ks encoder.
2365 The used encoder can be chosen with the @code{-vcodec} option.
2367 @subsection Private Options for prores-ks
2370 @item profile @var{integer}
2371 Select the ProRes profile to encode
2380 @item quant_mat @var{integer}
2381 Select quantization matrix.
2390 If set to @var{auto}, the matrix matching the profile will be picked.
2391 If not set, the matrix providing the highest quality, @var{default}, will be
2394 @item bits_per_mb @var{integer}
2395 How many bits to allot for coding one macroblock. Different profiles use
2396 between 200 and 2400 bits per macroblock, the maximum is 8000.
2398 @item mbs_per_slice @var{integer}
2399 Number of macroblocks in each slice (1-8); the default value (8)
2400 should be good in almost all situations.
2402 @item vendor @var{string}
2403 Override the 4-byte vendor ID.
2404 A custom vendor ID like @var{apl0} would claim the stream was produced by
2407 @item alpha_bits @var{integer}
2408 Specify number of bits for alpha component.
2409 Possible values are @var{0}, @var{8} and @var{16}.
2410 Use @var{0} to disable alpha plane coding.
2414 @subsection Speed considerations
2416 In the default mode of operation the encoder has to honor frame constraints
2417 (i.e. not produce frames with size bigger than requested) while still making
2418 output picture as good as possible.
2419 A frame containing a lot of small details is harder to compress and the encoder
2420 would spend more time searching for appropriate quantizers for each slice.
2422 Setting a higher @option{bits_per_mb} limit will improve the speed.
2424 For the fastest encoding speed set the @option{qscale} parameter (4 is the
2425 recommended value) and do not set a size constraint.
2429 Kvazaar H.265/HEVC encoder.
2431 Requires the presence of the libkvazaar headers and library during
2432 configuration. You need to explicitly configure the build with
2433 @option{--enable-libkvazaar}.
2440 Set target video bitrate in bit/s and enable rate control.
2442 @item kvazaar-params
2443 Set kvazaar parameters as a list of @var{name}=@var{value} pairs separated
2444 by commas (,). See kvazaar documentation for a list of options.
2448 @section QSV encoders
2450 The family of Intel QuickSync Video encoders (MPEG-2, H.264 and HEVC)
2452 The ratecontrol method is selected as follows:
2456 When @option{global_quality} is specified, a quality-based mode is used.
2457 Specifically this means either
2460 @var{CQP} - constant quantizer scale, when the @option{qscale} codec flag is
2461 also set (the @option{-qscale} ffmpeg option).
2464 @var{LA_ICQ} - intelligent constant quality with lookahead, when the
2465 @option{look_ahead} option is also set.
2468 @var{ICQ} -- intelligent constant quality otherwise.
2472 Otherwise, a bitrate-based mode is used. For all of those, you should specify at
2473 least the desired average bitrate with the @option{b} option.
2476 @var{LA} - VBR with lookahead, when the @option{look_ahead} option is specified.
2479 @var{VCM} - video conferencing mode, when the @option{vcm} option is set.
2482 @var{CBR} - constant bitrate, when @option{maxrate} is specified and equal to
2483 the average bitrate.
2486 @var{VBR} - variable bitrate, when @option{maxrate} is specified, but is higher
2487 than the average bitrate.
2490 @var{AVBR} - average VBR mode, when @option{maxrate} is not specified. This mode
2491 is further configured by the @option{avbr_accuracy} and
2492 @option{avbr_convergence} options.
2496 Note that depending on your system, a different mode than the one you specified
2497 may be selected by the encoder. Set the verbosity level to @var{verbose} or
2498 higher to see the actual settings used by the QSV runtime.
2500 Additional libavcodec global options are mapped to MSDK options as follows:
2504 @option{g/gop_size} -> @option{GopPicSize}
2507 @option{bf/max_b_frames}+1 -> @option{GopRefDist}
2510 @option{rc_init_occupancy/rc_initial_buffer_occupancy} ->
2511 @option{InitialDelayInKB}
2514 @option{slices} -> @option{NumSlice}
2517 @option{refs} -> @option{NumRefFrame}
2520 @option{b_strategy/b_frame_strategy} -> @option{BRefType}
2523 @option{cgop/CLOSED_GOP} codec flag -> @option{GopOptFlag}
2526 For the @var{CQP} mode, the @option{i_qfactor/i_qoffset} and
2527 @option{b_qfactor/b_qoffset} set the difference between @var{QPP} and @var{QPI},
2528 and @var{QPP} and @var{QPB} respectively.
2531 Setting the @option{coder} option to the value @var{vlc} will make the H.264
2532 encoder use CAVLC instead of CABAC.
2538 SMPTE VC-2 (previously BBC Dirac Pro). This codec was primarily aimed at
2539 professional broadcasting but since it supports yuv420, yuv422 and yuv444 at
2540 8 (limited range or full range), 10 or 12 bits, this makes it suitable for
2541 other tasks which require low overhead and low compression (like screen
2549 Sets target video bitrate. Usually that's around 1:6 of the uncompressed
2550 video bitrate (e.g. for 1920x1080 50fps yuv422p10 that's around 400Mbps). Higher
2551 values (close to the uncompressed bitrate) turn on lossless compression mode.
2554 Enables field coding when set (e.g. to tt - top field first) for interlaced
2555 inputs. Should increase compression with interlaced content as it splits the
2556 fields and encodes each separately.
2559 Sets the total amount of wavelet transforms to apply, between 1 and 5 (default).
2560 Lower values reduce compression and quality. Less capable decoders may not be
2561 able to handle values of @option{wavelet_depth} over 3.
2564 Sets the transform type. Currently only @var{5_3} (LeGall) and @var{9_7}
2566 are implemented, with 9_7 being the one with better compression and thus
2571 Sets the slice size for each slice. Larger values result in better compression.
2572 For compatibility with other more limited decoders use @option{slice_width} of
2573 32 and @option{slice_height} of 8.
2576 Sets the undershoot tolerance of the rate control system in percent. This is
2577 to prevent an expensive search from being run.
2580 Sets the quantization matrix preset to use by default or when @option{wavelet_depth}
2585 Uses the default quantization matrix from the specifications, extended with
2586 values for the fifth level. This provides a good balance between keeping detail
2587 and omitting artifacts.
2591 Use a completely zeroed out quantization matrix. This increases PSNR but might
2592 reduce perception. Use in bogus benchmarks.
2596 Reduces detail but attempts to preserve color at extremely low bitrates.
2601 @c man end VIDEO ENCODERS
2603 @chapter Subtitles Encoders
2604 @c man begin SUBTITLES ENCODERS
2608 This codec encodes the bitmap subtitle format that is used in DVDs.
2609 Typically they are stored in VOBSUB file pairs (*.idx + *.sub),
2610 and they can also be used in Matroska files.
2616 When set to 1, enable a work-around that makes the number of pixel rows
2617 even in all subtitles. This fixes a problem with some players that
2618 cut off the bottom row if the number is odd. The work-around just adds
2619 a fully transparent row if needed. The overhead is low, typically
2620 one byte per subtitle on average.
2622 By default, this work-around is disabled.
2625 @c man end SUBTITLES ENCODERS