4 Encoders are configured elements in FFmpeg which allow the encoding of
7 When you configure your FFmpeg build, all the supported native encoders
8 are enabled by default. Encoders requiring an external library must be enabled
9 manually via the corresponding @code{--enable-lib} option. You can list all
10 available encoders using the configure option @code{--list-encoders}.
12 You can disable all the encoders with the configure option
13 @code{--disable-encoders} and selectively enable / disable single encoders
14 with the options @code{--enable-encoder=@var{ENCODER}} /
15 @code{--disable-encoder=@var{ENCODER}}.
17 The option @code{-encoders} of the ff* tools will display the list of
22 @chapter Audio Encoders
23 @c man begin AUDIO ENCODERS
25 A description of some of the currently available audio encoders
31 Advanced Audio Coding (AAC) encoder.
33 This encoder is the default AAC encoder, natively implemented into FFmpeg. Its
34 quality is on par or better than libfdk_aac at the default bitrate of 128kbps.
35 This encoder also implements more options, profiles and samplerates than
36 other encoders (with only the AAC-HE profile pending to be implemented) so this
37 encoder has become the default and is the recommended choice.
43 Set bit rate in bits/s. Setting this automatically activates constant bit rate
44 (CBR) mode. If this option is unspecified it is set to 128kbps.
47 Set quality for variable bit rate (VBR) mode. This option is valid only using
48 the @command{ffmpeg} command-line tool. For library interface users, use
49 @option{global_quality}.
52 Set cutoff frequency. If unspecified will allow the encoder to dynamically
53 adjust the cutoff to improve clarity on low bitrates.
56 Set AAC encoder coding method. Possible values:
60 Two loop searching (TLS) method.
62 This method first sets quantizers depending on band thresholds and then tries
63 to find an optimal combination by adding or subtracting a specific value from
64 all quantizers and adjusting some individual quantizer a little. Will tune
65 itself based on whether @option{aac_is}, @option{aac_ms} and @option{aac_pns}
67 This is the default choice for a coder.
70 Average noise to mask ratio (ANMR) trellis-based solution.
72 This is an experimental coder which currently produces a lower quality, is more
73 unstable and is slower than the default twoloop coder but has potential.
74 Currently has no support for the @option{aac_is} or @option{aac_pns} options.
75 Not currently recommended.
78 Constant quantizer method.
80 This method sets a constant quantizer for all bands. This is the fastest of all
81 the methods and has no rate control or support for @option{aac_is} or
88 Sets mid/side coding mode. The default value of "auto" will automatically use
89 M/S with bands which will benefit from such coding. Can be forced for all bands
90 using the value "enable", which is mainly useful for debugging or disabled using
94 Sets intensity stereo coding tool usage. By default, it's enabled and will
95 automatically toggle IS for similar pairs of stereo bands if it's benefitial.
96 Can be disabled for debugging by setting the value to "disable".
99 Uses perceptual noise substitution to replace low entropy high frequency bands
100 with imperceivable white noise during the decoding process. By default, it's
101 enabled, but can be disabled for debugging purposes by using "disable".
104 Enables the use of a multitap FIR filter which spans through the high frequency
105 bands to hide quantization noise during the encoding process and is reverted
106 by the decoder. As well as decreasing unpleasant artifacts in the high range
107 this also reduces the entropy in the high bands and allows for more bits to
108 be used by the mid-low bands. By default it's enabled but can be disabled for
109 debugging by setting the option to "disable".
112 Enables the use of the long term prediction extension which increases coding
113 efficiency in very low bandwidth situations such as encoding of voice or
114 solo piano music by extending constant harmonic peaks in bands throughout
115 frames. This option is implied by profile:a aac_low and is incompatible with
116 aac_pred. Use in conjunction with @option{-ar} to decrease the samplerate.
119 Enables the use of a more traditional style of prediction where the spectral
120 coefficients transmitted are replaced by the difference of the current
121 coefficients minus the previous "predicted" coefficients. In theory and sometimes
122 in practice this can improve quality for low to mid bitrate audio.
123 This option implies the aac_main profile and is incompatible with aac_ltp.
126 Sets the encoding profile, possible values:
130 The default, AAC "Low-complexity" profile. Is the most compatible and produces
134 Equivalent to @code{-profile:a aac_low -aac_pns 0}. PNS was introduced with the
135 MPEG4 specifications.
138 Long term prediction profile, is enabled by and will enable the @option{aac_ltp}
139 option. Introduced in MPEG4.
142 Main-type prediction profile, is enabled by and will enable the @option{aac_pred}
143 option. Introduced in MPEG2.
146 If this option is unspecified it is set to @samp{aac_low}.
149 @section ac3 and ac3_fixed
153 These encoders implement part of ATSC A/52:2010 and ETSI TS 102 366, as well as
154 the undocumented RealAudio 3 (a.k.a. dnet).
156 The @var{ac3} encoder uses floating-point math, while the @var{ac3_fixed}
157 encoder only uses fixed-point integer math. This does not mean that one is
158 always faster, just that one or the other may be better suited to a
159 particular system. The floating-point encoder will generally produce better
160 quality audio for a given bitrate. The @var{ac3_fixed} encoder is not the
161 default codec for any of the output formats, so it must be specified explicitly
162 using the option @code{-acodec ac3_fixed} in order to use it.
164 @subsection AC-3 Metadata
166 The AC-3 metadata options are used to set parameters that describe the audio,
167 but in most cases do not affect the audio encoding itself. Some of the options
168 do directly affect or influence the decoding and playback of the resulting
169 bitstream, while others are just for informational purposes. A few of the
170 options will add bits to the output stream that could otherwise be used for
171 audio data, and will thus affect the quality of the output. Those will be
172 indicated accordingly with a note in the option list below.
174 These parameters are described in detail in several publicly-available
177 @item @uref{http://www.atsc.org/cms/standards/a_52-2010.pdf,A/52:2010 - Digital Audio Compression (AC-3) (E-AC-3) Standard}
178 @item @uref{http://www.atsc.org/cms/standards/a_54a_with_corr_1.pdf,A/54 - Guide to the Use of the ATSC Digital Television Standard}
179 @item @uref{http://www.dolby.com/uploadedFiles/zz-_Shared_Assets/English_PDFs/Professional/18_Metadata.Guide.pdf,Dolby Metadata Guide}
180 @item @uref{http://www.dolby.com/uploadedFiles/zz-_Shared_Assets/English_PDFs/Professional/46_DDEncodingGuidelines.pdf,Dolby Digital Professional Encoding Guidelines}
183 @subsubsection Metadata Control Options
187 @item -per_frame_metadata @var{boolean}
188 Allow Per-Frame Metadata. Specifies if the encoder should check for changing
189 metadata for each frame.
192 The metadata values set at initialization will be used for every frame in the
195 Metadata values can be changed before encoding each frame.
200 @subsubsection Downmix Levels
204 @item -center_mixlev @var{level}
205 Center Mix Level. The amount of gain the decoder should apply to the center
206 channel when downmixing to stereo. This field will only be written to the
207 bitstream if a center channel is present. The value is specified as a scale
208 factor. There are 3 valid values:
213 Apply -4.5dB gain (default)
218 @item -surround_mixlev @var{level}
219 Surround Mix Level. The amount of gain the decoder should apply to the surround
220 channel(s) when downmixing to stereo. This field will only be written to the
221 bitstream if one or more surround channels are present. The value is specified
222 as a scale factor. There are 3 valid values:
227 Apply -6dB gain (default)
229 Silence Surround Channel(s)
234 @subsubsection Audio Production Information
235 Audio Production Information is optional information describing the mixing
236 environment. Either none or both of the fields are written to the bitstream.
240 @item -mixing_level @var{number}
241 Mixing Level. Specifies peak sound pressure level (SPL) in the production
242 environment when the mix was mastered. Valid values are 80 to 111, or -1 for
243 unknown or not indicated. The default value is -1, but that value cannot be
244 used if the Audio Production Information is written to the bitstream. Therefore,
245 if the @code{room_type} option is not the default value, the @code{mixing_level}
246 option must not be -1.
248 @item -room_type @var{type}
249 Room Type. Describes the equalization used during the final mixing session at
250 the studio or on the dubbing stage. A large room is a dubbing stage with the
251 industry standard X-curve equalization; a small room has flat equalization.
252 This field will not be written to the bitstream if both the @code{mixing_level}
253 option and the @code{room_type} option have the default values.
257 Not Indicated (default)
268 @subsubsection Other Metadata Options
272 @item -copyright @var{boolean}
273 Copyright Indicator. Specifies whether a copyright exists for this audio.
277 No Copyright Exists (default)
283 @item -dialnorm @var{value}
284 Dialogue Normalization. Indicates how far the average dialogue level of the
285 program is below digital 100% full scale (0 dBFS). This parameter determines a
286 level shift during audio reproduction that sets the average volume of the
287 dialogue to a preset level. The goal is to match volume level between program
288 sources. A value of -31dB will result in no volume level change, relative to
289 the source volume, during audio reproduction. Valid values are whole numbers in
290 the range -31 to -1, with -31 being the default.
292 @item -dsur_mode @var{mode}
293 Dolby Surround Mode. Specifies whether the stereo signal uses Dolby Surround
294 (Pro Logic). This field will only be written to the bitstream if the audio
295 stream is stereo. Using this option does @b{NOT} mean the encoder will actually
296 apply Dolby Surround processing.
300 Not Indicated (default)
303 Not Dolby Surround Encoded
306 Dolby Surround Encoded
309 @item -original @var{boolean}
310 Original Bit Stream Indicator. Specifies whether this audio is from the
311 original source and not a copy.
318 Original Source (default)
323 @subsection Extended Bitstream Information
324 The extended bitstream options are part of the Alternate Bit Stream Syntax as
325 specified in Annex D of the A/52:2010 standard. It is grouped into 2 parts.
326 If any one parameter in a group is specified, all values in that group will be
327 written to the bitstream. Default values are used for those that are written
328 but have not been specified. If the mixing levels are written, the decoder
329 will use these values instead of the ones specified in the @code{center_mixlev}
330 and @code{surround_mixlev} options if it supports the Alternate Bit Stream
333 @subsubsection Extended Bitstream Information - Part 1
337 @item -dmix_mode @var{mode}
338 Preferred Stereo Downmix Mode. Allows the user to select either Lt/Rt
339 (Dolby Surround) or Lo/Ro (normal stereo) as the preferred stereo downmix mode.
343 Not Indicated (default)
346 Lt/Rt Downmix Preferred
349 Lo/Ro Downmix Preferred
352 @item -ltrt_cmixlev @var{level}
353 Lt/Rt Center Mix Level. The amount of gain the decoder should apply to the
354 center channel when downmixing to stereo in Lt/Rt mode.
367 Apply -4.5dB gain (default)
371 Silence Center Channel
374 @item -ltrt_surmixlev @var{level}
375 Lt/Rt Surround Mix Level. The amount of gain the decoder should apply to the
376 surround channel(s) when downmixing to stereo in Lt/Rt mode.
385 Apply -6.0dB gain (default)
387 Silence Surround Channel(s)
390 @item -loro_cmixlev @var{level}
391 Lo/Ro Center Mix Level. The amount of gain the decoder should apply to the
392 center channel when downmixing to stereo in Lo/Ro mode.
405 Apply -4.5dB gain (default)
409 Silence Center Channel
412 @item -loro_surmixlev @var{level}
413 Lo/Ro Surround Mix Level. The amount of gain the decoder should apply to the
414 surround channel(s) when downmixing to stereo in Lo/Ro mode.
423 Apply -6.0dB gain (default)
425 Silence Surround Channel(s)
430 @subsubsection Extended Bitstream Information - Part 2
434 @item -dsurex_mode @var{mode}
435 Dolby Surround EX Mode. Indicates whether the stream uses Dolby Surround EX
436 (7.1 matrixed to 5.1). Using this option does @b{NOT} mean the encoder will actually
437 apply Dolby Surround EX processing.
441 Not Indicated (default)
444 Dolby Surround EX Off
450 @item -dheadphone_mode @var{mode}
451 Dolby Headphone Mode. Indicates whether the stream uses Dolby Headphone
452 encoding (multi-channel matrixed to 2.0 for use with headphones). Using this
453 option does @b{NOT} mean the encoder will actually apply Dolby Headphone
458 Not Indicated (default)
467 @item -ad_conv_type @var{type}
468 A/D Converter Type. Indicates whether the audio has passed through HDCD A/D
473 Standard A/D Converter (default)
481 @subsection Other AC-3 Encoding Options
485 @item -stereo_rematrixing @var{boolean}
486 Stereo Rematrixing. Enables/Disables use of rematrixing for stereo input. This
487 is an optional AC-3 feature that increases quality by selectively encoding
488 the left/right channels as mid/side. This option is enabled by default, and it
489 is highly recommended that it be left as enabled except for testing purposes.
493 @subsection Floating-Point-Only AC-3 Encoding Options
495 These options are only valid for the floating-point encoder and do not exist
496 for the fixed-point encoder due to the corresponding features not being
497 implemented in fixed-point.
501 @item -channel_coupling @var{boolean}
502 Enables/Disables use of channel coupling, which is an optional AC-3 feature
503 that increases quality by combining high frequency information from multiple
504 channels into a single channel. The per-channel high frequency information is
505 sent with less accuracy in both the frequency and time domains. This allows
506 more bits to be used for lower frequencies while preserving enough information
507 to reconstruct the high frequencies. This option is enabled by default for the
508 floating-point encoder and should generally be left as enabled except for
509 testing purposes or to increase encoding speed.
513 Selected by Encoder (default)
516 Disable Channel Coupling
519 Enable Channel Coupling
522 @item -cpl_start_band @var{number}
523 Coupling Start Band. Sets the channel coupling start band, from 1 to 15. If a
524 value higher than the bandwidth is used, it will be reduced to 1 less than the
525 coupling end band. If @var{auto} is used, the start band will be determined by
526 the encoder based on the bit rate, sample rate, and channel layout. This option
527 has no effect if channel coupling is disabled.
531 Selected by Encoder (default)
539 FLAC (Free Lossless Audio Codec) Encoder
543 The following options are supported by FFmpeg's flac encoder.
546 @item compression_level
547 Sets the compression level, which chooses defaults for many other options
548 if they are not set explicitly.
551 Sets the size of the frames in samples per channel.
553 @item lpc_coeff_precision
554 Sets the LPC coefficient precision, valid values are from 1 to 15, 15 is the
558 Sets the first stage LPC algorithm
564 fixed LPC coefficients
572 Number of passes to use for Cholesky factorization during LPC analysis
574 @item min_partition_order
575 The minimum partition order
577 @item max_partition_order
578 The maximum partition order
580 @item prediction_order_method
595 The mode is chosen automatically for each frame
597 Chanels are independently coded
603 @item exact_rice_parameters
604 Chooses if rice parameters are calculated exactly or approximately.
605 if set to 1 then they are chosen exactly, which slows the code down slightly and
606 improves compression slightly.
608 @item multi_dim_quant
609 Multi Dimensional Quantization. If set to 1 then a 2nd stage LPC algorithm is
610 applied after the first stage to finetune the coefficients. This is quite slow
611 and slightly improves compression.
615 @anchor{libfdk-aac-enc}
618 libfdk-aac AAC (Advanced Audio Coding) encoder wrapper.
620 The libfdk-aac library is based on the Fraunhofer FDK AAC code from
623 Requires the presence of the libfdk-aac headers and library during
624 configuration. You need to explicitly configure the build with
625 @code{--enable-libfdk-aac}. The library is also incompatible with GPL,
626 so if you allow the use of GPL, you should configure with
627 @code{--enable-gpl --enable-nonfree --enable-libfdk-aac}.
629 This encoder is considered to produce output on par or worse at 128kbps to the
630 @ref{aacenc,,the native FFmpeg AAC encoder} but can often produce better
631 sounding audio at identical or lower bitrates and has support for the
634 VBR encoding, enabled through the @option{vbr} or @option{flags
635 +qscale} options, is experimental and only works with some
636 combinations of parameters.
638 Support for encoding 7.1 audio is only available with libfdk-aac 0.1.3 or
641 For more information see the fdk-aac project at
642 @url{http://sourceforge.net/p/opencore-amr/fdk-aac/}.
646 The following options are mapped on the shared FFmpeg codec options.
650 Set bit rate in bits/s. If the bitrate is not explicitly specified, it
651 is automatically set to a suitable value depending on the selected
654 In case VBR mode is enabled the option is ignored.
657 Set audio sampling rate (in Hz).
660 Set the number of audio channels.
663 Enable fixed quality, VBR (Variable Bit Rate) mode.
664 Note that VBR is implicitly enabled when the @option{vbr} value is
668 Set cutoff frequency. If not specified (or explicitly set to 0) it
669 will use a value automatically computed by the library. Default value
675 The following profiles are recognized:
678 Low Complexity AAC (LC)
681 High Efficiency AAC (HE-AAC)
684 High Efficiency AAC version 2 (HE-AACv2)
690 Enhanced Low Delay AAC (ELD)
693 If not specified it is set to @samp{aac_low}.
696 The following are private options of the libfdk_aac encoder.
700 Enable afterburner feature if set to 1, disabled if set to 0. This
701 improves the quality but also the required processing power.
706 Enable SBR (Spectral Band Replication) for ELD if set to 1, disabled
712 Set SBR/PS signaling style.
714 It can assume one of the following values:
717 choose signaling implicitly (explicit hierarchical by default,
718 implicit if global header is disabled)
721 implicit backwards compatible signaling
724 explicit SBR, implicit PS signaling
726 @item explicit_hierarchical
727 explicit hierarchical signaling
730 Default value is @samp{default}.
733 Output LATM/LOAS encapsulated data if set to 1, disabled if set to 0.
738 Set StreamMuxConfig and PCE repetition period (in frames) for sending
739 in-band configuration buffers within LATM/LOAS transport layer.
741 Must be a 16-bits non-negative integer.
746 Set VBR mode, from 1 to 5. 1 is lowest quality (though still pretty
747 good) and 5 is highest quality. A value of 0 will disable VBR, and CBR
748 (Constant Bit Rate) is enabled.
750 Currently only the @samp{aac_low} profile supports VBR encoding.
752 VBR modes 1-5 correspond to roughly the following average bit rates:
764 about 80-96 kbps/channel
774 Use @command{ffmpeg} to convert an audio file to VBR AAC in an M4A (MP4)
777 ffmpeg -i input.wav -codec:a libfdk_aac -vbr 3 output.m4a
781 Use @command{ffmpeg} to convert an audio file to CBR 64k kbps AAC, using the
782 High-Efficiency AAC profile:
784 ffmpeg -i input.wav -c:a libfdk_aac -profile:a aac_he -b:a 64k output.m4a
791 LAME (Lame Ain't an MP3 Encoder) MP3 encoder wrapper.
793 Requires the presence of the libmp3lame headers and library during
794 configuration. You need to explicitly configure the build with
795 @code{--enable-libmp3lame}.
797 See @ref{libshine} for a fixed-point MP3 encoder, although with a
802 The following options are supported by the libmp3lame wrapper. The
803 @command{lame}-equivalent of the options are listed in parentheses.
807 Set bitrate expressed in bits/s for CBR or ABR. LAME @code{bitrate} is
808 expressed in kilobits/s.
811 Set constant quality setting for VBR. This option is valid only
812 using the @command{ffmpeg} command-line tool. For library interface
813 users, use @option{global_quality}.
815 @item compression_level (@emph{-q})
816 Set algorithm quality. Valid arguments are integers in the 0-9 range,
817 with 0 meaning highest quality but slowest, and 9 meaning fastest
818 while producing the worst quality.
821 Enable use of bit reservoir when set to 1. Default value is 1. LAME
822 has this enabled by default, but can be overridden by use
823 @option{--nores} option.
825 @item joint_stereo (@emph{-m j})
826 Enable the encoder to use (on a frame by frame basis) either L/R
827 stereo or mid/side stereo. Default value is 1.
829 @item abr (@emph{--abr})
830 Enable the encoder to use ABR when set to 1. The @command{lame}
831 @option{--abr} sets the target bitrate, while this options only
832 tells FFmpeg to use ABR still relies on @option{b} to set bitrate.
836 @section libopencore-amrnb
838 OpenCORE Adaptive Multi-Rate Narrowband encoder.
840 Requires the presence of the libopencore-amrnb headers and library during
841 configuration. You need to explicitly configure the build with
842 @code{--enable-libopencore-amrnb --enable-version3}.
844 This is a mono-only encoder. Officially it only supports 8000Hz sample rate,
845 but you can override it by setting @option{strict} to @samp{unofficial} or
853 Set bitrate in bits per second. Only the following bitrates are supported,
854 otherwise libavcodec will round to the nearest valid bitrate.
868 Allow discontinuous transmission (generate comfort noise) when set to 1. The
869 default value is 0 (disabled).
875 libopus Opus Interactive Audio Codec encoder wrapper.
877 Requires the presence of the libopus headers and library during
878 configuration. You need to explicitly configure the build with
879 @code{--enable-libopus}.
881 @subsection Option Mapping
883 Most libopus options are modelled after the @command{opusenc} utility from
884 opus-tools. The following is an option mapping chart describing options
885 supported by the libopus wrapper, and their @command{opusenc}-equivalent
890 @item b (@emph{bitrate})
891 Set the bit rate in bits/s. FFmpeg's @option{b} option is
892 expressed in bits/s, while @command{opusenc}'s @option{bitrate} in
895 @item vbr (@emph{vbr}, @emph{hard-cbr}, and @emph{cvbr})
896 Set VBR mode. The FFmpeg @option{vbr} option has the following
897 valid arguments, with the @command{opusenc} equivalent options
901 @item off (@emph{hard-cbr})
902 Use constant bit rate encoding.
904 @item on (@emph{vbr})
905 Use variable bit rate encoding (the default).
907 @item constrained (@emph{cvbr})
908 Use constrained variable bit rate encoding.
911 @item compression_level (@emph{comp})
912 Set encoding algorithm complexity. Valid options are integers in
913 the 0-10 range. 0 gives the fastest encodes but lower quality, while 10
914 gives the highest quality but slowest encoding. The default is 10.
916 @item frame_duration (@emph{framesize})
917 Set maximum frame size, or duration of a frame in milliseconds. The
918 argument must be exactly the following: 2.5, 5, 10, 20, 40, 60. Smaller
919 frame sizes achieve lower latency but less quality at a given bitrate.
920 Sizes greater than 20ms are only interesting at fairly low bitrates.
923 @item packet_loss (@emph{expect-loss})
924 Set expected packet loss percentage. The default is 0.
926 @item application (N.A.)
927 Set intended application type. Valid options are listed below:
931 Favor improved speech intelligibility.
933 Favor faithfulness to the input (the default).
935 Restrict to only the lowest delay modes.
939 Set cutoff bandwidth in Hz. The argument must be exactly one of the
940 following: 4000, 6000, 8000, 12000, or 20000, corresponding to
941 narrowband, mediumband, wideband, super wideband, and fullband
942 respectively. The default is 0 (cutoff disabled).
944 @item mapping_family (@emph{mapping_family})
945 Set channel mapping family to be used by the encoder. The default value of -1
946 uses mapping family 0 for mono and stereo inputs, and mapping family 1
947 otherwise. The default also disables the surround masking and LFE bandwidth
948 optimzations in libopus, and requires that the input contains 8 channels or
951 Other values include 0 for mono and stereo, 1 for surround sound with masking
952 and LFE bandwidth optimizations, and 255 for independent streams with an
953 unspecified channel layout.
960 Shine Fixed-Point MP3 encoder wrapper.
962 Shine is a fixed-point MP3 encoder. It has a far better performance on
963 platforms without an FPU, e.g. armel CPUs, and some phones and tablets.
964 However, as it is more targeted on performance than quality, it is not on par
965 with LAME and other production-grade encoders quality-wise. Also, according to
966 the project's homepage, this encoder may not be free of bugs as the code was
967 written a long time ago and the project was dead for at least 5 years.
969 This encoder only supports stereo and mono input. This is also CBR-only.
971 The original project (last updated in early 2007) is at
972 @url{http://sourceforge.net/projects/libshine-fxp/}. We only support the
973 updated fork by the Savonet/Liquidsoap project at @url{https://github.com/savonet/shine}.
975 Requires the presence of the libshine headers and library during
976 configuration. You need to explicitly configure the build with
977 @code{--enable-libshine}.
979 See also @ref{libmp3lame}.
983 The following options are supported by the libshine wrapper. The
984 @command{shineenc}-equivalent of the options are listed in parentheses.
988 Set bitrate expressed in bits/s for CBR. @command{shineenc} @option{-b} option
989 is expressed in kilobits/s.
995 TwoLAME MP2 encoder wrapper.
997 Requires the presence of the libtwolame headers and library during
998 configuration. You need to explicitly configure the build with
999 @code{--enable-libtwolame}.
1003 The following options are supported by the libtwolame wrapper. The
1004 @command{twolame}-equivalent options follow the FFmpeg ones and are in
1009 Set bitrate expressed in bits/s for CBR. @command{twolame} @option{b}
1010 option is expressed in kilobits/s. Default value is 128k.
1013 Set quality for experimental VBR support. Maximum value range is
1014 from -50 to 50, useful range is from -10 to 10. The higher the
1015 value, the better the quality. This option is valid only using the
1016 @command{ffmpeg} command-line tool. For library interface users,
1017 use @option{global_quality}.
1019 @item mode (@emph{--mode})
1020 Set the mode of the resulting audio. Possible values:
1024 Choose mode automatically based on the input. This is the default.
1035 @item psymodel (@emph{--psyc-mode})
1036 Set psychoacoustic model to use in encoding. The argument must be
1037 an integer between -1 and 4, inclusive. The higher the value, the
1038 better the quality. The default value is 3.
1040 @item energy_levels (@emph{--energy})
1041 Enable energy levels extensions when set to 1. The default value is
1044 @item error_protection (@emph{--protect})
1045 Enable CRC error protection when set to 1. The default value is 0
1048 @item copyright (@emph{--copyright})
1049 Set MPEG audio copyright flag when set to 1. The default value is 0
1052 @item original (@emph{--original})
1053 Set MPEG audio original flag when set to 1. The default value is 0
1058 @section libvo-amrwbenc
1060 VisualOn Adaptive Multi-Rate Wideband encoder.
1062 Requires the presence of the libvo-amrwbenc headers and library during
1063 configuration. You need to explicitly configure the build with
1064 @code{--enable-libvo-amrwbenc --enable-version3}.
1066 This is a mono-only encoder. Officially it only supports 16000Hz sample
1067 rate, but you can override it by setting @option{strict} to
1068 @samp{unofficial} or lower.
1075 Set bitrate in bits/s. Only the following bitrates are supported, otherwise
1076 libavcodec will round to the nearest valid bitrate.
1091 Allow discontinuous transmission (generate comfort noise) when set to 1. The
1092 default value is 0 (disabled).
1098 libvorbis encoder wrapper.
1100 Requires the presence of the libvorbisenc headers and library during
1101 configuration. You need to explicitly configure the build with
1102 @code{--enable-libvorbis}.
1106 The following options are supported by the libvorbis wrapper. The
1107 @command{oggenc}-equivalent of the options are listed in parentheses.
1109 To get a more accurate and extensive documentation of the libvorbis
1110 options, consult the libvorbisenc's and @command{oggenc}'s documentations.
1111 See @url{http://xiph.org/vorbis/},
1112 @url{http://wiki.xiph.org/Vorbis-tools}, and oggenc(1).
1116 Set bitrate expressed in bits/s for ABR. @command{oggenc} @option{-b} is
1117 expressed in kilobits/s.
1120 Set constant quality setting for VBR. The value should be a float
1121 number in the range of -1.0 to 10.0. The higher the value, the better
1122 the quality. The default value is @samp{3.0}.
1124 This option is valid only using the @command{ffmpeg} command-line tool.
1125 For library interface users, use @option{global_quality}.
1127 @item cutoff (@emph{--advanced-encode-option lowpass_frequency=N})
1128 Set cutoff bandwidth in Hz, a value of 0 disables cutoff. @command{oggenc}'s
1129 related option is expressed in kHz. The default value is @samp{0} (cutoff
1132 @item minrate (@emph{-m})
1133 Set minimum bitrate expressed in bits/s. @command{oggenc} @option{-m} is
1134 expressed in kilobits/s.
1136 @item maxrate (@emph{-M})
1137 Set maximum bitrate expressed in bits/s. @command{oggenc} @option{-M} is
1138 expressed in kilobits/s. This only has effect on ABR mode.
1140 @item iblock (@emph{--advanced-encode-option impulse_noisetune=N})
1141 Set noise floor bias for impulse blocks. The value is a float number from
1142 -15.0 to 0.0. A negative bias instructs the encoder to pay special attention
1143 to the crispness of transients in the encoded audio. The tradeoff for better
1144 transient response is a higher bitrate.
1151 A wrapper providing WavPack encoding through libwavpack.
1153 Only lossless mode using 32-bit integer samples is supported currently.
1155 Requires the presence of the libwavpack headers and library during
1156 configuration. You need to explicitly configure the build with
1157 @code{--enable-libwavpack}.
1159 Note that a libavcodec-native encoder for the WavPack codec exists so users can
1160 encode audios with this codec without using this encoder. See @ref{wavpackenc}.
1164 @command{wavpack} command line utility's corresponding options are listed in
1165 parentheses, if any.
1168 @item frame_size (@emph{--blocksize})
1171 @item compression_level
1172 Set speed vs. compression tradeoff. Acceptable arguments are listed below:
1179 Normal (default) settings.
1184 @item 3 (@emph{-hh})
1187 @item 4-8 (@emph{-hh -x}@var{EXTRAPROC})
1188 Same as @samp{3}, but with extra processing enabled.
1190 @samp{4} is the same as @option{-x2} and @samp{8} is the same as @option{-x6}.
1198 WavPack lossless audio encoder.
1200 This is a libavcodec-native WavPack encoder. There is also an encoder based on
1201 libwavpack, but there is virtually no reason to use that encoder.
1203 See also @ref{libwavpack}.
1207 The equivalent options for @command{wavpack} command line utility are listed in
1210 @subsubsection Shared options
1212 The following shared options are effective for this encoder. Only special notes
1213 about this particular encoder will be documented here. For the general meaning
1214 of the options, see @ref{codec-options,,the Codec Options chapter}.
1217 @item frame_size (@emph{--blocksize})
1218 For this encoder, the range for this option is between 128 and 131072. Default
1219 is automatically decided based on sample rate and number of channel.
1221 For the complete formula of calculating default, see
1222 @file{libavcodec/wavpackenc.c}.
1224 @item compression_level (@emph{-f}, @emph{-h}, @emph{-hh}, and @emph{-x})
1225 This option's syntax is consistent with @ref{libwavpack}'s.
1228 @subsubsection Private options
1231 @item joint_stereo (@emph{-j})
1232 Set whether to enable joint stereo. Valid values are:
1236 Force mid/side audio encoding.
1237 @item off (@emph{0})
1238 Force left/right audio encoding.
1240 Let the encoder decide automatically.
1244 Set whether to enable optimization for mono. This option is only effective for
1245 non-mono streams. Available values:
1256 @c man end AUDIO ENCODERS
1258 @chapter Video Encoders
1259 @c man begin VIDEO ENCODERS
1261 A description of some of the currently available video encoders
1266 Vidvox Hap video encoder.
1271 @item format @var{integer}
1272 Specifies the Hap format to encode.
1280 Default value is @option{hap}.
1282 @item chunks @var{integer}
1283 Specifies the number of chunks to split frames into, between 1 and 64. This
1284 permits multithreaded decoding of large frames, potentially at the cost of
1285 data-rate. The encoder may modify this value to divide frames evenly.
1287 Default value is @var{1}.
1289 @item compressor @var{integer}
1290 Specifies the second-stage compressor to use. If set to @option{none},
1291 @option{chunks} will be limited to 1, as chunked uncompressed frames offer no
1299 Default value is @option{snappy}.
1305 The native jpeg 2000 encoder is lossy by default, the @code{-q:v}
1306 option can be used to set the encoding quality. Lossless encoding
1307 can be selected with @code{-pred 1}.
1313 Can be set to either @code{j2k} or @code{jp2} (the default) that
1314 makes it possible to store non-rgb pix_fmts.
1320 Kvazaar H.265/HEVC encoder.
1322 Requires the presence of the libkvazaar headers and library during
1323 configuration. You need to explicitly configure the build with
1324 @option{--enable-libkvazaar}.
1331 Set target video bitrate in bit/s and enable rate control.
1333 @item kvazaar-params
1334 Set kvazaar parameters as a list of @var{name}=@var{value} pairs separated
1335 by commas (,). See kvazaar documentation for a list of options.
1339 @section libopenh264
1341 Cisco libopenh264 H.264/MPEG-4 AVC encoder wrapper.
1343 This encoder requires the presence of the libopenh264 headers and
1344 library during configuration. You need to explicitly configure the
1345 build with @code{--enable-libopenh264}. The library is detected using
1346 @command{pkg-config}.
1348 For more information about the library see
1349 @url{http://www.openh264.org}.
1353 The following FFmpeg global options affect the configurations of the
1354 libopenh264 encoder.
1358 Set the bitrate (as a number of bits per second).
1364 Set the max bitrate (as a number of bits per second).
1366 @item flags +global_header
1367 Set global header in the bitstream.
1370 Set the number of slices, used in parallelized encoding. Default value
1371 is 0. This is only used when @option{slice_mode} is set to
1375 Set slice mode. Can assume one of the following possible values:
1379 a fixed number of slices
1381 one slice per row of macroblocks
1383 automatic number of slices according to number of threads
1388 Default value is @samp{auto}.
1391 Enable loop filter, if set to 1 (automatically enabled). To disable
1395 Set profile restrictions. If set to the value of @samp{main} enable
1396 CABAC (set the @code{SEncParamExt.iEntropyCodingModeFlag} flag to 1).
1399 Set maximum NAL size in bytes.
1401 @item allow_skip_frames
1402 Allow skipping frames to hit the target bitrate if set to 1.
1407 libtheora Theora encoder wrapper.
1409 Requires the presence of the libtheora headers and library during
1410 configuration. You need to explicitly configure the build with
1411 @code{--enable-libtheora}.
1413 For more information about the libtheora project see
1414 @url{http://www.theora.org/}.
1418 The following global options are mapped to internal libtheora options
1419 which affect the quality and the bitrate of the encoded stream.
1423 Set the video bitrate in bit/s for CBR (Constant Bit Rate) mode. In
1424 case VBR (Variable Bit Rate) mode is enabled this option is ignored.
1427 Used to enable constant quality mode (VBR) encoding through the
1428 @option{qscale} flag, and to enable the @code{pass1} and @code{pass2}
1434 @item global_quality
1435 Set the global quality as an integer in lambda units.
1437 Only relevant when VBR mode is enabled with @code{flags +qscale}. The
1438 value is converted to QP units by dividing it by @code{FF_QP2LAMBDA},
1439 clipped in the [0 - 10] range, and then multiplied by 6.3 to get a
1440 value in the native libtheora range [0-63]. A higher value corresponds
1441 to a higher quality.
1444 Enable VBR mode when set to a non-negative value, and set constant
1445 quality value as a double floating point value in QP units.
1447 The value is clipped in the [0-10] range, and then multiplied by 6.3
1448 to get a value in the native libtheora range [0-63].
1450 This option is valid only using the @command{ffmpeg} command-line
1451 tool. For library interface users, use @option{global_quality}.
1454 @subsection Examples
1458 Set maximum constant quality (VBR) encoding with @command{ffmpeg}:
1460 ffmpeg -i INPUT -codec:v libtheora -q:v 10 OUTPUT.ogg
1464 Use @command{ffmpeg} to convert a CBR 1000 kbps Theora video stream:
1466 ffmpeg -i INPUT -codec:v libtheora -b:v 1000k OUTPUT.ogg
1472 VP8/VP9 format supported through libvpx.
1474 Requires the presence of the libvpx headers and library during configuration.
1475 You need to explicitly configure the build with @code{--enable-libvpx}.
1479 The following options are supported by the libvpx wrapper. The
1480 @command{vpxenc}-equivalent options or values are listed in parentheses
1483 To reduce the duplication of documentation, only the private options
1484 and some others requiring special attention are documented here. For
1485 the documentation of the undocumented generic options, see
1486 @ref{codec-options,,the Codec Options chapter}.
1488 To get more documentation of the libvpx options, invoke the command
1489 @command{ffmpeg -h encoder=libvpx}, @command{ffmpeg -h encoder=libvpx-vp9} or
1490 @command{vpxenc --help}. Further information is available in the libvpx API
1495 @item b (@emph{target-bitrate})
1496 Set bitrate in bits/s. Note that FFmpeg's @option{b} option is
1497 expressed in bits/s, while @command{vpxenc}'s @option{target-bitrate} is in
1500 @item g (@emph{kf-max-dist})
1502 @item keyint_min (@emph{kf-min-dist})
1504 @item qmin (@emph{min-q})
1506 @item qmax (@emph{max-q})
1508 @item bufsize (@emph{buf-sz}, @emph{buf-optimal-sz})
1509 Set ratecontrol buffer size (in bits). Note @command{vpxenc}'s options are
1510 specified in milliseconds, the libvpx wrapper converts this value as follows:
1511 @code{buf-sz = bufsize * 1000 / bitrate},
1512 @code{buf-optimal-sz = bufsize * 1000 / bitrate * 5 / 6}.
1514 @item rc_init_occupancy (@emph{buf-initial-sz})
1515 Set number of bits which should be loaded into the rc buffer before decoding
1516 starts. Note @command{vpxenc}'s option is specified in milliseconds, the libvpx
1517 wrapper converts this value as follows:
1518 @code{rc_init_occupancy * 1000 / bitrate}.
1520 @item undershoot-pct
1521 Set datarate undershoot (min) percentage of the target bitrate.
1524 Set datarate overshoot (max) percentage of the target bitrate.
1526 @item skip_threshold (@emph{drop-frame})
1528 @item qcomp (@emph{bias-pct})
1530 @item maxrate (@emph{maxsection-pct})
1531 Set GOP max bitrate in bits/s. Note @command{vpxenc}'s option is specified as a
1532 percentage of the target bitrate, the libvpx wrapper converts this value as
1533 follows: @code{(maxrate * 100 / bitrate)}.
1535 @item minrate (@emph{minsection-pct})
1536 Set GOP min bitrate in bits/s. Note @command{vpxenc}'s option is specified as a
1537 percentage of the target bitrate, the libvpx wrapper converts this value as
1538 follows: @code{(minrate * 100 / bitrate)}.
1540 @item minrate, maxrate, b @emph{end-usage=cbr}
1541 @code{(minrate == maxrate == bitrate)}.
1543 @item crf (@emph{end-usage=cq}, @emph{cq-level})
1545 @item tune (@emph{tune})
1547 @item psnr (@emph{psnr})
1548 @item ssim (@emph{ssim})
1551 @item quality, deadline (@emph{deadline})
1554 Use best quality deadline. Poorly named and quite slow, this option should be
1555 avoided as it may give worse quality output than good.
1557 Use good quality deadline. This is a good trade-off between speed and quality
1558 when used with the @option{cpu-used} option.
1560 Use realtime quality deadline.
1563 @item speed, cpu-used (@emph{cpu-used})
1564 Set quality/speed ratio modifier. Higher values speed up the encode at the cost
1567 @item nr (@emph{noise-sensitivity})
1570 Set a change threshold on blocks below which they will be skipped by the
1573 @item slices (@emph{token-parts})
1574 Note that FFmpeg's @option{slices} option gives the total number of partitions,
1575 while @command{vpxenc}'s @option{token-parts} is given as
1576 @code{log2(partitions)}.
1578 @item max-intra-rate
1579 Set maximum I-frame bitrate as a percentage of the target bitrate. A value of 0
1582 @item force_key_frames
1583 @code{VPX_EFLAG_FORCE_KF}
1585 @item Alternate reference frame related
1588 Enable use of alternate reference frames (2-pass only).
1589 @item arnr-max-frames
1590 Set altref noise reduction max frame count.
1592 Set altref noise reduction filter type: backward, forward, centered.
1594 Set altref noise reduction filter strength.
1595 @item rc-lookahead, lag-in-frames (@emph{lag-in-frames})
1596 Set number of frames to look ahead for frametype and ratecontrol.
1599 @item error-resilient
1600 Enable error resiliency features.
1602 @item VP9-specific options
1605 Enable lossless mode.
1607 Set number of tile columns to use. Note this is given as
1608 @code{log2(tile_columns)}. For example, 8 tile columns would be requested by
1609 setting the @option{tile-columns} option to 3.
1611 Set number of tile rows to use. Note this is given as @code{log2(tile_rows)}.
1612 For example, 4 tile rows would be requested by setting the @option{tile-rows}
1614 @item frame-parallel
1615 Enable frame parallel decodability features.
1617 Set adaptive quantization mode (0: off (default), 1: variance 2: complexity, 3:
1619 @item colorspace @emph{color-space}
1620 Set input color space. The VP9 bitstream supports signaling the following
1623 @item @samp{rgb} @emph{sRGB}
1624 @item @samp{bt709} @emph{bt709}
1625 @item @samp{unspecified} @emph{unknown}
1626 @item @samp{bt470bg} @emph{bt601}
1627 @item @samp{smpte170m} @emph{smpte170}
1628 @item @samp{smpte240m} @emph{smpte240}
1629 @item @samp{bt2020_ncl} @emph{bt2020}
1635 For more information about libvpx see:
1636 @url{http://www.webmproject.org/}
1640 libwebp WebP Image encoder wrapper
1642 libwebp is Google's official encoder for WebP images. It can encode in either
1643 lossy or lossless mode. Lossy images are essentially a wrapper around a VP8
1644 frame. Lossless images are a separate codec developed by Google.
1646 @subsection Pixel Format
1648 Currently, libwebp only supports YUV420 for lossy and RGB for lossless due
1649 to limitations of the format and libwebp. Alpha is supported for either mode.
1650 Because of API limitations, if RGB is passed in when encoding lossy or YUV is
1651 passed in for encoding lossless, the pixel format will automatically be
1652 converted using functions from libwebp. This is not ideal and is done only for
1659 @item -lossless @var{boolean}
1660 Enables/Disables use of lossless mode. Default is 0.
1662 @item -compression_level @var{integer}
1663 For lossy, this is a quality/speed tradeoff. Higher values give better quality
1664 for a given size at the cost of increased encoding time. For lossless, this is
1665 a size/speed tradeoff. Higher values give smaller size at the cost of increased
1666 encoding time. More specifically, it controls the number of extra algorithms
1667 and compression tools used, and varies the combination of these tools. This
1668 maps to the @var{method} option in libwebp. The valid range is 0 to 6.
1671 @item -qscale @var{float}
1672 For lossy encoding, this controls image quality, 0 to 100. For lossless
1673 encoding, this controls the effort and time spent at compressing more. The
1674 default value is 75. Note that for usage via libavcodec, this option is called
1675 @var{global_quality} and must be multiplied by @var{FF_QP2LAMBDA}.
1677 @item -preset @var{type}
1678 Configuration preset. This does some automatic settings based on the general
1682 Do not use a preset.
1684 Use the encoder default.
1686 Digital picture, like portrait, inner shot
1688 Outdoor photograph, with natural lighting
1690 Hand or line drawing, with high-contrast details
1692 Small-sized colorful images
1699 @section libx264, libx264rgb
1701 x264 H.264/MPEG-4 AVC encoder wrapper.
1703 This encoder requires the presence of the libx264 headers and library
1704 during configuration. You need to explicitly configure the build with
1705 @code{--enable-libx264}.
1707 libx264 supports an impressive number of features, including 8x8 and
1708 4x4 adaptive spatial transform, adaptive B-frame placement, CAVLC/CABAC
1709 entropy coding, interlacing (MBAFF), lossless mode, psy optimizations
1710 for detail retention (adaptive quantization, psy-RD, psy-trellis).
1712 Many libx264 encoder options are mapped to FFmpeg global codec
1713 options, while unique encoder options are provided through private
1714 options. Additionally the @option{x264opts} and @option{x264-params}
1715 private options allows one to pass a list of key=value tuples as accepted
1716 by the libx264 @code{x264_param_parse} function.
1718 The x264 project website is at
1719 @url{http://www.videolan.org/developers/x264.html}.
1721 The libx264rgb encoder is the same as libx264, except it accepts packed RGB
1722 pixel formats as input instead of YUV.
1724 @subsection Supported Pixel Formats
1726 x264 supports 8- to 10-bit color spaces. The exact bit depth is controlled at
1727 x264's configure time. FFmpeg only supports one bit depth in one particular
1728 build. In other words, it is not possible to build one FFmpeg with multiple
1729 versions of x264 with different bit depths.
1733 The following options are supported by the libx264 wrapper. The
1734 @command{x264}-equivalent options or values are listed in parentheses
1737 To reduce the duplication of documentation, only the private options
1738 and some others requiring special attention are documented here. For
1739 the documentation of the undocumented generic options, see
1740 @ref{codec-options,,the Codec Options chapter}.
1742 To get a more accurate and extensive documentation of the libx264
1743 options, invoke the command @command{x264 --full-help} or consult
1744 the libx264 documentation.
1747 @item b (@emph{bitrate})
1748 Set bitrate in bits/s. Note that FFmpeg's @option{b} option is
1749 expressed in bits/s, while @command{x264}'s @option{bitrate} is in
1752 @item bf (@emph{bframes})
1754 @item g (@emph{keyint})
1756 @item qmin (@emph{qpmin})
1757 Minimum quantizer scale.
1759 @item qmax (@emph{qpmax})
1760 Maximum quantizer scale.
1762 @item qdiff (@emph{qpstep})
1763 Maximum difference between quantizer scales.
1765 @item qblur (@emph{qblur})
1766 Quantizer curve blur
1768 @item qcomp (@emph{qcomp})
1769 Quantizer curve compression factor
1771 @item refs (@emph{ref})
1772 Number of reference frames each P-frame can use. The range is from @var{0-16}.
1774 @item sc_threshold (@emph{scenecut})
1775 Sets the threshold for the scene change detection.
1777 @item trellis (@emph{trellis})
1778 Performs Trellis quantization to increase efficiency. Enabled by default.
1780 @item nr (@emph{nr})
1782 @item me_range (@emph{merange})
1783 Maximum range of the motion search in pixels.
1785 @item me_method (@emph{me})
1786 Set motion estimation method. Possible values in the decreasing order
1790 @item dia (@emph{dia})
1791 @item epzs (@emph{dia})
1792 Diamond search with radius 1 (fastest). @samp{epzs} is an alias for
1794 @item hex (@emph{hex})
1795 Hexagonal search with radius 2.
1796 @item umh (@emph{umh})
1797 Uneven multi-hexagon search.
1798 @item esa (@emph{esa})
1800 @item tesa (@emph{tesa})
1801 Hadamard exhaustive search (slowest).
1805 Normally, when forcing a I-frame type, the encoder can select any type
1806 of I-frame. This option forces it to choose an IDR-frame.
1808 @item subq (@emph{subme})
1809 Sub-pixel motion estimation method.
1811 @item b_strategy (@emph{b-adapt})
1812 Adaptive B-frame placement decision algorithm. Use only on first-pass.
1814 @item keyint_min (@emph{min-keyint})
1818 Set entropy encoder. Possible values:
1825 Enable CAVLC and disable CABAC. It generates the same effect as
1826 @command{x264}'s @option{--no-cabac} option.
1830 Set full pixel motion estimation comparison algorithm. Possible values:
1834 Enable chroma in motion estimation.
1837 Ignore chroma in motion estimation. It generates the same effect as
1838 @command{x264}'s @option{--no-chroma-me} option.
1841 @item threads (@emph{threads})
1842 Number of encoding threads.
1845 Set multithreading technique. Possible values:
1849 Slice-based multithreading. It generates the same effect as
1850 @command{x264}'s @option{--sliced-threads} option.
1852 Frame-based multithreading.
1856 Set encoding flags. It can be used to disable closed GOP and enable
1857 open GOP by setting it to @code{-cgop}. The result is similar to
1858 the behavior of @command{x264}'s @option{--open-gop} option.
1860 @item rc_init_occupancy (@emph{vbv-init})
1862 @item preset (@emph{preset})
1863 Set the encoding preset.
1865 @item tune (@emph{tune})
1866 Set tuning of the encoding params.
1868 @item profile (@emph{profile})
1869 Set profile restrictions.
1872 Enable fast settings when encoding first pass, when set to 1. When set
1873 to 0, it has the same effect of @command{x264}'s
1874 @option{--slow-firstpass} option.
1876 @item crf (@emph{crf})
1877 Set the quality for constant quality mode.
1879 @item crf_max (@emph{crf-max})
1880 In CRF mode, prevents VBV from lowering quality beyond this point.
1882 @item qp (@emph{qp})
1883 Set constant quantization rate control method parameter.
1885 @item aq-mode (@emph{aq-mode})
1886 Set AQ method. Possible values:
1889 @item none (@emph{0})
1892 @item variance (@emph{1})
1893 Variance AQ (complexity mask).
1895 @item autovariance (@emph{2})
1896 Auto-variance AQ (experimental).
1899 @item aq-strength (@emph{aq-strength})
1900 Set AQ strength, reduce blocking and blurring in flat and textured areas.
1903 Use psychovisual optimizations when set to 1. When set to 0, it has the
1904 same effect as @command{x264}'s @option{--no-psy} option.
1906 @item psy-rd (@emph{psy-rd})
1907 Set strength of psychovisual optimization, in
1908 @var{psy-rd}:@var{psy-trellis} format.
1910 @item rc-lookahead (@emph{rc-lookahead})
1911 Set number of frames to look ahead for frametype and ratecontrol.
1914 Enable weighted prediction for B-frames when set to 1. When set to 0,
1915 it has the same effect as @command{x264}'s @option{--no-weightb} option.
1917 @item weightp (@emph{weightp})
1918 Set weighted prediction method for P-frames. Possible values:
1921 @item none (@emph{0})
1923 @item simple (@emph{1})
1924 Enable only weighted refs
1925 @item smart (@emph{2})
1926 Enable both weighted refs and duplicates
1929 @item ssim (@emph{ssim})
1930 Enable calculation and printing SSIM stats after the encoding.
1932 @item intra-refresh (@emph{intra-refresh})
1933 Enable the use of Periodic Intra Refresh instead of IDR frames when set
1936 @item avcintra-class (@emph{class})
1937 Configure the encoder to generate AVC-Intra.
1938 Valid values are 50,100 and 200
1940 @item bluray-compat (@emph{bluray-compat})
1941 Configure the encoder to be compatible with the bluray standard.
1942 It is a shorthand for setting "bluray-compat=1 force-cfr=1".
1944 @item b-bias (@emph{b-bias})
1945 Set the influence on how often B-frames are used.
1947 @item b-pyramid (@emph{b-pyramid})
1948 Set method for keeping of some B-frames as references. Possible values:
1951 @item none (@emph{none})
1953 @item strict (@emph{strict})
1954 Strictly hierarchical pyramid.
1955 @item normal (@emph{normal})
1956 Non-strict (not Blu-ray compatible).
1960 Enable the use of one reference per partition, as opposed to one
1961 reference per macroblock when set to 1. When set to 0, it has the
1962 same effect as @command{x264}'s @option{--no-mixed-refs} option.
1965 Enable adaptive spatial transform (high profile 8x8 transform)
1966 when set to 1. When set to 0, it has the same effect as
1967 @command{x264}'s @option{--no-8x8dct} option.
1970 Enable early SKIP detection on P-frames when set to 1. When set
1971 to 0, it has the same effect as @command{x264}'s
1972 @option{--no-fast-pskip} option.
1974 @item aud (@emph{aud})
1975 Enable use of access unit delimiters when set to 1.
1978 Enable use macroblock tree ratecontrol when set to 1. When set
1979 to 0, it has the same effect as @command{x264}'s
1980 @option{--no-mbtree} option.
1982 @item deblock (@emph{deblock})
1983 Set loop filter parameters, in @var{alpha}:@var{beta} form.
1985 @item cplxblur (@emph{cplxblur})
1986 Set fluctuations reduction in QP (before curve compression).
1988 @item partitions (@emph{partitions})
1989 Set partitions to consider as a comma-separated list of. Possible
1994 8x8 P-frame partition.
1996 4x4 P-frame partition.
1998 4x4 B-frame partition.
2000 8x8 I-frame partition.
2002 4x4 I-frame partition.
2003 (Enabling @samp{p4x4} requires @samp{p8x8} to be enabled. Enabling
2004 @samp{i8x8} requires adaptive spatial transform (@option{8x8dct}
2005 option) to be enabled.)
2006 @item none (@emph{none})
2007 Do not consider any partitions.
2008 @item all (@emph{all})
2009 Consider every partition.
2012 @item direct-pred (@emph{direct})
2013 Set direct MV prediction mode. Possible values:
2016 @item none (@emph{none})
2017 Disable MV prediction.
2018 @item spatial (@emph{spatial})
2019 Enable spatial predicting.
2020 @item temporal (@emph{temporal})
2021 Enable temporal predicting.
2022 @item auto (@emph{auto})
2023 Automatically decided.
2026 @item slice-max-size (@emph{slice-max-size})
2027 Set the limit of the size of each slice in bytes. If not specified
2028 but RTP payload size (@option{ps}) is specified, that is used.
2030 @item stats (@emph{stats})
2031 Set the file name for multi-pass stats.
2033 @item nal-hrd (@emph{nal-hrd})
2034 Set signal HRD information (requires @option{vbv-bufsize} to be set).
2038 @item none (@emph{none})
2039 Disable HRD information signaling.
2040 @item vbr (@emph{vbr})
2042 @item cbr (@emph{cbr})
2043 Constant bit rate (not allowed in MP4 container).
2046 @item x264opts (N.A.)
2047 Set any x264 option, see @command{x264 --fullhelp} for a list.
2049 Argument is a list of @var{key}=@var{value} couples separated by
2050 ":". In @var{filter} and @var{psy-rd} options that use ":" as a separator
2051 themselves, use "," instead. They accept it as well since long ago but this
2052 is kept undocumented for some reason.
2054 For example to specify libx264 encoding options with @command{ffmpeg}:
2056 ffmpeg -i foo.mpg -vcodec libx264 -x264opts keyint=123:min-keyint=20 -an out.mkv
2059 @item a53cc @var{boolean}
2060 Import closed captions (which must be ATSC compatible format) into output.
2061 Only the mpeg2 and h264 decoders provide these. Default is 1 (on).
2063 @item x264-params (N.A.)
2064 Override the x264 configuration using a :-separated list of key=value
2067 This option is functionally the same as the @option{x264opts}, but is
2068 duplicated for compatibility with the Libav fork.
2070 For example to specify libx264 encoding options with @command{ffmpeg}:
2072 ffmpeg -i INPUT -c:v libx264 -x264-params level=30:bframes=0:weightp=0:\
2073 cabac=0:ref=1:vbv-maxrate=768:vbv-bufsize=2000:analyse=all:me=umh:\
2074 no-fast-pskip=1:subq=6:8x8dct=0:trellis=0 OUTPUT
2078 Encoding ffpresets for common usages are provided so they can be used with the
2079 general presets system (e.g. passing the @option{pre} option).
2083 x265 H.265/HEVC encoder wrapper.
2085 This encoder requires the presence of the libx265 headers and library
2086 during configuration. You need to explicitly configure the build with
2087 @option{--enable-libx265}.
2093 Set the x265 preset.
2096 Set the x265 tune parameter.
2099 Normally, when forcing a I-frame type, the encoder can select any type
2100 of I-frame. This option forces it to choose an IDR-frame.
2103 Set x265 options using a list of @var{key}=@var{value} couples separated
2104 by ":". See @command{x265 --help} for a list of options.
2106 For example to specify libx265 encoding options with @option{-x265-params}:
2109 ffmpeg -i input -c:v libx265 -x265-params crf=26:psy-rd=1 output.mp4
2115 Xvid MPEG-4 Part 2 encoder wrapper.
2117 This encoder requires the presence of the libxvidcore headers and library
2118 during configuration. You need to explicitly configure the build with
2119 @code{--enable-libxvid --enable-gpl}.
2121 The native @code{mpeg4} encoder supports the MPEG-4 Part 2 format, so
2122 users can encode to this format without this library.
2126 The following options are supported by the libxvid wrapper. Some of
2127 the following options are listed but are not documented, and
2128 correspond to shared codec options. See @ref{codec-options,,the Codec
2129 Options chapter} for their documentation. The other shared options
2130 which are not listed have no effect for the libxvid encoder.
2152 Set specific encoding flags. Possible values:
2157 Use four motion vector by macroblock.
2160 Enable high quality AC prediction.
2163 Only encode grayscale.
2166 Enable the use of global motion compensation (GMC).
2169 Enable quarter-pixel motion compensation.
2175 Place global headers in extradata instead of every keyframe.
2182 Set motion estimation method. Possible values in decreasing order of
2183 speed and increasing order of quality:
2187 Use no motion estimation (default).
2192 Enable advanced diamond zonal search for 16x16 blocks and half-pixel
2193 refinement for 16x16 blocks. @samp{x1} and @samp{log} are aliases for
2197 Enable all of the things described above, plus advanced diamond zonal
2198 search for 8x8 blocks, half-pixel refinement for 8x8 blocks, and motion
2199 estimation on chroma planes.
2202 Enable all of the things described above, plus extended 16x16 and 8x8
2207 Set macroblock decision algorithm. Possible values in the increasing
2212 Use macroblock comparing function algorithm (default).
2215 Enable rate distortion-based half pixel and quarter pixel refinement for
2219 Enable all of the things described above, plus rate distortion-based
2220 half pixel and quarter pixel refinement for 8x8 blocks, and rate
2221 distortion-based search using square pattern.
2225 Enable lumi masking adaptive quantization when set to 1. Default is 0
2229 Enable variance adaptive quantization when set to 1. Default is 0
2232 When combined with @option{lumi_aq}, the resulting quality will not
2233 be better than any of the two specified individually. In other
2234 words, the resulting quality will be the worse one of the two
2238 Set structural similarity (SSIM) displaying method. Possible values:
2242 Disable displaying of SSIM information.
2245 Output average SSIM at the end of encoding to stdout. The format of
2246 showing the average SSIM is:
2252 For users who are not familiar with C, %f means a float number, or
2253 a decimal (e.g. 0.939232).
2256 Output both per-frame SSIM data during encoding and average SSIM at
2257 the end of encoding to stdout. The format of per-frame information
2261 SSIM: avg: %1.3f min: %1.3f max: %1.3f
2264 For users who are not familiar with C, %1.3f means a float number
2265 rounded to 3 digits after the dot (e.g. 0.932).
2270 Set SSIM accuracy. Valid options are integers within the range of
2271 0-4, while 0 gives the most accurate result and 4 computes the
2278 MPEG-2 video encoder.
2283 @item seq_disp_ext @var{integer}
2284 Specifies if the encoder should write a sequence_display_extension to the
2289 Decide automatically to write it or not (this is the default) by checking if
2290 the data to be written is different from the default or unspecified values.
2304 @subsection Private options
2307 @item dpi @var{integer}
2308 Set physical density of pixels, in dots per inch, unset by default
2309 @item dpm @var{integer}
2310 Set physical density of pixels, in dots per meter, unset by default
2315 Apple ProRes encoder.
2317 FFmpeg contains 2 ProRes encoders, the prores-aw and prores-ks encoder.
2318 The used encoder can be chosen with the @code{-vcodec} option.
2320 @subsection Private Options for prores-ks
2323 @item profile @var{integer}
2324 Select the ProRes profile to encode
2333 @item quant_mat @var{integer}
2334 Select quantization matrix.
2343 If set to @var{auto}, the matrix matching the profile will be picked.
2344 If not set, the matrix providing the highest quality, @var{default}, will be
2347 @item bits_per_mb @var{integer}
2348 How many bits to allot for coding one macroblock. Different profiles use
2349 between 200 and 2400 bits per macroblock, the maximum is 8000.
2351 @item mbs_per_slice @var{integer}
2352 Number of macroblocks in each slice (1-8); the default value (8)
2353 should be good in almost all situations.
2355 @item vendor @var{string}
2356 Override the 4-byte vendor ID.
2357 A custom vendor ID like @var{apl0} would claim the stream was produced by
2360 @item alpha_bits @var{integer}
2361 Specify number of bits for alpha component.
2362 Possible values are @var{0}, @var{8} and @var{16}.
2363 Use @var{0} to disable alpha plane coding.
2367 @subsection Speed considerations
2369 In the default mode of operation the encoder has to honor frame constraints
2370 (i.e. not produce frames with size bigger than requested) while still making
2371 output picture as good as possible.
2372 A frame containing a lot of small details is harder to compress and the encoder
2373 would spend more time searching for appropriate quantizers for each slice.
2375 Setting a higher @option{bits_per_mb} limit will improve the speed.
2377 For the fastest encoding speed set the @option{qscale} parameter (4 is the
2378 recommended value) and do not set a size constraint.
2380 @section QSV encoders
2382 The family of Intel QuickSync Video encoders (MPEG-2, H.264 and HEVC)
2384 The ratecontrol method is selected as follows:
2388 When @option{global_quality} is specified, a quality-based mode is used.
2389 Specifically this means either
2392 @var{CQP} - constant quantizer scale, when the @option{qscale} codec flag is
2393 also set (the @option{-qscale} ffmpeg option).
2396 @var{LA_ICQ} - intelligent constant quality with lookahead, when the
2397 @option{look_ahead} option is also set.
2400 @var{ICQ} -- intelligent constant quality otherwise.
2404 Otherwise, a bitrate-based mode is used. For all of those, you should specify at
2405 least the desired average bitrate with the @option{b} option.
2408 @var{LA} - VBR with lookahead, when the @option{look_ahead} option is specified.
2411 @var{VCM} - video conferencing mode, when the @option{vcm} option is set.
2414 @var{CBR} - constant bitrate, when @option{maxrate} is specified and equal to
2415 the average bitrate.
2418 @var{VBR} - variable bitrate, when @option{maxrate} is specified, but is higher
2419 than the average bitrate.
2422 @var{AVBR} - average VBR mode, when @option{maxrate} is not specified. This mode
2423 is further configured by the @option{avbr_accuracy} and
2424 @option{avbr_convergence} options.
2428 Note that depending on your system, a different mode than the one you specified
2429 may be selected by the encoder. Set the verbosity level to @var{verbose} or
2430 higher to see the actual settings used by the QSV runtime.
2432 Additional libavcodec global options are mapped to MSDK options as follows:
2436 @option{g/gop_size} -> @option{GopPicSize}
2439 @option{bf/max_b_frames}+1 -> @option{GopRefDist}
2442 @option{rc_init_occupancy/rc_initial_buffer_occupancy} ->
2443 @option{InitialDelayInKB}
2446 @option{slices} -> @option{NumSlice}
2449 @option{refs} -> @option{NumRefFrame}
2452 @option{b_strategy/b_frame_strategy} -> @option{BRefType}
2455 @option{cgop/CLOSED_GOP} codec flag -> @option{GopOptFlag}
2458 For the @var{CQP} mode, the @option{i_qfactor/i_qoffset} and
2459 @option{b_qfactor/b_qoffset} set the difference between @var{QPP} and @var{QPI},
2460 and @var{QPP} and @var{QPB} respectively.
2463 Setting the @option{coder} option to the value @var{vlc} will make the H.264
2464 encoder use CAVLC instead of CABAC.
2473 @item iterative_dia_size
2474 dia size for the iterative motion estimation
2479 SMPTE VC-2 (previously BBC Dirac Pro). This codec was primarily aimed at
2480 professional broadcasting but since it supports yuv420, yuv422 and yuv444 at
2481 8 (limited range or full range), 10 or 12 bits, this makes it suitable for
2482 other tasks which require low overhead and low compression (like screen
2490 Sets target video bitrate. Usually that's around 1:6 of the uncompressed
2491 video bitrate (e.g. for 1920x1080 50fps yuv422p10 that's around 400Mbps). Higher
2492 values (close to the uncompressed bitrate) turn on lossless compression mode.
2495 Enables field coding when set (e.g. to tt - top field first) for interlaced
2496 inputs. Should increase compression with interlaced content as it splits the
2497 fields and encodes each separately.
2500 Sets the total amount of wavelet transforms to apply, between 1 and 5 (default).
2501 Lower values reduce compression and quality. Less capable decoders may not be
2502 able to handle values of @option{wavelet_depth} over 3.
2505 Sets the transform type. Currently only @var{5_3} (LeGall) and @var{9_7}
2507 are implemented, with 9_7 being the one with better compression and thus
2512 Sets the slice size for each slice. Larger values result in better compression.
2513 For compatibility with other more limited decoders use @option{slice_width} of
2514 32 and @option{slice_height} of 8.
2517 Sets the undershoot tolerance of the rate control system in percent. This is
2518 to prevent an expensive search from being run.
2521 Sets the quantization matrix preset to use by default or when @option{wavelet_depth}
2526 Uses the default quantization matrix from the specifications, extended with
2527 values for the fifth level. This provides a good balance between keeping detail
2528 and omitting artifacts.
2532 Use a completely zeroed out quantization matrix. This increases PSNR but might
2533 reduce perception. Use in bogus benchmarks.
2537 Reduces detail but attempts to preserve color at extremely low bitrates.
2542 @c man end VIDEO ENCODERS
2544 @chapter Subtitles Encoders
2545 @c man begin SUBTITLES ENCODERS
2549 This codec encodes the bitmap subtitle format that is used in DVDs.
2550 Typically they are stored in VOBSUB file pairs (*.idx + *.sub),
2551 and they can also be used in Matroska files.
2557 When set to 1, enable a work-around that makes the number of pixel rows
2558 even in all subtitles. This fixes a problem with some players that
2559 cut off the bottom row if the number is odd. The work-around just adds
2560 a fully transparent row if needed. The overhead is low, typically
2561 one byte per subtitle on average.
2563 By default, this work-around is disabled.
2566 @c man end SUBTITLES ENCODERS