4 Encoders are configured elements in FFmpeg which allow the encoding of
7 When you configure your FFmpeg build, all the supported native encoders
8 are enabled by default. Encoders requiring an external library must be enabled
9 manually via the corresponding @code{--enable-lib} option. You can list all
10 available encoders using the configure option @code{--list-encoders}.
12 You can disable all the encoders with the configure option
13 @code{--disable-encoders} and selectively enable / disable single encoders
14 with the options @code{--enable-encoder=@var{ENCODER}} /
15 @code{--disable-encoder=@var{ENCODER}}.
17 The option @code{-encoders} of the ff* tools will display the list of
22 @chapter Audio Encoders
23 @c man begin AUDIO ENCODERS
25 A description of some of the currently available audio encoders
31 Advanced Audio Coding (AAC) encoder.
33 This encoder is the default AAC encoder, natively implemented into FFmpeg. Its
34 quality is on par or better than libfdk_aac at the default bitrate of 128kbps.
35 This encoder also implements more options, profiles and samplerates than
36 other encoders (with only the AAC-HE profile pending to be implemented) so this
37 encoder has become the default and is the recommended choice.
43 Set bit rate in bits/s. Setting this automatically activates constant bit rate
44 (CBR) mode. If this option is unspecified it is set to 128kbps.
47 Set quality for variable bit rate (VBR) mode. This option is valid only using
48 the @command{ffmpeg} command-line tool. For library interface users, use
49 @option{global_quality}.
52 Set cutoff frequency. If unspecified will allow the encoder to dynamically
53 adjust the cutoff to improve clarity on low bitrates.
56 Set AAC encoder coding method. Possible values:
60 Two loop searching (TLS) method.
62 This method first sets quantizers depending on band thresholds and then tries
63 to find an optimal combination by adding or subtracting a specific value from
64 all quantizers and adjusting some individual quantizer a little. Will tune
65 itself based on whether @option{aac_is}, @option{aac_ms} and @option{aac_pns}
67 This is the default choice for a coder.
70 Average noise to mask ratio (ANMR) trellis-based solution.
72 This is an experimental coder which currently produces a lower quality, is more
73 unstable and is slower than the default twoloop coder but has potential.
74 Currently has no support for the @option{aac_is} or @option{aac_pns} options.
75 Not currently recommended.
78 Constant quantizer method.
80 This method sets a constant quantizer for all bands. This is the fastest of all
81 the methods and has no rate control or support for @option{aac_is} or
88 Sets mid/side coding mode. The default value of "auto" will automatically use
89 M/S with bands which will benefit from such coding. Can be forced for all bands
90 using the value "enable", which is mainly useful for debugging or disabled using
94 Sets intensity stereo coding tool usage. By default, it's enabled and will
95 automatically toggle IS for similar pairs of stereo bands if it's benefitial.
96 Can be disabled for debugging by setting the value to "disable".
99 Uses perceptual noise substitution to replace low entropy high frequency bands
100 with imperceivable white noise during the decoding process. By default, it's
101 enabled, but can be disabled for debugging purposes by using "disable".
104 Enables the use of a multitap FIR filter which spans through the high frequency
105 bands to hide quantization noise during the encoding process and is reverted
106 by the decoder. As well as decreasing unpleasant artifacts in the high range
107 this also reduces the entropy in the high bands and allows for more bits to
108 be used by the mid-low bands. By default it's enabled but can be disabled for
109 debugging by setting the option to "disable".
112 Enables the use of the long term prediction extension which increases coding
113 efficiency in very low bandwidth situations such as encoding of voice or
114 solo piano music by extending constant harmonic peaks in bands throughout
115 frames. This option is implied by profile:a aac_low and is incompatible with
116 aac_pred. Use in conjunction with @option{-ar} to decrease the samplerate.
119 Enables the use of a more traditional style of prediction where the spectral
120 coefficients transmitted are replaced by the difference of the current
121 coefficients minus the previous "predicted" coefficients. In theory and sometimes
122 in practice this can improve quality for low to mid bitrate audio.
123 This option implies the aac_main profile and is incompatible with aac_ltp.
126 Sets the encoding profile, possible values:
130 The default, AAC "Low-complexity" profile. Is the most compatible and produces
134 Equivalent to @code{-profile:a aac_low -aac_pns 0}. PNS was introduced with the
135 MPEG4 specifications.
138 Long term prediction profile, is enabled by and will enable the @option{aac_ltp}
139 option. Introduced in MPEG4.
142 Main-type prediction profile, is enabled by and will enable the @option{aac_pred}
143 option. Introduced in MPEG2.
146 If this option is unspecified it is set to @samp{aac_low}.
149 @section ac3 and ac3_fixed
153 These encoders implement part of ATSC A/52:2010 and ETSI TS 102 366, as well as
154 the undocumented RealAudio 3 (a.k.a. dnet).
156 The @var{ac3} encoder uses floating-point math, while the @var{ac3_fixed}
157 encoder only uses fixed-point integer math. This does not mean that one is
158 always faster, just that one or the other may be better suited to a
159 particular system. The floating-point encoder will generally produce better
160 quality audio for a given bitrate. The @var{ac3_fixed} encoder is not the
161 default codec for any of the output formats, so it must be specified explicitly
162 using the option @code{-acodec ac3_fixed} in order to use it.
164 @subsection AC-3 Metadata
166 The AC-3 metadata options are used to set parameters that describe the audio,
167 but in most cases do not affect the audio encoding itself. Some of the options
168 do directly affect or influence the decoding and playback of the resulting
169 bitstream, while others are just for informational purposes. A few of the
170 options will add bits to the output stream that could otherwise be used for
171 audio data, and will thus affect the quality of the output. Those will be
172 indicated accordingly with a note in the option list below.
174 These parameters are described in detail in several publicly-available
177 @item @uref{http://www.atsc.org/cms/standards/a_52-2010.pdf,A/52:2010 - Digital Audio Compression (AC-3) (E-AC-3) Standard}
178 @item @uref{http://www.atsc.org/cms/standards/a_54a_with_corr_1.pdf,A/54 - Guide to the Use of the ATSC Digital Television Standard}
179 @item @uref{http://www.dolby.com/uploadedFiles/zz-_Shared_Assets/English_PDFs/Professional/18_Metadata.Guide.pdf,Dolby Metadata Guide}
180 @item @uref{http://www.dolby.com/uploadedFiles/zz-_Shared_Assets/English_PDFs/Professional/46_DDEncodingGuidelines.pdf,Dolby Digital Professional Encoding Guidelines}
183 @subsubsection Metadata Control Options
187 @item -per_frame_metadata @var{boolean}
188 Allow Per-Frame Metadata. Specifies if the encoder should check for changing
189 metadata for each frame.
192 The metadata values set at initialization will be used for every frame in the
195 Metadata values can be changed before encoding each frame.
200 @subsubsection Downmix Levels
204 @item -center_mixlev @var{level}
205 Center Mix Level. The amount of gain the decoder should apply to the center
206 channel when downmixing to stereo. This field will only be written to the
207 bitstream if a center channel is present. The value is specified as a scale
208 factor. There are 3 valid values:
213 Apply -4.5dB gain (default)
218 @item -surround_mixlev @var{level}
219 Surround Mix Level. The amount of gain the decoder should apply to the surround
220 channel(s) when downmixing to stereo. This field will only be written to the
221 bitstream if one or more surround channels are present. The value is specified
222 as a scale factor. There are 3 valid values:
227 Apply -6dB gain (default)
229 Silence Surround Channel(s)
234 @subsubsection Audio Production Information
235 Audio Production Information is optional information describing the mixing
236 environment. Either none or both of the fields are written to the bitstream.
240 @item -mixing_level @var{number}
241 Mixing Level. Specifies peak sound pressure level (SPL) in the production
242 environment when the mix was mastered. Valid values are 80 to 111, or -1 for
243 unknown or not indicated. The default value is -1, but that value cannot be
244 used if the Audio Production Information is written to the bitstream. Therefore,
245 if the @code{room_type} option is not the default value, the @code{mixing_level}
246 option must not be -1.
248 @item -room_type @var{type}
249 Room Type. Describes the equalization used during the final mixing session at
250 the studio or on the dubbing stage. A large room is a dubbing stage with the
251 industry standard X-curve equalization; a small room has flat equalization.
252 This field will not be written to the bitstream if both the @code{mixing_level}
253 option and the @code{room_type} option have the default values.
257 Not Indicated (default)
268 @subsubsection Other Metadata Options
272 @item -copyright @var{boolean}
273 Copyright Indicator. Specifies whether a copyright exists for this audio.
277 No Copyright Exists (default)
283 @item -dialnorm @var{value}
284 Dialogue Normalization. Indicates how far the average dialogue level of the
285 program is below digital 100% full scale (0 dBFS). This parameter determines a
286 level shift during audio reproduction that sets the average volume of the
287 dialogue to a preset level. The goal is to match volume level between program
288 sources. A value of -31dB will result in no volume level change, relative to
289 the source volume, during audio reproduction. Valid values are whole numbers in
290 the range -31 to -1, with -31 being the default.
292 @item -dsur_mode @var{mode}
293 Dolby Surround Mode. Specifies whether the stereo signal uses Dolby Surround
294 (Pro Logic). This field will only be written to the bitstream if the audio
295 stream is stereo. Using this option does @b{NOT} mean the encoder will actually
296 apply Dolby Surround processing.
300 Not Indicated (default)
303 Not Dolby Surround Encoded
306 Dolby Surround Encoded
309 @item -original @var{boolean}
310 Original Bit Stream Indicator. Specifies whether this audio is from the
311 original source and not a copy.
318 Original Source (default)
323 @subsection Extended Bitstream Information
324 The extended bitstream options are part of the Alternate Bit Stream Syntax as
325 specified in Annex D of the A/52:2010 standard. It is grouped into 2 parts.
326 If any one parameter in a group is specified, all values in that group will be
327 written to the bitstream. Default values are used for those that are written
328 but have not been specified. If the mixing levels are written, the decoder
329 will use these values instead of the ones specified in the @code{center_mixlev}
330 and @code{surround_mixlev} options if it supports the Alternate Bit Stream
333 @subsubsection Extended Bitstream Information - Part 1
337 @item -dmix_mode @var{mode}
338 Preferred Stereo Downmix Mode. Allows the user to select either Lt/Rt
339 (Dolby Surround) or Lo/Ro (normal stereo) as the preferred stereo downmix mode.
343 Not Indicated (default)
346 Lt/Rt Downmix Preferred
349 Lo/Ro Downmix Preferred
352 @item -ltrt_cmixlev @var{level}
353 Lt/Rt Center Mix Level. The amount of gain the decoder should apply to the
354 center channel when downmixing to stereo in Lt/Rt mode.
367 Apply -4.5dB gain (default)
371 Silence Center Channel
374 @item -ltrt_surmixlev @var{level}
375 Lt/Rt Surround Mix Level. The amount of gain the decoder should apply to the
376 surround channel(s) when downmixing to stereo in Lt/Rt mode.
385 Apply -6.0dB gain (default)
387 Silence Surround Channel(s)
390 @item -loro_cmixlev @var{level}
391 Lo/Ro Center Mix Level. The amount of gain the decoder should apply to the
392 center channel when downmixing to stereo in Lo/Ro mode.
405 Apply -4.5dB gain (default)
409 Silence Center Channel
412 @item -loro_surmixlev @var{level}
413 Lo/Ro Surround Mix Level. The amount of gain the decoder should apply to the
414 surround channel(s) when downmixing to stereo in Lo/Ro mode.
423 Apply -6.0dB gain (default)
425 Silence Surround Channel(s)
430 @subsubsection Extended Bitstream Information - Part 2
434 @item -dsurex_mode @var{mode}
435 Dolby Surround EX Mode. Indicates whether the stream uses Dolby Surround EX
436 (7.1 matrixed to 5.1). Using this option does @b{NOT} mean the encoder will actually
437 apply Dolby Surround EX processing.
441 Not Indicated (default)
444 Dolby Surround EX Off
450 @item -dheadphone_mode @var{mode}
451 Dolby Headphone Mode. Indicates whether the stream uses Dolby Headphone
452 encoding (multi-channel matrixed to 2.0 for use with headphones). Using this
453 option does @b{NOT} mean the encoder will actually apply Dolby Headphone
458 Not Indicated (default)
467 @item -ad_conv_type @var{type}
468 A/D Converter Type. Indicates whether the audio has passed through HDCD A/D
473 Standard A/D Converter (default)
481 @subsection Other AC-3 Encoding Options
485 @item -stereo_rematrixing @var{boolean}
486 Stereo Rematrixing. Enables/Disables use of rematrixing for stereo input. This
487 is an optional AC-3 feature that increases quality by selectively encoding
488 the left/right channels as mid/side. This option is enabled by default, and it
489 is highly recommended that it be left as enabled except for testing purposes.
491 @item cutoff @var{frequency}
492 Set lowpass cutoff frequency. If unspecified, the encoder selects a default
493 determined by various other encoding parameters.
497 @subsection Floating-Point-Only AC-3 Encoding Options
499 These options are only valid for the floating-point encoder and do not exist
500 for the fixed-point encoder due to the corresponding features not being
501 implemented in fixed-point.
505 @item -channel_coupling @var{boolean}
506 Enables/Disables use of channel coupling, which is an optional AC-3 feature
507 that increases quality by combining high frequency information from multiple
508 channels into a single channel. The per-channel high frequency information is
509 sent with less accuracy in both the frequency and time domains. This allows
510 more bits to be used for lower frequencies while preserving enough information
511 to reconstruct the high frequencies. This option is enabled by default for the
512 floating-point encoder and should generally be left as enabled except for
513 testing purposes or to increase encoding speed.
517 Selected by Encoder (default)
520 Disable Channel Coupling
523 Enable Channel Coupling
526 @item -cpl_start_band @var{number}
527 Coupling Start Band. Sets the channel coupling start band, from 1 to 15. If a
528 value higher than the bandwidth is used, it will be reduced to 1 less than the
529 coupling end band. If @var{auto} is used, the start band will be determined by
530 the encoder based on the bit rate, sample rate, and channel layout. This option
531 has no effect if channel coupling is disabled.
535 Selected by Encoder (default)
543 FLAC (Free Lossless Audio Codec) Encoder
547 The following options are supported by FFmpeg's flac encoder.
550 @item compression_level
551 Sets the compression level, which chooses defaults for many other options
552 if they are not set explicitly. Valid values are from 0 to 12, 5 is the
556 Sets the size of the frames in samples per channel.
558 @item lpc_coeff_precision
559 Sets the LPC coefficient precision, valid values are from 1 to 15, 15 is the
563 Sets the first stage LPC algorithm
569 fixed LPC coefficients
577 Number of passes to use for Cholesky factorization during LPC analysis
579 @item min_partition_order
580 The minimum partition order
582 @item max_partition_order
583 The maximum partition order
585 @item prediction_order_method
600 The mode is chosen automatically for each frame
602 Chanels are independently coded
608 @item exact_rice_parameters
609 Chooses if rice parameters are calculated exactly or approximately.
610 if set to 1 then they are chosen exactly, which slows the code down slightly and
611 improves compression slightly.
613 @item multi_dim_quant
614 Multi Dimensional Quantization. If set to 1 then a 2nd stage LPC algorithm is
615 applied after the first stage to finetune the coefficients. This is quite slow
616 and slightly improves compression.
625 This is a native FFmpeg encoder for the Opus format. Currently its in development and
626 only implements the CELT part of the codec. Its quality is usually worse and at best
627 is equal to the libopus encoder.
633 Set bit rate in bits/s. If unspecified it uses the number of channels and the layout
634 to make a good guess.
637 Sets the maximum delay in milliseconds. Lower delays than 20ms will very quickly
641 @anchor{libfdk-aac-enc}
644 libfdk-aac AAC (Advanced Audio Coding) encoder wrapper.
646 The libfdk-aac library is based on the Fraunhofer FDK AAC code from
649 Requires the presence of the libfdk-aac headers and library during
650 configuration. You need to explicitly configure the build with
651 @code{--enable-libfdk-aac}. The library is also incompatible with GPL,
652 so if you allow the use of GPL, you should configure with
653 @code{--enable-gpl --enable-nonfree --enable-libfdk-aac}.
655 This encoder is considered to produce output on par or worse at 128kbps to the
656 @ref{aacenc,,the native FFmpeg AAC encoder} but can often produce better
657 sounding audio at identical or lower bitrates and has support for the
660 VBR encoding, enabled through the @option{vbr} or @option{flags
661 +qscale} options, is experimental and only works with some
662 combinations of parameters.
664 Support for encoding 7.1 audio is only available with libfdk-aac 0.1.3 or
667 For more information see the fdk-aac project at
668 @url{http://sourceforge.net/p/opencore-amr/fdk-aac/}.
672 The following options are mapped on the shared FFmpeg codec options.
676 Set bit rate in bits/s. If the bitrate is not explicitly specified, it
677 is automatically set to a suitable value depending on the selected
680 In case VBR mode is enabled the option is ignored.
683 Set audio sampling rate (in Hz).
686 Set the number of audio channels.
689 Enable fixed quality, VBR (Variable Bit Rate) mode.
690 Note that VBR is implicitly enabled when the @option{vbr} value is
694 Set cutoff frequency. If not specified (or explicitly set to 0) it
695 will use a value automatically computed by the library. Default value
701 The following profiles are recognized:
704 Low Complexity AAC (LC)
707 High Efficiency AAC (HE-AAC)
710 High Efficiency AAC version 2 (HE-AACv2)
716 Enhanced Low Delay AAC (ELD)
719 If not specified it is set to @samp{aac_low}.
722 The following are private options of the libfdk_aac encoder.
726 Enable afterburner feature if set to 1, disabled if set to 0. This
727 improves the quality but also the required processing power.
732 Enable SBR (Spectral Band Replication) for ELD if set to 1, disabled
738 Set SBR/PS signaling style.
740 It can assume one of the following values:
743 choose signaling implicitly (explicit hierarchical by default,
744 implicit if global header is disabled)
747 implicit backwards compatible signaling
750 explicit SBR, implicit PS signaling
752 @item explicit_hierarchical
753 explicit hierarchical signaling
756 Default value is @samp{default}.
759 Output LATM/LOAS encapsulated data if set to 1, disabled if set to 0.
764 Set StreamMuxConfig and PCE repetition period (in frames) for sending
765 in-band configuration buffers within LATM/LOAS transport layer.
767 Must be a 16-bits non-negative integer.
772 Set VBR mode, from 1 to 5. 1 is lowest quality (though still pretty
773 good) and 5 is highest quality. A value of 0 will disable VBR, and CBR
774 (Constant Bit Rate) is enabled.
776 Currently only the @samp{aac_low} profile supports VBR encoding.
778 VBR modes 1-5 correspond to roughly the following average bit rates:
790 about 80-96 kbps/channel
800 Use @command{ffmpeg} to convert an audio file to VBR AAC in an M4A (MP4)
803 ffmpeg -i input.wav -codec:a libfdk_aac -vbr 3 output.m4a
807 Use @command{ffmpeg} to convert an audio file to CBR 64k kbps AAC, using the
808 High-Efficiency AAC profile:
810 ffmpeg -i input.wav -c:a libfdk_aac -profile:a aac_he -b:a 64k output.m4a
817 LAME (Lame Ain't an MP3 Encoder) MP3 encoder wrapper.
819 Requires the presence of the libmp3lame headers and library during
820 configuration. You need to explicitly configure the build with
821 @code{--enable-libmp3lame}.
823 See @ref{libshine} for a fixed-point MP3 encoder, although with a
828 The following options are supported by the libmp3lame wrapper. The
829 @command{lame}-equivalent of the options are listed in parentheses.
833 Set bitrate expressed in bits/s for CBR or ABR. LAME @code{bitrate} is
834 expressed in kilobits/s.
837 Set constant quality setting for VBR. This option is valid only
838 using the @command{ffmpeg} command-line tool. For library interface
839 users, use @option{global_quality}.
841 @item compression_level (@emph{-q})
842 Set algorithm quality. Valid arguments are integers in the 0-9 range,
843 with 0 meaning highest quality but slowest, and 9 meaning fastest
844 while producing the worst quality.
846 @item cutoff (@emph{--lowpass})
847 Set lowpass cutoff frequency. If unspecified, the encoder dynamically
851 Enable use of bit reservoir when set to 1. Default value is 1. LAME
852 has this enabled by default, but can be overridden by use
853 @option{--nores} option.
855 @item joint_stereo (@emph{-m j})
856 Enable the encoder to use (on a frame by frame basis) either L/R
857 stereo or mid/side stereo. Default value is 1.
859 @item abr (@emph{--abr})
860 Enable the encoder to use ABR when set to 1. The @command{lame}
861 @option{--abr} sets the target bitrate, while this options only
862 tells FFmpeg to use ABR still relies on @option{b} to set bitrate.
866 @section libopencore-amrnb
868 OpenCORE Adaptive Multi-Rate Narrowband encoder.
870 Requires the presence of the libopencore-amrnb headers and library during
871 configuration. You need to explicitly configure the build with
872 @code{--enable-libopencore-amrnb --enable-version3}.
874 This is a mono-only encoder. Officially it only supports 8000Hz sample rate,
875 but you can override it by setting @option{strict} to @samp{unofficial} or
883 Set bitrate in bits per second. Only the following bitrates are supported,
884 otherwise libavcodec will round to the nearest valid bitrate.
898 Allow discontinuous transmission (generate comfort noise) when set to 1. The
899 default value is 0 (disabled).
905 libopus Opus Interactive Audio Codec encoder wrapper.
907 Requires the presence of the libopus headers and library during
908 configuration. You need to explicitly configure the build with
909 @code{--enable-libopus}.
911 @subsection Option Mapping
913 Most libopus options are modelled after the @command{opusenc} utility from
914 opus-tools. The following is an option mapping chart describing options
915 supported by the libopus wrapper, and their @command{opusenc}-equivalent
920 @item b (@emph{bitrate})
921 Set the bit rate in bits/s. FFmpeg's @option{b} option is
922 expressed in bits/s, while @command{opusenc}'s @option{bitrate} in
925 @item vbr (@emph{vbr}, @emph{hard-cbr}, and @emph{cvbr})
926 Set VBR mode. The FFmpeg @option{vbr} option has the following
927 valid arguments, with the @command{opusenc} equivalent options
931 @item off (@emph{hard-cbr})
932 Use constant bit rate encoding.
934 @item on (@emph{vbr})
935 Use variable bit rate encoding (the default).
937 @item constrained (@emph{cvbr})
938 Use constrained variable bit rate encoding.
941 @item compression_level (@emph{comp})
942 Set encoding algorithm complexity. Valid options are integers in
943 the 0-10 range. 0 gives the fastest encodes but lower quality, while 10
944 gives the highest quality but slowest encoding. The default is 10.
946 @item frame_duration (@emph{framesize})
947 Set maximum frame size, or duration of a frame in milliseconds. The
948 argument must be exactly the following: 2.5, 5, 10, 20, 40, 60. Smaller
949 frame sizes achieve lower latency but less quality at a given bitrate.
950 Sizes greater than 20ms are only interesting at fairly low bitrates.
953 @item packet_loss (@emph{expect-loss})
954 Set expected packet loss percentage. The default is 0.
956 @item application (N.A.)
957 Set intended application type. Valid options are listed below:
961 Favor improved speech intelligibility.
963 Favor faithfulness to the input (the default).
965 Restrict to only the lowest delay modes.
969 Set cutoff bandwidth in Hz. The argument must be exactly one of the
970 following: 4000, 6000, 8000, 12000, or 20000, corresponding to
971 narrowband, mediumband, wideband, super wideband, and fullband
972 respectively. The default is 0 (cutoff disabled).
974 @item mapping_family (@emph{mapping_family})
975 Set channel mapping family to be used by the encoder. The default value of -1
976 uses mapping family 0 for mono and stereo inputs, and mapping family 1
977 otherwise. The default also disables the surround masking and LFE bandwidth
978 optimzations in libopus, and requires that the input contains 8 channels or
981 Other values include 0 for mono and stereo, 1 for surround sound with masking
982 and LFE bandwidth optimizations, and 255 for independent streams with an
983 unspecified channel layout.
990 Shine Fixed-Point MP3 encoder wrapper.
992 Shine is a fixed-point MP3 encoder. It has a far better performance on
993 platforms without an FPU, e.g. armel CPUs, and some phones and tablets.
994 However, as it is more targeted on performance than quality, it is not on par
995 with LAME and other production-grade encoders quality-wise. Also, according to
996 the project's homepage, this encoder may not be free of bugs as the code was
997 written a long time ago and the project was dead for at least 5 years.
999 This encoder only supports stereo and mono input. This is also CBR-only.
1001 The original project (last updated in early 2007) is at
1002 @url{http://sourceforge.net/projects/libshine-fxp/}. We only support the
1003 updated fork by the Savonet/Liquidsoap project at @url{https://github.com/savonet/shine}.
1005 Requires the presence of the libshine headers and library during
1006 configuration. You need to explicitly configure the build with
1007 @code{--enable-libshine}.
1009 See also @ref{libmp3lame}.
1013 The following options are supported by the libshine wrapper. The
1014 @command{shineenc}-equivalent of the options are listed in parentheses.
1018 Set bitrate expressed in bits/s for CBR. @command{shineenc} @option{-b} option
1019 is expressed in kilobits/s.
1025 TwoLAME MP2 encoder wrapper.
1027 Requires the presence of the libtwolame headers and library during
1028 configuration. You need to explicitly configure the build with
1029 @code{--enable-libtwolame}.
1033 The following options are supported by the libtwolame wrapper. The
1034 @command{twolame}-equivalent options follow the FFmpeg ones and are in
1039 Set bitrate expressed in bits/s for CBR. @command{twolame} @option{b}
1040 option is expressed in kilobits/s. Default value is 128k.
1043 Set quality for experimental VBR support. Maximum value range is
1044 from -50 to 50, useful range is from -10 to 10. The higher the
1045 value, the better the quality. This option is valid only using the
1046 @command{ffmpeg} command-line tool. For library interface users,
1047 use @option{global_quality}.
1049 @item mode (@emph{--mode})
1050 Set the mode of the resulting audio. Possible values:
1054 Choose mode automatically based on the input. This is the default.
1065 @item psymodel (@emph{--psyc-mode})
1066 Set psychoacoustic model to use in encoding. The argument must be
1067 an integer between -1 and 4, inclusive. The higher the value, the
1068 better the quality. The default value is 3.
1070 @item energy_levels (@emph{--energy})
1071 Enable energy levels extensions when set to 1. The default value is
1074 @item error_protection (@emph{--protect})
1075 Enable CRC error protection when set to 1. The default value is 0
1078 @item copyright (@emph{--copyright})
1079 Set MPEG audio copyright flag when set to 1. The default value is 0
1082 @item original (@emph{--original})
1083 Set MPEG audio original flag when set to 1. The default value is 0
1088 @section libvo-amrwbenc
1090 VisualOn Adaptive Multi-Rate Wideband encoder.
1092 Requires the presence of the libvo-amrwbenc headers and library during
1093 configuration. You need to explicitly configure the build with
1094 @code{--enable-libvo-amrwbenc --enable-version3}.
1096 This is a mono-only encoder. Officially it only supports 16000Hz sample
1097 rate, but you can override it by setting @option{strict} to
1098 @samp{unofficial} or lower.
1105 Set bitrate in bits/s. Only the following bitrates are supported, otherwise
1106 libavcodec will round to the nearest valid bitrate.
1121 Allow discontinuous transmission (generate comfort noise) when set to 1. The
1122 default value is 0 (disabled).
1128 libvorbis encoder wrapper.
1130 Requires the presence of the libvorbisenc headers and library during
1131 configuration. You need to explicitly configure the build with
1132 @code{--enable-libvorbis}.
1136 The following options are supported by the libvorbis wrapper. The
1137 @command{oggenc}-equivalent of the options are listed in parentheses.
1139 To get a more accurate and extensive documentation of the libvorbis
1140 options, consult the libvorbisenc's and @command{oggenc}'s documentations.
1141 See @url{http://xiph.org/vorbis/},
1142 @url{http://wiki.xiph.org/Vorbis-tools}, and oggenc(1).
1146 Set bitrate expressed in bits/s for ABR. @command{oggenc} @option{-b} is
1147 expressed in kilobits/s.
1150 Set constant quality setting for VBR. The value should be a float
1151 number in the range of -1.0 to 10.0. The higher the value, the better
1152 the quality. The default value is @samp{3.0}.
1154 This option is valid only using the @command{ffmpeg} command-line tool.
1155 For library interface users, use @option{global_quality}.
1157 @item cutoff (@emph{--advanced-encode-option lowpass_frequency=N})
1158 Set cutoff bandwidth in Hz, a value of 0 disables cutoff. @command{oggenc}'s
1159 related option is expressed in kHz. The default value is @samp{0} (cutoff
1162 @item minrate (@emph{-m})
1163 Set minimum bitrate expressed in bits/s. @command{oggenc} @option{-m} is
1164 expressed in kilobits/s.
1166 @item maxrate (@emph{-M})
1167 Set maximum bitrate expressed in bits/s. @command{oggenc} @option{-M} is
1168 expressed in kilobits/s. This only has effect on ABR mode.
1170 @item iblock (@emph{--advanced-encode-option impulse_noisetune=N})
1171 Set noise floor bias for impulse blocks. The value is a float number from
1172 -15.0 to 0.0. A negative bias instructs the encoder to pay special attention
1173 to the crispness of transients in the encoded audio. The tradeoff for better
1174 transient response is a higher bitrate.
1181 A wrapper providing WavPack encoding through libwavpack.
1183 Only lossless mode using 32-bit integer samples is supported currently.
1185 Requires the presence of the libwavpack headers and library during
1186 configuration. You need to explicitly configure the build with
1187 @code{--enable-libwavpack}.
1189 Note that a libavcodec-native encoder for the WavPack codec exists so users can
1190 encode audios with this codec without using this encoder. See @ref{wavpackenc}.
1194 @command{wavpack} command line utility's corresponding options are listed in
1195 parentheses, if any.
1198 @item frame_size (@emph{--blocksize})
1201 @item compression_level
1202 Set speed vs. compression tradeoff. Acceptable arguments are listed below:
1209 Normal (default) settings.
1214 @item 3 (@emph{-hh})
1217 @item 4-8 (@emph{-hh -x}@var{EXTRAPROC})
1218 Same as @samp{3}, but with extra processing enabled.
1220 @samp{4} is the same as @option{-x2} and @samp{8} is the same as @option{-x6}.
1228 Motion JPEG encoder.
1234 Set the huffman encoding strategy. Possible values:
1238 Use the default huffman tables. This is the default strategy.
1241 Compute and use optimal huffman tables.
1249 WavPack lossless audio encoder.
1251 This is a libavcodec-native WavPack encoder. There is also an encoder based on
1252 libwavpack, but there is virtually no reason to use that encoder.
1254 See also @ref{libwavpack}.
1258 The equivalent options for @command{wavpack} command line utility are listed in
1261 @subsubsection Shared options
1263 The following shared options are effective for this encoder. Only special notes
1264 about this particular encoder will be documented here. For the general meaning
1265 of the options, see @ref{codec-options,,the Codec Options chapter}.
1268 @item frame_size (@emph{--blocksize})
1269 For this encoder, the range for this option is between 128 and 131072. Default
1270 is automatically decided based on sample rate and number of channel.
1272 For the complete formula of calculating default, see
1273 @file{libavcodec/wavpackenc.c}.
1275 @item compression_level (@emph{-f}, @emph{-h}, @emph{-hh}, and @emph{-x})
1276 This option's syntax is consistent with @ref{libwavpack}'s.
1279 @subsubsection Private options
1282 @item joint_stereo (@emph{-j})
1283 Set whether to enable joint stereo. Valid values are:
1287 Force mid/side audio encoding.
1288 @item off (@emph{0})
1289 Force left/right audio encoding.
1291 Let the encoder decide automatically.
1295 Set whether to enable optimization for mono. This option is only effective for
1296 non-mono streams. Available values:
1307 @c man end AUDIO ENCODERS
1309 @chapter Video Encoders
1310 @c man begin VIDEO ENCODERS
1312 A description of some of the currently available video encoders
1317 Vidvox Hap video encoder.
1322 @item format @var{integer}
1323 Specifies the Hap format to encode.
1331 Default value is @option{hap}.
1333 @item chunks @var{integer}
1334 Specifies the number of chunks to split frames into, between 1 and 64. This
1335 permits multithreaded decoding of large frames, potentially at the cost of
1336 data-rate. The encoder may modify this value to divide frames evenly.
1338 Default value is @var{1}.
1340 @item compressor @var{integer}
1341 Specifies the second-stage compressor to use. If set to @option{none},
1342 @option{chunks} will be limited to 1, as chunked uncompressed frames offer no
1350 Default value is @option{snappy}.
1356 The native jpeg 2000 encoder is lossy by default, the @code{-q:v}
1357 option can be used to set the encoding quality. Lossless encoding
1358 can be selected with @code{-pred 1}.
1364 Can be set to either @code{j2k} or @code{jp2} (the default) that
1365 makes it possible to store non-rgb pix_fmts.
1371 Kvazaar H.265/HEVC encoder.
1373 Requires the presence of the libkvazaar headers and library during
1374 configuration. You need to explicitly configure the build with
1375 @option{--enable-libkvazaar}.
1382 Set target video bitrate in bit/s and enable rate control.
1384 @item kvazaar-params
1385 Set kvazaar parameters as a list of @var{name}=@var{value} pairs separated
1386 by commas (,). See kvazaar documentation for a list of options.
1390 @section libopenh264
1392 Cisco libopenh264 H.264/MPEG-4 AVC encoder wrapper.
1394 This encoder requires the presence of the libopenh264 headers and
1395 library during configuration. You need to explicitly configure the
1396 build with @code{--enable-libopenh264}. The library is detected using
1397 @command{pkg-config}.
1399 For more information about the library see
1400 @url{http://www.openh264.org}.
1404 The following FFmpeg global options affect the configurations of the
1405 libopenh264 encoder.
1409 Set the bitrate (as a number of bits per second).
1415 Set the max bitrate (as a number of bits per second).
1417 @item flags +global_header
1418 Set global header in the bitstream.
1421 Set the number of slices, used in parallelized encoding. Default value
1422 is 0. This is only used when @option{slice_mode} is set to
1426 Set slice mode. Can assume one of the following possible values:
1430 a fixed number of slices
1432 one slice per row of macroblocks
1434 automatic number of slices according to number of threads
1439 Default value is @samp{auto}.
1442 Enable loop filter, if set to 1 (automatically enabled). To disable
1446 Set profile restrictions. If set to the value of @samp{main} enable
1447 CABAC (set the @code{SEncParamExt.iEntropyCodingModeFlag} flag to 1).
1450 Set maximum NAL size in bytes.
1452 @item allow_skip_frames
1453 Allow skipping frames to hit the target bitrate if set to 1.
1458 libtheora Theora encoder wrapper.
1460 Requires the presence of the libtheora headers and library during
1461 configuration. You need to explicitly configure the build with
1462 @code{--enable-libtheora}.
1464 For more information about the libtheora project see
1465 @url{http://www.theora.org/}.
1469 The following global options are mapped to internal libtheora options
1470 which affect the quality and the bitrate of the encoded stream.
1474 Set the video bitrate in bit/s for CBR (Constant Bit Rate) mode. In
1475 case VBR (Variable Bit Rate) mode is enabled this option is ignored.
1478 Used to enable constant quality mode (VBR) encoding through the
1479 @option{qscale} flag, and to enable the @code{pass1} and @code{pass2}
1485 @item global_quality
1486 Set the global quality as an integer in lambda units.
1488 Only relevant when VBR mode is enabled with @code{flags +qscale}. The
1489 value is converted to QP units by dividing it by @code{FF_QP2LAMBDA},
1490 clipped in the [0 - 10] range, and then multiplied by 6.3 to get a
1491 value in the native libtheora range [0-63]. A higher value corresponds
1492 to a higher quality.
1495 Enable VBR mode when set to a non-negative value, and set constant
1496 quality value as a double floating point value in QP units.
1498 The value is clipped in the [0-10] range, and then multiplied by 6.3
1499 to get a value in the native libtheora range [0-63].
1501 This option is valid only using the @command{ffmpeg} command-line
1502 tool. For library interface users, use @option{global_quality}.
1505 @subsection Examples
1509 Set maximum constant quality (VBR) encoding with @command{ffmpeg}:
1511 ffmpeg -i INPUT -codec:v libtheora -q:v 10 OUTPUT.ogg
1515 Use @command{ffmpeg} to convert a CBR 1000 kbps Theora video stream:
1517 ffmpeg -i INPUT -codec:v libtheora -b:v 1000k OUTPUT.ogg
1523 VP8/VP9 format supported through libvpx.
1525 Requires the presence of the libvpx headers and library during configuration.
1526 You need to explicitly configure the build with @code{--enable-libvpx}.
1530 The following options are supported by the libvpx wrapper. The
1531 @command{vpxenc}-equivalent options or values are listed in parentheses
1534 To reduce the duplication of documentation, only the private options
1535 and some others requiring special attention are documented here. For
1536 the documentation of the undocumented generic options, see
1537 @ref{codec-options,,the Codec Options chapter}.
1539 To get more documentation of the libvpx options, invoke the command
1540 @command{ffmpeg -h encoder=libvpx}, @command{ffmpeg -h encoder=libvpx-vp9} or
1541 @command{vpxenc --help}. Further information is available in the libvpx API
1546 @item b (@emph{target-bitrate})
1547 Set bitrate in bits/s. Note that FFmpeg's @option{b} option is
1548 expressed in bits/s, while @command{vpxenc}'s @option{target-bitrate} is in
1551 @item g (@emph{kf-max-dist})
1553 @item keyint_min (@emph{kf-min-dist})
1555 @item qmin (@emph{min-q})
1557 @item qmax (@emph{max-q})
1559 @item bufsize (@emph{buf-sz}, @emph{buf-optimal-sz})
1560 Set ratecontrol buffer size (in bits). Note @command{vpxenc}'s options are
1561 specified in milliseconds, the libvpx wrapper converts this value as follows:
1562 @code{buf-sz = bufsize * 1000 / bitrate},
1563 @code{buf-optimal-sz = bufsize * 1000 / bitrate * 5 / 6}.
1565 @item rc_init_occupancy (@emph{buf-initial-sz})
1566 Set number of bits which should be loaded into the rc buffer before decoding
1567 starts. Note @command{vpxenc}'s option is specified in milliseconds, the libvpx
1568 wrapper converts this value as follows:
1569 @code{rc_init_occupancy * 1000 / bitrate}.
1571 @item undershoot-pct
1572 Set datarate undershoot (min) percentage of the target bitrate.
1575 Set datarate overshoot (max) percentage of the target bitrate.
1577 @item skip_threshold (@emph{drop-frame})
1579 @item qcomp (@emph{bias-pct})
1581 @item maxrate (@emph{maxsection-pct})
1582 Set GOP max bitrate in bits/s. Note @command{vpxenc}'s option is specified as a
1583 percentage of the target bitrate, the libvpx wrapper converts this value as
1584 follows: @code{(maxrate * 100 / bitrate)}.
1586 @item minrate (@emph{minsection-pct})
1587 Set GOP min bitrate in bits/s. Note @command{vpxenc}'s option is specified as a
1588 percentage of the target bitrate, the libvpx wrapper converts this value as
1589 follows: @code{(minrate * 100 / bitrate)}.
1591 @item minrate, maxrate, b @emph{end-usage=cbr}
1592 @code{(minrate == maxrate == bitrate)}.
1594 @item crf (@emph{end-usage=cq}, @emph{cq-level})
1596 @item tune (@emph{tune})
1598 @item psnr (@emph{psnr})
1599 @item ssim (@emph{ssim})
1602 @item quality, deadline (@emph{deadline})
1605 Use best quality deadline. Poorly named and quite slow, this option should be
1606 avoided as it may give worse quality output than good.
1608 Use good quality deadline. This is a good trade-off between speed and quality
1609 when used with the @option{cpu-used} option.
1611 Use realtime quality deadline.
1614 @item speed, cpu-used (@emph{cpu-used})
1615 Set quality/speed ratio modifier. Higher values speed up the encode at the cost
1618 @item nr (@emph{noise-sensitivity})
1621 Set a change threshold on blocks below which they will be skipped by the
1624 @item slices (@emph{token-parts})
1625 Note that FFmpeg's @option{slices} option gives the total number of partitions,
1626 while @command{vpxenc}'s @option{token-parts} is given as
1627 @code{log2(partitions)}.
1629 @item max-intra-rate
1630 Set maximum I-frame bitrate as a percentage of the target bitrate. A value of 0
1633 @item force_key_frames
1634 @code{VPX_EFLAG_FORCE_KF}
1636 @item Alternate reference frame related
1639 Enable use of alternate reference frames (2-pass only).
1640 @item arnr-max-frames
1641 Set altref noise reduction max frame count.
1643 Set altref noise reduction filter type: backward, forward, centered.
1645 Set altref noise reduction filter strength.
1646 @item rc-lookahead, lag-in-frames (@emph{lag-in-frames})
1647 Set number of frames to look ahead for frametype and ratecontrol.
1650 @item error-resilient
1651 Enable error resiliency features.
1653 @item VP9-specific options
1656 Enable lossless mode.
1658 Set number of tile columns to use. Note this is given as
1659 @code{log2(tile_columns)}. For example, 8 tile columns would be requested by
1660 setting the @option{tile-columns} option to 3.
1662 Set number of tile rows to use. Note this is given as @code{log2(tile_rows)}.
1663 For example, 4 tile rows would be requested by setting the @option{tile-rows}
1665 @item frame-parallel
1666 Enable frame parallel decodability features.
1668 Set adaptive quantization mode (0: off (default), 1: variance 2: complexity, 3:
1670 @item colorspace @emph{color-space}
1671 Set input color space. The VP9 bitstream supports signaling the following
1674 @item @samp{rgb} @emph{sRGB}
1675 @item @samp{bt709} @emph{bt709}
1676 @item @samp{unspecified} @emph{unknown}
1677 @item @samp{bt470bg} @emph{bt601}
1678 @item @samp{smpte170m} @emph{smpte170}
1679 @item @samp{smpte240m} @emph{smpte240}
1680 @item @samp{bt2020_ncl} @emph{bt2020}
1686 For more information about libvpx see:
1687 @url{http://www.webmproject.org/}
1691 libwebp WebP Image encoder wrapper
1693 libwebp is Google's official encoder for WebP images. It can encode in either
1694 lossy or lossless mode. Lossy images are essentially a wrapper around a VP8
1695 frame. Lossless images are a separate codec developed by Google.
1697 @subsection Pixel Format
1699 Currently, libwebp only supports YUV420 for lossy and RGB for lossless due
1700 to limitations of the format and libwebp. Alpha is supported for either mode.
1701 Because of API limitations, if RGB is passed in when encoding lossy or YUV is
1702 passed in for encoding lossless, the pixel format will automatically be
1703 converted using functions from libwebp. This is not ideal and is done only for
1710 @item -lossless @var{boolean}
1711 Enables/Disables use of lossless mode. Default is 0.
1713 @item -compression_level @var{integer}
1714 For lossy, this is a quality/speed tradeoff. Higher values give better quality
1715 for a given size at the cost of increased encoding time. For lossless, this is
1716 a size/speed tradeoff. Higher values give smaller size at the cost of increased
1717 encoding time. More specifically, it controls the number of extra algorithms
1718 and compression tools used, and varies the combination of these tools. This
1719 maps to the @var{method} option in libwebp. The valid range is 0 to 6.
1722 @item -qscale @var{float}
1723 For lossy encoding, this controls image quality, 0 to 100. For lossless
1724 encoding, this controls the effort and time spent at compressing more. The
1725 default value is 75. Note that for usage via libavcodec, this option is called
1726 @var{global_quality} and must be multiplied by @var{FF_QP2LAMBDA}.
1728 @item -preset @var{type}
1729 Configuration preset. This does some automatic settings based on the general
1733 Do not use a preset.
1735 Use the encoder default.
1737 Digital picture, like portrait, inner shot
1739 Outdoor photograph, with natural lighting
1741 Hand or line drawing, with high-contrast details
1743 Small-sized colorful images
1750 @section libx264, libx264rgb
1752 x264 H.264/MPEG-4 AVC encoder wrapper.
1754 This encoder requires the presence of the libx264 headers and library
1755 during configuration. You need to explicitly configure the build with
1756 @code{--enable-libx264}.
1758 libx264 supports an impressive number of features, including 8x8 and
1759 4x4 adaptive spatial transform, adaptive B-frame placement, CAVLC/CABAC
1760 entropy coding, interlacing (MBAFF), lossless mode, psy optimizations
1761 for detail retention (adaptive quantization, psy-RD, psy-trellis).
1763 Many libx264 encoder options are mapped to FFmpeg global codec
1764 options, while unique encoder options are provided through private
1765 options. Additionally the @option{x264opts} and @option{x264-params}
1766 private options allows one to pass a list of key=value tuples as accepted
1767 by the libx264 @code{x264_param_parse} function.
1769 The x264 project website is at
1770 @url{http://www.videolan.org/developers/x264.html}.
1772 The libx264rgb encoder is the same as libx264, except it accepts packed RGB
1773 pixel formats as input instead of YUV.
1775 @subsection Supported Pixel Formats
1777 x264 supports 8- to 10-bit color spaces. The exact bit depth is controlled at
1778 x264's configure time. FFmpeg only supports one bit depth in one particular
1779 build. In other words, it is not possible to build one FFmpeg with multiple
1780 versions of x264 with different bit depths.
1784 The following options are supported by the libx264 wrapper. The
1785 @command{x264}-equivalent options or values are listed in parentheses
1788 To reduce the duplication of documentation, only the private options
1789 and some others requiring special attention are documented here. For
1790 the documentation of the undocumented generic options, see
1791 @ref{codec-options,,the Codec Options chapter}.
1793 To get a more accurate and extensive documentation of the libx264
1794 options, invoke the command @command{x264 --full-help} or consult
1795 the libx264 documentation.
1798 @item b (@emph{bitrate})
1799 Set bitrate in bits/s. Note that FFmpeg's @option{b} option is
1800 expressed in bits/s, while @command{x264}'s @option{bitrate} is in
1803 @item bf (@emph{bframes})
1805 @item g (@emph{keyint})
1807 @item qmin (@emph{qpmin})
1808 Minimum quantizer scale.
1810 @item qmax (@emph{qpmax})
1811 Maximum quantizer scale.
1813 @item qdiff (@emph{qpstep})
1814 Maximum difference between quantizer scales.
1816 @item qblur (@emph{qblur})
1817 Quantizer curve blur
1819 @item qcomp (@emph{qcomp})
1820 Quantizer curve compression factor
1822 @item refs (@emph{ref})
1823 Number of reference frames each P-frame can use. The range is from @var{0-16}.
1825 @item sc_threshold (@emph{scenecut})
1826 Sets the threshold for the scene change detection.
1828 @item trellis (@emph{trellis})
1829 Performs Trellis quantization to increase efficiency. Enabled by default.
1831 @item nr (@emph{nr})
1833 @item me_range (@emph{merange})
1834 Maximum range of the motion search in pixels.
1836 @item me_method (@emph{me})
1837 Set motion estimation method. Possible values in the decreasing order
1841 @item dia (@emph{dia})
1842 @item epzs (@emph{dia})
1843 Diamond search with radius 1 (fastest). @samp{epzs} is an alias for
1845 @item hex (@emph{hex})
1846 Hexagonal search with radius 2.
1847 @item umh (@emph{umh})
1848 Uneven multi-hexagon search.
1849 @item esa (@emph{esa})
1851 @item tesa (@emph{tesa})
1852 Hadamard exhaustive search (slowest).
1856 Normally, when forcing a I-frame type, the encoder can select any type
1857 of I-frame. This option forces it to choose an IDR-frame.
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 comparison 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 1 (on).
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 Normally, when forcing a I-frame type, the encoder can select any type
2151 of I-frame. This option forces it to choose an IDR-frame.
2154 Set x265 options using a list of @var{key}=@var{value} couples separated
2155 by ":". See @command{x265 --help} for a list of options.
2157 For example to specify libx265 encoding options with @option{-x265-params}:
2160 ffmpeg -i input -c:v libx265 -x265-params crf=26:psy-rd=1 output.mp4
2166 Xvid MPEG-4 Part 2 encoder wrapper.
2168 This encoder requires the presence of the libxvidcore headers and library
2169 during configuration. You need to explicitly configure the build with
2170 @code{--enable-libxvid --enable-gpl}.
2172 The native @code{mpeg4} encoder supports the MPEG-4 Part 2 format, so
2173 users can encode to this format without this library.
2177 The following options are supported by the libxvid wrapper. Some of
2178 the following options are listed but are not documented, and
2179 correspond to shared codec options. See @ref{codec-options,,the Codec
2180 Options chapter} for their documentation. The other shared options
2181 which are not listed have no effect for the libxvid encoder.
2203 Set specific encoding flags. Possible values:
2208 Use four motion vector by macroblock.
2211 Enable high quality AC prediction.
2214 Only encode grayscale.
2217 Enable the use of global motion compensation (GMC).
2220 Enable quarter-pixel motion compensation.
2226 Place global headers in extradata instead of every keyframe.
2233 Set motion estimation method. Possible values in decreasing order of
2234 speed and increasing order of quality:
2238 Use no motion estimation (default).
2243 Enable advanced diamond zonal search for 16x16 blocks and half-pixel
2244 refinement for 16x16 blocks. @samp{x1} and @samp{log} are aliases for
2248 Enable all of the things described above, plus advanced diamond zonal
2249 search for 8x8 blocks, half-pixel refinement for 8x8 blocks, and motion
2250 estimation on chroma planes.
2253 Enable all of the things described above, plus extended 16x16 and 8x8
2258 Set macroblock decision algorithm. Possible values in the increasing
2263 Use macroblock comparing function algorithm (default).
2266 Enable rate distortion-based half pixel and quarter pixel refinement for
2270 Enable all of the things described above, plus rate distortion-based
2271 half pixel and quarter pixel refinement for 8x8 blocks, and rate
2272 distortion-based search using square pattern.
2276 Enable lumi masking adaptive quantization when set to 1. Default is 0
2280 Enable variance adaptive quantization when set to 1. Default is 0
2283 When combined with @option{lumi_aq}, the resulting quality will not
2284 be better than any of the two specified individually. In other
2285 words, the resulting quality will be the worse one of the two
2289 Set structural similarity (SSIM) displaying method. Possible values:
2293 Disable displaying of SSIM information.
2296 Output average SSIM at the end of encoding to stdout. The format of
2297 showing the average SSIM is:
2303 For users who are not familiar with C, %f means a float number, or
2304 a decimal (e.g. 0.939232).
2307 Output both per-frame SSIM data during encoding and average SSIM at
2308 the end of encoding to stdout. The format of per-frame information
2312 SSIM: avg: %1.3f min: %1.3f max: %1.3f
2315 For users who are not familiar with C, %1.3f means a float number
2316 rounded to 3 digits after the dot (e.g. 0.932).
2321 Set SSIM accuracy. Valid options are integers within the range of
2322 0-4, while 0 gives the most accurate result and 4 computes the
2329 MPEG-2 video encoder.
2334 @item seq_disp_ext @var{integer}
2335 Specifies if the encoder should write a sequence_display_extension to the
2340 Decide automatically to write it or not (this is the default) by checking if
2341 the data to be written is different from the default or unspecified values.
2355 @subsection Private options
2358 @item dpi @var{integer}
2359 Set physical density of pixels, in dots per inch, unset by default
2360 @item dpm @var{integer}
2361 Set physical density of pixels, in dots per meter, unset by default
2366 Apple ProRes encoder.
2368 FFmpeg contains 2 ProRes encoders, the prores-aw and prores-ks encoder.
2369 The used encoder can be chosen with the @code{-vcodec} option.
2371 @subsection Private Options for prores-ks
2374 @item profile @var{integer}
2375 Select the ProRes profile to encode
2384 @item quant_mat @var{integer}
2385 Select quantization matrix.
2394 If set to @var{auto}, the matrix matching the profile will be picked.
2395 If not set, the matrix providing the highest quality, @var{default}, will be
2398 @item bits_per_mb @var{integer}
2399 How many bits to allot for coding one macroblock. Different profiles use
2400 between 200 and 2400 bits per macroblock, the maximum is 8000.
2402 @item mbs_per_slice @var{integer}
2403 Number of macroblocks in each slice (1-8); the default value (8)
2404 should be good in almost all situations.
2406 @item vendor @var{string}
2407 Override the 4-byte vendor ID.
2408 A custom vendor ID like @var{apl0} would claim the stream was produced by
2411 @item alpha_bits @var{integer}
2412 Specify number of bits for alpha component.
2413 Possible values are @var{0}, @var{8} and @var{16}.
2414 Use @var{0} to disable alpha plane coding.
2418 @subsection Speed considerations
2420 In the default mode of operation the encoder has to honor frame constraints
2421 (i.e. not produce frames with size bigger than requested) while still making
2422 output picture as good as possible.
2423 A frame containing a lot of small details is harder to compress and the encoder
2424 would spend more time searching for appropriate quantizers for each slice.
2426 Setting a higher @option{bits_per_mb} limit will improve the speed.
2428 For the fastest encoding speed set the @option{qscale} parameter (4 is the
2429 recommended value) and do not set a size constraint.
2431 @section QSV encoders
2433 The family of Intel QuickSync Video encoders (MPEG-2, H.264 and HEVC)
2435 The ratecontrol method is selected as follows:
2439 When @option{global_quality} is specified, a quality-based mode is used.
2440 Specifically this means either
2443 @var{CQP} - constant quantizer scale, when the @option{qscale} codec flag is
2444 also set (the @option{-qscale} ffmpeg option).
2447 @var{LA_ICQ} - intelligent constant quality with lookahead, when the
2448 @option{look_ahead} option is also set.
2451 @var{ICQ} -- intelligent constant quality otherwise.
2455 Otherwise, a bitrate-based mode is used. For all of those, you should specify at
2456 least the desired average bitrate with the @option{b} option.
2459 @var{LA} - VBR with lookahead, when the @option{look_ahead} option is specified.
2462 @var{VCM} - video conferencing mode, when the @option{vcm} option is set.
2465 @var{CBR} - constant bitrate, when @option{maxrate} is specified and equal to
2466 the average bitrate.
2469 @var{VBR} - variable bitrate, when @option{maxrate} is specified, but is higher
2470 than the average bitrate.
2473 @var{AVBR} - average VBR mode, when @option{maxrate} is not specified. This mode
2474 is further configured by the @option{avbr_accuracy} and
2475 @option{avbr_convergence} options.
2479 Note that depending on your system, a different mode than the one you specified
2480 may be selected by the encoder. Set the verbosity level to @var{verbose} or
2481 higher to see the actual settings used by the QSV runtime.
2483 Additional libavcodec global options are mapped to MSDK options as follows:
2487 @option{g/gop_size} -> @option{GopPicSize}
2490 @option{bf/max_b_frames}+1 -> @option{GopRefDist}
2493 @option{rc_init_occupancy/rc_initial_buffer_occupancy} ->
2494 @option{InitialDelayInKB}
2497 @option{slices} -> @option{NumSlice}
2500 @option{refs} -> @option{NumRefFrame}
2503 @option{b_strategy/b_frame_strategy} -> @option{BRefType}
2506 @option{cgop/CLOSED_GOP} codec flag -> @option{GopOptFlag}
2509 For the @var{CQP} mode, the @option{i_qfactor/i_qoffset} and
2510 @option{b_qfactor/b_qoffset} set the difference between @var{QPP} and @var{QPI},
2511 and @var{QPP} and @var{QPB} respectively.
2514 Setting the @option{coder} option to the value @var{vlc} will make the H.264
2515 encoder use CAVLC instead of CABAC.
2524 @item iterative_dia_size
2525 dia size for the iterative motion estimation
2530 SMPTE VC-2 (previously BBC Dirac Pro). This codec was primarily aimed at
2531 professional broadcasting but since it supports yuv420, yuv422 and yuv444 at
2532 8 (limited range or full range), 10 or 12 bits, this makes it suitable for
2533 other tasks which require low overhead and low compression (like screen
2541 Sets target video bitrate. Usually that's around 1:6 of the uncompressed
2542 video bitrate (e.g. for 1920x1080 50fps yuv422p10 that's around 400Mbps). Higher
2543 values (close to the uncompressed bitrate) turn on lossless compression mode.
2546 Enables field coding when set (e.g. to tt - top field first) for interlaced
2547 inputs. Should increase compression with interlaced content as it splits the
2548 fields and encodes each separately.
2551 Sets the total amount of wavelet transforms to apply, between 1 and 5 (default).
2552 Lower values reduce compression and quality. Less capable decoders may not be
2553 able to handle values of @option{wavelet_depth} over 3.
2556 Sets the transform type. Currently only @var{5_3} (LeGall) and @var{9_7}
2558 are implemented, with 9_7 being the one with better compression and thus
2563 Sets the slice size for each slice. Larger values result in better compression.
2564 For compatibility with other more limited decoders use @option{slice_width} of
2565 32 and @option{slice_height} of 8.
2568 Sets the undershoot tolerance of the rate control system in percent. This is
2569 to prevent an expensive search from being run.
2572 Sets the quantization matrix preset to use by default or when @option{wavelet_depth}
2577 Uses the default quantization matrix from the specifications, extended with
2578 values for the fifth level. This provides a good balance between keeping detail
2579 and omitting artifacts.
2583 Use a completely zeroed out quantization matrix. This increases PSNR but might
2584 reduce perception. Use in bogus benchmarks.
2588 Reduces detail but attempts to preserve color at extremely low bitrates.
2593 @c man end VIDEO ENCODERS
2595 @chapter Subtitles Encoders
2596 @c man begin SUBTITLES ENCODERS
2600 This codec encodes the bitmap subtitle format that is used in DVDs.
2601 Typically they are stored in VOBSUB file pairs (*.idx + *.sub),
2602 and they can also be used in Matroska files.
2608 When set to 1, enable a work-around that makes the number of pixel rows
2609 even in all subtitles. This fixes a problem with some players that
2610 cut off the bottom row if the number is odd. The work-around just adds
2611 a fully transparent row if needed. The overhead is low, typically
2612 one byte per subtitle on average.
2614 By default, this work-around is disabled.
2617 @c man end SUBTITLES ENCODERS