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}
69 Average noise to mask ratio (ANMR) trellis-based solution.
71 This is an experimental coder which currently produces a lower quality, is more
72 unstable and is slower than the default twoloop coder but has potential.
73 Currently has no support for the @option{aac_is} or @option{aac_pns} options.
74 Not currently recommended.
77 Constant quantizer method.
79 Uses a cheaper version of twoloop algorithm that doesn't try to do as many
80 clever adjustments. Worse with low bitrates (less than 64kbps), but is better
81 and much faster at higher bitrates.
82 This is the default choice for a coder
87 Sets mid/side coding mode. The default value of "auto" will automatically use
88 M/S with bands which will benefit from such coding. Can be forced for all bands
89 using the value "enable", which is mainly useful for debugging or disabled using
93 Sets intensity stereo coding tool usage. By default, it's enabled and will
94 automatically toggle IS for similar pairs of stereo bands if it's beneficial.
95 Can be disabled for debugging by setting the value to "disable".
98 Uses perceptual noise substitution to replace low entropy high frequency bands
99 with imperceptible white noise during the decoding process. By default, it's
100 enabled, but can be disabled for debugging purposes by using "disable".
103 Enables the use of a multitap FIR filter which spans through the high frequency
104 bands to hide quantization noise during the encoding process and is reverted
105 by the decoder. As well as decreasing unpleasant artifacts in the high range
106 this also reduces the entropy in the high bands and allows for more bits to
107 be used by the mid-low bands. By default it's enabled but can be disabled for
108 debugging by setting the option to "disable".
111 Enables the use of the long term prediction extension which increases coding
112 efficiency in very low bandwidth situations such as encoding of voice or
113 solo piano music by extending constant harmonic peaks in bands throughout
114 frames. This option is implied by profile:a aac_low and is incompatible with
115 aac_pred. Use in conjunction with @option{-ar} to decrease the samplerate.
118 Enables the use of a more traditional style of prediction where the spectral
119 coefficients transmitted are replaced by the difference of the current
120 coefficients minus the previous "predicted" coefficients. In theory and sometimes
121 in practice this can improve quality for low to mid bitrate audio.
122 This option implies the aac_main profile and is incompatible with aac_ltp.
125 Sets the encoding profile, possible values:
129 The default, AAC "Low-complexity" profile. Is the most compatible and produces
133 Equivalent to @code{-profile:a aac_low -aac_pns 0}. PNS was introduced with the
134 MPEG4 specifications.
137 Long term prediction profile, is enabled by and will enable the @option{aac_ltp}
138 option. Introduced in MPEG4.
141 Main-type prediction profile, is enabled by and will enable the @option{aac_pred}
142 option. Introduced in MPEG2.
145 If this option is unspecified it is set to @samp{aac_low}.
148 @section ac3 and ac3_fixed
152 These encoders implement part of ATSC A/52:2010 and ETSI TS 102 366, as well as
153 the undocumented RealAudio 3 (a.k.a. dnet).
155 The @var{ac3} encoder uses floating-point math, while the @var{ac3_fixed}
156 encoder only uses fixed-point integer math. This does not mean that one is
157 always faster, just that one or the other may be better suited to a
158 particular system. The floating-point encoder will generally produce better
159 quality audio for a given bitrate. The @var{ac3_fixed} encoder is not the
160 default codec for any of the output formats, so it must be specified explicitly
161 using the option @code{-acodec ac3_fixed} in order to use it.
163 @subsection AC-3 Metadata
165 The AC-3 metadata options are used to set parameters that describe the audio,
166 but in most cases do not affect the audio encoding itself. Some of the options
167 do directly affect or influence the decoding and playback of the resulting
168 bitstream, while others are just for informational purposes. A few of the
169 options will add bits to the output stream that could otherwise be used for
170 audio data, and will thus affect the quality of the output. Those will be
171 indicated accordingly with a note in the option list below.
173 These parameters are described in detail in several publicly-available
176 @item @uref{http://www.atsc.org/cms/standards/a_52-2010.pdf,A/52:2010 - Digital Audio Compression (AC-3) (E-AC-3) Standard}
177 @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}
178 @item @uref{http://www.dolby.com/uploadedFiles/zz-_Shared_Assets/English_PDFs/Professional/18_Metadata.Guide.pdf,Dolby Metadata Guide}
179 @item @uref{http://www.dolby.com/uploadedFiles/zz-_Shared_Assets/English_PDFs/Professional/46_DDEncodingGuidelines.pdf,Dolby Digital Professional Encoding Guidelines}
182 @subsubsection Metadata Control Options
186 @item -per_frame_metadata @var{boolean}
187 Allow Per-Frame Metadata. Specifies if the encoder should check for changing
188 metadata for each frame.
191 The metadata values set at initialization will be used for every frame in the
194 Metadata values can be changed before encoding each frame.
199 @subsubsection Downmix Levels
203 @item -center_mixlev @var{level}
204 Center Mix Level. The amount of gain the decoder should apply to the center
205 channel when downmixing to stereo. This field will only be written to the
206 bitstream if a center channel is present. The value is specified as a scale
207 factor. There are 3 valid values:
212 Apply -4.5dB gain (default)
217 @item -surround_mixlev @var{level}
218 Surround Mix Level. The amount of gain the decoder should apply to the surround
219 channel(s) when downmixing to stereo. This field will only be written to the
220 bitstream if one or more surround channels are present. The value is specified
221 as a scale factor. There are 3 valid values:
226 Apply -6dB gain (default)
228 Silence Surround Channel(s)
233 @subsubsection Audio Production Information
234 Audio Production Information is optional information describing the mixing
235 environment. Either none or both of the fields are written to the bitstream.
239 @item -mixing_level @var{number}
240 Mixing Level. Specifies peak sound pressure level (SPL) in the production
241 environment when the mix was mastered. Valid values are 80 to 111, or -1 for
242 unknown or not indicated. The default value is -1, but that value cannot be
243 used if the Audio Production Information is written to the bitstream. Therefore,
244 if the @code{room_type} option is not the default value, the @code{mixing_level}
245 option must not be -1.
247 @item -room_type @var{type}
248 Room Type. Describes the equalization used during the final mixing session at
249 the studio or on the dubbing stage. A large room is a dubbing stage with the
250 industry standard X-curve equalization; a small room has flat equalization.
251 This field will not be written to the bitstream if both the @code{mixing_level}
252 option and the @code{room_type} option have the default values.
256 Not Indicated (default)
267 @subsubsection Other Metadata Options
271 @item -copyright @var{boolean}
272 Copyright Indicator. Specifies whether a copyright exists for this audio.
276 No Copyright Exists (default)
282 @item -dialnorm @var{value}
283 Dialogue Normalization. Indicates how far the average dialogue level of the
284 program is below digital 100% full scale (0 dBFS). This parameter determines a
285 level shift during audio reproduction that sets the average volume of the
286 dialogue to a preset level. The goal is to match volume level between program
287 sources. A value of -31dB will result in no volume level change, relative to
288 the source volume, during audio reproduction. Valid values are whole numbers in
289 the range -31 to -1, with -31 being the default.
291 @item -dsur_mode @var{mode}
292 Dolby Surround Mode. Specifies whether the stereo signal uses Dolby Surround
293 (Pro Logic). This field will only be written to the bitstream if the audio
294 stream is stereo. Using this option does @b{NOT} mean the encoder will actually
295 apply Dolby Surround processing.
299 Not Indicated (default)
302 Not Dolby Surround Encoded
305 Dolby Surround Encoded
308 @item -original @var{boolean}
309 Original Bit Stream Indicator. Specifies whether this audio is from the
310 original source and not a copy.
317 Original Source (default)
322 @subsection Extended Bitstream Information
323 The extended bitstream options are part of the Alternate Bit Stream Syntax as
324 specified in Annex D of the A/52:2010 standard. It is grouped into 2 parts.
325 If any one parameter in a group is specified, all values in that group will be
326 written to the bitstream. Default values are used for those that are written
327 but have not been specified. If the mixing levels are written, the decoder
328 will use these values instead of the ones specified in the @code{center_mixlev}
329 and @code{surround_mixlev} options if it supports the Alternate Bit Stream
332 @subsubsection Extended Bitstream Information - Part 1
336 @item -dmix_mode @var{mode}
337 Preferred Stereo Downmix Mode. Allows the user to select either Lt/Rt
338 (Dolby Surround) or Lo/Ro (normal stereo) as the preferred stereo downmix mode.
342 Not Indicated (default)
345 Lt/Rt Downmix Preferred
348 Lo/Ro Downmix Preferred
351 @item -ltrt_cmixlev @var{level}
352 Lt/Rt Center Mix Level. The amount of gain the decoder should apply to the
353 center channel when downmixing to stereo in Lt/Rt mode.
366 Apply -4.5dB gain (default)
370 Silence Center Channel
373 @item -ltrt_surmixlev @var{level}
374 Lt/Rt Surround Mix Level. The amount of gain the decoder should apply to the
375 surround channel(s) when downmixing to stereo in Lt/Rt mode.
384 Apply -6.0dB gain (default)
386 Silence Surround Channel(s)
389 @item -loro_cmixlev @var{level}
390 Lo/Ro Center Mix Level. The amount of gain the decoder should apply to the
391 center channel when downmixing to stereo in Lo/Ro mode.
404 Apply -4.5dB gain (default)
408 Silence Center Channel
411 @item -loro_surmixlev @var{level}
412 Lo/Ro Surround Mix Level. The amount of gain the decoder should apply to the
413 surround channel(s) when downmixing to stereo in Lo/Ro mode.
422 Apply -6.0dB gain (default)
424 Silence Surround Channel(s)
429 @subsubsection Extended Bitstream Information - Part 2
433 @item -dsurex_mode @var{mode}
434 Dolby Surround EX Mode. Indicates whether the stream uses Dolby Surround EX
435 (7.1 matrixed to 5.1). Using this option does @b{NOT} mean the encoder will actually
436 apply Dolby Surround EX processing.
440 Not Indicated (default)
443 Dolby Surround EX Off
449 @item -dheadphone_mode @var{mode}
450 Dolby Headphone Mode. Indicates whether the stream uses Dolby Headphone
451 encoding (multi-channel matrixed to 2.0 for use with headphones). Using this
452 option does @b{NOT} mean the encoder will actually apply Dolby Headphone
457 Not Indicated (default)
466 @item -ad_conv_type @var{type}
467 A/D Converter Type. Indicates whether the audio has passed through HDCD A/D
472 Standard A/D Converter (default)
480 @subsection Other AC-3 Encoding Options
484 @item -stereo_rematrixing @var{boolean}
485 Stereo Rematrixing. Enables/Disables use of rematrixing for stereo input. This
486 is an optional AC-3 feature that increases quality by selectively encoding
487 the left/right channels as mid/side. This option is enabled by default, and it
488 is highly recommended that it be left as enabled except for testing purposes.
490 @item cutoff @var{frequency}
491 Set lowpass cutoff frequency. If unspecified, the encoder selects a default
492 determined by various other encoding parameters.
496 @subsection Floating-Point-Only AC-3 Encoding Options
498 These options are only valid for the floating-point encoder and do not exist
499 for the fixed-point encoder due to the corresponding features not being
500 implemented in fixed-point.
504 @item -channel_coupling @var{boolean}
505 Enables/Disables use of channel coupling, which is an optional AC-3 feature
506 that increases quality by combining high frequency information from multiple
507 channels into a single channel. The per-channel high frequency information is
508 sent with less accuracy in both the frequency and time domains. This allows
509 more bits to be used for lower frequencies while preserving enough information
510 to reconstruct the high frequencies. This option is enabled by default for the
511 floating-point encoder and should generally be left as enabled except for
512 testing purposes or to increase encoding speed.
516 Selected by Encoder (default)
519 Disable Channel Coupling
522 Enable Channel Coupling
525 @item -cpl_start_band @var{number}
526 Coupling Start Band. Sets the channel coupling start band, from 1 to 15. If a
527 value higher than the bandwidth is used, it will be reduced to 1 less than the
528 coupling end band. If @var{auto} is used, the start band will be determined by
529 the encoder based on the bit rate, sample rate, and channel layout. This option
530 has no effect if channel coupling is disabled.
534 Selected by Encoder (default)
542 FLAC (Free Lossless Audio Codec) Encoder
546 The following options are supported by FFmpeg's flac encoder.
549 @item compression_level
550 Sets the compression level, which chooses defaults for many other options
551 if they are not set explicitly. Valid values are from 0 to 12, 5 is the
555 Sets the size of the frames in samples per channel.
557 @item lpc_coeff_precision
558 Sets the LPC coefficient precision, valid values are from 1 to 15, 15 is the
562 Sets the first stage LPC algorithm
568 fixed LPC coefficients
576 Number of passes to use for Cholesky factorization during LPC analysis
578 @item min_partition_order
579 The minimum partition order
581 @item max_partition_order
582 The maximum partition order
584 @item prediction_order_method
599 The mode is chosen automatically for each frame
601 Channels are independently coded
607 @item exact_rice_parameters
608 Chooses if rice parameters are calculated exactly or approximately.
609 if set to 1 then they are chosen exactly, which slows the code down slightly and
610 improves compression slightly.
612 @item multi_dim_quant
613 Multi Dimensional Quantization. If set to 1 then a 2nd stage LPC algorithm is
614 applied after the first stage to finetune the coefficients. This is quite slow
615 and slightly improves compression.
624 This is a native FFmpeg encoder for the Opus format. Currently its in development and
625 only implements the CELT part of the codec. Its quality is usually worse and at best
626 is equal to the libopus encoder.
632 Set bit rate in bits/s. If unspecified it uses the number of channels and the layout
633 to make a good guess.
636 Sets the maximum delay in milliseconds. Lower delays than 20ms will very quickly
640 @anchor{libfdk-aac-enc}
643 libfdk-aac AAC (Advanced Audio Coding) encoder wrapper.
645 The libfdk-aac library is based on the Fraunhofer FDK AAC code from
648 Requires the presence of the libfdk-aac headers and library during
649 configuration. You need to explicitly configure the build with
650 @code{--enable-libfdk-aac}. The library is also incompatible with GPL,
651 so if you allow the use of GPL, you should configure with
652 @code{--enable-gpl --enable-nonfree --enable-libfdk-aac}.
654 This encoder is considered to produce output on par or worse at 128kbps to the
655 @ref{aacenc,,the native FFmpeg AAC encoder} but can often produce better
656 sounding audio at identical or lower bitrates and has support for the
659 VBR encoding, enabled through the @option{vbr} or @option{flags
660 +qscale} options, is experimental and only works with some
661 combinations of parameters.
663 Support for encoding 7.1 audio is only available with libfdk-aac 0.1.3 or
666 For more information see the fdk-aac project at
667 @url{http://sourceforge.net/p/opencore-amr/fdk-aac/}.
671 The following options are mapped on the shared FFmpeg codec options.
675 Set bit rate in bits/s. If the bitrate is not explicitly specified, it
676 is automatically set to a suitable value depending on the selected
679 In case VBR mode is enabled the option is ignored.
682 Set audio sampling rate (in Hz).
685 Set the number of audio channels.
688 Enable fixed quality, VBR (Variable Bit Rate) mode.
689 Note that VBR is implicitly enabled when the @option{vbr} value is
693 Set cutoff frequency. If not specified (or explicitly set to 0) it
694 will use a value automatically computed by the library. Default value
700 The following profiles are recognized:
703 Low Complexity AAC (LC)
706 High Efficiency AAC (HE-AAC)
709 High Efficiency AAC version 2 (HE-AACv2)
715 Enhanced Low Delay AAC (ELD)
718 If not specified it is set to @samp{aac_low}.
721 The following are private options of the libfdk_aac encoder.
725 Enable afterburner feature if set to 1, disabled if set to 0. This
726 improves the quality but also the required processing power.
731 Enable SBR (Spectral Band Replication) for ELD if set to 1, disabled
737 Set SBR/PS signaling style.
739 It can assume one of the following values:
742 choose signaling implicitly (explicit hierarchical by default,
743 implicit if global header is disabled)
746 implicit backwards compatible signaling
749 explicit SBR, implicit PS signaling
751 @item explicit_hierarchical
752 explicit hierarchical signaling
755 Default value is @samp{default}.
758 Output LATM/LOAS encapsulated data if set to 1, disabled if set to 0.
763 Set StreamMuxConfig and PCE repetition period (in frames) for sending
764 in-band configuration buffers within LATM/LOAS transport layer.
766 Must be a 16-bits non-negative integer.
771 Set VBR mode, from 1 to 5. 1 is lowest quality (though still pretty
772 good) and 5 is highest quality. A value of 0 will disable VBR, and CBR
773 (Constant Bit Rate) is enabled.
775 Currently only the @samp{aac_low} profile supports VBR encoding.
777 VBR modes 1-5 correspond to roughly the following average bit rates:
789 about 80-96 kbps/channel
799 Use @command{ffmpeg} to convert an audio file to VBR AAC in an M4A (MP4)
802 ffmpeg -i input.wav -codec:a libfdk_aac -vbr 3 output.m4a
806 Use @command{ffmpeg} to convert an audio file to CBR 64k kbps AAC, using the
807 High-Efficiency AAC profile:
809 ffmpeg -i input.wav -c:a libfdk_aac -profile:a aac_he -b:a 64k output.m4a
816 LAME (Lame Ain't an MP3 Encoder) MP3 encoder wrapper.
818 Requires the presence of the libmp3lame headers and library during
819 configuration. You need to explicitly configure the build with
820 @code{--enable-libmp3lame}.
822 See @ref{libshine} for a fixed-point MP3 encoder, although with a
827 The following options are supported by the libmp3lame wrapper. The
828 @command{lame}-equivalent of the options are listed in parentheses.
832 Set bitrate expressed in bits/s for CBR or ABR. LAME @code{bitrate} is
833 expressed in kilobits/s.
836 Set constant quality setting for VBR. This option is valid only
837 using the @command{ffmpeg} command-line tool. For library interface
838 users, use @option{global_quality}.
840 @item compression_level (@emph{-q})
841 Set algorithm quality. Valid arguments are integers in the 0-9 range,
842 with 0 meaning highest quality but slowest, and 9 meaning fastest
843 while producing the worst quality.
845 @item cutoff (@emph{--lowpass})
846 Set lowpass cutoff frequency. If unspecified, the encoder dynamically
850 Enable use of bit reservoir when set to 1. Default value is 1. LAME
851 has this enabled by default, but can be overridden by use
852 @option{--nores} option.
854 @item joint_stereo (@emph{-m j})
855 Enable the encoder to use (on a frame by frame basis) either L/R
856 stereo or mid/side stereo. Default value is 1.
858 @item abr (@emph{--abr})
859 Enable the encoder to use ABR when set to 1. The @command{lame}
860 @option{--abr} sets the target bitrate, while this options only
861 tells FFmpeg to use ABR still relies on @option{b} to set bitrate.
865 @section libopencore-amrnb
867 OpenCORE Adaptive Multi-Rate Narrowband encoder.
869 Requires the presence of the libopencore-amrnb headers and library during
870 configuration. You need to explicitly configure the build with
871 @code{--enable-libopencore-amrnb --enable-version3}.
873 This is a mono-only encoder. Officially it only supports 8000Hz sample rate,
874 but you can override it by setting @option{strict} to @samp{unofficial} or
882 Set bitrate in bits per second. Only the following bitrates are supported,
883 otherwise libavcodec will round to the nearest valid bitrate.
897 Allow discontinuous transmission (generate comfort noise) when set to 1. The
898 default value is 0 (disabled).
904 libopus Opus Interactive Audio Codec encoder wrapper.
906 Requires the presence of the libopus headers and library during
907 configuration. You need to explicitly configure the build with
908 @code{--enable-libopus}.
910 @subsection Option Mapping
912 Most libopus options are modelled after the @command{opusenc} utility from
913 opus-tools. The following is an option mapping chart describing options
914 supported by the libopus wrapper, and their @command{opusenc}-equivalent
919 @item b (@emph{bitrate})
920 Set the bit rate in bits/s. FFmpeg's @option{b} option is
921 expressed in bits/s, while @command{opusenc}'s @option{bitrate} in
924 @item vbr (@emph{vbr}, @emph{hard-cbr}, and @emph{cvbr})
925 Set VBR mode. The FFmpeg @option{vbr} option has the following
926 valid arguments, with the @command{opusenc} equivalent options
930 @item off (@emph{hard-cbr})
931 Use constant bit rate encoding.
933 @item on (@emph{vbr})
934 Use variable bit rate encoding (the default).
936 @item constrained (@emph{cvbr})
937 Use constrained variable bit rate encoding.
940 @item compression_level (@emph{comp})
941 Set encoding algorithm complexity. Valid options are integers in
942 the 0-10 range. 0 gives the fastest encodes but lower quality, while 10
943 gives the highest quality but slowest encoding. The default is 10.
945 @item frame_duration (@emph{framesize})
946 Set maximum frame size, or duration of a frame in milliseconds. The
947 argument must be exactly the following: 2.5, 5, 10, 20, 40, 60. Smaller
948 frame sizes achieve lower latency but less quality at a given bitrate.
949 Sizes greater than 20ms are only interesting at fairly low bitrates.
952 @item packet_loss (@emph{expect-loss})
953 Set expected packet loss percentage. The default is 0.
955 @item application (N.A.)
956 Set intended application type. Valid options are listed below:
960 Favor improved speech intelligibility.
962 Favor faithfulness to the input (the default).
964 Restrict to only the lowest delay modes.
968 Set cutoff bandwidth in Hz. The argument must be exactly one of the
969 following: 4000, 6000, 8000, 12000, or 20000, corresponding to
970 narrowband, mediumband, wideband, super wideband, and fullband
971 respectively. The default is 0 (cutoff disabled).
973 @item mapping_family (@emph{mapping_family})
974 Set channel mapping family to be used by the encoder. The default value of -1
975 uses mapping family 0 for mono and stereo inputs, and mapping family 1
976 otherwise. The default also disables the surround masking and LFE bandwidth
977 optimzations in libopus, and requires that the input contains 8 channels or
980 Other values include 0 for mono and stereo, 1 for surround sound with masking
981 and LFE bandwidth optimizations, and 255 for independent streams with an
982 unspecified channel layout.
984 @item apply_phase_inv (N.A.) (requires libopus >= 1.2)
985 If set to 0, disables the use of phase inversion for intensity stereo,
986 improving the quality of mono downmixes, but slightly reducing normal stereo
987 quality. The default is 1 (phase inversion enabled).
994 Shine Fixed-Point MP3 encoder wrapper.
996 Shine is a fixed-point MP3 encoder. It has a far better performance on
997 platforms without an FPU, e.g. armel CPUs, and some phones and tablets.
998 However, as it is more targeted on performance than quality, it is not on par
999 with LAME and other production-grade encoders quality-wise. Also, according to
1000 the project's homepage, this encoder may not be free of bugs as the code was
1001 written a long time ago and the project was dead for at least 5 years.
1003 This encoder only supports stereo and mono input. This is also CBR-only.
1005 The original project (last updated in early 2007) is at
1006 @url{http://sourceforge.net/projects/libshine-fxp/}. We only support the
1007 updated fork by the Savonet/Liquidsoap project at @url{https://github.com/savonet/shine}.
1009 Requires the presence of the libshine headers and library during
1010 configuration. You need to explicitly configure the build with
1011 @code{--enable-libshine}.
1013 See also @ref{libmp3lame}.
1017 The following options are supported by the libshine wrapper. The
1018 @command{shineenc}-equivalent of the options are listed in parentheses.
1022 Set bitrate expressed in bits/s for CBR. @command{shineenc} @option{-b} option
1023 is expressed in kilobits/s.
1029 TwoLAME MP2 encoder wrapper.
1031 Requires the presence of the libtwolame headers and library during
1032 configuration. You need to explicitly configure the build with
1033 @code{--enable-libtwolame}.
1037 The following options are supported by the libtwolame wrapper. The
1038 @command{twolame}-equivalent options follow the FFmpeg ones and are in
1043 Set bitrate expressed in bits/s for CBR. @command{twolame} @option{b}
1044 option is expressed in kilobits/s. Default value is 128k.
1047 Set quality for experimental VBR support. Maximum value range is
1048 from -50 to 50, useful range is from -10 to 10. The higher the
1049 value, the better the quality. This option is valid only using the
1050 @command{ffmpeg} command-line tool. For library interface users,
1051 use @option{global_quality}.
1053 @item mode (@emph{--mode})
1054 Set the mode of the resulting audio. Possible values:
1058 Choose mode automatically based on the input. This is the default.
1069 @item psymodel (@emph{--psyc-mode})
1070 Set psychoacoustic model to use in encoding. The argument must be
1071 an integer between -1 and 4, inclusive. The higher the value, the
1072 better the quality. The default value is 3.
1074 @item energy_levels (@emph{--energy})
1075 Enable energy levels extensions when set to 1. The default value is
1078 @item error_protection (@emph{--protect})
1079 Enable CRC error protection when set to 1. The default value is 0
1082 @item copyright (@emph{--copyright})
1083 Set MPEG audio copyright flag when set to 1. The default value is 0
1086 @item original (@emph{--original})
1087 Set MPEG audio original flag when set to 1. The default value is 0
1092 @section libvo-amrwbenc
1094 VisualOn Adaptive Multi-Rate Wideband encoder.
1096 Requires the presence of the libvo-amrwbenc headers and library during
1097 configuration. You need to explicitly configure the build with
1098 @code{--enable-libvo-amrwbenc --enable-version3}.
1100 This is a mono-only encoder. Officially it only supports 16000Hz sample
1101 rate, but you can override it by setting @option{strict} to
1102 @samp{unofficial} or lower.
1109 Set bitrate in bits/s. Only the following bitrates are supported, otherwise
1110 libavcodec will round to the nearest valid bitrate.
1125 Allow discontinuous transmission (generate comfort noise) when set to 1. The
1126 default value is 0 (disabled).
1132 libvorbis encoder wrapper.
1134 Requires the presence of the libvorbisenc headers and library during
1135 configuration. You need to explicitly configure the build with
1136 @code{--enable-libvorbis}.
1140 The following options are supported by the libvorbis wrapper. The
1141 @command{oggenc}-equivalent of the options are listed in parentheses.
1143 To get a more accurate and extensive documentation of the libvorbis
1144 options, consult the libvorbisenc's and @command{oggenc}'s documentations.
1145 See @url{http://xiph.org/vorbis/},
1146 @url{http://wiki.xiph.org/Vorbis-tools}, and oggenc(1).
1150 Set bitrate expressed in bits/s for ABR. @command{oggenc} @option{-b} is
1151 expressed in kilobits/s.
1154 Set constant quality setting for VBR. The value should be a float
1155 number in the range of -1.0 to 10.0. The higher the value, the better
1156 the quality. The default value is @samp{3.0}.
1158 This option is valid only using the @command{ffmpeg} command-line tool.
1159 For library interface users, use @option{global_quality}.
1161 @item cutoff (@emph{--advanced-encode-option lowpass_frequency=N})
1162 Set cutoff bandwidth in Hz, a value of 0 disables cutoff. @command{oggenc}'s
1163 related option is expressed in kHz. The default value is @samp{0} (cutoff
1166 @item minrate (@emph{-m})
1167 Set minimum bitrate expressed in bits/s. @command{oggenc} @option{-m} is
1168 expressed in kilobits/s.
1170 @item maxrate (@emph{-M})
1171 Set maximum bitrate expressed in bits/s. @command{oggenc} @option{-M} is
1172 expressed in kilobits/s. This only has effect on ABR mode.
1174 @item iblock (@emph{--advanced-encode-option impulse_noisetune=N})
1175 Set noise floor bias for impulse blocks. The value is a float number from
1176 -15.0 to 0.0. A negative bias instructs the encoder to pay special attention
1177 to the crispness of transients in the encoded audio. The tradeoff for better
1178 transient response is a higher bitrate.
1185 A wrapper providing WavPack encoding through libwavpack.
1187 Only lossless mode using 32-bit integer samples is supported currently.
1189 Requires the presence of the libwavpack headers and library during
1190 configuration. You need to explicitly configure the build with
1191 @code{--enable-libwavpack}.
1193 Note that a libavcodec-native encoder for the WavPack codec exists so users can
1194 encode audios with this codec without using this encoder. See @ref{wavpackenc}.
1198 @command{wavpack} command line utility's corresponding options are listed in
1199 parentheses, if any.
1202 @item frame_size (@emph{--blocksize})
1205 @item compression_level
1206 Set speed vs. compression tradeoff. Acceptable arguments are listed below:
1213 Normal (default) settings.
1218 @item 3 (@emph{-hh})
1221 @item 4-8 (@emph{-hh -x}@var{EXTRAPROC})
1222 Same as @samp{3}, but with extra processing enabled.
1224 @samp{4} is the same as @option{-x2} and @samp{8} is the same as @option{-x6}.
1232 Motion JPEG encoder.
1238 Set the huffman encoding strategy. Possible values:
1242 Use the default huffman tables. This is the default strategy.
1245 Compute and use optimal huffman tables.
1253 WavPack lossless audio encoder.
1255 This is a libavcodec-native WavPack encoder. There is also an encoder based on
1256 libwavpack, but there is virtually no reason to use that encoder.
1258 See also @ref{libwavpack}.
1262 The equivalent options for @command{wavpack} command line utility are listed in
1265 @subsubsection Shared options
1267 The following shared options are effective for this encoder. Only special notes
1268 about this particular encoder will be documented here. For the general meaning
1269 of the options, see @ref{codec-options,,the Codec Options chapter}.
1272 @item frame_size (@emph{--blocksize})
1273 For this encoder, the range for this option is between 128 and 131072. Default
1274 is automatically decided based on sample rate and number of channel.
1276 For the complete formula of calculating default, see
1277 @file{libavcodec/wavpackenc.c}.
1279 @item compression_level (@emph{-f}, @emph{-h}, @emph{-hh}, and @emph{-x})
1280 This option's syntax is consistent with @ref{libwavpack}'s.
1283 @subsubsection Private options
1286 @item joint_stereo (@emph{-j})
1287 Set whether to enable joint stereo. Valid values are:
1291 Force mid/side audio encoding.
1292 @item off (@emph{0})
1293 Force left/right audio encoding.
1295 Let the encoder decide automatically.
1299 Set whether to enable optimization for mono. This option is only effective for
1300 non-mono streams. Available values:
1311 @c man end AUDIO ENCODERS
1313 @chapter Video Encoders
1314 @c man begin VIDEO ENCODERS
1316 A description of some of the currently available video encoders
1321 Vidvox Hap video encoder.
1326 @item format @var{integer}
1327 Specifies the Hap format to encode.
1335 Default value is @option{hap}.
1337 @item chunks @var{integer}
1338 Specifies the number of chunks to split frames into, between 1 and 64. This
1339 permits multithreaded decoding of large frames, potentially at the cost of
1340 data-rate. The encoder may modify this value to divide frames evenly.
1342 Default value is @var{1}.
1344 @item compressor @var{integer}
1345 Specifies the second-stage compressor to use. If set to @option{none},
1346 @option{chunks} will be limited to 1, as chunked uncompressed frames offer no
1354 Default value is @option{snappy}.
1360 The native jpeg 2000 encoder is lossy by default, the @code{-q:v}
1361 option can be used to set the encoding quality. Lossless encoding
1362 can be selected with @code{-pred 1}.
1368 Can be set to either @code{j2k} or @code{jp2} (the default) that
1369 makes it possible to store non-rgb pix_fmts.
1375 Kvazaar H.265/HEVC encoder.
1377 Requires the presence of the libkvazaar headers and library during
1378 configuration. You need to explicitly configure the build with
1379 @option{--enable-libkvazaar}.
1386 Set target video bitrate in bit/s and enable rate control.
1388 @item kvazaar-params
1389 Set kvazaar parameters as a list of @var{name}=@var{value} pairs separated
1390 by commas (,). See kvazaar documentation for a list of options.
1394 @section libopenh264
1396 Cisco libopenh264 H.264/MPEG-4 AVC encoder wrapper.
1398 This encoder requires the presence of the libopenh264 headers and
1399 library during configuration. You need to explicitly configure the
1400 build with @code{--enable-libopenh264}. The library is detected using
1401 @command{pkg-config}.
1403 For more information about the library see
1404 @url{http://www.openh264.org}.
1408 The following FFmpeg global options affect the configurations of the
1409 libopenh264 encoder.
1413 Set the bitrate (as a number of bits per second).
1419 Set the max bitrate (as a number of bits per second).
1421 @item flags +global_header
1422 Set global header in the bitstream.
1425 Set the number of slices, used in parallelized encoding. Default value
1426 is 0. This is only used when @option{slice_mode} is set to
1430 Set slice mode. Can assume one of the following possible values:
1434 a fixed number of slices
1436 one slice per row of macroblocks
1438 automatic number of slices according to number of threads
1443 Default value is @samp{auto}.
1446 Enable loop filter, if set to 1 (automatically enabled). To disable
1450 Set profile restrictions. If set to the value of @samp{main} enable
1451 CABAC (set the @code{SEncParamExt.iEntropyCodingModeFlag} flag to 1).
1454 Set maximum NAL size in bytes.
1456 @item allow_skip_frames
1457 Allow skipping frames to hit the target bitrate if set to 1.
1462 libtheora Theora encoder wrapper.
1464 Requires the presence of the libtheora headers and library during
1465 configuration. You need to explicitly configure the build with
1466 @code{--enable-libtheora}.
1468 For more information about the libtheora project see
1469 @url{http://www.theora.org/}.
1473 The following global options are mapped to internal libtheora options
1474 which affect the quality and the bitrate of the encoded stream.
1478 Set the video bitrate in bit/s for CBR (Constant Bit Rate) mode. In
1479 case VBR (Variable Bit Rate) mode is enabled this option is ignored.
1482 Used to enable constant quality mode (VBR) encoding through the
1483 @option{qscale} flag, and to enable the @code{pass1} and @code{pass2}
1489 @item global_quality
1490 Set the global quality as an integer in lambda units.
1492 Only relevant when VBR mode is enabled with @code{flags +qscale}. The
1493 value is converted to QP units by dividing it by @code{FF_QP2LAMBDA},
1494 clipped in the [0 - 10] range, and then multiplied by 6.3 to get a
1495 value in the native libtheora range [0-63]. A higher value corresponds
1496 to a higher quality.
1499 Enable VBR mode when set to a non-negative value, and set constant
1500 quality value as a double floating point value in QP units.
1502 The value is clipped in the [0-10] range, and then multiplied by 6.3
1503 to get a value in the native libtheora range [0-63].
1505 This option is valid only using the @command{ffmpeg} command-line
1506 tool. For library interface users, use @option{global_quality}.
1509 @subsection Examples
1513 Set maximum constant quality (VBR) encoding with @command{ffmpeg}:
1515 ffmpeg -i INPUT -codec:v libtheora -q:v 10 OUTPUT.ogg
1519 Use @command{ffmpeg} to convert a CBR 1000 kbps Theora video stream:
1521 ffmpeg -i INPUT -codec:v libtheora -b:v 1000k OUTPUT.ogg
1527 VP8/VP9 format supported through libvpx.
1529 Requires the presence of the libvpx headers and library during configuration.
1530 You need to explicitly configure the build with @code{--enable-libvpx}.
1534 The following options are supported by the libvpx wrapper. The
1535 @command{vpxenc}-equivalent options or values are listed in parentheses
1538 To reduce the duplication of documentation, only the private options
1539 and some others requiring special attention are documented here. For
1540 the documentation of the undocumented generic options, see
1541 @ref{codec-options,,the Codec Options chapter}.
1543 To get more documentation of the libvpx options, invoke the command
1544 @command{ffmpeg -h encoder=libvpx}, @command{ffmpeg -h encoder=libvpx-vp9} or
1545 @command{vpxenc --help}. Further information is available in the libvpx API
1550 @item b (@emph{target-bitrate})
1551 Set bitrate in bits/s. Note that FFmpeg's @option{b} option is
1552 expressed in bits/s, while @command{vpxenc}'s @option{target-bitrate} is in
1555 @item g (@emph{kf-max-dist})
1557 @item keyint_min (@emph{kf-min-dist})
1559 @item qmin (@emph{min-q})
1561 @item qmax (@emph{max-q})
1563 @item bufsize (@emph{buf-sz}, @emph{buf-optimal-sz})
1564 Set ratecontrol buffer size (in bits). Note @command{vpxenc}'s options are
1565 specified in milliseconds, the libvpx wrapper converts this value as follows:
1566 @code{buf-sz = bufsize * 1000 / bitrate},
1567 @code{buf-optimal-sz = bufsize * 1000 / bitrate * 5 / 6}.
1569 @item rc_init_occupancy (@emph{buf-initial-sz})
1570 Set number of bits which should be loaded into the rc buffer before decoding
1571 starts. Note @command{vpxenc}'s option is specified in milliseconds, the libvpx
1572 wrapper converts this value as follows:
1573 @code{rc_init_occupancy * 1000 / bitrate}.
1575 @item undershoot-pct
1576 Set datarate undershoot (min) percentage of the target bitrate.
1579 Set datarate overshoot (max) percentage of the target bitrate.
1581 @item skip_threshold (@emph{drop-frame})
1583 @item qcomp (@emph{bias-pct})
1585 @item maxrate (@emph{maxsection-pct})
1586 Set GOP max bitrate in bits/s. Note @command{vpxenc}'s option is specified as a
1587 percentage of the target bitrate, the libvpx wrapper converts this value as
1588 follows: @code{(maxrate * 100 / bitrate)}.
1590 @item minrate (@emph{minsection-pct})
1591 Set GOP min bitrate in bits/s. Note @command{vpxenc}'s option is specified as a
1592 percentage of the target bitrate, the libvpx wrapper converts this value as
1593 follows: @code{(minrate * 100 / bitrate)}.
1595 @item minrate, maxrate, b @emph{end-usage=cbr}
1596 @code{(minrate == maxrate == bitrate)}.
1598 @item crf (@emph{end-usage=cq}, @emph{cq-level})
1600 @item tune (@emph{tune})
1602 @item psnr (@emph{psnr})
1603 @item ssim (@emph{ssim})
1606 @item quality, deadline (@emph{deadline})
1609 Use best quality deadline. Poorly named and quite slow, this option should be
1610 avoided as it may give worse quality output than good.
1612 Use good quality deadline. This is a good trade-off between speed and quality
1613 when used with the @option{cpu-used} option.
1615 Use realtime quality deadline.
1618 @item speed, cpu-used (@emph{cpu-used})
1619 Set quality/speed ratio modifier. Higher values speed up the encode at the cost
1622 @item nr (@emph{noise-sensitivity})
1625 Set a change threshold on blocks below which they will be skipped by the
1628 @item slices (@emph{token-parts})
1629 Note that FFmpeg's @option{slices} option gives the total number of partitions,
1630 while @command{vpxenc}'s @option{token-parts} is given as
1631 @code{log2(partitions)}.
1633 @item max-intra-rate
1634 Set maximum I-frame bitrate as a percentage of the target bitrate. A value of 0
1637 @item force_key_frames
1638 @code{VPX_EFLAG_FORCE_KF}
1640 @item Alternate reference frame related
1643 Enable use of alternate reference frames (2-pass only).
1644 @item arnr-max-frames
1645 Set altref noise reduction max frame count.
1647 Set altref noise reduction filter type: backward, forward, centered.
1649 Set altref noise reduction filter strength.
1650 @item rc-lookahead, lag-in-frames (@emph{lag-in-frames})
1651 Set number of frames to look ahead for frametype and ratecontrol.
1654 @item error-resilient
1655 Enable error resiliency features.
1657 @item VP9-specific options
1660 Enable lossless mode.
1662 Set number of tile columns to use. Note this is given as
1663 @code{log2(tile_columns)}. For example, 8 tile columns would be requested by
1664 setting the @option{tile-columns} option to 3.
1666 Set number of tile rows to use. Note this is given as @code{log2(tile_rows)}.
1667 For example, 4 tile rows would be requested by setting the @option{tile-rows}
1669 @item frame-parallel
1670 Enable frame parallel decodability features.
1672 Set adaptive quantization mode (0: off (default), 1: variance 2: complexity, 3:
1673 cyclic refresh, 4: equator360).
1674 @item colorspace @emph{color-space}
1675 Set input color space. The VP9 bitstream supports signaling the following
1678 @item @samp{rgb} @emph{sRGB}
1679 @item @samp{bt709} @emph{bt709}
1680 @item @samp{unspecified} @emph{unknown}
1681 @item @samp{bt470bg} @emph{bt601}
1682 @item @samp{smpte170m} @emph{smpte170}
1683 @item @samp{smpte240m} @emph{smpte240}
1684 @item @samp{bt2020_ncl} @emph{bt2020}
1686 @item row-mt @var{boolean}
1687 Enable row based multi-threading.
1689 Set content type: default (0), screen (1), film (2).
1690 @item corpus-complexity
1691 Corpus VBR mode is a variant of standard VBR where the complexity distribution
1692 midpoint is passed in rather than calculated for a specific clip or chunk.
1694 The valid range is [0, 10000]. 0 (default) uses standard VBR.
1699 For more information about libvpx see:
1700 @url{http://www.webmproject.org/}
1704 libwebp WebP Image encoder wrapper
1706 libwebp is Google's official encoder for WebP images. It can encode in either
1707 lossy or lossless mode. Lossy images are essentially a wrapper around a VP8
1708 frame. Lossless images are a separate codec developed by Google.
1710 @subsection Pixel Format
1712 Currently, libwebp only supports YUV420 for lossy and RGB for lossless due
1713 to limitations of the format and libwebp. Alpha is supported for either mode.
1714 Because of API limitations, if RGB is passed in when encoding lossy or YUV is
1715 passed in for encoding lossless, the pixel format will automatically be
1716 converted using functions from libwebp. This is not ideal and is done only for
1723 @item -lossless @var{boolean}
1724 Enables/Disables use of lossless mode. Default is 0.
1726 @item -compression_level @var{integer}
1727 For lossy, this is a quality/speed tradeoff. Higher values give better quality
1728 for a given size at the cost of increased encoding time. For lossless, this is
1729 a size/speed tradeoff. Higher values give smaller size at the cost of increased
1730 encoding time. More specifically, it controls the number of extra algorithms
1731 and compression tools used, and varies the combination of these tools. This
1732 maps to the @var{method} option in libwebp. The valid range is 0 to 6.
1735 @item -qscale @var{float}
1736 For lossy encoding, this controls image quality, 0 to 100. For lossless
1737 encoding, this controls the effort and time spent at compressing more. The
1738 default value is 75. Note that for usage via libavcodec, this option is called
1739 @var{global_quality} and must be multiplied by @var{FF_QP2LAMBDA}.
1741 @item -preset @var{type}
1742 Configuration preset. This does some automatic settings based on the general
1746 Do not use a preset.
1748 Use the encoder default.
1750 Digital picture, like portrait, inner shot
1752 Outdoor photograph, with natural lighting
1754 Hand or line drawing, with high-contrast details
1756 Small-sized colorful images
1763 @section libx264, libx264rgb
1765 x264 H.264/MPEG-4 AVC encoder wrapper.
1767 This encoder requires the presence of the libx264 headers and library
1768 during configuration. You need to explicitly configure the build with
1769 @code{--enable-libx264}.
1771 libx264 supports an impressive number of features, including 8x8 and
1772 4x4 adaptive spatial transform, adaptive B-frame placement, CAVLC/CABAC
1773 entropy coding, interlacing (MBAFF), lossless mode, psy optimizations
1774 for detail retention (adaptive quantization, psy-RD, psy-trellis).
1776 Many libx264 encoder options are mapped to FFmpeg global codec
1777 options, while unique encoder options are provided through private
1778 options. Additionally the @option{x264opts} and @option{x264-params}
1779 private options allows one to pass a list of key=value tuples as accepted
1780 by the libx264 @code{x264_param_parse} function.
1782 The x264 project website is at
1783 @url{http://www.videolan.org/developers/x264.html}.
1785 The libx264rgb encoder is the same as libx264, except it accepts packed RGB
1786 pixel formats as input instead of YUV.
1788 @subsection Supported Pixel Formats
1790 x264 supports 8- to 10-bit color spaces. The exact bit depth is controlled at
1791 x264's configure time. FFmpeg only supports one bit depth in one particular
1792 build. In other words, it is not possible to build one FFmpeg with multiple
1793 versions of x264 with different bit depths.
1797 The following options are supported by the libx264 wrapper. The
1798 @command{x264}-equivalent options or values are listed in parentheses
1801 To reduce the duplication of documentation, only the private options
1802 and some others requiring special attention are documented here. For
1803 the documentation of the undocumented generic options, see
1804 @ref{codec-options,,the Codec Options chapter}.
1806 To get a more accurate and extensive documentation of the libx264
1807 options, invoke the command @command{x264 --fullhelp} or consult
1808 the libx264 documentation.
1811 @item b (@emph{bitrate})
1812 Set bitrate in bits/s. Note that FFmpeg's @option{b} option is
1813 expressed in bits/s, while @command{x264}'s @option{bitrate} is in
1816 @item bf (@emph{bframes})
1818 @item g (@emph{keyint})
1820 @item qmin (@emph{qpmin})
1821 Minimum quantizer scale.
1823 @item qmax (@emph{qpmax})
1824 Maximum quantizer scale.
1826 @item qdiff (@emph{qpstep})
1827 Maximum difference between quantizer scales.
1829 @item qblur (@emph{qblur})
1830 Quantizer curve blur
1832 @item qcomp (@emph{qcomp})
1833 Quantizer curve compression factor
1835 @item refs (@emph{ref})
1836 Number of reference frames each P-frame can use. The range is from @var{0-16}.
1838 @item sc_threshold (@emph{scenecut})
1839 Sets the threshold for the scene change detection.
1841 @item trellis (@emph{trellis})
1842 Performs Trellis quantization to increase efficiency. Enabled by default.
1844 @item nr (@emph{nr})
1846 @item me_range (@emph{merange})
1847 Maximum range of the motion search in pixels.
1849 @item me_method (@emph{me})
1850 Set motion estimation method. Possible values in the decreasing order
1854 @item dia (@emph{dia})
1855 @item epzs (@emph{dia})
1856 Diamond search with radius 1 (fastest). @samp{epzs} is an alias for
1858 @item hex (@emph{hex})
1859 Hexagonal search with radius 2.
1860 @item umh (@emph{umh})
1861 Uneven multi-hexagon search.
1862 @item esa (@emph{esa})
1864 @item tesa (@emph{tesa})
1865 Hadamard exhaustive search (slowest).
1869 Normally, when forcing a I-frame type, the encoder can select any type
1870 of I-frame. This option forces it to choose an IDR-frame.
1872 @item subq (@emph{subme})
1873 Sub-pixel motion estimation method.
1875 @item b_strategy (@emph{b-adapt})
1876 Adaptive B-frame placement decision algorithm. Use only on first-pass.
1878 @item keyint_min (@emph{min-keyint})
1882 Set entropy encoder. Possible values:
1889 Enable CAVLC and disable CABAC. It generates the same effect as
1890 @command{x264}'s @option{--no-cabac} option.
1894 Set full pixel motion estimation comparison algorithm. Possible values:
1898 Enable chroma in motion estimation.
1901 Ignore chroma in motion estimation. It generates the same effect as
1902 @command{x264}'s @option{--no-chroma-me} option.
1905 @item threads (@emph{threads})
1906 Number of encoding threads.
1909 Set multithreading technique. Possible values:
1913 Slice-based multithreading. It generates the same effect as
1914 @command{x264}'s @option{--sliced-threads} option.
1916 Frame-based multithreading.
1920 Set encoding flags. It can be used to disable closed GOP and enable
1921 open GOP by setting it to @code{-cgop}. The result is similar to
1922 the behavior of @command{x264}'s @option{--open-gop} option.
1924 @item rc_init_occupancy (@emph{vbv-init})
1926 @item preset (@emph{preset})
1927 Set the encoding preset.
1929 @item tune (@emph{tune})
1930 Set tuning of the encoding params.
1932 @item profile (@emph{profile})
1933 Set profile restrictions.
1936 Enable fast settings when encoding first pass, when set to 1. When set
1937 to 0, it has the same effect of @command{x264}'s
1938 @option{--slow-firstpass} option.
1940 @item crf (@emph{crf})
1941 Set the quality for constant quality mode.
1943 @item crf_max (@emph{crf-max})
1944 In CRF mode, prevents VBV from lowering quality beyond this point.
1946 @item qp (@emph{qp})
1947 Set constant quantization rate control method parameter.
1949 @item aq-mode (@emph{aq-mode})
1950 Set AQ method. Possible values:
1953 @item none (@emph{0})
1956 @item variance (@emph{1})
1957 Variance AQ (complexity mask).
1959 @item autovariance (@emph{2})
1960 Auto-variance AQ (experimental).
1963 @item aq-strength (@emph{aq-strength})
1964 Set AQ strength, reduce blocking and blurring in flat and textured areas.
1967 Use psychovisual optimizations when set to 1. When set to 0, it has the
1968 same effect as @command{x264}'s @option{--no-psy} option.
1970 @item psy-rd (@emph{psy-rd})
1971 Set strength of psychovisual optimization, in
1972 @var{psy-rd}:@var{psy-trellis} format.
1974 @item rc-lookahead (@emph{rc-lookahead})
1975 Set number of frames to look ahead for frametype and ratecontrol.
1978 Enable weighted prediction for B-frames when set to 1. When set to 0,
1979 it has the same effect as @command{x264}'s @option{--no-weightb} option.
1981 @item weightp (@emph{weightp})
1982 Set weighted prediction method for P-frames. Possible values:
1985 @item none (@emph{0})
1987 @item simple (@emph{1})
1988 Enable only weighted refs
1989 @item smart (@emph{2})
1990 Enable both weighted refs and duplicates
1993 @item ssim (@emph{ssim})
1994 Enable calculation and printing SSIM stats after the encoding.
1996 @item intra-refresh (@emph{intra-refresh})
1997 Enable the use of Periodic Intra Refresh instead of IDR frames when set
2000 @item avcintra-class (@emph{class})
2001 Configure the encoder to generate AVC-Intra.
2002 Valid values are 50,100 and 200
2004 @item bluray-compat (@emph{bluray-compat})
2005 Configure the encoder to be compatible with the bluray standard.
2006 It is a shorthand for setting "bluray-compat=1 force-cfr=1".
2008 @item b-bias (@emph{b-bias})
2009 Set the influence on how often B-frames are used.
2011 @item b-pyramid (@emph{b-pyramid})
2012 Set method for keeping of some B-frames as references. Possible values:
2015 @item none (@emph{none})
2017 @item strict (@emph{strict})
2018 Strictly hierarchical pyramid.
2019 @item normal (@emph{normal})
2020 Non-strict (not Blu-ray compatible).
2024 Enable the use of one reference per partition, as opposed to one
2025 reference per macroblock when set to 1. When set to 0, it has the
2026 same effect as @command{x264}'s @option{--no-mixed-refs} option.
2029 Enable adaptive spatial transform (high profile 8x8 transform)
2030 when set to 1. When set to 0, it has the same effect as
2031 @command{x264}'s @option{--no-8x8dct} option.
2034 Enable early SKIP detection on P-frames when set to 1. When set
2035 to 0, it has the same effect as @command{x264}'s
2036 @option{--no-fast-pskip} option.
2038 @item aud (@emph{aud})
2039 Enable use of access unit delimiters when set to 1.
2042 Enable use macroblock tree ratecontrol when set to 1. When set
2043 to 0, it has the same effect as @command{x264}'s
2044 @option{--no-mbtree} option.
2046 @item deblock (@emph{deblock})
2047 Set loop filter parameters, in @var{alpha}:@var{beta} form.
2049 @item cplxblur (@emph{cplxblur})
2050 Set fluctuations reduction in QP (before curve compression).
2052 @item partitions (@emph{partitions})
2053 Set partitions to consider as a comma-separated list of. Possible
2058 8x8 P-frame partition.
2060 4x4 P-frame partition.
2062 4x4 B-frame partition.
2064 8x8 I-frame partition.
2066 4x4 I-frame partition.
2067 (Enabling @samp{p4x4} requires @samp{p8x8} to be enabled. Enabling
2068 @samp{i8x8} requires adaptive spatial transform (@option{8x8dct}
2069 option) to be enabled.)
2070 @item none (@emph{none})
2071 Do not consider any partitions.
2072 @item all (@emph{all})
2073 Consider every partition.
2076 @item direct-pred (@emph{direct})
2077 Set direct MV prediction mode. Possible values:
2080 @item none (@emph{none})
2081 Disable MV prediction.
2082 @item spatial (@emph{spatial})
2083 Enable spatial predicting.
2084 @item temporal (@emph{temporal})
2085 Enable temporal predicting.
2086 @item auto (@emph{auto})
2087 Automatically decided.
2090 @item slice-max-size (@emph{slice-max-size})
2091 Set the limit of the size of each slice in bytes. If not specified
2092 but RTP payload size (@option{ps}) is specified, that is used.
2094 @item stats (@emph{stats})
2095 Set the file name for multi-pass stats.
2097 @item nal-hrd (@emph{nal-hrd})
2098 Set signal HRD information (requires @option{vbv-bufsize} to be set).
2102 @item none (@emph{none})
2103 Disable HRD information signaling.
2104 @item vbr (@emph{vbr})
2106 @item cbr (@emph{cbr})
2107 Constant bit rate (not allowed in MP4 container).
2110 @item x264opts (N.A.)
2111 Set any x264 option, see @command{x264 --fullhelp} for a list.
2113 Argument is a list of @var{key}=@var{value} couples separated by
2114 ":". In @var{filter} and @var{psy-rd} options that use ":" as a separator
2115 themselves, use "," instead. They accept it as well since long ago but this
2116 is kept undocumented for some reason.
2118 For example to specify libx264 encoding options with @command{ffmpeg}:
2120 ffmpeg -i foo.mpg -c:v libx264 -x264opts keyint=123:min-keyint=20 -an out.mkv
2123 @item a53cc @var{boolean}
2124 Import closed captions (which must be ATSC compatible format) into output.
2125 Only the mpeg2 and h264 decoders provide these. Default is 1 (on).
2127 @item x264-params (N.A.)
2128 Override the x264 configuration using a :-separated list of key=value
2131 This option is functionally the same as the @option{x264opts}, but is
2132 duplicated for compatibility with the Libav fork.
2134 For example to specify libx264 encoding options with @command{ffmpeg}:
2136 ffmpeg -i INPUT -c:v libx264 -x264-params level=30:bframes=0:weightp=0:\
2137 cabac=0:ref=1:vbv-maxrate=768:vbv-bufsize=2000:analyse=all:me=umh:\
2138 no-fast-pskip=1:subq=6:8x8dct=0:trellis=0 OUTPUT
2142 Encoding ffpresets for common usages are provided so they can be used with the
2143 general presets system (e.g. passing the @option{pre} option).
2147 x265 H.265/HEVC encoder wrapper.
2149 This encoder requires the presence of the libx265 headers and library
2150 during configuration. You need to explicitly configure the build with
2151 @option{--enable-libx265}.
2157 Set the x265 preset.
2160 Set the x265 tune parameter.
2163 Set profile restrictions.
2166 Set the quality for constant quality mode.
2169 Normally, when forcing a I-frame type, the encoder can select any type
2170 of I-frame. This option forces it to choose an IDR-frame.
2173 Set x265 options using a list of @var{key}=@var{value} couples separated
2174 by ":". See @command{x265 --help} for a list of options.
2176 For example to specify libx265 encoding options with @option{-x265-params}:
2179 ffmpeg -i input -c:v libx265 -x265-params crf=26:psy-rd=1 output.mp4
2185 Xvid MPEG-4 Part 2 encoder wrapper.
2187 This encoder requires the presence of the libxvidcore headers and library
2188 during configuration. You need to explicitly configure the build with
2189 @code{--enable-libxvid --enable-gpl}.
2191 The native @code{mpeg4} encoder supports the MPEG-4 Part 2 format, so
2192 users can encode to this format without this library.
2196 The following options are supported by the libxvid wrapper. Some of
2197 the following options are listed but are not documented, and
2198 correspond to shared codec options. See @ref{codec-options,,the Codec
2199 Options chapter} for their documentation. The other shared options
2200 which are not listed have no effect for the libxvid encoder.
2222 Set specific encoding flags. Possible values:
2227 Use four motion vector by macroblock.
2230 Enable high quality AC prediction.
2233 Only encode grayscale.
2236 Enable the use of global motion compensation (GMC).
2239 Enable quarter-pixel motion compensation.
2245 Place global headers in extradata instead of every keyframe.
2252 Set motion estimation method. Possible values in decreasing order of
2253 speed and increasing order of quality:
2257 Use no motion estimation (default).
2262 Enable advanced diamond zonal search for 16x16 blocks and half-pixel
2263 refinement for 16x16 blocks. @samp{x1} and @samp{log} are aliases for
2267 Enable all of the things described above, plus advanced diamond zonal
2268 search for 8x8 blocks, half-pixel refinement for 8x8 blocks, and motion
2269 estimation on chroma planes.
2272 Enable all of the things described above, plus extended 16x16 and 8x8
2277 Set macroblock decision algorithm. Possible values in the increasing
2282 Use macroblock comparing function algorithm (default).
2285 Enable rate distortion-based half pixel and quarter pixel refinement for
2289 Enable all of the things described above, plus rate distortion-based
2290 half pixel and quarter pixel refinement for 8x8 blocks, and rate
2291 distortion-based search using square pattern.
2295 Enable lumi masking adaptive quantization when set to 1. Default is 0
2299 Enable variance adaptive quantization when set to 1. Default is 0
2302 When combined with @option{lumi_aq}, the resulting quality will not
2303 be better than any of the two specified individually. In other
2304 words, the resulting quality will be the worse one of the two
2308 Set structural similarity (SSIM) displaying method. Possible values:
2312 Disable displaying of SSIM information.
2315 Output average SSIM at the end of encoding to stdout. The format of
2316 showing the average SSIM is:
2322 For users who are not familiar with C, %f means a float number, or
2323 a decimal (e.g. 0.939232).
2326 Output both per-frame SSIM data during encoding and average SSIM at
2327 the end of encoding to stdout. The format of per-frame information
2331 SSIM: avg: %1.3f min: %1.3f max: %1.3f
2334 For users who are not familiar with C, %1.3f means a float number
2335 rounded to 3 digits after the dot (e.g. 0.932).
2340 Set SSIM accuracy. Valid options are integers within the range of
2341 0-4, while 0 gives the most accurate result and 4 computes the
2348 MPEG-2 video encoder.
2353 @item seq_disp_ext @var{integer}
2354 Specifies if the encoder should write a sequence_display_extension to the
2359 Decide automatically to write it or not (this is the default) by checking if
2360 the data to be written is different from the default or unspecified values.
2368 @item video_format @var{integer}
2369 Specifies the video_format written into the sequence display extension
2370 indicating the source of the video pictures. The default is @samp{unspecified},
2371 can be @samp{component}, @samp{pal}, @samp{ntsc}, @samp{secam} or @samp{mac}.
2372 For maximum compatibility, use @samp{component}.
2379 @subsection Private options
2382 @item dpi @var{integer}
2383 Set physical density of pixels, in dots per inch, unset by default
2384 @item dpm @var{integer}
2385 Set physical density of pixels, in dots per meter, unset by default
2390 Apple ProRes encoder.
2392 FFmpeg contains 2 ProRes encoders, the prores-aw and prores-ks encoder.
2393 The used encoder can be chosen with the @code{-vcodec} option.
2395 @subsection Private Options for prores-ks
2398 @item profile @var{integer}
2399 Select the ProRes profile to encode
2409 @item quant_mat @var{integer}
2410 Select quantization matrix.
2419 If set to @var{auto}, the matrix matching the profile will be picked.
2420 If not set, the matrix providing the highest quality, @var{default}, will be
2423 @item bits_per_mb @var{integer}
2424 How many bits to allot for coding one macroblock. Different profiles use
2425 between 200 and 2400 bits per macroblock, the maximum is 8000.
2427 @item mbs_per_slice @var{integer}
2428 Number of macroblocks in each slice (1-8); the default value (8)
2429 should be good in almost all situations.
2431 @item vendor @var{string}
2432 Override the 4-byte vendor ID.
2433 A custom vendor ID like @var{apl0} would claim the stream was produced by
2436 @item alpha_bits @var{integer}
2437 Specify number of bits for alpha component.
2438 Possible values are @var{0}, @var{8} and @var{16}.
2439 Use @var{0} to disable alpha plane coding.
2443 @subsection Speed considerations
2445 In the default mode of operation the encoder has to honor frame constraints
2446 (i.e. not produce frames with size bigger than requested) while still making
2447 output picture as good as possible.
2448 A frame containing a lot of small details is harder to compress and the encoder
2449 would spend more time searching for appropriate quantizers for each slice.
2451 Setting a higher @option{bits_per_mb} limit will improve the speed.
2453 For the fastest encoding speed set the @option{qscale} parameter (4 is the
2454 recommended value) and do not set a size constraint.
2456 @section QSV encoders
2458 The family of Intel QuickSync Video encoders (MPEG-2, H.264 and HEVC)
2460 The ratecontrol method is selected as follows:
2464 When @option{global_quality} is specified, a quality-based mode is used.
2465 Specifically this means either
2468 @var{CQP} - constant quantizer scale, when the @option{qscale} codec flag is
2469 also set (the @option{-qscale} ffmpeg option).
2472 @var{LA_ICQ} - intelligent constant quality with lookahead, when the
2473 @option{look_ahead} option is also set.
2476 @var{ICQ} -- intelligent constant quality otherwise.
2480 Otherwise, a bitrate-based mode is used. For all of those, you should specify at
2481 least the desired average bitrate with the @option{b} option.
2484 @var{LA} - VBR with lookahead, when the @option{look_ahead} option is specified.
2487 @var{VCM} - video conferencing mode, when the @option{vcm} option is set.
2490 @var{CBR} - constant bitrate, when @option{maxrate} is specified and equal to
2491 the average bitrate.
2494 @var{VBR} - variable bitrate, when @option{maxrate} is specified, but is higher
2495 than the average bitrate.
2498 @var{AVBR} - average VBR mode, when @option{maxrate} is not specified. This mode
2499 is further configured by the @option{avbr_accuracy} and
2500 @option{avbr_convergence} options.
2504 Note that depending on your system, a different mode than the one you specified
2505 may be selected by the encoder. Set the verbosity level to @var{verbose} or
2506 higher to see the actual settings used by the QSV runtime.
2508 Additional libavcodec global options are mapped to MSDK options as follows:
2512 @option{g/gop_size} -> @option{GopPicSize}
2515 @option{bf/max_b_frames}+1 -> @option{GopRefDist}
2518 @option{rc_init_occupancy/rc_initial_buffer_occupancy} ->
2519 @option{InitialDelayInKB}
2522 @option{slices} -> @option{NumSlice}
2525 @option{refs} -> @option{NumRefFrame}
2528 @option{b_strategy/b_frame_strategy} -> @option{BRefType}
2531 @option{cgop/CLOSED_GOP} codec flag -> @option{GopOptFlag}
2534 For the @var{CQP} mode, the @option{i_qfactor/i_qoffset} and
2535 @option{b_qfactor/b_qoffset} set the difference between @var{QPP} and @var{QPI},
2536 and @var{QPP} and @var{QPB} respectively.
2539 Setting the @option{coder} option to the value @var{vlc} will make the H.264
2540 encoder use CAVLC instead of CABAC.
2549 @item iterative_dia_size
2550 dia size for the iterative motion estimation
2553 @section VAAPI encoders
2555 Wrappers for hardware encoders accessible via VAAPI.
2557 These encoders only accept input in VAAPI hardware surfaces. If you have input
2558 in software frames, use the @option{hwupload} filter to upload them to the GPU.
2560 The following standard libavcodec options are used:
2563 @option{g} / @option{gop_size}
2565 @option{bf} / @option{max_b_frames}
2569 If not set, this will be determined automatically from the format of the input
2570 frames and the profiles supported by the driver.
2574 @option{b} / @option{bit_rate}
2576 @option{maxrate} / @option{rc_max_rate}
2578 @option{bufsize} / @option{rc_buffer_size}
2580 @option{rc_init_occupancy} / @option{rc_initial_buffer_occupancy}
2582 @option{compression_level}
2584 Speed / quality tradeoff: higher values are faster / worse quality.
2586 @option{q} / @option{global_quality}
2588 Size / quality tradeoff: higher values are smaller / worse quality.
2594 @option{i_qfactor} / @option{i_quant_factor}
2596 @option{i_qoffset} / @option{i_quant_offset}
2598 @option{b_qfactor} / @option{b_quant_factor}
2600 @option{b_qoffset} / @option{b_quant_offset}
2605 All encoders support the following options:
2610 Some drivers/platforms offer a second encoder for some codecs intended to use
2611 less power than the default encoder; setting this option will attempt to use
2612 that encoder. Note that it may support a reduced feature set, so some other
2613 options may not be available in this mode.
2616 Each encoder also has its own specific options:
2620 @option{profile} sets the value of @emph{profile_idc} and the @emph{constraint_set*_flag}s.
2621 @option{level} sets the value of @emph{level_idc}.
2625 Set entropy encoder (default is @emph{cabac}). Possible values:
2638 Include access unit delimiters in the stream (not included by default).
2641 Set SEI message types to include.
2642 Some combination of the following values:
2645 Include a @emph{user_data_unregistered} message containing information about
2648 Include picture timing parameters (@emph{buffering_period} and
2649 @emph{pic_timing} messages).
2650 @item recovery_point
2651 Include recovery points where appropriate (@emph{recovery_point} messages).
2657 @option{profile} and @option{level} set the values of
2658 @emph{general_profile_idc} and @emph{general_level_idc} respectively.
2662 Include access unit delimiters in the stream (not included by default).
2665 Set @emph{general_tier_flag}. This may affect the level chosen for the stream
2666 if it is not explicitly specified.
2669 Set SEI message types to include.
2670 Some combination of the following values:
2673 Include HDR metadata if the input frames have it
2674 (@emph{mastering_display_colour_volume} and @emph{content_light_level}
2681 Only baseline DCT encoding is supported. The encoder always uses the standard
2682 quantisation and huffman tables - @option{global_quality} scales the standard
2683 quantisation table (range 1-100).
2685 For YUV, 4:2:0, 4:2:2 and 4:4:4 subsampling modes are supported. RGB is also
2686 supported, and will create an RGB JPEG.
2690 Include JFIF header in each frame (not included by default).
2692 Include standard huffman tables (on by default). Turning this off will save
2693 a few hundred bytes in each output frame, but may lose compatibility with some
2694 JPEG decoders which don't fully handle MJPEG.
2698 @option{profile} and @option{level} set the value of @emph{profile_and_level_indication}.
2701 B-frames are not supported.
2703 @option{global_quality} sets the @emph{q_idx} used for non-key frames (range 0-127).
2706 @item loop_filter_level
2707 @item loop_filter_sharpness
2708 Manually set the loop filter parameters.
2712 @option{global_quality} sets the @emph{q_idx} used for P-frames (range 0-255).
2715 @item loop_filter_level
2716 @item loop_filter_sharpness
2717 Manually set the loop filter parameters.
2720 B-frames are supported, but the output stream is always in encode order rather than display
2721 order. If B-frames are enabled, it may be necessary to use the @option{vp9_raw_reorder}
2722 bitstream filter to modify the output stream to display frames in the correct order.
2724 Only normal frames are produced - the @option{vp9_superframe} bitstream filter may be
2725 required to produce a stream usable with all decoders.
2731 SMPTE VC-2 (previously BBC Dirac Pro). This codec was primarily aimed at
2732 professional broadcasting but since it supports yuv420, yuv422 and yuv444 at
2733 8 (limited range or full range), 10 or 12 bits, this makes it suitable for
2734 other tasks which require low overhead and low compression (like screen
2742 Sets target video bitrate. Usually that's around 1:6 of the uncompressed
2743 video bitrate (e.g. for 1920x1080 50fps yuv422p10 that's around 400Mbps). Higher
2744 values (close to the uncompressed bitrate) turn on lossless compression mode.
2747 Enables field coding when set (e.g. to tt - top field first) for interlaced
2748 inputs. Should increase compression with interlaced content as it splits the
2749 fields and encodes each separately.
2752 Sets the total amount of wavelet transforms to apply, between 1 and 5 (default).
2753 Lower values reduce compression and quality. Less capable decoders may not be
2754 able to handle values of @option{wavelet_depth} over 3.
2757 Sets the transform type. Currently only @var{5_3} (LeGall) and @var{9_7}
2759 are implemented, with 9_7 being the one with better compression and thus
2764 Sets the slice size for each slice. Larger values result in better compression.
2765 For compatibility with other more limited decoders use @option{slice_width} of
2766 32 and @option{slice_height} of 8.
2769 Sets the undershoot tolerance of the rate control system in percent. This is
2770 to prevent an expensive search from being run.
2773 Sets the quantization matrix preset to use by default or when @option{wavelet_depth}
2778 Uses the default quantization matrix from the specifications, extended with
2779 values for the fifth level. This provides a good balance between keeping detail
2780 and omitting artifacts.
2784 Use a completely zeroed out quantization matrix. This increases PSNR but might
2785 reduce perception. Use in bogus benchmarks.
2789 Reduces detail but attempts to preserve color at extremely low bitrates.
2796 xavs2 AVS2-P2/IEEE1857.4 encoder wrapper.
2798 This encoder requires the presence of the libxavs2 headers and library
2799 during configuration. You need to explicitly configure the build with
2800 @option{--enable-libxavs2}.
2805 @item lcu_row_threads
2806 Set the number of parallel threads for rows from 1 to 8 (default 5).
2809 Set the xavs2 quantization parameter from 1 to 63 (default 34). This is
2810 used to set the initial qp for the first frame.
2813 Set the xavs2 quantization parameter from 1 to 63 (default 34). This is
2814 used to set the qp value under constant-QP mode.
2817 Set the max qp for rate control from 1 to 63 (default 55).
2820 Set the min qp for rate control from 1 to 63 (default 20).
2823 Set the Speed level from 0 to 9 (default 0). Higher is better but slower.
2826 Set the log level from -1 to 3 (default 0). -1: none, 0: error,
2827 1: warning, 2: info, 3: debug.
2830 Set xavs2 options using a list of @var{key}=@var{value} couples separated
2833 For example to specify libxavs2 encoding options with @option{-xavs2-params}:
2836 ffmpeg -i input -c:v libxavs2 -xavs2-params preset_level=5 output.avs2
2840 @c man end VIDEO ENCODERS
2842 @chapter Subtitles Encoders
2843 @c man begin SUBTITLES ENCODERS
2847 This codec encodes the bitmap subtitle format that is used in DVDs.
2848 Typically they are stored in VOBSUB file pairs (*.idx + *.sub),
2849 and they can also be used in Matroska files.
2855 When set to 1, enable a work-around that makes the number of pixel rows
2856 even in all subtitles. This fixes a problem with some players that
2857 cut off the bottom row if the number is odd. The work-around just adds
2858 a fully transparent row if needed. The overhead is low, typically
2859 one byte per subtitle on average.
2861 By default, this work-around is disabled.
2864 @c man end SUBTITLES ENCODERS