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.
65 Will tune itself based on whether aac_is/aac_ms/aac_pns are enabled.
66 This is the default choice for a coder.
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 This method sets a constant quantizer for all bands. This is the fastest of all
80 the methods and has no rate control or support for @option{aac_is} or
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 benefitial.
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 imperceivable 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 -profile:a aac_low -aac_pns 0. PNS was introduced with the MPEG4
137 Long term prediction profile, is enabled by and will enable the aac_ltp option.
141 Main-type prediction profile, is enabled by and will enable the aac_pred option.
144 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.
492 @subsection Floating-Point-Only AC-3 Encoding Options
494 These options are only valid for the floating-point encoder and do not exist
495 for the fixed-point encoder due to the corresponding features not being
496 implemented in fixed-point.
500 @item -channel_coupling @var{boolean}
501 Enables/Disables use of channel coupling, which is an optional AC-3 feature
502 that increases quality by combining high frequency information from multiple
503 channels into a single channel. The per-channel high frequency information is
504 sent with less accuracy in both the frequency and time domains. This allows
505 more bits to be used for lower frequencies while preserving enough information
506 to reconstruct the high frequencies. This option is enabled by default for the
507 floating-point encoder and should generally be left as enabled except for
508 testing purposes or to increase encoding speed.
512 Selected by Encoder (default)
515 Disable Channel Coupling
518 Enable Channel Coupling
521 @item -cpl_start_band @var{number}
522 Coupling Start Band. Sets the channel coupling start band, from 1 to 15. If a
523 value higher than the bandwidth is used, it will be reduced to 1 less than the
524 coupling end band. If @var{auto} is used, the start band will be determined by
525 the encoder based on the bit rate, sample rate, and channel layout. This option
526 has no effect if channel coupling is disabled.
530 Selected by Encoder (default)
538 FLAC (Free Lossless Audio Codec) Encoder
542 The following options are supported by FFmpeg's flac encoder.
545 @item compression_level
546 Sets the compression level, which chooses defaults for many other options
547 if they are not set explicitly.
550 Sets the size of the frames in samples per channel.
552 @item lpc_coeff_precision
553 Sets the LPC coefficient precision, valid values are from 1 to 15, 15 is the
557 Sets the first stage LPC algorithm
563 fixed LPC coefficients
571 Number of passes to use for Cholesky factorization during LPC analysis
573 @item min_partition_order
574 The minimum partition order
576 @item max_partition_order
577 The maximum partition order
579 @item prediction_order_method
594 The mode is chosen automatically for each frame
596 Chanels are independently coded
602 @item exact_rice_parameters
603 Chooses if rice parameters are calculated exactly or approximately.
604 if set to 1 then they are chosen exactly, which slows the code down slightly and
605 improves compression slightly.
607 @item multi_dim_quant
608 Multi Dimensional Quantization. If set to 1 then a 2nd stage LPC algorithm is
609 applied after the first stage to finetune the coefficients. This is quite slow
610 and slightly improves compression.
617 libfaac AAC (Advanced Audio Coding) encoder wrapper.
619 This encoder is of much lower quality and is more unstable than any other AAC
620 encoders, so it's highly recommended to instead use other encoders, like
621 @ref{aacenc,,the native FFmpeg AAC encoder}.
623 This encoder also requires the presence of the libfaac headers and library
624 during configuration. You need to explicitly configure the build with
625 @code{--enable-libfaac --enable-nonfree}.
629 The following shared FFmpeg codec options are recognized.
631 The following options are supported by the libfaac wrapper. The
632 @command{faac}-equivalent of the options are listed in parentheses.
636 Set bit rate in bits/s for ABR (Average Bit Rate) mode. If the bit rate
637 is not explicitly specified, it is automatically set to a suitable
638 value depending on the selected profile. @command{faac} bitrate is
639 expressed in kilobits/s.
641 Note that libfaac does not support CBR (Constant Bit Rate) but only
642 ABR (Average Bit Rate).
644 If VBR mode is enabled this option is ignored.
647 Set audio sampling rate (in Hz).
650 Set the number of audio channels.
652 @item cutoff (@emph{-C})
653 Set cutoff frequency. If not specified (or explicitly set to 0) it
654 will use a value automatically computed by the library. Default value
660 The following profiles are recognized:
666 Low Complexity AAC (LC)
669 Scalable Sample Rate (SSR)
672 Long Term Prediction (LTP)
675 If not specified it is set to @samp{aac_low}.
678 Set constant quality VBR (Variable Bit Rate) mode.
681 Set quality in VBR mode as an integer number of lambda units.
683 Only relevant when VBR mode is enabled with @code{flags +qscale}. The
684 value is converted to QP units by dividing it by @code{FF_QP2LAMBDA},
685 and used to set the quality value used by libfaac. A reasonable range
686 for the option value in QP units is [10-500], the higher the value the
690 Enable VBR mode when set to a non-negative value, and set constant
691 quality value as a double floating point value in QP units.
693 The value sets the quality value used by libfaac. A reasonable range
694 for the option value is [10-500], the higher the value the higher the
697 This option is valid only using the @command{ffmpeg} command-line
698 tool. For library interface users, use @option{global_quality}.
705 Use @command{ffmpeg} to convert an audio file to ABR 128 kbps AAC in an M4A (MP4)
708 ffmpeg -i input.wav -codec:a libfaac -b:a 128k -output.m4a
712 Use @command{ffmpeg} to convert an audio file to VBR AAC, using the
715 ffmpeg -i input.wav -c:a libfaac -profile:a aac_ltp -q:a 100 output.m4a
719 @anchor{libfdk-aac-enc}
722 libfdk-aac AAC (Advanced Audio Coding) encoder wrapper.
724 The libfdk-aac library is based on the Fraunhofer FDK AAC code from
727 Requires the presence of the libfdk-aac headers and library during
728 configuration. You need to explicitly configure the build with
729 @code{--enable-libfdk-aac}. The library is also incompatible with GPL,
730 so if you allow the use of GPL, you should configure with
731 @code{--enable-gpl --enable-nonfree --enable-libfdk-aac}.
733 This encoder is considered to produce output on par or worse at 128kbps to the
734 @ref{aacenc,,the native FFmpeg AAC encoder} but can often produce better
735 sounding audio at identical or lower bitrates and has support for the
738 VBR encoding, enabled through the @option{vbr} or @option{flags
739 +qscale} options, is experimental and only works with some
740 combinations of parameters.
742 Support for encoding 7.1 audio is only available with libfdk-aac 0.1.3 or
745 For more information see the fdk-aac project at
746 @url{http://sourceforge.net/p/opencore-amr/fdk-aac/}.
750 The following options are mapped on the shared FFmpeg codec options.
754 Set bit rate in bits/s. If the bitrate is not explicitly specified, it
755 is automatically set to a suitable value depending on the selected
758 In case VBR mode is enabled the option is ignored.
761 Set audio sampling rate (in Hz).
764 Set the number of audio channels.
767 Enable fixed quality, VBR (Variable Bit Rate) mode.
768 Note that VBR is implicitly enabled when the @option{vbr} value is
772 Set cutoff frequency. If not specified (or explicitly set to 0) it
773 will use a value automatically computed by the library. Default value
779 The following profiles are recognized:
782 Low Complexity AAC (LC)
785 High Efficiency AAC (HE-AAC)
788 High Efficiency AAC version 2 (HE-AACv2)
794 Enhanced Low Delay AAC (ELD)
797 If not specified it is set to @samp{aac_low}.
800 The following are private options of the libfdk_aac encoder.
804 Enable afterburner feature if set to 1, disabled if set to 0. This
805 improves the quality but also the required processing power.
810 Enable SBR (Spectral Band Replication) for ELD if set to 1, disabled
816 Set SBR/PS signaling style.
818 It can assume one of the following values:
821 choose signaling implicitly (explicit hierarchical by default,
822 implicit if global header is disabled)
825 implicit backwards compatible signaling
828 explicit SBR, implicit PS signaling
830 @item explicit_hierarchical
831 explicit hierarchical signaling
834 Default value is @samp{default}.
837 Output LATM/LOAS encapsulated data if set to 1, disabled if set to 0.
842 Set StreamMuxConfig and PCE repetition period (in frames) for sending
843 in-band configuration buffers within LATM/LOAS transport layer.
845 Must be a 16-bits non-negative integer.
850 Set VBR mode, from 1 to 5. 1 is lowest quality (though still pretty
851 good) and 5 is highest quality. A value of 0 will disable VBR, and CBR
852 (Constant Bit Rate) is enabled.
854 Currently only the @samp{aac_low} profile supports VBR encoding.
856 VBR modes 1-5 correspond to roughly the following average bit rates:
868 about 80-96 kbps/channel
878 Use @command{ffmpeg} to convert an audio file to VBR AAC in an M4A (MP4)
881 ffmpeg -i input.wav -codec:a libfdk_aac -vbr 3 output.m4a
885 Use @command{ffmpeg} to convert an audio file to CBR 64k kbps AAC, using the
886 High-Efficiency AAC profile:
888 ffmpeg -i input.wav -c:a libfdk_aac -profile:a aac_he -b:a 64k output.m4a
895 LAME (Lame Ain't an MP3 Encoder) MP3 encoder wrapper.
897 Requires the presence of the libmp3lame headers and library during
898 configuration. You need to explicitly configure the build with
899 @code{--enable-libmp3lame}.
901 See @ref{libshine} for a fixed-point MP3 encoder, although with a
906 The following options are supported by the libmp3lame wrapper. The
907 @command{lame}-equivalent of the options are listed in parentheses.
911 Set bitrate expressed in bits/s for CBR or ABR. LAME @code{bitrate} is
912 expressed in kilobits/s.
915 Set constant quality setting for VBR. This option is valid only
916 using the @command{ffmpeg} command-line tool. For library interface
917 users, use @option{global_quality}.
919 @item compression_level (@emph{-q})
920 Set algorithm quality. Valid arguments are integers in the 0-9 range,
921 with 0 meaning highest quality but slowest, and 9 meaning fastest
922 while producing the worst quality.
925 Enable use of bit reservoir when set to 1. Default value is 1. LAME
926 has this enabled by default, but can be overridden by use
927 @option{--nores} option.
929 @item joint_stereo (@emph{-m j})
930 Enable the encoder to use (on a frame by frame basis) either L/R
931 stereo or mid/side stereo. Default value is 1.
933 @item abr (@emph{--abr})
934 Enable the encoder to use ABR when set to 1. The @command{lame}
935 @option{--abr} sets the target bitrate, while this options only
936 tells FFmpeg to use ABR still relies on @option{b} to set bitrate.
940 @section libopencore-amrnb
942 OpenCORE Adaptive Multi-Rate Narrowband encoder.
944 Requires the presence of the libopencore-amrnb headers and library during
945 configuration. You need to explicitly configure the build with
946 @code{--enable-libopencore-amrnb --enable-version3}.
948 This is a mono-only encoder. Officially it only supports 8000Hz sample rate,
949 but you can override it by setting @option{strict} to @samp{unofficial} or
957 Set bitrate in bits per second. Only the following bitrates are supported,
958 otherwise libavcodec will round to the nearest valid bitrate.
972 Allow discontinuous transmission (generate comfort noise) when set to 1. The
973 default value is 0 (disabled).
980 Shine Fixed-Point MP3 encoder wrapper.
982 Shine is a fixed-point MP3 encoder. It has a far better performance on
983 platforms without an FPU, e.g. armel CPUs, and some phones and tablets.
984 However, as it is more targeted on performance than quality, it is not on par
985 with LAME and other production-grade encoders quality-wise. Also, according to
986 the project's homepage, this encoder may not be free of bugs as the code was
987 written a long time ago and the project was dead for at least 5 years.
989 This encoder only supports stereo and mono input. This is also CBR-only.
991 The original project (last updated in early 2007) is at
992 @url{http://sourceforge.net/projects/libshine-fxp/}. We only support the
993 updated fork by the Savonet/Liquidsoap project at @url{https://github.com/savonet/shine}.
995 Requires the presence of the libshine headers and library during
996 configuration. You need to explicitly configure the build with
997 @code{--enable-libshine}.
999 See also @ref{libmp3lame}.
1003 The following options are supported by the libshine wrapper. The
1004 @command{shineenc}-equivalent of the options are listed in parentheses.
1008 Set bitrate expressed in bits/s for CBR. @command{shineenc} @option{-b} option
1009 is expressed in kilobits/s.
1015 TwoLAME MP2 encoder wrapper.
1017 Requires the presence of the libtwolame headers and library during
1018 configuration. You need to explicitly configure the build with
1019 @code{--enable-libtwolame}.
1023 The following options are supported by the libtwolame wrapper. The
1024 @command{twolame}-equivalent options follow the FFmpeg ones and are in
1029 Set bitrate expressed in bits/s for CBR. @command{twolame} @option{b}
1030 option is expressed in kilobits/s. Default value is 128k.
1033 Set quality for experimental VBR support. Maximum value range is
1034 from -50 to 50, useful range is from -10 to 10. The higher the
1035 value, the better the quality. This option is valid only using the
1036 @command{ffmpeg} command-line tool. For library interface users,
1037 use @option{global_quality}.
1039 @item mode (@emph{--mode})
1040 Set the mode of the resulting audio. Possible values:
1044 Choose mode automatically based on the input. This is the default.
1055 @item psymodel (@emph{--psyc-mode})
1056 Set psychoacoustic model to use in encoding. The argument must be
1057 an integer between -1 and 4, inclusive. The higher the value, the
1058 better the quality. The default value is 3.
1060 @item energy_levels (@emph{--energy})
1061 Enable energy levels extensions when set to 1. The default value is
1064 @item error_protection (@emph{--protect})
1065 Enable CRC error protection when set to 1. The default value is 0
1068 @item copyright (@emph{--copyright})
1069 Set MPEG audio copyright flag when set to 1. The default value is 0
1072 @item original (@emph{--original})
1073 Set MPEG audio original flag when set to 1. The default value is 0
1078 @anchor{libvo-aacenc}
1079 @section libvo-aacenc
1081 VisualOn AAC encoder.
1083 Requires the presence of the libvo-aacenc headers and library during
1084 configuration. You need to explicitly configure the build with
1085 @code{--enable-libvo-aacenc --enable-version3}.
1087 This encoder is considered to be worse than the
1088 @ref{aacenc,,native FFmpeg AAC encoder}, according to
1093 The VisualOn AAC encoder only support encoding AAC-LC and up to 2
1094 channels. It is also CBR-only.
1099 Set bit rate in bits/s.
1103 @section libvo-amrwbenc
1105 VisualOn Adaptive Multi-Rate Wideband encoder.
1107 Requires the presence of the libvo-amrwbenc headers and library during
1108 configuration. You need to explicitly configure the build with
1109 @code{--enable-libvo-amrwbenc --enable-version3}.
1111 This is a mono-only encoder. Officially it only supports 16000Hz sample
1112 rate, but you can override it by setting @option{strict} to
1113 @samp{unofficial} or lower.
1120 Set bitrate in bits/s. Only the following bitrates are supported, otherwise
1121 libavcodec will round to the nearest valid bitrate.
1136 Allow discontinuous transmission (generate comfort noise) when set to 1. The
1137 default value is 0 (disabled).
1143 libopus Opus Interactive Audio Codec encoder wrapper.
1145 Requires the presence of the libopus headers and library during
1146 configuration. You need to explicitly configure the build with
1147 @code{--enable-libopus}.
1149 @subsection Option Mapping
1151 Most libopus options are modelled after the @command{opusenc} utility from
1152 opus-tools. The following is an option mapping chart describing options
1153 supported by the libopus wrapper, and their @command{opusenc}-equivalent
1158 @item b (@emph{bitrate})
1159 Set the bit rate in bits/s. FFmpeg's @option{b} option is
1160 expressed in bits/s, while @command{opusenc}'s @option{bitrate} in
1163 @item vbr (@emph{vbr}, @emph{hard-cbr}, and @emph{cvbr})
1164 Set VBR mode. The FFmpeg @option{vbr} option has the following
1165 valid arguments, with the @command{opusenc} equivalent options
1169 @item off (@emph{hard-cbr})
1170 Use constant bit rate encoding.
1172 @item on (@emph{vbr})
1173 Use variable bit rate encoding (the default).
1175 @item constrained (@emph{cvbr})
1176 Use constrained variable bit rate encoding.
1179 @item compression_level (@emph{comp})
1180 Set encoding algorithm complexity. Valid options are integers in
1181 the 0-10 range. 0 gives the fastest encodes but lower quality, while 10
1182 gives the highest quality but slowest encoding. The default is 10.
1184 @item frame_duration (@emph{framesize})
1185 Set maximum frame size, or duration of a frame in milliseconds. The
1186 argument must be exactly the following: 2.5, 5, 10, 20, 40, 60. Smaller
1187 frame sizes achieve lower latency but less quality at a given bitrate.
1188 Sizes greater than 20ms are only interesting at fairly low bitrates.
1189 The default is 20ms.
1191 @item packet_loss (@emph{expect-loss})
1192 Set expected packet loss percentage. The default is 0.
1194 @item application (N.A.)
1195 Set intended application type. Valid options are listed below:
1199 Favor improved speech intelligibility.
1201 Favor faithfulness to the input (the default).
1203 Restrict to only the lowest delay modes.
1207 Set cutoff bandwidth in Hz. The argument must be exactly one of the
1208 following: 4000, 6000, 8000, 12000, or 20000, corresponding to
1209 narrowband, mediumband, wideband, super wideband, and fullband
1210 respectively. The default is 0 (cutoff disabled).
1216 libvorbis encoder wrapper.
1218 Requires the presence of the libvorbisenc headers and library during
1219 configuration. You need to explicitly configure the build with
1220 @code{--enable-libvorbis}.
1224 The following options are supported by the libvorbis wrapper. The
1225 @command{oggenc}-equivalent of the options are listed in parentheses.
1227 To get a more accurate and extensive documentation of the libvorbis
1228 options, consult the libvorbisenc's and @command{oggenc}'s documentations.
1229 See @url{http://xiph.org/vorbis/},
1230 @url{http://wiki.xiph.org/Vorbis-tools}, and oggenc(1).
1234 Set bitrate expressed in bits/s for ABR. @command{oggenc} @option{-b} is
1235 expressed in kilobits/s.
1238 Set constant quality setting for VBR. The value should be a float
1239 number in the range of -1.0 to 10.0. The higher the value, the better
1240 the quality. The default value is @samp{3.0}.
1242 This option is valid only using the @command{ffmpeg} command-line tool.
1243 For library interface users, use @option{global_quality}.
1245 @item cutoff (@emph{--advanced-encode-option lowpass_frequency=N})
1246 Set cutoff bandwidth in Hz, a value of 0 disables cutoff. @command{oggenc}'s
1247 related option is expressed in kHz. The default value is @samp{0} (cutoff
1250 @item minrate (@emph{-m})
1251 Set minimum bitrate expressed in bits/s. @command{oggenc} @option{-m} is
1252 expressed in kilobits/s.
1254 @item maxrate (@emph{-M})
1255 Set maximum bitrate expressed in bits/s. @command{oggenc} @option{-M} is
1256 expressed in kilobits/s. This only has effect on ABR mode.
1258 @item iblock (@emph{--advanced-encode-option impulse_noisetune=N})
1259 Set noise floor bias for impulse blocks. The value is a float number from
1260 -15.0 to 0.0. A negative bias instructs the encoder to pay special attention
1261 to the crispness of transients in the encoded audio. The tradeoff for better
1262 transient response is a higher bitrate.
1269 A wrapper providing WavPack encoding through libwavpack.
1271 Only lossless mode using 32-bit integer samples is supported currently.
1273 Requires the presence of the libwavpack headers and library during
1274 configuration. You need to explicitly configure the build with
1275 @code{--enable-libwavpack}.
1277 Note that a libavcodec-native encoder for the WavPack codec exists so users can
1278 encode audios with this codec without using this encoder. See @ref{wavpackenc}.
1282 @command{wavpack} command line utility's corresponding options are listed in
1283 parentheses, if any.
1286 @item frame_size (@emph{--blocksize})
1289 @item compression_level
1290 Set speed vs. compression tradeoff. Acceptable arguments are listed below:
1297 Normal (default) settings.
1302 @item 3 (@emph{-hh})
1305 @item 4-8 (@emph{-hh -x}@var{EXTRAPROC})
1306 Same as @samp{3}, but with extra processing enabled.
1308 @samp{4} is the same as @option{-x2} and @samp{8} is the same as @option{-x6}.
1316 WavPack lossless audio encoder.
1318 This is a libavcodec-native WavPack encoder. There is also an encoder based on
1319 libwavpack, but there is virtually no reason to use that encoder.
1321 See also @ref{libwavpack}.
1325 The equivalent options for @command{wavpack} command line utility are listed in
1328 @subsubsection Shared options
1330 The following shared options are effective for this encoder. Only special notes
1331 about this particular encoder will be documented here. For the general meaning
1332 of the options, see @ref{codec-options,,the Codec Options chapter}.
1335 @item frame_size (@emph{--blocksize})
1336 For this encoder, the range for this option is between 128 and 131072. Default
1337 is automatically decided based on sample rate and number of channel.
1339 For the complete formula of calculating default, see
1340 @file{libavcodec/wavpackenc.c}.
1342 @item compression_level (@emph{-f}, @emph{-h}, @emph{-hh}, and @emph{-x})
1343 This option's syntax is consistent with @ref{libwavpack}'s.
1346 @subsubsection Private options
1349 @item joint_stereo (@emph{-j})
1350 Set whether to enable joint stereo. Valid values are:
1354 Force mid/side audio encoding.
1355 @item off (@emph{0})
1356 Force left/right audio encoding.
1358 Let the encoder decide automatically.
1362 Set whether to enable optimization for mono. This option is only effective for
1363 non-mono streams. Available values:
1374 @c man end AUDIO ENCODERS
1376 @chapter Video Encoders
1377 @c man begin VIDEO ENCODERS
1379 A description of some of the currently available video encoders
1382 @section libopenh264
1384 Cisco libopenh264 H.264/MPEG-4 AVC encoder wrapper.
1386 This encoder requires the presence of the libopenh264 headers and
1387 library during configuration. You need to explicitly configure the
1388 build with @code{--enable-libopenh264}. The library is detected using
1389 @command{pkg-config}.
1391 For more information about the library see
1392 @url{http://www.openh264.org}.
1396 The following FFmpeg global options affect the configurations of the
1397 libopenh264 encoder.
1401 Set the bitrate (as a number of bits per second).
1407 Set the max bitrate (as a number of bits per second).
1409 @item flags +global_header
1410 Set global header in the bitstream.
1413 Set the number of slices, used in parallelized encoding. Default value
1414 is 0. This is only used when @option{slice_mode} is set to
1418 Set slice mode. Can assume one of the follwing possible values:
1422 a fixed number of slices
1424 one slice per row of macroblocks
1426 automatic number of slices according to number of thread
1429 Default value is @samp{auto}.
1432 Enable loop filter, if set to 1 (automatically enabled). To disable
1436 Set profile restrictions. If set to the value of @samp{main} enable
1437 CABAC (set the @code{SEncParamExt.iEntropyCodingModeFlag} flag to 1).
1442 The native jpeg 2000 encoder is lossy by default, the @code{-q:v}
1443 option can be used to set the encoding quality. Lossless encoding
1444 can be selected with @code{-pred 1}.
1450 Can be set to either @code{j2k} or @code{jp2} (the default) that
1451 makes it possible to store non-rgb pix_fmts.
1460 @item iterative_dia_size
1461 dia size for the iterative motion estimation
1466 libtheora Theora encoder wrapper.
1468 Requires the presence of the libtheora headers and library during
1469 configuration. You need to explicitly configure the build with
1470 @code{--enable-libtheora}.
1472 For more information about the libtheora project see
1473 @url{http://www.theora.org/}.
1477 The following global options are mapped to internal libtheora options
1478 which affect the quality and the bitrate of the encoded stream.
1482 Set the video bitrate in bit/s for CBR (Constant Bit Rate) mode. In
1483 case VBR (Variable Bit Rate) mode is enabled this option is ignored.
1486 Used to enable constant quality mode (VBR) encoding through the
1487 @option{qscale} flag, and to enable the @code{pass1} and @code{pass2}
1493 @item global_quality
1494 Set the global quality as an integer in lambda units.
1496 Only relevant when VBR mode is enabled with @code{flags +qscale}. The
1497 value is converted to QP units by dividing it by @code{FF_QP2LAMBDA},
1498 clipped in the [0 - 10] range, and then multiplied by 6.3 to get a
1499 value in the native libtheora range [0-63]. A higher value corresponds
1500 to a higher quality.
1503 Enable VBR mode when set to a non-negative value, and set constant
1504 quality value as a double floating point value in QP units.
1506 The value is clipped in the [0-10] range, and then multiplied by 6.3
1507 to get a value in the native libtheora range [0-63].
1509 This option is valid only using the @command{ffmpeg} command-line
1510 tool. For library interface users, use @option{global_quality}.
1513 @subsection Examples
1517 Set maximum constant quality (VBR) encoding with @command{ffmpeg}:
1519 ffmpeg -i INPUT -codec:v libtheora -q:v 10 OUTPUT.ogg
1523 Use @command{ffmpeg} to convert a CBR 1000 kbps Theora video stream:
1525 ffmpeg -i INPUT -codec:v libtheora -b:v 1000k OUTPUT.ogg
1531 VP8/VP9 format supported through libvpx.
1533 Requires the presence of the libvpx headers and library during configuration.
1534 You need to explicitly configure the build with @code{--enable-libvpx}.
1538 The following options are supported by the libvpx wrapper. The
1539 @command{vpxenc}-equivalent options or values are listed in parentheses
1542 To reduce the duplication of documentation, only the private options
1543 and some others requiring special attention are documented here. For
1544 the documentation of the undocumented generic options, see
1545 @ref{codec-options,,the Codec Options chapter}.
1547 To get more documentation of the libvpx options, invoke the command
1548 @command{ffmpeg -h encoder=libvpx}, @command{ffmpeg -h encoder=libvpx-vp9} or
1549 @command{vpxenc --help}. Further information is available in the libvpx API
1554 @item b (@emph{target-bitrate})
1555 Set bitrate in bits/s. Note that FFmpeg's @option{b} option is
1556 expressed in bits/s, while @command{vpxenc}'s @option{target-bitrate} is in
1559 @item g (@emph{kf-max-dist})
1561 @item keyint_min (@emph{kf-min-dist})
1563 @item qmin (@emph{min-q})
1565 @item qmax (@emph{max-q})
1567 @item bufsize (@emph{buf-sz}, @emph{buf-optimal-sz})
1568 Set ratecontrol buffer size (in bits). Note @command{vpxenc}'s options are
1569 specified in milliseconds, the libvpx wrapper converts this value as follows:
1570 @code{buf-sz = bufsize * 1000 / bitrate},
1571 @code{buf-optimal-sz = bufsize * 1000 / bitrate * 5 / 6}.
1573 @item rc_init_occupancy (@emph{buf-initial-sz})
1574 Set number of bits which should be loaded into the rc buffer before decoding
1575 starts. Note @command{vpxenc}'s option is specified in milliseconds, the libvpx
1576 wrapper converts this value as follows:
1577 @code{rc_init_occupancy * 1000 / bitrate}.
1579 @item undershoot-pct
1580 Set datarate undershoot (min) percentage of the target bitrate.
1583 Set datarate overshoot (max) percentage of the target bitrate.
1585 @item skip_threshold (@emph{drop-frame})
1587 @item qcomp (@emph{bias-pct})
1589 @item maxrate (@emph{maxsection-pct})
1590 Set GOP max bitrate in bits/s. Note @command{vpxenc}'s option is specified as a
1591 percentage of the target bitrate, the libvpx wrapper converts this value as
1592 follows: @code{(maxrate * 100 / bitrate)}.
1594 @item minrate (@emph{minsection-pct})
1595 Set GOP min bitrate in bits/s. Note @command{vpxenc}'s option is specified as a
1596 percentage of the target bitrate, the libvpx wrapper converts this value as
1597 follows: @code{(minrate * 100 / bitrate)}.
1599 @item minrate, maxrate, b @emph{end-usage=cbr}
1600 @code{(minrate == maxrate == bitrate)}.
1602 @item crf (@emph{end-usage=cq}, @emph{cq-level})
1604 @item quality, deadline (@emph{deadline})
1607 Use best quality deadline. Poorly named and quite slow, this option should be
1608 avoided as it may give worse quality output than good.
1610 Use good quality deadline. This is a good trade-off between speed and quality
1611 when used with the @option{cpu-used} option.
1613 Use realtime quality deadline.
1616 @item speed, cpu-used (@emph{cpu-used})
1617 Set quality/speed ratio modifier. Higher values speed up the encode at the cost
1620 @item nr (@emph{noise-sensitivity})
1623 Set a change threshold on blocks below which they will be skipped by the
1626 @item slices (@emph{token-parts})
1627 Note that FFmpeg's @option{slices} option gives the total number of partitions,
1628 while @command{vpxenc}'s @option{token-parts} is given as
1629 @code{log2(partitions)}.
1631 @item max-intra-rate
1632 Set maximum I-frame bitrate as a percentage of the target bitrate. A value of 0
1635 @item force_key_frames
1636 @code{VPX_EFLAG_FORCE_KF}
1638 @item Alternate reference frame related
1641 Enable use of alternate reference frames (2-pass only).
1642 @item arnr-max-frames
1643 Set altref noise reduction max frame count.
1645 Set altref noise reduction filter type: backward, forward, centered.
1647 Set altref noise reduction filter strength.
1648 @item rc-lookahead, lag-in-frames (@emph{lag-in-frames})
1649 Set number of frames to look ahead for frametype and ratecontrol.
1652 @item error-resilient
1653 Enable error resiliency features.
1655 @item VP9-specific options
1658 Enable lossless mode.
1660 Set number of tile columns to use. Note this is given as
1661 @code{log2(tile_columns)}. For example, 8 tile columns would be requested by
1662 setting the @option{tile-columns} option to 3.
1664 Set number of tile rows to use. Note this is given as @code{log2(tile_rows)}.
1665 For example, 4 tile rows would be requested by setting the @option{tile-rows}
1667 @item frame-parallel
1668 Enable frame parallel decodability features.
1670 Set adaptive quantization mode (0: off (default), 1: variance 2: complexity, 3:
1672 @item colorspace @emph{color-space}
1673 Set input color space. The VP9 bitstream supports signaling the following
1676 @item @samp{rgb} @emph{sRGB}
1677 @item @samp{bt709} @emph{bt709}
1678 @item @samp{unspecified} @emph{unknown}
1679 @item @samp{bt470bg} @emph{bt601}
1680 @item @samp{smpte170m} @emph{smpte170}
1681 @item @samp{smpte240m} @emph{smpte240}
1682 @item @samp{bt2020_ncl} @emph{bt2020}
1688 For more information about libvpx see:
1689 @url{http://www.webmproject.org/}
1694 libwebp WebP Image encoder wrapper
1696 libwebp is Google's official encoder for WebP images. It can encode in either
1697 lossy or lossless mode. Lossy images are essentially a wrapper around a VP8
1698 frame. Lossless images are a separate codec developed by Google.
1700 @subsection Pixel Format
1702 Currently, libwebp only supports YUV420 for lossy and RGB for lossless due
1703 to limitations of the format and libwebp. Alpha is supported for either mode.
1704 Because of API limitations, if RGB is passed in when encoding lossy or YUV is
1705 passed in for encoding lossless, the pixel format will automatically be
1706 converted using functions from libwebp. This is not ideal and is done only for
1713 @item -lossless @var{boolean}
1714 Enables/Disables use of lossless mode. Default is 0.
1716 @item -compression_level @var{integer}
1717 For lossy, this is a quality/speed tradeoff. Higher values give better quality
1718 for a given size at the cost of increased encoding time. For lossless, this is
1719 a size/speed tradeoff. Higher values give smaller size at the cost of increased
1720 encoding time. More specifically, it controls the number of extra algorithms
1721 and compression tools used, and varies the combination of these tools. This
1722 maps to the @var{method} option in libwebp. The valid range is 0 to 6.
1725 @item -qscale @var{float}
1726 For lossy encoding, this controls image quality, 0 to 100. For lossless
1727 encoding, this controls the effort and time spent at compressing more. The
1728 default value is 75. Note that for usage via libavcodec, this option is called
1729 @var{global_quality} and must be multiplied by @var{FF_QP2LAMBDA}.
1731 @item -preset @var{type}
1732 Configuration preset. This does some automatic settings based on the general
1736 Do not use a preset.
1738 Use the encoder default.
1740 Digital picture, like portrait, inner shot
1742 Outdoor photograph, with natural lighting
1744 Hand or line drawing, with high-contrast details
1746 Small-sized colorful images
1753 @section libx264, libx264rgb
1755 x264 H.264/MPEG-4 AVC encoder wrapper.
1757 This encoder requires the presence of the libx264 headers and library
1758 during configuration. You need to explicitly configure the build with
1759 @code{--enable-libx264}.
1761 libx264 supports an impressive number of features, including 8x8 and
1762 4x4 adaptive spatial transform, adaptive B-frame placement, CAVLC/CABAC
1763 entropy coding, interlacing (MBAFF), lossless mode, psy optimizations
1764 for detail retention (adaptive quantization, psy-RD, psy-trellis).
1766 Many libx264 encoder options are mapped to FFmpeg global codec
1767 options, while unique encoder options are provided through private
1768 options. Additionally the @option{x264opts} and @option{x264-params}
1769 private options allows one to pass a list of key=value tuples as accepted
1770 by the libx264 @code{x264_param_parse} function.
1772 The x264 project website is at
1773 @url{http://www.videolan.org/developers/x264.html}.
1775 The libx264rgb encoder is the same as libx264, except it accepts packed RGB
1776 pixel formats as input instead of YUV.
1778 @subsection Supported Pixel Formats
1780 x264 supports 8- to 10-bit color spaces. The exact bit depth is controlled at
1781 x264's configure time. FFmpeg only supports one bit depth in one particular
1782 build. In other words, it is not possible to build one FFmpeg with multiple
1783 versions of x264 with different bit depths.
1787 The following options are supported by the libx264 wrapper. The
1788 @command{x264}-equivalent options or values are listed in parentheses
1791 To reduce the duplication of documentation, only the private options
1792 and some others requiring special attention are documented here. For
1793 the documentation of the undocumented generic options, see
1794 @ref{codec-options,,the Codec Options chapter}.
1796 To get a more accurate and extensive documentation of the libx264
1797 options, invoke the command @command{x264 --full-help} or consult
1798 the libx264 documentation.
1801 @item b (@emph{bitrate})
1802 Set bitrate in bits/s. Note that FFmpeg's @option{b} option is
1803 expressed in bits/s, while @command{x264}'s @option{bitrate} is in
1806 @item bf (@emph{bframes})
1808 @item g (@emph{keyint})
1810 @item qmin (@emph{qpmin})
1811 Minimum quantizer scale.
1813 @item qmax (@emph{qpmax})
1814 Maximum quantizer scale.
1816 @item qdiff (@emph{qpstep})
1817 Maximum difference between quantizer scales.
1819 @item qblur (@emph{qblur})
1820 Quantizer curve blur
1822 @item qcomp (@emph{qcomp})
1823 Quantizer curve compression factor
1825 @item refs (@emph{ref})
1826 Number of reference frames each P-frame can use. The range is from @var{0-16}.
1828 @item sc_threshold (@emph{scenecut})
1829 Sets the threshold for the scene change detection.
1831 @item trellis (@emph{trellis})
1832 Performs Trellis quantization to increase efficiency. Enabled by default.
1834 @item nr (@emph{nr})
1836 @item me_range (@emph{merange})
1837 Maximum range of the motion search in pixels.
1839 @item me_method (@emph{me})
1840 Set motion estimation method. Possible values in the decreasing order
1844 @item dia (@emph{dia})
1845 @item epzs (@emph{dia})
1846 Diamond search with radius 1 (fastest). @samp{epzs} is an alias for
1848 @item hex (@emph{hex})
1849 Hexagonal search with radius 2.
1850 @item umh (@emph{umh})
1851 Uneven multi-hexagon search.
1852 @item esa (@emph{esa})
1854 @item tesa (@emph{tesa})
1855 Hadamard exhaustive search (slowest).
1858 @item subq (@emph{subme})
1859 Sub-pixel motion estimation method.
1861 @item b_strategy (@emph{b-adapt})
1862 Adaptive B-frame placement decision algorithm. Use only on first-pass.
1864 @item keyint_min (@emph{min-keyint})
1868 Set entropy encoder. Possible values:
1875 Enable CAVLC and disable CABAC. It generates the same effect as
1876 @command{x264}'s @option{--no-cabac} option.
1880 Set full pixel motion estimation comparation algorithm. Possible values:
1884 Enable chroma in motion estimation.
1887 Ignore chroma in motion estimation. It generates the same effect as
1888 @command{x264}'s @option{--no-chroma-me} option.
1891 @item threads (@emph{threads})
1892 Number of encoding threads.
1895 Set multithreading technique. Possible values:
1899 Slice-based multithreading. It generates the same effect as
1900 @command{x264}'s @option{--sliced-threads} option.
1902 Frame-based multithreading.
1906 Set encoding flags. It can be used to disable closed GOP and enable
1907 open GOP by setting it to @code{-cgop}. The result is similar to
1908 the behavior of @command{x264}'s @option{--open-gop} option.
1910 @item rc_init_occupancy (@emph{vbv-init})
1912 @item preset (@emph{preset})
1913 Set the encoding preset.
1915 @item tune (@emph{tune})
1916 Set tuning of the encoding params.
1918 @item profile (@emph{profile})
1919 Set profile restrictions.
1922 Enable fast settings when encoding first pass, when set to 1. When set
1923 to 0, it has the same effect of @command{x264}'s
1924 @option{--slow-firstpass} option.
1926 @item crf (@emph{crf})
1927 Set the quality for constant quality mode.
1929 @item crf_max (@emph{crf-max})
1930 In CRF mode, prevents VBV from lowering quality beyond this point.
1932 @item qp (@emph{qp})
1933 Set constant quantization rate control method parameter.
1935 @item aq-mode (@emph{aq-mode})
1936 Set AQ method. Possible values:
1939 @item none (@emph{0})
1942 @item variance (@emph{1})
1943 Variance AQ (complexity mask).
1945 @item autovariance (@emph{2})
1946 Auto-variance AQ (experimental).
1949 @item aq-strength (@emph{aq-strength})
1950 Set AQ strength, reduce blocking and blurring in flat and textured areas.
1953 Use psychovisual optimizations when set to 1. When set to 0, it has the
1954 same effect as @command{x264}'s @option{--no-psy} option.
1956 @item psy-rd (@emph{psy-rd})
1957 Set strength of psychovisual optimization, in
1958 @var{psy-rd}:@var{psy-trellis} format.
1960 @item rc-lookahead (@emph{rc-lookahead})
1961 Set number of frames to look ahead for frametype and ratecontrol.
1964 Enable weighted prediction for B-frames when set to 1. When set to 0,
1965 it has the same effect as @command{x264}'s @option{--no-weightb} option.
1967 @item weightp (@emph{weightp})
1968 Set weighted prediction method for P-frames. Possible values:
1971 @item none (@emph{0})
1973 @item simple (@emph{1})
1974 Enable only weighted refs
1975 @item smart (@emph{2})
1976 Enable both weighted refs and duplicates
1979 @item ssim (@emph{ssim})
1980 Enable calculation and printing SSIM stats after the encoding.
1982 @item intra-refresh (@emph{intra-refresh})
1983 Enable the use of Periodic Intra Refresh instead of IDR frames when set
1986 @item avcintra-class (@emph{class})
1987 Configure the encoder to generate AVC-Intra.
1988 Valid values are 50,100 and 200
1990 @item bluray-compat (@emph{bluray-compat})
1991 Configure the encoder to be compatible with the bluray standard.
1992 It is a shorthand for setting "bluray-compat=1 force-cfr=1".
1994 @item b-bias (@emph{b-bias})
1995 Set the influence on how often B-frames are used.
1997 @item b-pyramid (@emph{b-pyramid})
1998 Set method for keeping of some B-frames as references. Possible values:
2001 @item none (@emph{none})
2003 @item strict (@emph{strict})
2004 Strictly hierarchical pyramid.
2005 @item normal (@emph{normal})
2006 Non-strict (not Blu-ray compatible).
2010 Enable the use of one reference per partition, as opposed to one
2011 reference per macroblock when set to 1. When set to 0, it has the
2012 same effect as @command{x264}'s @option{--no-mixed-refs} option.
2015 Enable adaptive spatial transform (high profile 8x8 transform)
2016 when set to 1. When set to 0, it has the same effect as
2017 @command{x264}'s @option{--no-8x8dct} option.
2020 Enable early SKIP detection on P-frames when set to 1. When set
2021 to 0, it has the same effect as @command{x264}'s
2022 @option{--no-fast-pskip} option.
2024 @item aud (@emph{aud})
2025 Enable use of access unit delimiters when set to 1.
2028 Enable use macroblock tree ratecontrol when set to 1. When set
2029 to 0, it has the same effect as @command{x264}'s
2030 @option{--no-mbtree} option.
2032 @item deblock (@emph{deblock})
2033 Set loop filter parameters, in @var{alpha}:@var{beta} form.
2035 @item cplxblur (@emph{cplxblur})
2036 Set fluctuations reduction in QP (before curve compression).
2038 @item partitions (@emph{partitions})
2039 Set partitions to consider as a comma-separated list of. Possible
2044 8x8 P-frame partition.
2046 4x4 P-frame partition.
2048 4x4 B-frame partition.
2050 8x8 I-frame partition.
2052 4x4 I-frame partition.
2053 (Enabling @samp{p4x4} requires @samp{p8x8} to be enabled. Enabling
2054 @samp{i8x8} requires adaptive spatial transform (@option{8x8dct}
2055 option) to be enabled.)
2056 @item none (@emph{none})
2057 Do not consider any partitions.
2058 @item all (@emph{all})
2059 Consider every partition.
2062 @item direct-pred (@emph{direct})
2063 Set direct MV prediction mode. Possible values:
2066 @item none (@emph{none})
2067 Disable MV prediction.
2068 @item spatial (@emph{spatial})
2069 Enable spatial predicting.
2070 @item temporal (@emph{temporal})
2071 Enable temporal predicting.
2072 @item auto (@emph{auto})
2073 Automatically decided.
2076 @item slice-max-size (@emph{slice-max-size})
2077 Set the limit of the size of each slice in bytes. If not specified
2078 but RTP payload size (@option{ps}) is specified, that is used.
2080 @item stats (@emph{stats})
2081 Set the file name for multi-pass stats.
2083 @item nal-hrd (@emph{nal-hrd})
2084 Set signal HRD information (requires @option{vbv-bufsize} to be set).
2088 @item none (@emph{none})
2089 Disable HRD information signaling.
2090 @item vbr (@emph{vbr})
2092 @item cbr (@emph{cbr})
2093 Constant bit rate (not allowed in MP4 container).
2096 @item x264opts (N.A.)
2097 Set any x264 option, see @command{x264 --fullhelp} for a list.
2099 Argument is a list of @var{key}=@var{value} couples separated by
2100 ":". In @var{filter} and @var{psy-rd} options that use ":" as a separator
2101 themselves, use "," instead. They accept it as well since long ago but this
2102 is kept undocumented for some reason.
2104 For example to specify libx264 encoding options with @command{ffmpeg}:
2106 ffmpeg -i foo.mpg -vcodec libx264 -x264opts keyint=123:min-keyint=20 -an out.mkv
2109 @item a53cc @var{boolean}
2110 Import closed captions (which must be ATSC compatible format) into output.
2111 Only the mpeg2 and h264 decoders provide these. Default is 0 (off).
2113 @item x264-params (N.A.)
2114 Override the x264 configuration using a :-separated list of key=value
2117 This option is functionally the same as the @option{x264opts}, but is
2118 duplicated for compatibility with the Libav fork.
2120 For example to specify libx264 encoding options with @command{ffmpeg}:
2122 ffmpeg -i INPUT -c:v libx264 -x264-params level=30:bframes=0:weightp=0:\
2123 cabac=0:ref=1:vbv-maxrate=768:vbv-bufsize=2000:analyse=all:me=umh:\
2124 no-fast-pskip=1:subq=6:8x8dct=0:trellis=0 OUTPUT
2128 Encoding ffpresets for common usages are provided so they can be used with the
2129 general presets system (e.g. passing the @option{pre} option).
2133 x265 H.265/HEVC encoder wrapper.
2135 This encoder requires the presence of the libx265 headers and library
2136 during configuration. You need to explicitly configure the build with
2137 @option{--enable-libx265}.
2143 Set the x265 preset.
2146 Set the x265 tune parameter.
2149 Set x265 options using a list of @var{key}=@var{value} couples separated
2150 by ":". See @command{x265 --help} for a list of options.
2152 For example to specify libx265 encoding options with @option{-x265-params}:
2155 ffmpeg -i input -c:v libx265 -x265-params crf=26:psy-rd=1 output.mp4
2161 Xvid MPEG-4 Part 2 encoder wrapper.
2163 This encoder requires the presence of the libxvidcore headers and library
2164 during configuration. You need to explicitly configure the build with
2165 @code{--enable-libxvid --enable-gpl}.
2167 The native @code{mpeg4} encoder supports the MPEG-4 Part 2 format, so
2168 users can encode to this format without this library.
2172 The following options are supported by the libxvid wrapper. Some of
2173 the following options are listed but are not documented, and
2174 correspond to shared codec options. See @ref{codec-options,,the Codec
2175 Options chapter} for their documentation. The other shared options
2176 which are not listed have no effect for the libxvid encoder.
2198 Set specific encoding flags. Possible values:
2203 Use four motion vector by macroblock.
2206 Enable high quality AC prediction.
2209 Only encode grayscale.
2212 Enable the use of global motion compensation (GMC).
2215 Enable quarter-pixel motion compensation.
2221 Place global headers in extradata instead of every keyframe.
2228 Set motion estimation method. Possible values in decreasing order of
2229 speed and increasing order of quality:
2233 Use no motion estimation (default).
2238 Enable advanced diamond zonal search for 16x16 blocks and half-pixel
2239 refinement for 16x16 blocks. @samp{x1} and @samp{log} are aliases for
2243 Enable all of the things described above, plus advanced diamond zonal
2244 search for 8x8 blocks, half-pixel refinement for 8x8 blocks, and motion
2245 estimation on chroma planes.
2248 Enable all of the things described above, plus extended 16x16 and 8x8
2253 Set macroblock decision algorithm. Possible values in the increasing
2258 Use macroblock comparing function algorithm (default).
2261 Enable rate distortion-based half pixel and quarter pixel refinement for
2265 Enable all of the things described above, plus rate distortion-based
2266 half pixel and quarter pixel refinement for 8x8 blocks, and rate
2267 distortion-based search using square pattern.
2271 Enable lumi masking adaptive quantization when set to 1. Default is 0
2275 Enable variance adaptive quantization when set to 1. Default is 0
2278 When combined with @option{lumi_aq}, the resulting quality will not
2279 be better than any of the two specified individually. In other
2280 words, the resulting quality will be the worse one of the two
2284 Set structural similarity (SSIM) displaying method. Possible values:
2288 Disable displaying of SSIM information.
2291 Output average SSIM at the end of encoding to stdout. The format of
2292 showing the average SSIM is:
2298 For users who are not familiar with C, %f means a float number, or
2299 a decimal (e.g. 0.939232).
2302 Output both per-frame SSIM data during encoding and average SSIM at
2303 the end of encoding to stdout. The format of per-frame information
2307 SSIM: avg: %1.3f min: %1.3f max: %1.3f
2310 For users who are not familiar with C, %1.3f means a float number
2311 rounded to 3 digits after the dot (e.g. 0.932).
2316 Set SSIM accuracy. Valid options are integers within the range of
2317 0-4, while 0 gives the most accurate result and 4 computes the
2324 MPEG-2 video encoder.
2329 @item seq_disp_ext @var{integer}
2330 Specifies if the encoder should write a sequence_display_extension to the
2335 Decide automatically to write it or not (this is the default) by checking if
2336 the data to be written is different from the default or unspecified values.
2350 @subsection Private options
2353 @item dpi @var{integer}
2354 Set physical density of pixels, in dots per inch, unset by default
2355 @item dpm @var{integer}
2356 Set physical density of pixels, in dots per meter, unset by default
2361 Apple ProRes encoder.
2363 FFmpeg contains 2 ProRes encoders, the prores-aw and prores-ks encoder.
2364 The used encoder can be chosen with the @code{-vcodec} option.
2366 @subsection Private Options for prores-ks
2369 @item profile @var{integer}
2370 Select the ProRes profile to encode
2379 @item quant_mat @var{integer}
2380 Select quantization matrix.
2389 If set to @var{auto}, the matrix matching the profile will be picked.
2390 If not set, the matrix providing the highest quality, @var{default}, will be
2393 @item bits_per_mb @var{integer}
2394 How many bits to allot for coding one macroblock. Different profiles use
2395 between 200 and 2400 bits per macroblock, the maximum is 8000.
2397 @item mbs_per_slice @var{integer}
2398 Number of macroblocks in each slice (1-8); the default value (8)
2399 should be good in almost all situations.
2401 @item vendor @var{string}
2402 Override the 4-byte vendor ID.
2403 A custom vendor ID like @var{apl0} would claim the stream was produced by
2406 @item alpha_bits @var{integer}
2407 Specify number of bits for alpha component.
2408 Possible values are @var{0}, @var{8} and @var{16}.
2409 Use @var{0} to disable alpha plane coding.
2413 @subsection Speed considerations
2415 In the default mode of operation the encoder has to honor frame constraints
2416 (i.e. not produce frames with size bigger than requested) while still making
2417 output picture as good as possible.
2418 A frame containing a lot of small details is harder to compress and the encoder
2419 would spend more time searching for appropriate quantizers for each slice.
2421 Setting a higher @option{bits_per_mb} limit will improve the speed.
2423 For the fastest encoding speed set the @option{qscale} parameter (4 is the
2424 recommended value) and do not set a size constraint.
2428 Kvazaar H.265/HEVC encoder.
2430 Requires the presence of the libkvazaar headers and library during
2431 configuration. You need to explicitly configure the build with
2432 @option{--enable-libkvazaar}.
2439 Set target video bitrate in bit/s and enable rate control.
2441 @item kvazaar-params
2442 Set kvazaar parameters as a list of @var{name}=@var{value} pairs separated
2443 by commas (,). See kvazaar documentation for a list of options.
2447 @section QSV encoders
2449 The family of Intel QuickSync Video encoders (MPEG-2, H.264 and HEVC)
2451 The ratecontrol method is selected as follows:
2455 When @option{global_quality} is specified, a quality-based mode is used.
2456 Specifically this means either
2459 @var{CQP} - constant quantizer scale, when the @option{qscale} codec flag is
2460 also set (the @option{-qscale} avconv option).
2463 @var{LA_ICQ} - intelligent constant quality with lookahead, when the
2464 @option{look_ahead} option is also set.
2467 @var{ICQ} -- intelligent constant quality otherwise.
2471 Otherwise, a bitrate-based mode is used. For all of those, you should specify at
2472 least the desired average bitrate with the @option{b} option.
2475 @var{LA} - VBR with lookahead, when the @option{look_ahead} option is specified.
2478 @var{VCM} - video conferencing mode, when the @option{vcm} option is set.
2481 @var{CBR} - constant bitrate, when @option{maxrate} is specified and equal to
2482 the average bitrate.
2485 @var{VBR} - variable bitrate, when @option{maxrate} is specified, but is higher
2486 than the average bitrate.
2489 @var{AVBR} - average VBR mode, when @option{maxrate} is not specified. This mode
2490 is further configured by the @option{avbr_accuracy} and
2491 @option{avbr_convergence} options.
2495 Note that depending on your system, a different mode than the one you specified
2496 may be selected by the encoder. Set the verbosity level to @var{verbose} or
2497 higher to see the actual settings used by the QSV runtime.
2499 Additional libavcodec global options are mapped to MSDK options as follows:
2503 @option{g/gop_size} -> @option{GopPicSize}
2506 @option{bf/max_b_frames}+1 -> @option{GopRefDist}
2509 @option{rc_init_occupancy/rc_initial_buffer_occupancy} ->
2510 @option{InitialDelayInKB}
2513 @option{slices} -> @option{NumSlice}
2516 @option{refs} -> @option{NumRefFrame}
2519 @option{b_strategy/b_frame_strategy} -> @option{BRefType}
2522 @option{cgop/CLOSED_GOP} codec flag -> @option{GopOptFlag}
2525 For the @var{CQP} mode, the @option{i_qfactor/i_qoffset} and
2526 @option{b_qfactor/b_qoffset} set the difference between @var{QPP} and @var{QPI},
2527 and @var{QPP} and @var{QPB} respectively.
2530 Setting the @option{coder} option to the value @var{vlc} will make the H.264
2531 encoder use CAVLC instead of CABAC.
2535 @c man end VIDEO ENCODERS
2537 @chapter Subtitles Encoders
2538 @c man begin SUBTITLES ENCODERS
2542 This codec encodes the bitmap subtitle format that is used in DVDs.
2543 Typically they are stored in VOBSUB file pairs (*.idx + *.sub),
2544 and they can also be used in Matroska files.
2550 When set to 1, enable a work-around that makes the number of pixel rows
2551 even in all subtitles. This fixes a problem with some players that
2552 cut off the bottom row if the number is odd. The work-around just adds
2553 a fully transparent row if needed. The overhead is low, typically
2554 one byte per subtitle on average.
2556 By default, this work-around is disabled.
2559 @c man end SUBTITLES ENCODERS