6fe5f770db
* commit 'be7c323176e2e5fcf30e3d2ff20975b2f936811b': Add a libwebp encoder Conflicts: Changelog doc/encoders.texi doc/general.texi libavcodec/version.h libavformat/img2enc.c Merged-by: Michael Niedermayer <michaelni@gmx.at>
2021 lines
55 KiB
Plaintext
2021 lines
55 KiB
Plaintext
@chapter Encoders
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@c man begin ENCODERS
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Encoders are configured elements in FFmpeg which allow the encoding of
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multimedia streams.
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When you configure your FFmpeg build, all the supported native encoders
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are enabled by default. Encoders requiring an external library must be enabled
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manually via the corresponding @code{--enable-lib} option. You can list all
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available encoders using the configure option @code{--list-encoders}.
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You can disable all the encoders with the configure option
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@code{--disable-encoders} and selectively enable / disable single encoders
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with the options @code{--enable-encoder=@var{ENCODER}} /
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@code{--disable-encoder=@var{ENCODER}}.
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The option @code{-codecs} of the ff* tools will display the list of
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enabled encoders.
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@c man end ENCODERS
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@chapter Audio Encoders
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@c man begin AUDIO ENCODERS
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A description of some of the currently available audio encoders
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follows.
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@anchor{aacenc}
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@section aac
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Advanced Audio Coding (AAC) encoder.
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This encoder is an experimental FFmpeg-native AAC encoder. Currently only the
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low complexity (AAC-LC) profile is supported. To use this encoder, you must set
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@option{strict} option to @samp{experimental} or lower.
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As this encoder is experimental, unexpected behavior may exist from time to
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time. For a more stable AAC encoder, see @ref{libvo-aacenc}. However, be warned
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that it has a worse quality reported by some users.
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@c todo @ref{libaacplus}
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See also @ref{libfdk-aac-enc,,libfdk_aac} and @ref{libfaac}.
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@subsection Options
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@table @option
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@item b
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Set bit rate in bits/s. Setting this automatically activates constant bit rate
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(CBR) mode.
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@item q
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Set quality for variable bit rate (VBR) mode. This option is valid only using
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the @command{ffmpeg} command-line tool. For library interface users, use
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@option{global_quality}.
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@item stereo_mode
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Set stereo encoding mode. Possible values:
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@table @samp
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@item auto
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Automatically selected by the encoder.
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@item ms_off
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Disable middle/side encoding. This is the default.
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@item ms_force
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Force middle/side encoding.
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@end table
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@item aac_coder
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Set AAC encoder coding method. Possible values:
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@table @samp
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@item faac
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FAAC-inspired method.
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This method is a simplified reimplementation of the method used in FAAC, which
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sets thresholds proportional to the band energies, and then decreases all the
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thresholds with quantizer steps to find the appropriate quantization with
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distortion below threshold band by band.
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The quality of this method is comparable to the two loop searching method
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descibed below, but somewhat a little better and slower.
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@item anmr
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Average noise to mask ratio (ANMR) trellis-based solution.
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This has a theoretic best quality out of all the coding methods, but at the
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cost of the slowest speed.
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@item twoloop
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Two loop searching (TLS) method.
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This method first sets quantizers depending on band thresholds and then tries
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to find an optimal combination by adding or subtracting a specific value from
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all quantizers and adjusting some individual quantizer a little.
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This method produces similar quality with the FAAC method and is the default.
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@item fast
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Constant quantizer method.
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This method sets a constant quantizer for all bands. This is the fastest of all
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the methods, yet produces the worst quality.
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@end table
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@end table
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@section ac3 and ac3_fixed
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AC-3 audio encoders.
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These encoders implement part of ATSC A/52:2010 and ETSI TS 102 366, as well as
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the undocumented RealAudio 3 (a.k.a. dnet).
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The @var{ac3} encoder uses floating-point math, while the @var{ac3_fixed}
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encoder only uses fixed-point integer math. This does not mean that one is
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always faster, just that one or the other may be better suited to a
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particular system. The floating-point encoder will generally produce better
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quality audio for a given bitrate. The @var{ac3_fixed} encoder is not the
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default codec for any of the output formats, so it must be specified explicitly
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using the option @code{-acodec ac3_fixed} in order to use it.
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@subsection AC-3 Metadata
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The AC-3 metadata options are used to set parameters that describe the audio,
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but in most cases do not affect the audio encoding itself. Some of the options
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do directly affect or influence the decoding and playback of the resulting
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bitstream, while others are just for informational purposes. A few of the
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options will add bits to the output stream that could otherwise be used for
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audio data, and will thus affect the quality of the output. Those will be
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indicated accordingly with a note in the option list below.
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These parameters are described in detail in several publicly-available
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documents.
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@itemize
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@item @uref{http://www.atsc.org/cms/standards/a_52-2010.pdf,A/52:2010 - Digital Audio Compression (AC-3) (E-AC-3) Standard}
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@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}
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@item @uref{http://www.dolby.com/uploadedFiles/zz-_Shared_Assets/English_PDFs/Professional/18_Metadata.Guide.pdf,Dolby Metadata Guide}
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@item @uref{http://www.dolby.com/uploadedFiles/zz-_Shared_Assets/English_PDFs/Professional/46_DDEncodingGuidelines.pdf,Dolby Digital Professional Encoding Guidelines}
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@end itemize
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@subsubsection Metadata Control Options
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@table @option
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@item -per_frame_metadata @var{boolean}
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Allow Per-Frame Metadata. Specifies if the encoder should check for changing
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metadata for each frame.
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@table @option
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@item 0
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The metadata values set at initialization will be used for every frame in the
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stream. (default)
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@item 1
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Metadata values can be changed before encoding each frame.
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@end table
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@end table
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@subsubsection Downmix Levels
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@table @option
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@item -center_mixlev @var{level}
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Center Mix Level. The amount of gain the decoder should apply to the center
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channel when downmixing to stereo. This field will only be written to the
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bitstream if a center channel is present. The value is specified as a scale
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factor. There are 3 valid values:
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@table @option
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@item 0.707
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Apply -3dB gain
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@item 0.595
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Apply -4.5dB gain (default)
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@item 0.500
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Apply -6dB gain
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@end table
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@item -surround_mixlev @var{level}
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Surround Mix Level. The amount of gain the decoder should apply to the surround
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channel(s) when downmixing to stereo. This field will only be written to the
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bitstream if one or more surround channels are present. The value is specified
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as a scale factor. There are 3 valid values:
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@table @option
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@item 0.707
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Apply -3dB gain
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@item 0.500
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Apply -6dB gain (default)
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@item 0.000
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Silence Surround Channel(s)
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@end table
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@end table
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@subsubsection Audio Production Information
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Audio Production Information is optional information describing the mixing
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environment. Either none or both of the fields are written to the bitstream.
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@table @option
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@item -mixing_level @var{number}
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Mixing Level. Specifies peak sound pressure level (SPL) in the production
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environment when the mix was mastered. Valid values are 80 to 111, or -1 for
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unknown or not indicated. The default value is -1, but that value cannot be
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used if the Audio Production Information is written to the bitstream. Therefore,
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if the @code{room_type} option is not the default value, the @code{mixing_level}
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option must not be -1.
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@item -room_type @var{type}
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Room Type. Describes the equalization used during the final mixing session at
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the studio or on the dubbing stage. A large room is a dubbing stage with the
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industry standard X-curve equalization; a small room has flat equalization.
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This field will not be written to the bitstream if both the @code{mixing_level}
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option and the @code{room_type} option have the default values.
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@table @option
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@item 0
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@itemx notindicated
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Not Indicated (default)
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@item 1
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@itemx large
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Large Room
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@item 2
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@itemx small
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Small Room
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@end table
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@end table
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@subsubsection Other Metadata Options
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@table @option
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@item -copyright @var{boolean}
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Copyright Indicator. Specifies whether a copyright exists for this audio.
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@table @option
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@item 0
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@itemx off
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No Copyright Exists (default)
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@item 1
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@itemx on
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Copyright Exists
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@end table
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@item -dialnorm @var{value}
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Dialogue Normalization. Indicates how far the average dialogue level of the
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program is below digital 100% full scale (0 dBFS). This parameter determines a
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level shift during audio reproduction that sets the average volume of the
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dialogue to a preset level. The goal is to match volume level between program
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sources. A value of -31dB will result in no volume level change, relative to
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the source volume, during audio reproduction. Valid values are whole numbers in
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the range -31 to -1, with -31 being the default.
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@item -dsur_mode @var{mode}
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Dolby Surround Mode. Specifies whether the stereo signal uses Dolby Surround
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(Pro Logic). This field will only be written to the bitstream if the audio
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stream is stereo. Using this option does @b{NOT} mean the encoder will actually
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apply Dolby Surround processing.
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@table @option
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@item 0
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@itemx notindicated
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Not Indicated (default)
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@item 1
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@itemx off
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Not Dolby Surround Encoded
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@item 2
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@itemx on
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Dolby Surround Encoded
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@end table
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@item -original @var{boolean}
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Original Bit Stream Indicator. Specifies whether this audio is from the
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original source and not a copy.
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@table @option
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@item 0
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@itemx off
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Not Original Source
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@item 1
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@itemx on
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Original Source (default)
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@end table
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@end table
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@subsection Extended Bitstream Information
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The extended bitstream options are part of the Alternate Bit Stream Syntax as
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specified in Annex D of the A/52:2010 standard. It is grouped into 2 parts.
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If any one parameter in a group is specified, all values in that group will be
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written to the bitstream. Default values are used for those that are written
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but have not been specified. If the mixing levels are written, the decoder
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will use these values instead of the ones specified in the @code{center_mixlev}
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and @code{surround_mixlev} options if it supports the Alternate Bit Stream
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Syntax.
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@subsubsection Extended Bitstream Information - Part 1
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@table @option
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@item -dmix_mode @var{mode}
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Preferred Stereo Downmix Mode. Allows the user to select either Lt/Rt
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(Dolby Surround) or Lo/Ro (normal stereo) as the preferred stereo downmix mode.
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@table @option
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@item 0
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@itemx notindicated
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Not Indicated (default)
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@item 1
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@itemx ltrt
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Lt/Rt Downmix Preferred
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@item 2
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@itemx loro
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Lo/Ro Downmix Preferred
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@end table
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@item -ltrt_cmixlev @var{level}
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Lt/Rt Center Mix Level. The amount of gain the decoder should apply to the
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center channel when downmixing to stereo in Lt/Rt mode.
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@table @option
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@item 1.414
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Apply +3dB gain
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@item 1.189
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Apply +1.5dB gain
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@item 1.000
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Apply 0dB gain
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@item 0.841
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Apply -1.5dB gain
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@item 0.707
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Apply -3.0dB gain
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@item 0.595
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Apply -4.5dB gain (default)
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@item 0.500
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Apply -6.0dB gain
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@item 0.000
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Silence Center Channel
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@end table
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@item -ltrt_surmixlev @var{level}
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Lt/Rt Surround Mix Level. The amount of gain the decoder should apply to the
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surround channel(s) when downmixing to stereo in Lt/Rt mode.
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@table @option
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@item 0.841
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Apply -1.5dB gain
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@item 0.707
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Apply -3.0dB gain
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@item 0.595
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Apply -4.5dB gain
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@item 0.500
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Apply -6.0dB gain (default)
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@item 0.000
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Silence Surround Channel(s)
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@end table
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@item -loro_cmixlev @var{level}
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Lo/Ro Center Mix Level. The amount of gain the decoder should apply to the
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center channel when downmixing to stereo in Lo/Ro mode.
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@table @option
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@item 1.414
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Apply +3dB gain
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@item 1.189
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Apply +1.5dB gain
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@item 1.000
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Apply 0dB gain
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@item 0.841
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Apply -1.5dB gain
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@item 0.707
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Apply -3.0dB gain
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@item 0.595
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Apply -4.5dB gain (default)
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@item 0.500
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Apply -6.0dB gain
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@item 0.000
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Silence Center Channel
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@end table
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@item -loro_surmixlev @var{level}
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Lo/Ro Surround Mix Level. The amount of gain the decoder should apply to the
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surround channel(s) when downmixing to stereo in Lo/Ro mode.
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@table @option
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@item 0.841
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Apply -1.5dB gain
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@item 0.707
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Apply -3.0dB gain
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@item 0.595
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Apply -4.5dB gain
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@item 0.500
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Apply -6.0dB gain (default)
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@item 0.000
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Silence Surround Channel(s)
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@end table
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@end table
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@subsubsection Extended Bitstream Information - Part 2
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@table @option
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@item -dsurex_mode @var{mode}
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Dolby Surround EX Mode. Indicates whether the stream uses Dolby Surround EX
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(7.1 matrixed to 5.1). Using this option does @b{NOT} mean the encoder will actually
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apply Dolby Surround EX processing.
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@table @option
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@item 0
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@itemx notindicated
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Not Indicated (default)
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@item 1
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@itemx on
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Dolby Surround EX Off
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@item 2
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@itemx off
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Dolby Surround EX On
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@end table
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@item -dheadphone_mode @var{mode}
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Dolby Headphone Mode. Indicates whether the stream uses Dolby Headphone
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encoding (multi-channel matrixed to 2.0 for use with headphones). Using this
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option does @b{NOT} mean the encoder will actually apply Dolby Headphone
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processing.
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@table @option
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@item 0
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@itemx notindicated
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Not Indicated (default)
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@item 1
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@itemx on
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Dolby Headphone Off
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@item 2
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@itemx off
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Dolby Headphone On
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@end table
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@item -ad_conv_type @var{type}
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A/D Converter Type. Indicates whether the audio has passed through HDCD A/D
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conversion.
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@table @option
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@item 0
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@itemx standard
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Standard A/D Converter (default)
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@item 1
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@itemx hdcd
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HDCD A/D Converter
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@end table
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@end table
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@subsection Other AC-3 Encoding Options
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@table @option
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@item -stereo_rematrixing @var{boolean}
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Stereo Rematrixing. Enables/Disables use of rematrixing for stereo input. This
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is an optional AC-3 feature that increases quality by selectively encoding
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the left/right channels as mid/side. This option is enabled by default, and it
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is highly recommended that it be left as enabled except for testing purposes.
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@end table
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@subsection Floating-Point-Only AC-3 Encoding Options
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These options are only valid for the floating-point encoder and do not exist
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for the fixed-point encoder due to the corresponding features not being
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implemented in fixed-point.
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@table @option
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@item -channel_coupling @var{boolean}
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Enables/Disables use of channel coupling, which is an optional AC-3 feature
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that increases quality by combining high frequency information from multiple
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channels into a single channel. The per-channel high frequency information is
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sent with less accuracy in both the frequency and time domains. This allows
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more bits to be used for lower frequencies while preserving enough information
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to reconstruct the high frequencies. This option is enabled by default for the
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floating-point encoder and should generally be left as enabled except for
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testing purposes or to increase encoding speed.
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@table @option
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@item -1
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@itemx auto
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Selected by Encoder (default)
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@item 0
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@itemx off
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Disable Channel Coupling
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@item 1
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@itemx on
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Enable Channel Coupling
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@end table
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@item -cpl_start_band @var{number}
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Coupling Start Band. Sets the channel coupling start band, from 1 to 15. If a
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value higher than the bandwidth is used, it will be reduced to 1 less than the
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coupling end band. If @var{auto} is used, the start band will be determined by
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the encoder based on the bit rate, sample rate, and channel layout. This option
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has no effect if channel coupling is disabled.
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@table @option
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@item -1
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@itemx auto
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Selected by Encoder (default)
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@end table
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@end table
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@anchor{libfaac}
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@section libfaac
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libfaac AAC (Advanced Audio Coding) encoder wrapper.
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Requires the presence of the libfaac headers and library during
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configuration. You need to explicitly configure the build with
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@code{--enable-libfaac --enable-nonfree}.
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This encoder is considered to be of higher quality with respect to the
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@ref{aacenc,,the native experimental FFmpeg AAC encoder}.
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For more information see the libfaac project at
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@url{http://www.audiocoding.com/faac.html/}.
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@subsection Options
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The following shared FFmpeg codec options are recognized.
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The following options are supported by the libfaac wrapper. The
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@command{faac}-equivalent of the options are listed in parentheses.
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@table @option
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@item b (@emph{-b})
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Set bit rate in bits/s for ABR (Average Bit Rate) mode. If the bit rate
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is not explicitly specified, it is automatically set to a suitable
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value depending on the selected profile. @command{faac} bitrate is
|
|
expressed in kilobits/s.
|
|
|
|
Note that libfaac does not support CBR (Constant Bit Rate) but only
|
|
ABR (Average Bit Rate).
|
|
|
|
If VBR mode is enabled this option is ignored.
|
|
|
|
@item ar (@emph{-R})
|
|
Set audio sampling rate (in Hz).
|
|
|
|
@item ac (@emph{-c})
|
|
Set the number of audio channels.
|
|
|
|
@item cutoff (@emph{-C})
|
|
Set cutoff frequency. If not specified (or explicitly set to 0) it
|
|
will use a value automatically computed by the library. Default value
|
|
is 0.
|
|
|
|
@item profile
|
|
Set audio profile.
|
|
|
|
The following profiles are recognized:
|
|
@table @samp
|
|
@item aac_main
|
|
Main AAC (Main)
|
|
|
|
@item aac_low
|
|
Low Complexity AAC (LC)
|
|
|
|
@item aac_ssr
|
|
Scalable Sample Rate (SSR)
|
|
|
|
@item aac_ltp
|
|
Long Term Prediction (LTP)
|
|
@end table
|
|
|
|
If not specified it is set to @samp{aac_low}.
|
|
|
|
@item flags +qscale
|
|
Set constant quality VBR (Variable Bit Rate) mode.
|
|
|
|
@item global_quality
|
|
Set quality in VBR mode as an integer number of lambda units.
|
|
|
|
Only relevant when VBR mode is enabled with @code{flags +qscale}. The
|
|
value is converted to QP units by dividing it by @code{FF_QP2LAMBDA},
|
|
and used to set the quality value used by libfaac. A reasonable range
|
|
for the option value in QP units is [10-500], the higher the value the
|
|
higher the quality.
|
|
|
|
@item q (@emph{-q})
|
|
Enable VBR mode when set to a non-negative value, and set constant
|
|
quality value as a double floating point value in QP units.
|
|
|
|
The value sets the quality value used by libfaac. A reasonable range
|
|
for the option value is [10-500], the higher the value the higher the
|
|
quality.
|
|
|
|
This option is valid only using the @command{ffmpeg} command-line
|
|
tool. For library interface users, use @option{global_quality}.
|
|
@end table
|
|
|
|
@subsection Examples
|
|
|
|
@itemize
|
|
@item
|
|
Use @command{ffmpeg} to convert an audio file to ABR 128 kbps AAC in an M4A (MP4)
|
|
container:
|
|
@example
|
|
ffmpeg -i input.wav -codec:a libfaac -b:a 128k -output.m4a
|
|
@end example
|
|
|
|
@item
|
|
Use @command{ffmpeg} to convert an audio file to VBR AAC, using the
|
|
LTP AAC profile:
|
|
@example
|
|
ffmpeg -i input.wav -c:a libfaac -profile:a aac_ltp -q:a 100 output.m4a
|
|
@end example
|
|
@end itemize
|
|
|
|
@anchor{libfdk-aac-enc}
|
|
@section libfdk_aac
|
|
|
|
libfdk-aac AAC (Advanced Audio Coding) encoder wrapper.
|
|
|
|
The libfdk-aac library is based on the Fraunhofer FDK AAC code from
|
|
the Android project.
|
|
|
|
Requires the presence of the libfdk-aac headers and library during
|
|
configuration. You need to explicitly configure the build with
|
|
@code{--enable-libfdk-aac}. The library is also incompatible with GPL,
|
|
so if you allow the use of GPL, you should configure with
|
|
@code{--enable-gpl --enable-nonfree --enable-libfdk-aac}.
|
|
|
|
This encoder is considered to be of higher quality with respect to
|
|
both @ref{aacenc,,the native experimental FFmpeg AAC encoder} and
|
|
@ref{libfaac}.
|
|
|
|
VBR encoding, enabled through the @option{vbr} or @option{flags
|
|
+qscale} options, is experimental and only works with some
|
|
combinations of parameters.
|
|
|
|
For more information see the fdk-aac project at
|
|
@url{http://sourceforge.net/p/opencore-amr/fdk-aac/}.
|
|
|
|
@subsection Options
|
|
|
|
The following options are mapped on the shared FFmpeg codec options.
|
|
|
|
@table @option
|
|
@item b
|
|
Set bit rate in bits/s. If the bitrate is not explicitly specified, it
|
|
is automatically set to a suitable value depending on the selected
|
|
profile.
|
|
|
|
In case VBR mode is enabled the option is ignored.
|
|
|
|
@item ar
|
|
Set audio sampling rate (in Hz).
|
|
|
|
@item channels
|
|
Set the number of audio channels.
|
|
|
|
@item flags +qscale
|
|
Enable fixed quality, VBR (Variable Bit Rate) mode.
|
|
Note that VBR is implicitly enabled when the @option{vbr} value is
|
|
positive.
|
|
|
|
@item cutoff
|
|
Set cutoff frequency. If not specified (or explicitly set to 0) it
|
|
will use a value automatically computed by the library. Default value
|
|
is 0.
|
|
|
|
@item profile
|
|
Set audio profile.
|
|
|
|
The following profiles are recognized:
|
|
@table @samp
|
|
@item aac_low
|
|
Low Complexity AAC (LC)
|
|
|
|
@item aac_he
|
|
High Efficiency AAC (HE-AAC)
|
|
|
|
@item aac_he_v2
|
|
High Efficiency AAC version 2 (HE-AACv2)
|
|
|
|
@item aac_ld
|
|
Low Delay AAC (LD)
|
|
|
|
@item aac_eld
|
|
Enhanced Low Delay AAC (ELD)
|
|
@end table
|
|
|
|
If not specified it is set to @samp{aac_low}.
|
|
@end table
|
|
|
|
The following are private options of the libfdk_aac encoder.
|
|
|
|
@table @option
|
|
@item afterburner
|
|
Enable afterburner feature if set to 1, disabled if set to 0. This
|
|
improves the quality but also the required processing power.
|
|
|
|
Default value is 1.
|
|
|
|
@item eld_sbr
|
|
Enable SBR (Spectral Band Replication) for ELD if set to 1, disabled
|
|
if set to 0.
|
|
|
|
Default value is 0.
|
|
|
|
@item signaling
|
|
Set SBR/PS signaling style.
|
|
|
|
It can assume one of the following values:
|
|
@table @samp
|
|
@item default
|
|
choose signaling implicitly (explicit hierarchical by default,
|
|
implicit if global header is disabled)
|
|
|
|
@item implicit
|
|
implicit backwards compatible signaling
|
|
|
|
@item explicit_sbr
|
|
explicit SBR, implicit PS signaling
|
|
|
|
@item explicit_hierarchical
|
|
explicit hierarchical signaling
|
|
@end table
|
|
|
|
Default value is @samp{default}.
|
|
|
|
@item latm
|
|
Output LATM/LOAS encapsulated data if set to 1, disabled if set to 0.
|
|
|
|
Default value is 0.
|
|
|
|
@item header_period
|
|
Set StreamMuxConfig and PCE repetition period (in frames) for sending
|
|
in-band configuration buffers within LATM/LOAS transport layer.
|
|
|
|
Must be a 16-bits non-negative integer.
|
|
|
|
Default value is 0.
|
|
|
|
@item vbr
|
|
Set VBR mode, from 1 to 5. 1 is lowest quality (though still pretty
|
|
good) and 5 is highest quality. A value of 0 will disable VBR, and CBR
|
|
(Constant Bit Rate) is enabled.
|
|
|
|
Currently only the @samp{aac_low} profile supports VBR encoding.
|
|
|
|
VBR modes 1-5 correspond to roughly the following average bit rates:
|
|
|
|
@table @samp
|
|
@item 1
|
|
32 kbps/channel
|
|
@item 2
|
|
40 kbps/channel
|
|
@item 3
|
|
48-56 kbps/channel
|
|
@item 4
|
|
64 kbps/channel
|
|
@item 5
|
|
about 80-96 kbps/channel
|
|
@end table
|
|
|
|
Default value is 0.
|
|
@end table
|
|
|
|
@subsection Examples
|
|
|
|
@itemize
|
|
@item
|
|
Use @command{ffmpeg} to convert an audio file to VBR AAC in an M4A (MP4)
|
|
container:
|
|
@example
|
|
ffmpeg -i input.wav -codec:a libfdk_aac -vbr 3 output.m4a
|
|
@end example
|
|
|
|
@item
|
|
Use @command{ffmpeg} to convert an audio file to CBR 64k kbps AAC, using the
|
|
High-Efficiency AAC profile:
|
|
@example
|
|
ffmpeg -i input.wav -c:a libfdk_aac -profile:a aac_he -b:a 64k output.m4a
|
|
@end example
|
|
@end itemize
|
|
|
|
@anchor{libmp3lame}
|
|
@section libmp3lame
|
|
|
|
LAME (Lame Ain't an MP3 Encoder) MP3 encoder wrapper.
|
|
|
|
Requires the presence of the libmp3lame headers and library during
|
|
configuration. You need to explicitly configure the build with
|
|
@code{--enable-libmp3lame}.
|
|
|
|
See @ref{libshine} for a fixed-point MP3 encoder, although with a
|
|
lower quality.
|
|
|
|
@subsection Options
|
|
|
|
The following options are supported by the libmp3lame wrapper. The
|
|
@command{lame}-equivalent of the options are listed in parentheses.
|
|
|
|
@table @option
|
|
@item b (@emph{-b})
|
|
Set bitrate expressed in bits/s for CBR or ABR. LAME @code{bitrate} is
|
|
expressed in kilobits/s.
|
|
|
|
@item q (@emph{-V})
|
|
Set constant quality setting for VBR. This option is valid only
|
|
using the @command{ffmpeg} command-line tool. For library interface
|
|
users, use @option{global_quality}.
|
|
|
|
@item compression_level (@emph{-q})
|
|
Set algorithm quality. Valid arguments are integers in the 0-9 range,
|
|
with 0 meaning highest quality but slowest, and 9 meaning fastest
|
|
while producing the worst quality.
|
|
|
|
@item reservoir
|
|
Enable use of bit reservoir when set to 1. Default value is 1. LAME
|
|
has this enabled by default, but can be overriden by use
|
|
@option{--nores} option.
|
|
|
|
@item joint_stereo (@emph{-m j})
|
|
Enable the encoder to use (on a frame by frame basis) either L/R
|
|
stereo or mid/side stereo. Default value is 1.
|
|
|
|
@item abr (@emph{--abr})
|
|
Enable the encoder to use ABR when set to 1. The @command{lame}
|
|
@option{--abr} sets the target bitrate, while this options only
|
|
tells FFmpeg to use ABR still relies on @option{b} to set bitrate.
|
|
|
|
@end table
|
|
|
|
@section libopencore-amrnb
|
|
|
|
OpenCORE Adaptive Multi-Rate Narrowband encoder.
|
|
|
|
Requires the presence of the libopencore-amrnb headers and library during
|
|
configuration. You need to explicitly configure the build with
|
|
@code{--enable-libopencore-amrnb --enable-version3}.
|
|
|
|
This is a mono-only encoder. Officially it only supports 8000Hz sample rate,
|
|
but you can override it by setting @option{strict} to @samp{unofficial} or
|
|
lower.
|
|
|
|
@subsection Options
|
|
|
|
@table @option
|
|
|
|
@item b
|
|
Set bitrate in bits per second. Only the following bitrates are supported,
|
|
otherwise libavcodec will round to the nearest valid bitrate.
|
|
|
|
@table @option
|
|
@item 4750
|
|
@item 5150
|
|
@item 5900
|
|
@item 6700
|
|
@item 7400
|
|
@item 7950
|
|
@item 10200
|
|
@item 12200
|
|
@end table
|
|
|
|
@item dtx
|
|
Allow discontinuous transmission (generate comfort noise) when set to 1. The
|
|
default value is 0 (disabled).
|
|
|
|
@end table
|
|
|
|
@anchor{libshine}
|
|
@section libshine
|
|
|
|
Shine Fixed-Point MP3 encoder wrapper.
|
|
|
|
Shine is a fixed-point MP3 encoder. It has a far better performance on
|
|
platforms without an FPU, e.g. armel CPUs, and some phones and tablets.
|
|
However, as it is more targeted on performance than quality, it is not on par
|
|
with LAME and other production-grade encoders quality-wise. Also, according to
|
|
the project's homepage, this encoder may not be free of bugs as the code was
|
|
written a long time ago and the project was dead for at least 5 years.
|
|
|
|
This encoder only supports stereo and mono input. This is also CBR-only.
|
|
|
|
The original project (last updated in early 2007) is at
|
|
@url{http://sourceforge.net/projects/libshine-fxp/}. We only support the
|
|
updated fork by the Savonet/Liquidsoap project at @url{https://github.com/savonet/shine}.
|
|
|
|
Requires the presence of the libshine headers and library during
|
|
configuration. You need to explicitly configure the build with
|
|
@code{--enable-libshine}.
|
|
|
|
See also @ref{libmp3lame}.
|
|
|
|
@subsection Options
|
|
|
|
The following options are supported by the libshine wrapper. The
|
|
@command{shineenc}-equivalent of the options are listed in parentheses.
|
|
|
|
@table @option
|
|
@item b (@emph{-b})
|
|
Set bitrate expressed in bits/s for CBR. @command{shineenc} @option{-b} option
|
|
is expressed in kilobits/s.
|
|
|
|
@end table
|
|
|
|
@section libtwolame
|
|
|
|
TwoLAME MP2 encoder wrapper.
|
|
|
|
Requires the presence of the libtwolame headers and library during
|
|
configuration. You need to explicitly configure the build with
|
|
@code{--enable-libtwolame}.
|
|
|
|
@subsection Options
|
|
|
|
The following options are supported by the libtwolame wrapper. The
|
|
@command{twolame}-equivalent options follow the FFmpeg ones and are in
|
|
parentheses.
|
|
|
|
@table @option
|
|
@item b (@emph{-b})
|
|
Set bitrate expressed in bits/s for CBR. @command{twolame} @option{b}
|
|
option is expressed in kilobits/s. Default value is 128k.
|
|
|
|
@item q (@emph{-V})
|
|
Set quality for experimental VBR support. Maximum value range is
|
|
from -50 to 50, useful range is from -10 to 10. The higher the
|
|
value, the better the quality. This option is valid only using the
|
|
@command{ffmpeg} command-line tool. For library interface users,
|
|
use @option{global_quality}.
|
|
|
|
@item mode (@emph{--mode})
|
|
Set the mode of the resulting audio. Possible values:
|
|
|
|
@table @samp
|
|
@item auto
|
|
Choose mode automatically based on the input. This is the default.
|
|
@item stereo
|
|
Stereo
|
|
@item joint_stereo
|
|
Joint stereo
|
|
@item dual_channel
|
|
Dual channel
|
|
@item mono
|
|
Mono
|
|
@end table
|
|
|
|
@item psymodel (@emph{--psyc-mode})
|
|
Set psychoacoustic model to use in encoding. The argument must be
|
|
an integer between -1 and 4, inclusive. The higher the value, the
|
|
better the quality. The default value is 3.
|
|
|
|
@item energy_levels (@emph{--energy})
|
|
Enable energy levels extensions when set to 1. The default value is
|
|
0 (disabled).
|
|
|
|
@item error_protection (@emph{--protect})
|
|
Enable CRC error protection when set to 1. The default value is 0
|
|
(disabled).
|
|
|
|
@item copyright (@emph{--copyright})
|
|
Set MPEG audio copyright flag when set to 1. The default value is 0
|
|
(disabled).
|
|
|
|
@item original (@emph{--original})
|
|
Set MPEG audio original flag when set to 1. The default value is 0
|
|
(disabled).
|
|
|
|
@end table
|
|
|
|
@anchor{libvo-aacenc}
|
|
@section libvo-aacenc
|
|
|
|
VisualOn AAC encoder.
|
|
|
|
Requires the presence of the libvo-aacenc headers and library during
|
|
configuration. You need to explicitly configure the build with
|
|
@code{--enable-libvo-aacenc --enable-version3}.
|
|
|
|
This encoder is considered to be worse than the
|
|
@ref{aacenc,,native experimental FFmpeg AAC encoder}, according to
|
|
multiple sources.
|
|
|
|
@subsection Options
|
|
|
|
The VisualOn AAC encoder only support encoding AAC-LC and up to 2
|
|
channels. It is also CBR-only.
|
|
|
|
@table @option
|
|
|
|
@item b
|
|
Set bit rate in bits/s.
|
|
|
|
@end table
|
|
|
|
@section libvo-amrwbenc
|
|
|
|
VisualOn Adaptive Multi-Rate Wideband encoder.
|
|
|
|
Requires the presence of the libvo-amrwbenc headers and library during
|
|
configuration. You need to explicitly configure the build with
|
|
@code{--enable-libvo-amrwbenc --enable-version3}.
|
|
|
|
This is a mono-only encoder. Officially it only supports 16000Hz sample
|
|
rate, but you can override it by setting @option{strict} to
|
|
@samp{unofficial} or lower.
|
|
|
|
@subsection Options
|
|
|
|
@table @option
|
|
|
|
@item b
|
|
Set bitrate in bits/s. Only the following bitrates are supported, otherwise
|
|
libavcodec will round to the nearest valid bitrate.
|
|
|
|
@table @samp
|
|
@item 6600
|
|
@item 8850
|
|
@item 12650
|
|
@item 14250
|
|
@item 15850
|
|
@item 18250
|
|
@item 19850
|
|
@item 23050
|
|
@item 23850
|
|
@end table
|
|
|
|
@item dtx
|
|
Allow discontinuous transmission (generate comfort noise) when set to 1. The
|
|
default value is 0 (disabled).
|
|
|
|
@end table
|
|
|
|
@section libopus
|
|
|
|
libopus Opus Interactive Audio Codec encoder wrapper.
|
|
|
|
Requires the presence of the libopus headers and library during
|
|
configuration. You need to explicitly configure the build with
|
|
@code{--enable-libopus}.
|
|
|
|
@subsection Option Mapping
|
|
|
|
Most libopus options are modeled after the @command{opusenc} utility from
|
|
opus-tools. The following is an option mapping chart describing options
|
|
supported by the libopus wrapper, and their @command{opusenc}-equivalent
|
|
in parentheses.
|
|
|
|
@table @option
|
|
|
|
@item b (@emph{bitrate})
|
|
Set the bit rate in bits/s. FFmpeg's @option{b} option is
|
|
expressed in bits/s, while @command{opusenc}'s @option{bitrate} in
|
|
kilobits/s.
|
|
|
|
@item vbr (@emph{vbr}, @emph{hard-cbr}, and @emph{cvbr})
|
|
Set VBR mode. The FFmpeg @option{vbr} option has the following
|
|
valid arguments, with the their @command{opusenc} equivalent options
|
|
in parentheses:
|
|
|
|
@table @samp
|
|
@item off (@emph{hard-cbr})
|
|
Use constant bit rate encoding.
|
|
|
|
@item on (@emph{vbr})
|
|
Use variable bit rate encoding (the default).
|
|
|
|
@item constrained (@emph{cvbr})
|
|
Use constrained variable bit rate encoding.
|
|
@end table
|
|
|
|
@item compression_level (@emph{comp})
|
|
Set encoding algorithm complexity. Valid options are integers in
|
|
the 0-10 range. 0 gives the fastest encodes but lower quality, while 10
|
|
gives the highest quality but slowest encoding. The default is 10.
|
|
|
|
@item frame_duration (@emph{framesize})
|
|
Set maximum frame size, or duration of a frame in milliseconds. The
|
|
argument must be exactly the following: 2.5, 5, 10, 20, 40, 60. Smaller
|
|
frame sizes achieve lower latency but less quality at a given bitrate.
|
|
Sizes greater than 20ms are only interesting at fairly low bitrates.
|
|
The default is 20ms.
|
|
|
|
@item packet_loss (@emph{expect-loss})
|
|
Set expected packet loss percentage. The default is 0.
|
|
|
|
@item application (N.A.)
|
|
Set intended application type. Valid options are listed below:
|
|
|
|
@table @samp
|
|
@item voip
|
|
Favor improved speech intelligibility.
|
|
@item audio
|
|
Favor faithfulness to the input (the default).
|
|
@item lowdelay
|
|
Restrict to only the lowest delay modes.
|
|
@end table
|
|
|
|
@item cutoff (N.A.)
|
|
Set cutoff bandwidth in Hz. The argument must be exactly one of the
|
|
following: 4000, 6000, 8000, 12000, or 20000, corresponding to
|
|
narrowband, mediumband, wideband, super wideband, and fullband
|
|
respectively. The default is 0 (cutoff disabled).
|
|
|
|
@end table
|
|
|
|
@section libvorbis
|
|
|
|
libvorbis encoder wrapper.
|
|
|
|
Requires the presence of the libvorbisenc headers and library during
|
|
configuration. You need to explicitly configure the build with
|
|
@code{--enable-libvorbis}.
|
|
|
|
@subsection Options
|
|
|
|
The following options are supported by the libvorbis wrapper. The
|
|
@command{oggenc}-equivalent of the options are listed in parentheses.
|
|
|
|
To get a more accurate and extensive documentation of the libvorbis
|
|
options, consult the libvorbisenc's and @command{oggenc}'s documentations.
|
|
See @url{http://xiph.org/vorbis/},
|
|
@url{http://wiki.xiph.org/Vorbis-tools}, and oggenc(1).
|
|
|
|
@table @option
|
|
@item b (@emph{-b})
|
|
Set bitrate expressed in bits/s for ABR. @command{oggenc} @option{-b} is
|
|
expressed in kilobits/s.
|
|
|
|
@item q (@emph{-q})
|
|
Set constant quality setting for VBR. The value should be a float
|
|
number in the range of -1.0 to 10.0. The higher the value, the better
|
|
the quality. The default value is @samp{3.0}.
|
|
|
|
This option is valid only using the @command{ffmpeg} command-line tool.
|
|
For library interface users, use @option{global_quality}.
|
|
|
|
@item cutoff (@emph{--advanced-encode-option lowpass_frequency=N})
|
|
Set cutoff bandwidth in Hz, a value of 0 disables cutoff. @command{oggenc}'s
|
|
related option is expressed in kHz. The default value is @samp{0} (cutoff
|
|
disabled).
|
|
|
|
@item minrate (@emph{-m})
|
|
Set minimum bitrate expressed in bits/s. @command{oggenc} @option{-m} is
|
|
expressed in kilobits/s.
|
|
|
|
@item maxrate (@emph{-M})
|
|
Set maximum bitrate expressed in bits/s. @command{oggenc} @option{-M} is
|
|
expressed in kilobits/s. This only has effect on ABR mode.
|
|
|
|
@item iblock (@emph{--advanced-encode-option impulse_noisetune=N})
|
|
Set noise floor bias for impulse blocks. The value is a float number from
|
|
-15.0 to 0.0. A negative bias instructs the encoder to pay special attention
|
|
to the crispness of transients in the encoded audio. The tradeoff for better
|
|
transient response is a higher bitrate.
|
|
|
|
@end table
|
|
|
|
@section libwavpack
|
|
|
|
A wrapper providing WavPack encoding through libwavpack.
|
|
|
|
Only lossless mode using 32-bit integer samples is supported currently.
|
|
The @option{compression_level} option can be used to control speed vs.
|
|
compression tradeoff, with the values mapped to libwavpack as follows:
|
|
|
|
@table @option
|
|
|
|
@item 0
|
|
Fast mode - corresponding to the wavpack @option{-f} option.
|
|
|
|
@item 1
|
|
Normal (default) settings.
|
|
|
|
@item 2
|
|
High quality - corresponding to the wavpack @option{-h} option.
|
|
|
|
@item 3
|
|
Very high quality - corresponding to the wavpack @option{-hh} option.
|
|
|
|
@item 4-8
|
|
Same as 3, but with extra processing enabled - corresponding to the wavpack
|
|
@option{-x} option. I.e. 4 is the same as @option{-x2} and 8 is the same as
|
|
@option{-x6}.
|
|
|
|
@end table
|
|
|
|
@c man end AUDIO ENCODERS
|
|
|
|
@chapter Video Encoders
|
|
@c man begin VIDEO ENCODERS
|
|
|
|
A description of some of the currently available video encoders
|
|
follows.
|
|
|
|
@section libtheora
|
|
|
|
libtheora Theora encoder wrapper.
|
|
|
|
Requires the presence of the libtheora headers and library during
|
|
configuration. You need to explicitly configure the build with
|
|
@code{--enable-libtheora}.
|
|
|
|
For more informations about the libtheora project see
|
|
@url{http://www.theora.org/}.
|
|
|
|
@subsection Options
|
|
|
|
The following global options are mapped to internal libtheora options
|
|
which affect the quality and the bitrate of the encoded stream.
|
|
|
|
@table @option
|
|
@item b
|
|
Set the video bitrate in bit/s for CBR (Constant Bit Rate) mode. In
|
|
case VBR (Variable Bit Rate) mode is enabled this option is ignored.
|
|
|
|
@item flags
|
|
Used to enable constant quality mode (VBR) encoding through the
|
|
@option{qscale} flag, and to enable the @code{pass1} and @code{pass2}
|
|
modes.
|
|
|
|
@item g
|
|
Set the GOP size.
|
|
|
|
@item global_quality
|
|
Set the global quality as an integer in lambda units.
|
|
|
|
Only relevant when VBR mode is enabled with @code{flags +qscale}. The
|
|
value is converted to QP units by dividing it by @code{FF_QP2LAMBDA},
|
|
clipped in the [0 - 10] range, and then multiplied by 6.3 to get a
|
|
value in the native libtheora range [0-63]. A higher value corresponds
|
|
to a higher quality.
|
|
|
|
@item q
|
|
Enable VBR mode when set to a non-negative value, and set constant
|
|
quality value as a double floating point value in QP units.
|
|
|
|
The value is clipped in the [0-10] range, and then multiplied by 6.3
|
|
to get a value in the native libtheora range [0-63].
|
|
|
|
This option is valid only using the @command{ffmpeg} command-line
|
|
tool. For library interface users, use @option{global_quality}.
|
|
@end table
|
|
|
|
@subsection Examples
|
|
|
|
@itemize
|
|
@item
|
|
Set maximum constant quality (VBR) encoding with @command{ffmpeg}:
|
|
@example
|
|
ffmpeg -i INPUT -codec:v libtheora -q:v 10 OUTPUT.ogg
|
|
@end example
|
|
|
|
@item
|
|
Use @command{ffmpeg} to convert a CBR 1000 kbps Theora video stream:
|
|
@example
|
|
ffmpeg -i INPUT -codec:v libtheora -b:v 1000k OUTPUT.ogg
|
|
@end example
|
|
@end itemize
|
|
|
|
@section libvpx
|
|
|
|
VP8 format supported through libvpx.
|
|
|
|
Requires the presence of the libvpx headers and library during configuration.
|
|
You need to explicitly configure the build with @code{--enable-libvpx}.
|
|
|
|
@subsection Options
|
|
|
|
Mapping from FFmpeg to libvpx options with conversion notes in parentheses.
|
|
|
|
@table @option
|
|
|
|
@item threads
|
|
g_threads
|
|
|
|
@item profile
|
|
g_profile
|
|
|
|
@item vb
|
|
rc_target_bitrate
|
|
|
|
@item g
|
|
kf_max_dist
|
|
|
|
@item keyint_min
|
|
kf_min_dist
|
|
|
|
@item qmin
|
|
rc_min_quantizer
|
|
|
|
@item qmax
|
|
rc_max_quantizer
|
|
|
|
@item bufsize, vb
|
|
rc_buf_sz
|
|
@code{(bufsize * 1000 / vb)}
|
|
|
|
rc_buf_optimal_sz
|
|
@code{(bufsize * 1000 / vb * 5 / 6)}
|
|
|
|
@item rc_init_occupancy, vb
|
|
rc_buf_initial_sz
|
|
@code{(rc_init_occupancy * 1000 / vb)}
|
|
|
|
@item rc_buffer_aggressivity
|
|
rc_undershoot_pct
|
|
|
|
@item skip_threshold
|
|
rc_dropframe_thresh
|
|
|
|
@item qcomp
|
|
rc_2pass_vbr_bias_pct
|
|
|
|
@item maxrate, vb
|
|
rc_2pass_vbr_maxsection_pct
|
|
@code{(maxrate * 100 / vb)}
|
|
|
|
@item minrate, vb
|
|
rc_2pass_vbr_minsection_pct
|
|
@code{(minrate * 100 / vb)}
|
|
|
|
@item minrate, maxrate, vb
|
|
@code{VPX_CBR}
|
|
@code{(minrate == maxrate == vb)}
|
|
|
|
@item crf
|
|
@code{VPX_CQ}, @code{VP8E_SET_CQ_LEVEL}
|
|
|
|
@item quality
|
|
@table @option
|
|
@item @var{best}
|
|
@code{VPX_DL_BEST_QUALITY}
|
|
@item @var{good}
|
|
@code{VPX_DL_GOOD_QUALITY}
|
|
@item @var{realtime}
|
|
@code{VPX_DL_REALTIME}
|
|
@end table
|
|
|
|
@item speed
|
|
@code{VP8E_SET_CPUUSED}
|
|
|
|
@item nr
|
|
@code{VP8E_SET_NOISE_SENSITIVITY}
|
|
|
|
@item mb_threshold
|
|
@code{VP8E_SET_STATIC_THRESHOLD}
|
|
|
|
@item slices
|
|
@code{VP8E_SET_TOKEN_PARTITIONS}
|
|
|
|
@item max-intra-rate
|
|
@code{VP8E_SET_MAX_INTRA_BITRATE_PCT}
|
|
|
|
@item force_key_frames
|
|
@code{VPX_EFLAG_FORCE_KF}
|
|
|
|
@item Alternate reference frame related
|
|
@table @option
|
|
@item vp8flags altref
|
|
@code{VP8E_SET_ENABLEAUTOALTREF}
|
|
@item @var{arnr_max_frames}
|
|
@code{VP8E_SET_ARNR_MAXFRAMES}
|
|
@item @var{arnr_type}
|
|
@code{VP8E_SET_ARNR_TYPE}
|
|
@item @var{arnr_strength}
|
|
@code{VP8E_SET_ARNR_STRENGTH}
|
|
@item @var{rc_lookahead}
|
|
g_lag_in_frames
|
|
@end table
|
|
|
|
@item vp8flags error_resilient
|
|
g_error_resilient
|
|
|
|
@end table
|
|
|
|
For more information about libvpx see:
|
|
@url{http://www.webmproject.org/}
|
|
|
|
|
|
@section libwebp
|
|
|
|
libwebp WebP Image encoder wrapper
|
|
|
|
libwebp is Google's official encoder for WebP images. It can encode in either
|
|
lossy or lossless mode. Lossy images are essentially a wrapper around a VP8
|
|
frame. Lossless images are a separate codec developed by Google.
|
|
|
|
@subsection Pixel Format
|
|
|
|
Currently, libwebp only supports YUV420 for lossy and RGB for lossless due
|
|
to limitations of the format and libwebp. Alpha is supported for either mode.
|
|
Because of API limitations, if RGB is passed in when encoding lossy or YUV is
|
|
passed in for encoding lossless, the pixel format will automatically be
|
|
converted using functions from libwebp. This is not ideal and is done only for
|
|
convenience.
|
|
|
|
@subsection Options
|
|
|
|
@table @option
|
|
|
|
@item -lossless @var{boolean}
|
|
Enables/Disables use of lossless mode. Default is 0.
|
|
|
|
@item -compression_level @var{integer}
|
|
For lossy, this is a quality/speed tradeoff. Higher values give better quality
|
|
for a given size at the cost of increased encoding time. For lossless, this is
|
|
a size/speed tradeoff. Higher values give smaller size at the cost of increased
|
|
encoding time. More specifically, it controls the number of extra algorithms
|
|
and compression tools used, and varies the combination of these tools. This
|
|
maps to the @var{method} option in libwebp. The valid range is 0 to 6.
|
|
Default is 4.
|
|
|
|
@item -qscale @var{float}
|
|
For lossy encoding, this controls image quality, 0 to 100. For lossless
|
|
encoding, this controls the effort and time spent at compressing more. The
|
|
default value is 75. Note that for usage via libavcodec, this option is called
|
|
@var{global_quality} and must be multiplied by @var{FF_QP2LAMBDA}.
|
|
|
|
@item -preset @var{type}
|
|
Configuration preset. This does some automatic settings based on the general
|
|
type of the image.
|
|
@table @option
|
|
@item none
|
|
Do not use a preset.
|
|
@item default
|
|
Use the encoder default.
|
|
@item picture
|
|
Digital picture, like portrait, inner shot
|
|
@item photo
|
|
Outdoor photograph, with natural lighting
|
|
@item drawing
|
|
Hand or line drawing, with high-contrast details
|
|
@item icon
|
|
Small-sized colorful images
|
|
@item text
|
|
Text-like
|
|
@end table
|
|
|
|
@end table
|
|
|
|
@section libx264
|
|
|
|
x264 H.264/MPEG-4 AVC encoder wrapper.
|
|
|
|
This encoder requires the presence of the libx264 headers and library
|
|
during configuration. You need to explicitly configure the build with
|
|
@code{--enable-libx264}.
|
|
|
|
libx264 supports an impressive number of features, including 8x8 and
|
|
4x4 adaptive spatial transform, adaptive B-frame placement, CAVLC/CABAC
|
|
entropy coding, interlacing (MBAFF), lossless mode, psy optimizations
|
|
for detail retention (adaptive quantization, psy-RD, psy-trellis).
|
|
|
|
Many libx264 encoder options are mapped to FFmpeg global codec
|
|
options, while unique encoder options are provided through private
|
|
options. Additionally the @option{x264opts} and @option{x264-params}
|
|
private options allows to pass a list of key=value tuples as accepted
|
|
by the libx264 @code{x264_param_parse} function.
|
|
|
|
The x264 project website is at
|
|
@url{http://www.videolan.org/developers/x264.html}.
|
|
|
|
@subsection Options
|
|
|
|
The following options are supported by the libx264 wrapper. The
|
|
@command{x264}-equivalent options or values are listed in parentheses
|
|
for easy migration.
|
|
|
|
To reduce the duplication of documentation, only the private options
|
|
and some others requiring special attention are documented here. For
|
|
the documentation of the undocumented generic options, see
|
|
@ref{codec-options,,the Codec Options chapter}.
|
|
|
|
To get a more accurate and extensive documentation of the libx264
|
|
options, invoke the command @command{x264 --full-help} or consult
|
|
the libx264 documentation.
|
|
|
|
@table @option
|
|
@item b (@emph{bitrate})
|
|
Set bitrate in bits/s. Note that FFmpeg's @option{b} option is
|
|
expressed in bits/s, while @command{x264}'s @option{bitrate} is in
|
|
kilobits/s.
|
|
|
|
@item bf (@emph{bframes})
|
|
|
|
@item g (@emph{keyint})
|
|
|
|
@item qmax (@emph{qpmax})
|
|
|
|
@item qmin (@emph{qpmin})
|
|
|
|
@item qdiff (@emph{qpstep})
|
|
|
|
@item qblur (@emph{qblur})
|
|
|
|
@item qcomp (@emph{qcomp})
|
|
|
|
@item refs (@emph{ref})
|
|
|
|
@item sc_threshold (@emph{scenecut})
|
|
|
|
@item trellis (@emph{trellis})
|
|
|
|
@item nr (@emph{nr})
|
|
|
|
@item me_range (@emph{merange})
|
|
|
|
@item me_method (@emph{me})
|
|
Set motion estimation method. Possible values in the decreasing order
|
|
of speed:
|
|
|
|
@table @samp
|
|
@item dia (@emph{dia})
|
|
@item epzs (@emph{dia})
|
|
Diamond search with radius 1 (fastest). @samp{epzs} is an alias for
|
|
@samp{dia}.
|
|
@item hex (@emph{hex})
|
|
Hexagonal search with radius 2.
|
|
@item umh (@emph{umh})
|
|
Uneven multi-hexagon search.
|
|
@item esa (@emph{esa})
|
|
Exhaustive search.
|
|
@item tesa (@emph{tesa})
|
|
Hadamard exhaustive search (slowest).
|
|
@end table
|
|
|
|
@item subq (@emph{subme})
|
|
|
|
@item b_strategy (@emph{b-adapt})
|
|
|
|
@item keyint_min (@emph{min-keyint})
|
|
|
|
@item coder
|
|
Set entropy encoder. Possible values:
|
|
|
|
@table @samp
|
|
@item ac
|
|
Enable CABAC.
|
|
|
|
@item vlc
|
|
Enable CAVLC and disable CABAC. It generates the same effect as
|
|
@command{x264}'s @option{--no-cabac} option.
|
|
@end table
|
|
|
|
@item cmp
|
|
Set full pixel motion estimation comparation algorithm. Possible values:
|
|
|
|
@table @samp
|
|
@item chroma
|
|
Enable chroma in motion estimation.
|
|
|
|
@item sad
|
|
Ignore chroma in motion estimation. It generates the same effect as
|
|
@command{x264}'s @option{--no-chroma-me} option.
|
|
@end table
|
|
|
|
@item threads (@emph{threads})
|
|
|
|
@item thread_type
|
|
Set multithreading technique. Possible values:
|
|
|
|
@table @samp
|
|
@item slice
|
|
Slice-based multithreading. It generates the same effect as
|
|
@command{x264}'s @option{--sliced-threads} option.
|
|
@item frame
|
|
Frame-based multithreading.
|
|
@end table
|
|
|
|
@item flags
|
|
Set encoding flags. It can be used to disable closed GOP and enable
|
|
open GOP by setting it to @code{-cgop}. The result is similar to
|
|
the behavior of @command{x264}'s @option{--open-gop} option.
|
|
|
|
@item rc_init_occupancy (@emph{vbv-init})
|
|
|
|
@item preset (@emph{preset})
|
|
Set the encoding preset.
|
|
|
|
@item tune (@emph{tune})
|
|
Set tuning of the encoding params.
|
|
|
|
@item profile (@emph{profile})
|
|
Set profile restrictions.
|
|
|
|
@item fastfirstpass
|
|
Enable fast settings when encoding first pass, when set to 1. When set
|
|
to 0, it has the same effect of @command{x264}'s
|
|
@option{--slow-firstpass} option.
|
|
|
|
@item crf (@emph{crf})
|
|
Set the quality for constant quality mode.
|
|
|
|
@item crf_max (@emph{crf-max})
|
|
In CRF mode, prevents VBV from lowering quality beyond this point.
|
|
|
|
@item qp (@emph{qp})
|
|
Set constant quantization rate control method parameter.
|
|
|
|
@item aq-mode (@emph{aq-mode})
|
|
Set AQ method. Possible values:
|
|
|
|
@table @samp
|
|
@item none (@emph{0})
|
|
Disabled.
|
|
|
|
@item variance (@emph{1})
|
|
Variance AQ (complexity mask).
|
|
|
|
@item autovariance (@emph{2})
|
|
Auto-variance AQ (experimental).
|
|
@end table
|
|
|
|
@item aq-strength (@emph{aq-strength})
|
|
Set AQ strength, reduce blocking and blurring in flat and textured areas.
|
|
|
|
@item psy
|
|
Use psychovisual optimizations when set to 1. When set to 0, it has the
|
|
same effect as @command{x264}'s @option{--no-psy} option.
|
|
|
|
@item psy-rd (@emph{psy-rd})
|
|
Set strength of psychovisual optimization, in
|
|
@var{psy-rd}:@var{psy-trellis} format.
|
|
|
|
@item rc-lookahead (@emph{rc-lookahead})
|
|
Set number of frames to look ahead for frametype and ratecontrol.
|
|
|
|
@item weightb
|
|
Enable weighted prediction for B-frames when set to 1. When set to 0,
|
|
it has the same effect as @command{x264}'s @option{--no-weightb} option.
|
|
|
|
@item weightp (@emph{weightp})
|
|
Set weighted prediction method for P-frames. Possible values:
|
|
|
|
@table @samp
|
|
@item none (@emph{0})
|
|
Disabled
|
|
@item simple (@emph{1})
|
|
Enable only weighted refs
|
|
@item smart (@emph{2})
|
|
Enable both weighted refs and duplicates
|
|
@end table
|
|
|
|
@item ssim (@emph{ssim})
|
|
Enable calculation and printing SSIM stats after the encoding.
|
|
|
|
@item intra-refresh (@emph{intra-refresh})
|
|
Enable the use of Periodic Intra Refresh instead of IDR frames when set
|
|
to 1.
|
|
|
|
@item bluray-compat (@emph{bluray-compat})
|
|
Configure the encoder to be compatible with the bluray standard.
|
|
It is a shorthand for setting "bluray-compat=1 force-cfr=1".
|
|
|
|
@item b-bias (@emph{b-bias})
|
|
Set the influence on how often B-frames are used.
|
|
|
|
@item b-pyramid (@emph{b-pyramid})
|
|
Set method for keeping of some B-frames as references. Possible values:
|
|
|
|
@table @samp
|
|
@item none (@emph{none})
|
|
Disabled.
|
|
@item strict (@emph{strict})
|
|
Strictly hierarchical pyramid.
|
|
@item normal (@emph{normal})
|
|
Non-strict (not Blu-ray compatible).
|
|
@end table
|
|
|
|
@item mixed-refs
|
|
Enable the use of one reference per partition, as opposed to one
|
|
reference per macroblock when set to 1. When set to 0, it has the
|
|
same effect as @command{x264}'s @option{--no-mixed-refs} option.
|
|
|
|
@item 8x8dct
|
|
Enable adaptive spatial transform (high profile 8x8 transform)
|
|
when set to 1. When set to 0, it has the same effect as
|
|
@command{x264}'s @option{--no-8x8dct} option.
|
|
|
|
@item fast-pskip
|
|
Enable early SKIP detection on P-frames when set to 1. When set
|
|
to 0, it has the same effect as @command{x264}'s
|
|
@option{--no-fast-pskip} option.
|
|
|
|
@item aud (@emph{aud})
|
|
Enable use of access unit delimiters when set to 1.
|
|
|
|
@item mbtree
|
|
Enable use macroblock tree ratecontrol when set to 1. When set
|
|
to 0, it has the same effect as @command{x264}'s
|
|
@option{--no-mbtree} option.
|
|
|
|
@item deblock (@emph{deblock})
|
|
Set loop filter parameters, in @var{alpha}:@var{beta} form.
|
|
|
|
@item cplxblur (@emph{cplxblur})
|
|
Set fluctuations reduction in QP (before curve compression).
|
|
|
|
@item partitions (@emph{partitions})
|
|
Set partitions to consider as a comma-separated list of. Possible
|
|
values in the list:
|
|
|
|
@table @samp
|
|
@item p8x8
|
|
8x8 P-frame partition.
|
|
@item p4x4
|
|
4x4 P-frame partition.
|
|
@item b8x8
|
|
4x4 B-frame partition.
|
|
@item i8x8
|
|
8x8 I-frame partition.
|
|
@item i4x4
|
|
4x4 I-frame partition.
|
|
(Enabling @samp{p4x4} requires @samp{p8x8} to be enabled. Enabling
|
|
@samp{i8x8} requires adaptive spatial transform (@option{8x8dct}
|
|
option) to be enabled.)
|
|
@item none (@emph{none})
|
|
Do not consider any partitions.
|
|
@item all (@emph{all})
|
|
Consider every partition.
|
|
@end table
|
|
|
|
@item direct-pred (@emph{direct})
|
|
Set direct MV prediction mode. Possible values:
|
|
|
|
@table @samp
|
|
@item none (@emph{none})
|
|
Disable MV prediction.
|
|
@item spatial (@emph{spatial})
|
|
Enable spatial predicting.
|
|
@item temporal (@emph{temporal})
|
|
Enable temporal predicting.
|
|
@item auto (@emph{auto})
|
|
Automatically decided.
|
|
@end table
|
|
|
|
@item slice-max-size (@emph{slice-max-size})
|
|
Set the limit of the size of each slice in bytes. If not specified
|
|
but RTP payload size (@option{ps}) is specified, that is used.
|
|
|
|
@item stats (@emph{stats})
|
|
Set the file name for multi-pass stats.
|
|
|
|
@item nal-hrd (@emph{nal-hrd})
|
|
Set signal HRD information (requires @option{vbv-bufsize} to be set).
|
|
Possible values:
|
|
|
|
@table @samp
|
|
@item none (@emph{none})
|
|
Disable HRD information signaling.
|
|
@item vbr (@emph{vbr})
|
|
Variable bit rate.
|
|
@item cbr (@emph{cbr})
|
|
Constant bit rate (not allowed in MP4 container).
|
|
@end table
|
|
|
|
@item x264opts (N.A.)
|
|
Set any x264 option, see @command{x264 --fullhelp} for a list.
|
|
|
|
Argument is a list of @var{key}=@var{value} couples separated by
|
|
":". In @var{filter} and @var{psy-rd} options that use ":" as a separator
|
|
themselves, use "," instead. They accept it as well since long ago but this
|
|
is kept undocumented for some reason.
|
|
|
|
For example to specify libx264 encoding options with @command{ffmpeg}:
|
|
@example
|
|
ffmpeg -i foo.mpg -vcodec libx264 -x264opts keyint=123:min-keyint=20 -an out.mkv
|
|
@end example
|
|
|
|
@item x264-params (N.A.)
|
|
Override the x264 configuration using a :-separated list of key=value
|
|
parameters.
|
|
|
|
This option is functionally the same as the @option{x264opts}, but is
|
|
duplicated for compability with the Libav fork.
|
|
|
|
For example to specify libx264 encoding options with @command{ffmpeg}:
|
|
@example
|
|
ffmpeg -i INPUT -c:v libx264 -x264-params level=30:bframes=0:weightp=0:\
|
|
cabac=0:ref=1:vbv-maxrate=768:vbv-bufsize=2000:analyse=all:me=umh:\
|
|
no-fast-pskip=1:subq=6:8x8dct=0:trellis=0 OUTPUT
|
|
@end example
|
|
@end table
|
|
|
|
Encoding ffpresets for common usages are provided so they can be used with the
|
|
general presets system (e.g. passing the @option{pre} option).
|
|
|
|
@section libxvid
|
|
|
|
Xvid MPEG-4 Part 2 encoder wrapper.
|
|
|
|
This encoder requires the presence of the libxvidcore headers and library
|
|
during configuration. You need to explicitly configure the build with
|
|
@code{--enable-libxvid --enable-gpl}.
|
|
|
|
The native @code{mpeg4} encoder supports the MPEG-4 Part 2 format, so
|
|
users can encode to this format without this library.
|
|
|
|
@subsection Options
|
|
|
|
The following options are supported by the libxvid wrapper. Some of
|
|
the following options are listed but are not documented, and
|
|
correspond to shared codec options. See @ref{codec-options,,the Codec
|
|
Options chapter} for their documentation. The other shared options
|
|
which are not listed have no effect for the libxvid encoder.
|
|
|
|
@table @option
|
|
@item b
|
|
|
|
@item g
|
|
|
|
@item qmin
|
|
|
|
@item qmax
|
|
|
|
@item mpeg_quant
|
|
|
|
@item threads
|
|
|
|
@item bf
|
|
|
|
@item b_qfactor
|
|
|
|
@item b_qoffset
|
|
|
|
@item flags
|
|
Set specific encoding flags. Possible values:
|
|
|
|
@table @samp
|
|
|
|
@item mv4
|
|
Use four motion vector by macroblock.
|
|
|
|
@item aic
|
|
Enable high quality AC prediction.
|
|
|
|
@item gray
|
|
Only encode grayscale.
|
|
|
|
@item gmc
|
|
Enable the use of global motion compensation (GMC).
|
|
|
|
@item qpel
|
|
Enable quarter-pixel motion compensation.
|
|
|
|
@item cgop
|
|
Enable closed GOP.
|
|
|
|
@item global_header
|
|
Place global headers in extradata instead of every keyframe.
|
|
|
|
@end table
|
|
|
|
@item trellis
|
|
|
|
@item me_method
|
|
Set motion estimation method. Possible values in decreasing order of
|
|
speed and increasing order of quality:
|
|
|
|
@table @samp
|
|
@item zero
|
|
Use no motion estimation (default).
|
|
|
|
@item phods
|
|
@item x1
|
|
@item log
|
|
Enable advanced diamond zonal search for 16x16 blocks and half-pixel
|
|
refinement for 16x16 blocks. @samp{x1} and @samp{log} are aliases for
|
|
@samp{phods}.
|
|
|
|
@item epzs
|
|
Enable all of the things described above, plus advanced diamond zonal
|
|
search for 8x8 blocks, half-pixel refinement for 8x8 blocks, and motion
|
|
estimation on chroma planes.
|
|
|
|
@item full
|
|
Enable all of the things described above, plus extended 16x16 and 8x8
|
|
blocks search.
|
|
@end table
|
|
|
|
@item mbd
|
|
Set macroblock decision algorithm. Possible values in the increasing
|
|
order of quality:
|
|
|
|
@table @samp
|
|
@item simple
|
|
Use macroblock comparing function algorithm (default).
|
|
|
|
@item bits
|
|
Enable rate distortion-based half pixel and quarter pixel refinement for
|
|
16x16 blocks.
|
|
|
|
@item rd
|
|
Enable all of the things described above, plus rate distortion-based
|
|
half pixel and quarter pixel refinement for 8x8 blocks, and rate
|
|
distortion-based search using square pattern.
|
|
@end table
|
|
|
|
@item lumi_aq
|
|
Enable lumi masking adaptive quantization when set to 1. Default is 0
|
|
(disabled).
|
|
|
|
@item variance_aq
|
|
Enable variance adaptive quantization when set to 1. Default is 0
|
|
(disabled).
|
|
|
|
When combined with @option{lumi_aq}, the resulting quality will not
|
|
be better than any of the two specified individually. In other
|
|
words, the resulting quality will be the worse one of the two
|
|
effects.
|
|
|
|
@item ssim
|
|
Set structural similarity (SSIM) displaying method. Possible values:
|
|
|
|
@table @samp
|
|
@item off
|
|
Disable displaying of SSIM information.
|
|
|
|
@item avg
|
|
Output average SSIM at the end of encoding to stdout. The format of
|
|
showing the average SSIM is:
|
|
|
|
@example
|
|
Average SSIM: %f
|
|
@end example
|
|
|
|
For users who are not familiar with C, %f means a float number, or
|
|
a decimal (e.g. 0.939232).
|
|
|
|
@item frame
|
|
Output both per-frame SSIM data during encoding and average SSIM at
|
|
the end of encoding to stdout. The format of per-frame information
|
|
is:
|
|
|
|
@example
|
|
SSIM: avg: %1.3f min: %1.3f max: %1.3f
|
|
@end example
|
|
|
|
For users who are not familiar with C, %1.3f means a float number
|
|
rounded to 3 digits after the dot (e.g. 0.932).
|
|
|
|
@end table
|
|
|
|
@item ssim_acc
|
|
Set SSIM accuracy. Valid options are integers within the range of
|
|
0-4, while 0 gives the most accurate result and 4 computes the
|
|
fastest.
|
|
|
|
@end table
|
|
|
|
@section png
|
|
|
|
PNG image encoder.
|
|
|
|
@subsection Private options
|
|
|
|
@table @option
|
|
@item dpi @var{integer}
|
|
Set physical density of pixels, in dots per inch, unset by default
|
|
@item dpm @var{integer}
|
|
Set physical density of pixels, in dots per meter, unset by default
|
|
@end table
|
|
|
|
@section ProRes
|
|
|
|
Apple ProRes encoder.
|
|
|
|
FFmpeg contains 2 ProRes encoders, the prores-aw and prores-ks encoder.
|
|
The used encoder can be choosen with the @code{-vcodec} option.
|
|
|
|
@subsection Private Options for prores-ks
|
|
|
|
@table @option
|
|
@item profile @var{integer}
|
|
Select the ProRes profile to encode
|
|
@table @samp
|
|
@item proxy
|
|
@item lt
|
|
@item standard
|
|
@item hq
|
|
@item 4444
|
|
@end table
|
|
|
|
@item quant_mat @var{integer}
|
|
Select quantization matrix.
|
|
@table @samp
|
|
@item auto
|
|
@item default
|
|
@item proxy
|
|
@item lt
|
|
@item standard
|
|
@item hq
|
|
@end table
|
|
If set to @var{auto}, the matrix matching the profile will be picked.
|
|
If not set, the matrix providing the highest quality, @var{default}, will be
|
|
picked.
|
|
|
|
@item bits_per_mb @var{integer}
|
|
How many bits to allot for coding one macroblock. Different profiles use
|
|
between 200 and 2400 bits per macroblock, the maximum is 8000.
|
|
|
|
@item mbs_per_slice @var{integer}
|
|
Number of macroblocks in each slice (1-8); the default value (8)
|
|
should be good in almost all situations.
|
|
|
|
@item vendor @var{string}
|
|
Override the 4-byte vendor ID.
|
|
A custom vendor ID like @var{apl0} would claim the stream was produced by
|
|
the Apple encoder.
|
|
|
|
@item alpha_bits @var{integer}
|
|
Specify number of bits for alpha component.
|
|
Possible values are @var{0}, @var{8} and @var{16}.
|
|
Use @var{0} to disable alpha plane coding.
|
|
|
|
@end table
|
|
|
|
@subsection Speed considerations
|
|
|
|
In the default mode of operation the encoder has to honor frame constraints
|
|
(i.e. not produc frames with size bigger than requested) while still making
|
|
output picture as good as possible.
|
|
A frame containing a lot of small details is harder to compress and the encoder
|
|
would spend more time searching for appropriate quantizers for each slice.
|
|
|
|
Setting a higher @option{bits_per_mb} limit will improve the speed.
|
|
|
|
For the fastest encoding speed set the @option{qscale} parameter (4 is the
|
|
recommended value) and do not set a size constraint.
|
|
|
|
@c man end VIDEO ENCODERS
|