mirror of
https://github.com/FFmpeg/FFmpeg.git
synced 2024-12-12 19:18:44 +02:00
407 lines
12 KiB
Plaintext
407 lines
12 KiB
Plaintext
@chapter Decoders
|
|
@c man begin DECODERS
|
|
|
|
Decoders are configured elements in FFmpeg which allow the decoding of
|
|
multimedia streams.
|
|
|
|
When you configure your FFmpeg build, all the supported native decoders
|
|
are enabled by default. Decoders requiring an external library must be enabled
|
|
manually via the corresponding @code{--enable-lib} option. You can list all
|
|
available decoders using the configure option @code{--list-decoders}.
|
|
|
|
You can disable all the decoders with the configure option
|
|
@code{--disable-decoders} and selectively enable / disable single decoders
|
|
with the options @code{--enable-decoder=@var{DECODER}} /
|
|
@code{--disable-decoder=@var{DECODER}}.
|
|
|
|
The option @code{-decoders} of the ff* tools will display the list of
|
|
enabled decoders.
|
|
|
|
@c man end DECODERS
|
|
|
|
@chapter Video Decoders
|
|
@c man begin VIDEO DECODERS
|
|
|
|
A description of some of the currently available video decoders
|
|
follows.
|
|
|
|
@section av1
|
|
|
|
AOMedia Video 1 (AV1) decoder.
|
|
|
|
@subsection Options
|
|
|
|
@table @option
|
|
|
|
@item operating_point
|
|
Select an operating point of a scalable AV1 bitstream (0 - 31). Default is 0.
|
|
|
|
@end table
|
|
|
|
@section rawvideo
|
|
|
|
Raw video decoder.
|
|
|
|
This decoder decodes rawvideo streams.
|
|
|
|
@subsection Options
|
|
|
|
@table @option
|
|
@item top @var{top_field_first}
|
|
Specify the assumed field type of the input video.
|
|
@table @option
|
|
@item -1
|
|
the video is assumed to be progressive (default)
|
|
@item 0
|
|
bottom-field-first is assumed
|
|
@item 1
|
|
top-field-first is assumed
|
|
@end table
|
|
|
|
@end table
|
|
|
|
@section libdav1d
|
|
|
|
dav1d AV1 decoder.
|
|
|
|
libdav1d allows libavcodec to decode the AOMedia Video 1 (AV1) codec.
|
|
Requires the presence of the libdav1d headers and library during configuration.
|
|
You need to explicitly configure the build with @code{--enable-libdav1d}.
|
|
|
|
@subsection Options
|
|
|
|
The following options are supported by the libdav1d wrapper.
|
|
|
|
@table @option
|
|
|
|
@item framethreads
|
|
Set amount of frame threads to use during decoding. The default value is 0 (autodetect).
|
|
This option is deprecated for libdav1d >= 1.0 and will be removed in the future. Use the
|
|
global option @code{threads} instead.
|
|
|
|
@item tilethreads
|
|
Set amount of tile threads to use during decoding. The default value is 0 (autodetect).
|
|
This option is deprecated for libdav1d >= 1.0 and will be removed in the future. Use the
|
|
global option @code{threads} instead.
|
|
|
|
@item filmgrain
|
|
Apply film grain to the decoded video if present in the bitstream. Defaults to the
|
|
internal default of the library.
|
|
This option is deprecated and will be removed in the future. See the global option
|
|
@code{export_side_data} to export Film Grain parameters instead of applying it.
|
|
|
|
@item oppoint
|
|
Select an operating point of a scalable AV1 bitstream (0 - 31). Defaults to the
|
|
internal default of the library.
|
|
|
|
@item alllayers
|
|
Output all spatial layers of a scalable AV1 bitstream. The default value is false.
|
|
|
|
@end table
|
|
|
|
@section libdavs2
|
|
|
|
AVS2-P2/IEEE1857.4 video decoder wrapper.
|
|
|
|
This decoder allows libavcodec to decode AVS2 streams with davs2 library.
|
|
|
|
@c man end VIDEO DECODERS
|
|
|
|
@section libuavs3d
|
|
|
|
AVS3-P2/IEEE1857.10 video decoder.
|
|
|
|
libuavs3d allows libavcodec to decode AVS3 streams.
|
|
Requires the presence of the libuavs3d headers and library during configuration.
|
|
You need to explicitly configure the build with @code{--enable-libuavs3d}.
|
|
|
|
@subsection Options
|
|
|
|
The following option is supported by the libuavs3d wrapper.
|
|
|
|
@table @option
|
|
|
|
@item frame_threads
|
|
Set amount of frame threads to use during decoding. The default value is 0 (autodetect).
|
|
|
|
@end table
|
|
|
|
@c man end VIDEO DECODERS
|
|
|
|
@chapter Audio Decoders
|
|
@c man begin AUDIO DECODERS
|
|
|
|
A description of some of the currently available audio decoders
|
|
follows.
|
|
|
|
@section ac3
|
|
|
|
AC-3 audio decoder.
|
|
|
|
This decoder implements part of ATSC A/52:2010 and ETSI TS 102 366, as well as
|
|
the undocumented RealAudio 3 (a.k.a. dnet).
|
|
|
|
@subsection AC-3 Decoder Options
|
|
|
|
@table @option
|
|
|
|
@item -drc_scale @var{value}
|
|
Dynamic Range Scale Factor. The factor to apply to dynamic range values
|
|
from the AC-3 stream. This factor is applied exponentially. The default value is 1.
|
|
There are 3 notable scale factor ranges:
|
|
@table @option
|
|
@item drc_scale == 0
|
|
DRC disabled. Produces full range audio.
|
|
@item 0 < drc_scale <= 1
|
|
DRC enabled. Applies a fraction of the stream DRC value.
|
|
Audio reproduction is between full range and full compression.
|
|
@item drc_scale > 1
|
|
DRC enabled. Applies drc_scale asymmetrically.
|
|
Loud sounds are fully compressed. Soft sounds are enhanced.
|
|
@end table
|
|
|
|
@end table
|
|
|
|
@section flac
|
|
|
|
FLAC audio decoder.
|
|
|
|
This decoder aims to implement the complete FLAC specification from Xiph.
|
|
|
|
@subsection FLAC Decoder options
|
|
|
|
@table @option
|
|
|
|
@item -use_buggy_lpc
|
|
The lavc FLAC encoder used to produce buggy streams with high lpc values
|
|
(like the default value). This option makes it possible to decode such streams
|
|
correctly by using lavc's old buggy lpc logic for decoding.
|
|
|
|
@end table
|
|
|
|
@section ffwavesynth
|
|
|
|
Internal wave synthesizer.
|
|
|
|
This decoder generates wave patterns according to predefined sequences. Its
|
|
use is purely internal and the format of the data it accepts is not publicly
|
|
documented.
|
|
|
|
@section libcelt
|
|
|
|
libcelt decoder wrapper.
|
|
|
|
libcelt allows libavcodec to decode the Xiph CELT ultra-low delay audio codec.
|
|
Requires the presence of the libcelt headers and library during configuration.
|
|
You need to explicitly configure the build with @code{--enable-libcelt}.
|
|
|
|
@section libgsm
|
|
|
|
libgsm decoder wrapper.
|
|
|
|
libgsm allows libavcodec to decode the GSM full rate audio codec. Requires
|
|
the presence of the libgsm headers and library during configuration. You need
|
|
to explicitly configure the build with @code{--enable-libgsm}.
|
|
|
|
This decoder supports both the ordinary GSM and the Microsoft variant.
|
|
|
|
@section libilbc
|
|
|
|
libilbc decoder wrapper.
|
|
|
|
libilbc allows libavcodec to decode the Internet Low Bitrate Codec (iLBC)
|
|
audio codec. Requires the presence of the libilbc headers and library during
|
|
configuration. You need to explicitly configure the build with
|
|
@code{--enable-libilbc}.
|
|
|
|
@subsection Options
|
|
|
|
The following option is supported by the libilbc wrapper.
|
|
|
|
@table @option
|
|
@item enhance
|
|
|
|
Enable the enhancement of the decoded audio when set to 1. The default
|
|
value is 0 (disabled).
|
|
|
|
@end table
|
|
|
|
@section libopencore-amrnb
|
|
|
|
libopencore-amrnb decoder wrapper.
|
|
|
|
libopencore-amrnb allows libavcodec to decode the Adaptive Multi-Rate
|
|
Narrowband audio codec. Using it requires the presence of the
|
|
libopencore-amrnb headers and library during configuration. You need to
|
|
explicitly configure the build with @code{--enable-libopencore-amrnb}.
|
|
|
|
An FFmpeg native decoder for AMR-NB exists, so users can decode AMR-NB
|
|
without this library.
|
|
|
|
@section libopencore-amrwb
|
|
|
|
libopencore-amrwb decoder wrapper.
|
|
|
|
libopencore-amrwb allows libavcodec to decode the Adaptive Multi-Rate
|
|
Wideband audio codec. Using it requires the presence of the
|
|
libopencore-amrwb headers and library during configuration. You need to
|
|
explicitly configure the build with @code{--enable-libopencore-amrwb}.
|
|
|
|
An FFmpeg native decoder for AMR-WB exists, so users can decode AMR-WB
|
|
without this library.
|
|
|
|
@section libopus
|
|
|
|
libopus decoder wrapper.
|
|
|
|
libopus allows libavcodec to decode the Opus Interactive Audio Codec.
|
|
Requires the presence of the libopus headers and library during
|
|
configuration. You need to explicitly configure the build with
|
|
@code{--enable-libopus}.
|
|
|
|
An FFmpeg native decoder for Opus exists, so users can decode Opus
|
|
without this library.
|
|
|
|
@c man end AUDIO DECODERS
|
|
|
|
@chapter Subtitles Decoders
|
|
@c man begin SUBTILES DECODERS
|
|
|
|
@section libaribb24
|
|
|
|
ARIB STD-B24 caption decoder.
|
|
|
|
Implements profiles A and C of the ARIB STD-B24 standard.
|
|
|
|
@subsection libaribb24 Decoder Options
|
|
|
|
@table @option
|
|
|
|
@item -aribb24-base-path @var{path}
|
|
Sets the base path for the libaribb24 library. This is utilized for reading of
|
|
configuration files (for custom unicode conversions), and for dumping of
|
|
non-text symbols as images under that location.
|
|
|
|
Unset by default.
|
|
|
|
@item -aribb24-skip-ruby-text @var{boolean}
|
|
Tells the decoder wrapper to skip text blocks that contain half-height ruby
|
|
text.
|
|
|
|
Enabled by default.
|
|
|
|
@end table
|
|
|
|
@section dvbsub
|
|
|
|
@subsection Options
|
|
|
|
@table @option
|
|
@item compute_clut
|
|
@table @option
|
|
@item -2
|
|
Compute clut once if no matching CLUT is in the stream.
|
|
@item -1
|
|
Compute clut if no matching CLUT is in the stream.
|
|
@item 0
|
|
Never compute CLUT
|
|
@item 1
|
|
Always compute CLUT and override the one provided in the stream.
|
|
@end table
|
|
@item dvb_substream
|
|
Selects the dvb substream, or all substreams if -1 which is default.
|
|
|
|
@end table
|
|
|
|
@section dvdsub
|
|
|
|
This codec decodes the bitmap subtitles used in DVDs; the same subtitles can
|
|
also be found in VobSub file pairs and in some Matroska files.
|
|
|
|
@subsection Options
|
|
|
|
@table @option
|
|
@item palette
|
|
Specify the global palette used by the bitmaps. When stored in VobSub, the
|
|
palette is normally specified in the index file; in Matroska, the palette is
|
|
stored in the codec extra-data in the same format as in VobSub. In DVDs, the
|
|
palette is stored in the IFO file, and therefore not available when reading
|
|
from dumped VOB files.
|
|
|
|
The format for this option is a string containing 16 24-bits hexadecimal
|
|
numbers (without 0x prefix) separated by commas, for example @code{0d00ee,
|
|
ee450d, 101010, eaeaea, 0ce60b, ec14ed, ebff0b, 0d617a, 7b7b7b, d1d1d1,
|
|
7b2a0e, 0d950c, 0f007b, cf0dec, cfa80c, 7c127b}.
|
|
|
|
@item ifo_palette
|
|
Specify the IFO file from which the global palette is obtained.
|
|
(experimental)
|
|
|
|
@item forced_subs_only
|
|
Only decode subtitle entries marked as forced. Some titles have forced
|
|
and non-forced subtitles in the same track. Setting this flag to @code{1}
|
|
will only keep the forced subtitles. Default value is @code{0}.
|
|
@end table
|
|
|
|
@section libzvbi-teletext
|
|
|
|
Libzvbi allows libavcodec to decode DVB teletext pages and DVB teletext
|
|
subtitles. Requires the presence of the libzvbi headers and library during
|
|
configuration. You need to explicitly configure the build with
|
|
@code{--enable-libzvbi}.
|
|
|
|
@subsection Options
|
|
|
|
@table @option
|
|
@item txt_page
|
|
List of teletext page numbers to decode. Pages that do not match the specified
|
|
list are dropped. You may use the special @code{*} string to match all pages,
|
|
or @code{subtitle} to match all subtitle pages.
|
|
Default value is *.
|
|
@item txt_default_region
|
|
Set default character set used for decoding, a value between 0 and 87 (see
|
|
ETS 300 706, Section 15, Table 32). Default value is -1, which does not
|
|
override the libzvbi default. This option is needed for some legacy level 1.0
|
|
transmissions which cannot signal the proper charset.
|
|
@item txt_chop_top
|
|
Discards the top teletext line. Default value is 1.
|
|
@item txt_format
|
|
Specifies the format of the decoded subtitles.
|
|
@table @option
|
|
@item bitmap
|
|
The default format, you should use this for teletext pages, because certain
|
|
graphics and colors cannot be expressed in simple text or even ASS.
|
|
@item text
|
|
Simple text based output without formatting.
|
|
@item ass
|
|
Formatted ASS output, subtitle pages and teletext pages are returned in
|
|
different styles, subtitle pages are stripped down to text, but an effort is
|
|
made to keep the text alignment and the formatting.
|
|
@end table
|
|
@item txt_left
|
|
X offset of generated bitmaps, default is 0.
|
|
@item txt_top
|
|
Y offset of generated bitmaps, default is 0.
|
|
@item txt_chop_spaces
|
|
Chops leading and trailing spaces and removes empty lines from the generated
|
|
text. This option is useful for teletext based subtitles where empty spaces may
|
|
be present at the start or at the end of the lines or empty lines may be
|
|
present between the subtitle lines because of double-sized teletext characters.
|
|
Default value is 1.
|
|
@item txt_duration
|
|
Sets the display duration of the decoded teletext pages or subtitles in
|
|
milliseconds. Default value is -1 which means infinity or until the next
|
|
subtitle event comes.
|
|
@item txt_transparent
|
|
Force transparent background of the generated teletext bitmaps. Default value
|
|
is 0 which means an opaque background.
|
|
@item txt_opacity
|
|
Sets the opacity (0-255) of the teletext background. If
|
|
@option{txt_transparent} is not set, it only affects characters between a start
|
|
box and an end box, typically subtitles. Default value is 0 if
|
|
@option{txt_transparent} is set, 255 otherwise.
|
|
|
|
@end table
|
|
|
|
@c man end SUBTILES DECODERS
|