4 Decoders are configured elements in FFmpeg which allow the decoding of
7 When you configure your FFmpeg build, all the supported native decoders
8 are enabled by default. Decoders requiring an external library must be enabled
9 manually via the corresponding @code{--enable-lib} option. You can list all
10 available decoders using the configure option @code{--list-decoders}.
12 You can disable all the decoders with the configure option
13 @code{--disable-decoders} and selectively enable / disable single decoders
14 with the options @code{--enable-decoder=@var{DECODER}} /
15 @code{--disable-decoder=@var{DECODER}}.
17 The option @code{-codecs} of the ff* tools will display the list of
22 @chapter Video Decoders
23 @c man begin VIDEO DECODERS
25 A description of some of the currently available video decoders
32 This decoder decodes rawvideo streams.
37 @item top @var{top_field_first}
38 Specify the assumed field type of the input video.
41 the video is assumed to be progressive (default)
43 bottom-field-first is assumed
45 top-field-first is assumed
50 @c man end VIDEO DECODERS
52 @chapter Audio Decoders
53 @c man begin AUDIO DECODERS
57 Internal wave synthetizer.
59 This decoder generates wave patterns according to predefined sequences. Its
60 use is purely internal and the format of the data it accepts is not publicly
65 libcelt decoder wrapper.
67 libcelt allows libavcodec to decode the Xiph CELT ultra-low delay audio codec.
68 Requires the presence of the libcelt headers and library during configuration.
69 You need to explicitly configure the build with @code{--enable-libcelt}.
73 libgsm decoder wrapper.
75 libgsm allows libavcodec to decode the GSM full rate audio codec. Requires
76 the presence of the libgsm headers and library during configuration. You need
77 to explicitly configure the build with @code{--enable-libgsm}.
79 This decoder supports both the ordinary GSM and the Microsoft variant.
83 libilbc decoder wrapper.
85 libilbc allows libavcodec to decode the Internet Low Bitrate Codec (iLBC)
86 audio codec. Requires the presence of the libilbc headers and library during
87 configuration. You need to explicitly configure the build with
88 @code{--enable-libilbc}.
92 The following option is supported by the libilbc wrapper.
97 Enable the enhancement of the decoded audio when set to 1. The default
98 value is 0 (disabled).
102 @section libopencore-amrnb
104 libopencore-amrnb decoder wrapper.
106 libopencore-amrnb allows libavcodec to decode the Adaptive Multi-Rate
107 Narrowband audio codec. Using it requires the presence of the
108 libopencore-amrnb headers and library during configuration. You need to
109 explicitly configure the build with @code{--enable-libopencore-amrnb}.
111 An FFmpeg native decoder for AMR-NB exists, so users can decode AMR-NB
112 without this library.
114 @section libopencore-amrwb
116 libopencore-amrwb decoder wrapper.
118 libopencore-amrwb allows libavcodec to decode the Adaptive Multi-Rate
119 Wideband audio codec. Using it requires the presence of the
120 libopencore-amrwb headers and library during configuration. You need to
121 explicitly configure the build with @code{--enable-libopencore-amrwb}.
123 An FFmpeg native decoder for AMR-WB exists, so users can decode AMR-WB
124 without this library.
128 libopus decoder wrapper.
130 libopus allows libavcodec to decode the Opus Interactive Audio Codec.
131 Requires the presence of the libopus headers and library during
132 configuration. You need to explicitly configure the build with
133 @code{--enable-libopus}.
135 @c man end AUDIO DECODERS
137 @chapter Subtitles Decoders
138 @c man begin SUBTILES DECODERS
142 This codec decodes the bitmap subtitles used in DVDs; the same subtitles can
143 also be found in VobSub file pairs and in some Matroska files.
149 Specify the global palette used by the bitmaps. When stored in VobSub, the
150 palette is normally specified in the index file; in Matroska, the palette is
151 stored in the codec extra-data in the same format as in VobSub. In DVDs, the
152 palette is stored in the IFO file, and therefore not available when reading
153 from dumped VOB files.
155 The format for this option is a string containing 16 24-bits hexadecimal
156 numbers (without 0x prefix) separated by comas, for example @code{0d00ee,
157 ee450d, 101010, eaeaea, 0ce60b, ec14ed, ebff0b, 0d617a, 7b7b7b, d1d1d1,
158 7b2a0e, 0d950c, 0f007b, cf0dec, cfa80c, 7c127b}.
161 @section libzvbi-teletext
163 Libzvbi allows libavcodec to decode DVB teletext pages and DVB teletext
164 subtitles. Requires the presence of the libzvbi headers and library during
165 configuration. You need to explicitly configure the build with
166 @code{--enable-libzvbi}.
172 List of teletext page numbers to decode. You may use the special * string to
173 match all pages. Pages that do not match the specified list are dropped.
176 Discards the top teletext line. Default value is 1.
178 Specifies the format of the decoded subtitles. The teletext decoder is capable
179 of decoding the teletext pages to bitmaps or to simple text, you should use
180 "bitmap" for teletext pages, because certain graphics and colors cannot be
181 expressed in simple text. You might use "text" for teletext based subtitles if
182 your application can handle simple text based subtitles. Default value is
185 X offset of generated bitmaps, default is 0.
187 Y offset of generated bitmaps, default is 0.
188 @item txt_chop_spaces
189 Chops leading and trailing spaces and removes empty lines from the generated
190 text. This option is useful for teletext based subtitles where empty spaces may
191 be present at the start or at the end of the lines or empty lines may be
192 present between the subtitle lines because of double-sized teletext charactes.
195 Sets the display duration of the decoded teletext pages or subtitles in
196 miliseconds. Default value is 30000 which is 30 seconds.
197 @item txt_transparent
198 Force transparent background of the generated teletext bitmaps. Default value
199 is 0 which means an opaque (black) background.
202 @c man end SUBTILES DECODERS