1All the numerical options, if not specified otherwise, accept in input
2a string representing a number, which may contain one of the
3International System number postfixes, for example 'K', 'M', 'G'.
4If 'i' is appended after the postfix, powers of 2 are used instead of
5powers of 10. The 'B' postfix multiplies the value for 8, and can be
6appended after another postfix or used alone. This allows using for
7example 'KB', 'MiB', 'G' and 'B' as postfix.
8
9Options which do not take arguments are boolean options, and set the
10corresponding value to true. They can be set to false by prefixing
11with "no" the option name, for example using "-nofoo" in the
12command line will set to false the boolean option with name "foo".
13
14@anchor{Stream specifiers}
15@section Stream specifiers
16Some options are applied per-stream, e.g. bitrate or codec. Stream specifiers
17are used to precisely specify which stream(s) does a given option belong to.
18
19A stream specifier is a string generally appended to the option name and
20separated from it by a colon. E.g. @code{-codec:a:1 ac3} option contains
21@code{a:1} stream specifer, which matches the second audio stream. Therefore it
22would select the ac3 codec for the second audio stream.
23
24A stream specifier can match several stream, the option is then applied to all
25of them. E.g. the stream specifier in @code{-b:a 128k} matches all audio
26streams.
27
28An empty stream specifier matches all streams, for example @code{-codec copy}
29or @code{-codec: copy} would copy all the streams without reencoding.
30
31Possible forms of stream specifiers are:
32@table @option
33@item @var{stream_index}
34Matches the stream with this index. E.g. @code{-threads:1 4} would set the
35thread count for the second stream to 4.
36@item @var{stream_type}[:@var{stream_index}]
37@var{stream_type} is one of: 'v' for video, 'a' for audio, 's' for subtitle,
38'd' for data and 't' for attachments. If @var{stream_index} is given, then
39matches stream number @var{stream_index} of this type. Otherwise matches all
40streams of this type.
41@item p:@var{program_id}[:@var{stream_index}]
42If @var{stream_index} is given, then matches stream number @var{stream_index} in
43program with id @var{program_id}. Otherwise matches all streams in this program.
44@end table
45@section Generic options
46
47These options are shared amongst the av* tools.
48
49@table @option
50
51@item -L
52Show license.
53
54@item -h, -?, -help, --help
55Show help.
56
57@item -version
58Show version.
59
60@item -formats
61Show available formats.
62
63The fields preceding the format names have the following meanings:
64@table @samp
65@item D
66Decoding available
67@item E
68Encoding available
69@end table
70
71@item -codecs
72Show available codecs.
73
74The fields preceding the codec names have the following meanings:
75@table @samp
76@item D
77Decoding available
78@item E
79Encoding available
80@item V/A/S
81Video/audio/subtitle codec
82@item S
83Codec supports slices
84@item D
85Codec supports direct rendering
86@item T
87Codec can handle input truncated at random locations instead of only at frame boundaries
88@end table
89
90@item -bsfs
91Show available bitstream filters.
92
93@item -protocols
94Show available protocols.
95
96@item -filters
97Show available libavfilter filters.
98
99@item -pix_fmts
100Show available pixel formats.
101
102@item -sample_fmts
103Show available sample formats.
104
105@item -loglevel @var{loglevel} | -v @var{loglevel}
106Set the logging level used by the library.
107@var{loglevel} is a number or a string containing one of the following values:
108@table @samp
109@item quiet
110@item panic
111@item fatal
112@item error
113@item warning
114@item info
115@item verbose
116@item debug
117@end table
118
119By default the program logs to stderr, if coloring is supported by the
120terminal, colors are used to mark errors and warnings. Log coloring
121can be disabled setting the environment variable
122@env{AV_LOG_FORCE_NOCOLOR} or @env{NO_COLOR}, or can be forced setting
123the environment variable @env{AV_LOG_FORCE_COLOR}.
124The use of the environment variable @env{NO_COLOR} is deprecated and
125will be dropped in a following Libav version.
126
127@end table
128
129@section AVOptions
130
131These options are provided directly by the libavformat, libavdevice and
132libavcodec libraries. To see the list of available AVOptions, use the
133@option{-help} option. They are separated into two categories:
134@table @option
135@item generic
136These options can be set for any container, codec or device. Generic options
137are listed under AVFormatContext options for containers/devices and under
138AVCodecContext options for codecs.
139@item private
140These options are specific to the given container, device or codec. Private
141options are listed under their corresponding containers/devices/codecs.
142@end table
143
144For example to write an ID3v2.3 header instead of a default ID3v2.4 to
145an MP3 file, use the @option{id3v2_version} private option of the MP3
146muxer:
147@example
148avconv -i input.flac -id3v2_version 3 out.mp3
149@end example
150
151All codec AVOptions are obviously per-stream, so the chapter on stream
152specifiers applies to them
153
154Note @option{-nooption} syntax cannot be used for boolean AVOptions,
155use @option{-option 0}/@option{-option 1}.
156
157Note2 old undocumented way of specifying per-stream AVOptions by prepending
158v/a/s to the options name is now obsolete and will be removed soon.
159