cmdutils: extend -h to allow printing codec details.
[libav.git] / doc / avtools-common-opts.texi
1 All the numerical options, if not specified otherwise, accept in input
2 a string representing a number, which may contain one of the
3 International System number postfixes, for example 'K', 'M', 'G'.
4 If 'i' is appended after the postfix, powers of 2 are used instead of
5 powers of 10. The 'B' postfix multiplies the value for 8, and can be
6 appended after another postfix or used alone. This allows using for
7 example 'KB', 'MiB', 'G' and 'B' as postfix.
9 Options which do not take arguments are boolean options, and set the
10 corresponding value to true. They can be set to false by prefixing
11 with "no" the option name, for example using "-nofoo" in the
12 command line will set to false the boolean option with name "foo".
14 @anchor{Stream specifiers}
15 @section Stream specifiers
16 Some options are applied per-stream, e.g. bitrate or codec. Stream specifiers
17 are used to precisely specify which stream(s) does a given option belong to.
19 A stream specifier is a string generally appended to the option name and
20 separated 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
22 would select the ac3 codec for the second audio stream.
24 A stream specifier can match several stream, the option is then applied to all
25 of them. E.g. the stream specifier in @code{-b:a 128k} matches all audio
26 streams.
28 An empty stream specifier matches all streams, for example @code{-codec copy}
29 or @code{-codec: copy} would copy all the streams without reencoding.
31 Possible forms of stream specifiers are:
32 @table @option
33 @item @var{stream_index}
34 Matches the stream with this index. E.g. @code{-threads:1 4} would set the
35 thread 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
39 matches stream number @var{stream_index} of this type. Otherwise matches all
40 streams of this type.
41 @item p:@var{program_id}[:@var{stream_index}]
42 If @var{stream_index} is given, then matches stream number @var{stream_index} in
43 program with id @var{program_id}. Otherwise matches all streams in this program.
44 @end table
45 @section Generic options
47 These options are shared amongst the av* tools.
49 @table @option
51 @item -L
52 Show license.
54 @item -h, -?, -help, --help [@var{arg}]
55 Show help. An optional parameter may be specified to print help about a specific
56 item.
58 Possible values of @var{arg} are:
59 @table @option
60 @item decoder=@var{decoder_name}
61 Print detailed information about the decoder named @var{decoder_name}. Use the
62 @option{-decoders} option to get a list of all decoders.
64 @item encoder=@var{encoder_name}
65 Print detailed information about the encoder named @var{encoder_name}. Use the
66 @option{-encoders} option to get a list of all encoders.
67 @end table
69 @item -version
70 Show version.
72 @item -formats
73 Show available formats.
75 The fields preceding the format names have the following meanings:
76 @table @samp
77 @item D
78 Decoding available
79 @item E
80 Encoding available
81 @end table
83 @item -codecs
84 Show all codecs known to libavcodec.
86 Note that the term 'codec' is used throughout this documentation as a shortcut
87 for what is more correctly called a media bitstream format.
89 @item -decoders
90 Show available decoders.
92 @item -encoders
93 Show all available encoders.
95 @item -bsfs
96 Show available bitstream filters.
98 @item -protocols
99 Show available protocols.
101 @item -filters
102 Show available libavfilter filters.
104 @item -pix_fmts
105 Show available pixel formats.
107 @item -sample_fmts
108 Show available sample formats.
110 @item -loglevel @var{loglevel} | -v @var{loglevel}
111 Set the logging level used by the library.
112 @var{loglevel} is a number or a string containing one of the following values:
113 @table @samp
114 @item quiet
115 @item panic
116 @item fatal
117 @item error
118 @item warning
119 @item info
120 @item verbose
121 @item debug
122 @end table
124 By default the program logs to stderr, if coloring is supported by the
125 terminal, colors are used to mark errors and warnings. Log coloring
126 can be disabled setting the environment variable
127 @env{AV_LOG_FORCE_NOCOLOR} or @env{NO_COLOR}, or can be forced setting
128 the environment variable @env{AV_LOG_FORCE_COLOR}.
129 The use of the environment variable @env{NO_COLOR} is deprecated and
130 will be dropped in a following Libav version.
132 @end table
134 @section AVOptions
136 These options are provided directly by the libavformat, libavdevice and
137 libavcodec libraries. To see the list of available AVOptions, use the
138 @option{-help} option. They are separated into two categories:
139 @table @option
140 @item generic
141 These options can be set for any container, codec or device. Generic options
142 are listed under AVFormatContext options for containers/devices and under
143 AVCodecContext options for codecs.
144 @item private
145 These options are specific to the given container, device or codec. Private
146 options are listed under their corresponding containers/devices/codecs.
147 @end table
149 For example to write an ID3v2.3 header instead of a default ID3v2.4 to
150 an MP3 file, use the @option{id3v2_version} private option of the MP3
151 muxer:
152 @example
153 avconv -i input.flac -id3v2_version 3 out.mp3
154 @end example
156 All codec AVOptions are obviously per-stream, so the chapter on stream
157 specifiers applies to them
159 Note @option{-nooption} syntax cannot be used for boolean AVOptions,
160 use @option{-option 0}/@option{-option 1}.
162 Note2 old undocumented way of specifying per-stream AVOptions by prepending
163 v/a/s to the options name is now obsolete and will be removed soon.
165 @include avoptions_codec.texi
166 @include avoptions_format.texi