1 @chapter Format Options
2 @c man begin FORMAT OPTIONS
4 The libavformat library provides some generic global options, which
5 can be set on all the muxers and demuxers. In addition each muxer or
6 demuxer may support so-called private options, which are specific for
9 Options may be set by specifying -@var{option} @var{value} in the
10 FFmpeg tools, or by setting the value explicitly in the
11 @code{AVFormatContext} options or using the @file{libavutil/opt.h} API
14 The list of supported options follows:
17 @item avioflags @var{flags} (@emph{input/output})
24 @item probesize @var{integer} (@emph{input})
25 Set probing size in bytes, i.e. the size of the data to analyze to get
26 stream information. A higher value will allow to detect more
27 information in case it is dispersed into the stream, but will increase
28 latency. Must be an integer not lesser than 32. It is 5000000 by default.
30 @item packetsize @var{integer} (@emph{output})
33 @item fflags @var{flags} (@emph{input/output})
43 Do not fill in missing values that can be exactly calculated.
45 Disable AVParsers, this needs @code{+nofillin} too.
49 Discard corrupted frames.
51 Try to interleave output packets by DTS.
53 Do not merge side data.
55 Enable RTP MP4A-LATM payload.
57 Reduce the latency introduced by optional buffering
59 Only write binary portable, build and time independant data.
62 @item seek2any @var{integer} (@emph{input})
63 Allow seeking to non-keyframes on demuxer level when supported if set to 1.
66 @item analyzeduration @var{integer} (@emph{input})
67 Specify how many microseconds are analyzed to probe the input. A
68 higher value will allow to detect more accurate information, but will
69 increase latency. It defaults to 5,000,000 microseconds = 5 seconds.
71 @item cryptokey @var{hexadecimal string} (@emph{input})
74 @item indexmem @var{integer} (@emph{input})
75 Set max memory used for timestamp index (per stream).
77 @item rtbufsize @var{integer} (@emph{input})
78 Set max memory used for buffering real-time frames.
80 @item fdebug @var{flags} (@emph{input/output})
81 Print specific debug info.
88 @item max_delay @var{integer} (@emph{input/output})
89 Set maximum muxing or demuxing delay in microseconds.
91 @item fpsprobesize @var{integer} (@emph{input})
92 Set number of frames used to probe fps.
94 @item audio_preload @var{integer} (@emph{output})
95 Set microseconds by which audio packets should be interleaved earlier.
97 @item chunk_duration @var{integer} (@emph{output})
98 Set microseconds for each chunk.
100 @item chunk_size @var{integer} (@emph{output})
101 Set size in bytes for each chunk.
103 @item err_detect, f_err_detect @var{flags} (@emph{input})
104 Set error detection flags. @code{f_err_detect} is deprecated and
105 should be used only via the @command{ffmpeg} tool.
110 Verify embedded CRCs.
112 Detect bitstream specification deviations.
114 Detect improper bitstream length.
116 Abort decoding on minor error detection.
118 Consider things that violate the spec and have not been seen in the
121 Consider all spec non compliancies as errors.
123 Consider things that a sane encoder should not do as an error.
126 @item use_wallclock_as_timestamps @var{integer} (@emph{input})
127 Use wallclock as timestamps.
129 @item avoid_negative_ts @var{integer} (@emph{output})
133 @item make_non_negative
134 Shift timestamps to make them non-negative.
135 Also note that this affects only leading negative timestamps, and not
136 non-monotonic negative timestamps.
138 Shift timestamps so that the first timestamp is 0.
140 Enables shifting when required by the target format.
142 Disables shifting of timestamp.
145 When shifting is enabled, all output timestamps are shifted by the
146 same amount. Audio, video, and subtitles desynching and relative
147 timestamp differences are preserved compared to how they would have
148 been without shifting.
150 @item skip_initial_bytes @var{integer} (@emph{input})
151 Set number of bytes to skip before reading header and frames if set to 1.
154 @item correct_ts_overflow @var{integer} (@emph{input})
155 Correct single timestamp overflows if set to 1. Default is 1.
157 @item flush_packets @var{integer} (@emph{output})
158 Flush the underlying I/O stream after each packet. Default 1 enables it, and
159 has the effect of reducing the latency; 0 disables it and may slightly
160 increase performance in some cases.
162 @item output_ts_offset @var{offset} (@emph{output})
163 Set the output time offset.
165 @var{offset} must be a time duration specification,
166 see @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}.
168 The offset is added by the muxer to the output timestamps.
170 Specifying a positive offset means that the corresponding streams are
171 delayed bt the time duration specified in @var{offset}. Default value
172 is @code{0} (meaning that no offset is applied).
174 @item format_whitelist @var{list} (@emph{input})
175 "," separated List of allowed demuxers. By default all are allowed.
177 @item dump_separator @var{string} (@emph{input})
178 Separator used to separate the fields printed on the command line about the
180 For example to separate the fields with newlines and indention:
182 ffprobe -dump_separator "
183 " -i ~/videos/matrixbench_mpeg2.mpg
187 @c man end FORMAT OPTIONS
189 @anchor{Format stream specifiers}
190 @section Format stream specifiers
192 Format stream specifiers allow selection of one or more streams that
193 match specific properties.
195 Possible forms of stream specifiers are:
197 @item @var{stream_index}
198 Matches the stream with this index.
200 @item @var{stream_type}[:@var{stream_index}]
201 @var{stream_type} is one of following: 'v' for video, 'a' for audio,
202 's' for subtitle, 'd' for data, and 't' for attachments. If
203 @var{stream_index} is given, then it matches the stream number
204 @var{stream_index} of this type. Otherwise, it matches all streams of
207 @item p:@var{program_id}[:@var{stream_index}]
208 If @var{stream_index} is given, then it matches the stream with number
209 @var{stream_index} in the program with the id
210 @var{program_id}. Otherwise, it matches all streams in the program.
212 @item #@var{stream_id}
213 Matches the stream by a format-specific ID.
216 The exact semantics of stream specifiers is defined by the
217 @code{avformat_match_stream_specifier()} function declared in the
218 @file{libavformat/avformat.h} header.
220 @ifclear config-writeonly
221 @include demuxers.texi
223 @ifclear config-readonly
226 @include metadata.texi