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 platform-, build- and time-independent data.
60 This ensures that file and data checksums are reproducible and match between
61 platforms. Its primary use is for regression testing.
64 @item seek2any @var{integer} (@emph{input})
65 Allow seeking to non-keyframes on demuxer level when supported if set to 1.
68 @item analyzeduration @var{integer} (@emph{input})
69 Specify how many microseconds are analyzed to probe the input. A
70 higher value will allow to detect more accurate information, but will
71 increase latency. It defaults to 5,000,000 microseconds = 5 seconds.
73 @item cryptokey @var{hexadecimal string} (@emph{input})
76 @item indexmem @var{integer} (@emph{input})
77 Set max memory used for timestamp index (per stream).
79 @item rtbufsize @var{integer} (@emph{input})
80 Set max memory used for buffering real-time frames.
82 @item fdebug @var{flags} (@emph{input/output})
83 Print specific debug info.
90 @item max_delay @var{integer} (@emph{input/output})
91 Set maximum muxing or demuxing delay in microseconds.
93 @item fpsprobesize @var{integer} (@emph{input})
94 Set number of frames used to probe fps.
96 @item audio_preload @var{integer} (@emph{output})
97 Set microseconds by which audio packets should be interleaved earlier.
99 @item chunk_duration @var{integer} (@emph{output})
100 Set microseconds for each chunk.
102 @item chunk_size @var{integer} (@emph{output})
103 Set size in bytes for each chunk.
105 @item err_detect, f_err_detect @var{flags} (@emph{input})
106 Set error detection flags. @code{f_err_detect} is deprecated and
107 should be used only via the @command{ffmpeg} tool.
112 Verify embedded CRCs.
114 Detect bitstream specification deviations.
116 Detect improper bitstream length.
118 Abort decoding on minor error detection.
120 Consider things that violate the spec and have not been seen in the
123 Consider all spec non compliancies as errors.
125 Consider things that a sane encoder should not do as an error.
128 @item use_wallclock_as_timestamps @var{integer} (@emph{input})
129 Use wallclock as timestamps.
131 @item avoid_negative_ts @var{integer} (@emph{output})
135 @item make_non_negative
136 Shift timestamps to make them non-negative.
137 Also note that this affects only leading negative timestamps, and not
138 non-monotonic negative timestamps.
140 Shift timestamps so that the first timestamp is 0.
142 Enables shifting when required by the target format.
144 Disables shifting of timestamp.
147 When shifting is enabled, all output timestamps are shifted by the
148 same amount. Audio, video, and subtitles desynching and relative
149 timestamp differences are preserved compared to how they would have
150 been without shifting.
152 @item skip_initial_bytes @var{integer} (@emph{input})
153 Set number of bytes to skip before reading header and frames if set to 1.
156 @item correct_ts_overflow @var{integer} (@emph{input})
157 Correct single timestamp overflows if set to 1. Default is 1.
159 @item flush_packets @var{integer} (@emph{output})
160 Flush the underlying I/O stream after each packet. Default 1 enables it, and
161 has the effect of reducing the latency; 0 disables it and may slightly
162 increase performance in some cases.
164 @item output_ts_offset @var{offset} (@emph{output})
165 Set the output time offset.
167 @var{offset} must be a time duration specification,
168 see @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}.
170 The offset is added by the muxer to the output timestamps.
172 Specifying a positive offset means that the corresponding streams are
173 delayed bt the time duration specified in @var{offset}. Default value
174 is @code{0} (meaning that no offset is applied).
176 @item format_whitelist @var{list} (@emph{input})
177 "," separated List of allowed demuxers. By default all are allowed.
179 @item dump_separator @var{string} (@emph{input})
180 Separator used to separate the fields printed on the command line about the
182 For example to separate the fields with newlines and indention:
184 ffprobe -dump_separator "
185 " -i ~/videos/matrixbench_mpeg2.mpg
189 @c man end FORMAT OPTIONS
191 @anchor{Format stream specifiers}
192 @section Format stream specifiers
194 Format stream specifiers allow selection of one or more streams that
195 match specific properties.
197 Possible forms of stream specifiers are:
199 @item @var{stream_index}
200 Matches the stream with this index.
202 @item @var{stream_type}[:@var{stream_index}]
203 @var{stream_type} is one of following: 'v' for video, 'a' for audio,
204 's' for subtitle, 'd' for data, and 't' for attachments. If
205 @var{stream_index} is given, then it matches the stream number
206 @var{stream_index} of this type. Otherwise, it matches all streams of
209 @item p:@var{program_id}[:@var{stream_index}]
210 If @var{stream_index} is given, then it matches the stream with number
211 @var{stream_index} in the program with the id
212 @var{program_id}. Otherwise, it matches all streams in the program.
214 @item #@var{stream_id}
215 Matches the stream by a format-specific ID.
218 The exact semantics of stream specifiers is defined by the
219 @code{avformat_match_stream_specifier()} function declared in the
220 @file{libavformat/avformat.h} header.
222 @ifclear config-writeonly
223 @include demuxers.texi
225 @ifclear config-readonly
228 @include metadata.texi