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
60 @item analyzeduration @var{integer} (@emph{input})
61 Specify how many microseconds are analyzed to probe the input. A
62 higher value will allow to detect more accurate information, but will
63 increase latency. It defaults to 5,000,000 microseconds = 5 seconds.
65 @item cryptokey @var{hexadecimal string} (@emph{input})
68 @item indexmem @var{integer} (@emph{input})
69 Set max memory used for timestamp index (per stream).
71 @item rtbufsize @var{integer} (@emph{input})
72 Set max memory used for buffering real-time frames.
74 @item fdebug @var{flags} (@emph{input/output})
75 Print specific debug info.
82 @item max_delay @var{integer} (@emph{input/output})
83 Set maximum muxing or demuxing delay in microseconds.
85 @item fpsprobesize @var{integer} (@emph{input})
86 Set number of frames used to probe fps.
88 @item audio_preload @var{integer} (@emph{output})
89 Set microseconds by which audio packets should be interleaved earlier.
91 @item chunk_duration @var{integer} (@emph{output})
92 Set microseconds for each chunk.
94 @item chunk_size @var{integer} (@emph{output})
95 Set size in bytes for each chunk.
97 @item err_detect, f_err_detect @var{flags} (@emph{input})
98 Set error detection flags. @code{f_err_detect} is deprecated and
99 should be used only via the @command{ffmpeg} tool.
104 Verify embedded CRCs.
106 Detect bitstream specification deviations.
108 Detect improper bitstream length.
110 Abort decoding on minor error detection.
112 Consider things that violate the spec and have not been seen in the
115 Consider all spec non compliancies as errors.
117 Consider things that a sane encoder should not do as an error.
120 @item use_wallclock_as_timestamps @var{integer} (@emph{input})
121 Use wallclock as timestamps.
123 @item avoid_negative_ts @var{integer} (@emph{output})
124 Shift timestamps to make them positive. A value of 1 enables shifting,
125 a value of 0 disables it, the default value of -1 enables shifting
126 when required by the target format.
128 When shifting is enabled, all output timestamps are shifted by the
129 same amount. Audio, video, and subtitles desynching and relative
130 timestamp differences are preserved compared to how they would have
131 been without shifting.
133 Also note that this affects only leading negative timestamps, and not
134 non-monotonic negative timestamps.
136 @item flush_packets @var{integer} (@emph{output})
137 Flush the underlying I/O stream after each packet. Default 1 enables it, and
138 has the effect of reducing the latency; 0 disables it and may slightly
139 increase performance in some cases.
142 @c man end FORMAT OPTIONS
144 @include demuxers.texi
146 @include metadata.texi