ffmpeg/doc/formats.texi

   1 @chapter Format Options
   2 @c man begin FORMAT OPTIONS
   3
   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
   7 that component.
   8
   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
  12 for programmatic use.
  13
  14 The list of supported options follows:
  15
  16 @table @option
  17 @item avioflags @var{flags} (@emph{input/output})
  18 Possible values:
  19 @table @samp
  20 @item direct
  21 Reduce buffering.
  22 @end table
  23
  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.
  29
  30 @item packetsize @var{integer} (@emph{output})
  31 Set packet size.
  32
  33 @item fflags @var{flags} (@emph{input/output})
  34 Set format flags.
  35
  36 Possible values:
  37 @table @samp
  38 @item ignidx
  39 Ignore index.
  40 @item genpts
  41 Generate PTS.
  42 @item nofillin
  43 Do not fill in missing values that can be exactly calculated.
  44 @item noparse
  45 Disable AVParsers, this needs @code{+nofillin} too.
  46 @item igndts
  47 Ignore DTS.
  48 @item discardcorrupt
  49 Discard corrupted frames.
  50 @item sortdts
  51 Try to interleave output packets by DTS.
  52 @item keepside
  53 Do not merge side data.
  54 @item latm
  55 Enable RTP MP4A-LATM payload.
  56 @item nobuffer
  57 Reduce the latency introduced by optional buffering
  58 @end table
  59
  60 @item seek2any @var{integer} (@emph{input})
  61 Allow seeking to non-keyframes on demuxer level when supported if set to 1.
  62 Default is 0.
  63
  64 @item analyzeduration @var{integer} (@emph{input})
  65 Specify how many microseconds are analyzed to probe the input. A
  66 higher value will allow to detect more accurate information, but will
  67 increase latency. It defaults to 5,000,000 microseconds = 5 seconds.
  68
  69 @item cryptokey @var{hexadecimal string} (@emph{input})
  70 Set decryption key.
  71
  72 @item indexmem @var{integer} (@emph{input})
  73 Set max memory used for timestamp index (per stream).
  74
  75 @item rtbufsize @var{integer} (@emph{input})
  76 Set max memory used for buffering real-time frames.
  77
  78 @item fdebug @var{flags} (@emph{input/output})
  79 Print specific debug info.
  80
  81 Possible values:
  82 @table @samp
  83 @item ts
  84 @end table
  85
  86 @item max_delay @var{integer} (@emph{input/output})
  87 Set maximum muxing or demuxing delay in microseconds.
  88
  89 @item fpsprobesize @var{integer} (@emph{input})
  90 Set number of frames used to probe fps.
  91
  92 @item audio_preload @var{integer} (@emph{output})
  93 Set microseconds by which audio packets should be interleaved earlier.
  94
  95 @item chunk_duration @var{integer} (@emph{output})
  96 Set microseconds for each chunk.
  97
  98 @item chunk_size @var{integer} (@emph{output})
  99 Set size in bytes for each chunk.
 100
 101 @item err_detect, f_err_detect @var{flags} (@emph{input})
 102 Set error detection flags. @code{f_err_detect} is deprecated and
 103 should be used only via the @command{ffmpeg} tool.
 104
 105 Possible values:
 106 @table @samp
 107 @item crccheck
 108 Verify embedded CRCs.
 109 @item bitstream
 110 Detect bitstream specification deviations.
 111 @item buffer
 112 Detect improper bitstream length.
 113 @item explode
 114 Abort decoding on minor error detection.
 115 @item careful
 116 Consider things that violate the spec and have not been seen in the
 117 wild as errors.
 118 @item compliant
 119 Consider all spec non compliancies as errors.
 120 @item aggressive
 121 Consider things that a sane encoder should not do as an error.
 122 @end table
 123
 124 @item use_wallclock_as_timestamps @var{integer} (@emph{input})
 125 Use wallclock as timestamps.
 126
 127 @item avoid_negative_ts @var{integer} (@emph{output})
 128
 129 Possible values:
 130 @table @samp
 131 @item make_non_negative
 132 Shift timestamps to make them non-negative.
 133 Also note that this affects only leading negative timestamps, and not
 134 non-monotonic negative timestamps.
 135 @item make_zero
 136 Shift timestamps so that the first timestamp is 0.
 137 @item auto (default)
 138 Enables shifting when required by the target format.
 139 @item disabled
 140 Disables shifting of timestamp.
 141 @end table
 142
 143 When shifting is enabled, all output timestamps are shifted by the
 144 same amount. Audio, video, and subtitles desynching and relative
 145 timestamp differences are preserved compared to how they would have
 146 been without shifting.
 147
 148 @item skip_initial_bytes @var{integer} (@emph{input})
 149 Set number of bytes to skip before reading header and frames if set to 1.
 150 Default is 0.
 151
 152 @item correct_ts_overflow @var{integer} (@emph{input})
 153 Correct single timestamp overflows if set to 1. Default is 1.
 154
 155 @item flush_packets @var{integer} (@emph{output})
 156 Flush the underlying I/O stream after each packet. Default 1 enables it, and
 157 has the effect of reducing the latency; 0 disables it and may slightly
 158 increase performance in some cases.
 159
 160 @item output_ts_offset @var{offset} (@emph{output})
 161 Set the output time offset.
 162
 163 @var{offset} must be a time duration specification,
 164 see @ref{time duration syntax,,the Time duration section in the ffmpeg-utils(1) manual,ffmpeg-utils}.
 165
 166 The offset is added by the muxer to the output timestamps.
 167
 168 Specifying a positive offset means that the corresponding streams are
 169 delayed bt the time duration specified in @var{offset}. Default value
 170 is @code{0} (meaning that no offset is applied).
 171 @end table
 172
 173 @c man end FORMAT OPTIONS
 174
 175 @anchor{Format stream specifiers}
 176 @section Format stream specifiers
 177
 178 Format stream specifiers allow selection of one or more streams that
 179 match specific properties.
 180
 181 Possible forms of stream specifiers are:
 182 @table @option
 183 @item @var{stream_index}
 184 Matches the stream with this index.
 185
 186 @item @var{stream_type}[:@var{stream_index}]
 187 @var{stream_type} is one of following: 'v' for video, 'a' for audio,
 188 's' for subtitle, 'd' for data, and 't' for attachments. If
 189 @var{stream_index} is given, then it matches the stream number
 190 @var{stream_index} of this type. Otherwise, it matches all streams of
 191 this type.
 192
 193 @item p:@var{program_id}[:@var{stream_index}]
 194 If @var{stream_index} is given, then it matches the stream with number
 195 @var{stream_index} in the program with the id
 196 @var{program_id}. Otherwise, it matches all streams in the program.
 197
 198 @item #@var{stream_id}
 199 Matches the stream by a format-specific ID.
 200 @end table
 201
 202 The exact semantics of stream specifiers is defined by the
 203 @code{avformat_match_stream_specifier()} function declared in the
 204 @file{libavformat/avformat.h} header.
 205
 206 @ifclear config-writeonly
 207 @include demuxers.texi
 208 @end ifclear
 209 @ifclear config-readonly
 210 @include muxers.texi
 211 @end ifclear
 212 @include metadata.texi