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  1. @chapter Format Options
  2. @c man begin FORMAT OPTIONS
  3. The libavformat library provides some generic global options, which
  4. can be set on all the muxers and demuxers. In addition each muxer or
  5. demuxer may support so-called private options, which are specific for
  6. that component.
  7. Options may be set by specifying -@var{option} @var{value} in the
  8. FFmpeg tools, or by setting the value explicitly in the
  9. @code{AVFormatContext} options or using the @file{libavutil/opt.h} API
  10. for programmatic use.
  11. The list of supported options follows:
  12. @table @option
  13. @item avioflags @var{flags} (@emph{input/output})
  14. Possible values:
  15. @table @samp
  16. @item direct
  17. Reduce buffering.
  18. @end table
  19. @item probesize @var{integer} (@emph{input})
  20. Set probing size in bytes, i.e. the size of the data to analyze to get
  21. stream information. A higher value will allow to detect more
  22. information in case it is dispersed into the stream, but will increase
  23. latency. Must be an integer not lesser than 32. It is 5000000 by default.
  24. @item packetsize @var{integer} (@emph{output})
  25. Set packet size.
  26. @item fflags @var{flags} (@emph{input/output})
  27. Set format flags.
  28. Possible values:
  29. @table @samp
  30. @item ignidx
  31. Ignore index.
  32. @item genpts
  33. Generate PTS.
  34. @item nofillin
  35. Do not fill in missing values that can be exactly calculated.
  36. @item noparse
  37. Disable AVParsers, this needs @code{+nofillin} too.
  38. @item igndts
  39. Ignore DTS.
  40. @item discardcorrupt
  41. Discard corrupted frames.
  42. @item sortdts
  43. Try to interleave output packets by DTS.
  44. @item keepside
  45. Do not merge side data.
  46. @item latm
  47. Enable RTP MP4A-LATM payload.
  48. @item nobuffer
  49. Reduce the latency introduced by optional buffering
  50. @end table
  51. @item analyzeduration @var{integer} (@emph{input})
  52. Specify how many microseconds are analyzed to probe the input. A
  53. higher value will allow to detect more accurate information, but will
  54. increase latency. It defaults to 5,000,000 microseconds = 5 seconds.
  55. @item cryptokey @var{hexadecimal string} (@emph{input})
  56. Set decryption key.
  57. @item indexmem @var{integer} (@emph{input})
  58. Set max memory used for timestamp index (per stream).
  59. @item rtbufsize @var{integer} (@emph{input})
  60. Set max memory used for buffering real-time frames.
  61. @item fdebug @var{flags} (@emph{input/output})
  62. Print specific debug info.
  63. Possible values:
  64. @table @samp
  65. @item ts
  66. @end table
  67. @item max_delay @var{integer} (@emph{input/output})
  68. Set maximum muxing or demuxing delay in microseconds.
  69. @item fpsprobesize @var{integer} (@emph{input})
  70. Set number of frames used to probe fps.
  71. @item audio_preload @var{integer} (@emph{output})
  72. Set microseconds by which audio packets should be interleaved earlier.
  73. @item chunk_duration @var{integer} (@emph{output})
  74. Set microseconds for each chunk.
  75. @item chunk_size @var{integer} (@emph{output})
  76. Set size in bytes for each chunk.
  77. @item err_detect, f_err_detect @var{flags} (@emph{input})
  78. Set error detection flags. @code{f_err_detect} is deprecated and
  79. should be used only via the @command{ffmpeg} tool.
  80. Possible values:
  81. @table @samp
  82. @item crccheck
  83. Verify embedded CRCs.
  84. @item bitstream
  85. Detect bitstream specification deviations.
  86. @item buffer
  87. Detect improper bitstream length.
  88. @item explode
  89. Abort decoding on minor error detection.
  90. @item careful
  91. Consider things that violate the spec and have not been seen in the
  92. wild as errors.
  93. @item compliant
  94. Consider all spec non compliancies as errors.
  95. @item aggressive
  96. Consider things that a sane encoder should not do as an error.
  97. @end table
  98. @item use_wallclock_as_timestamps @var{integer} (@emph{input})
  99. Use wallclock as timestamps.
  100. @item avoid_negative_ts @var{integer} (@emph{output})
  101. Shift timestamps to make them positive. A value of 1 enables shifting,
  102. a value of 0 disables it, the default value of -1 enables shifting
  103. when required by the target format.
  104. When shifting is enabled, all output timestamps are shifted by the
  105. same amount. Audio, video, and subtitles desynching and relative
  106. timestamp differences are preserved compared to how they would have
  107. been without shifting.
  108. Also note that this affects only leading negative timestamps, and not
  109. non-monotonic negative timestamps.
  110. @item flush_packets @var{integer} (@emph{output})
  111. Flush the underlying I/O stream after each packet. Default 1 enables it, and
  112. has the effect of reducing the latency; 0 disables it and may slightly
  113. increase performance in some cases.
  114. @end table
  115. @c man end FORMAT OPTIONS
  116. @include demuxers.texi
  117. @include muxers.texi
  118. @include metadata.texi