decoders.texi 3.5 KB

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  1. @chapter Decoders
  2. @c man begin DECODERS
  3. Decoders are configured elements in FFmpeg which allow the decoding of
  4. multimedia streams.
  5. When you configure your FFmpeg build, all the supported native decoders
  6. are enabled by default. Decoders requiring an external library must be enabled
  7. manually via the corresponding @code{--enable-lib} option. You can list all
  8. available decoders using the configure option @code{--list-decoders}.
  9. You can disable all the decoders with the configure option
  10. @code{--disable-decoders} and selectively enable / disable single decoders
  11. with the options @code{--enable-decoder=@var{DECODER}} /
  12. @code{--disable-decoder=@var{DECODER}}.
  13. The option @code{-codecs} of the ff* tools will display the list of
  14. enabled decoders.
  15. @c man end DECODERS
  16. @chapter Video Decoders
  17. @c man begin VIDEO DECODERS
  18. A description of some of the currently available video decoders
  19. follows.
  20. @section rawvideo
  21. Raw video decoder.
  22. This decoder decodes rawvideo streams.
  23. @subsection Options
  24. @table @option
  25. @item top @var{top_field_first}
  26. Specify the assumed field type of the input video.
  27. @table @option
  28. @item -1
  29. the video is assumed to be progressive (default)
  30. @item 0
  31. bottom-field-first is assumed
  32. @item 1
  33. top-field-first is assumed
  34. @end table
  35. @end table
  36. @c man end VIDEO DECODERS
  37. @chapter Audio Decoders
  38. @c man begin AUDIO DECODERS
  39. @section ffwavesynth
  40. Internal wave synthetizer.
  41. This decoder generates wave patterns according to predefined sequences. Its
  42. use is purely internal and the format of the data it accepts is not publicly
  43. documented.
  44. @section libcelt
  45. libcelt decoder wrapper
  46. libcelt allows libavcodec to decode the Xiph CELT ultra-low delay audio codec.
  47. Requires the presence of the libcelt headers and library during configuration.
  48. You need to explicitly configure the build with @code{--enable-libcelt}.
  49. @section libgsm
  50. libgsm decoder wrapper
  51. libgsm allows libavcodec to decode the GSM full rate audio codec. Requires
  52. the presence of the libgsm headers and library during configuration. You need
  53. to explicitly configure the build with @code{--enable-libgsm}.
  54. This decoder supports both the ordinary GSM and the Microsoft variant.
  55. @section libilbc
  56. libilbc decoder wrapper
  57. libilbc allows libavcodec to decode the Internet Low Bitrate Codec (iLBC)
  58. audio codec. Requires the presence of the libilbc headers and library during
  59. configuration. You need to explicitly configure the build with
  60. @code{--enable-libilbc}.
  61. @subsection Options
  62. The following option is supported by the libilbc wrapper.
  63. @table @option
  64. @item enhance
  65. Enable the enhancement of the decoded audio when set to 1. The default
  66. value is 0 (disabled).
  67. @end table
  68. @section libopencore-amrnb
  69. libopencore-amrnb decoder wrapper
  70. libopencore-amrnb allows libavcodec to decode the Adaptive Multi-Rate
  71. Narrowband audio codec. Using it requires the presence of the
  72. libopencore-amrnb headers and library during configuration. You need to
  73. explicitly configure the build with @code{--enable-libopencore-amrnb}.
  74. An FFmpeg native decoder for AMR-NB exists, so users can decode AMR-NB
  75. without this library.
  76. @section libopencore-amrwb
  77. libopencore-amrwb decoder wrapper.
  78. libopencore-amrwb allows libavcodec to decode the Adaptive Multi-Rate
  79. Wideband audio codec. Using it requires the presence of the
  80. libopencore-amrwb headers and library during configuration. You need to
  81. explicitly configure the build with @code{--enable-libopencore-amrwb}.
  82. An FFmpeg native decoder for AMR-WB exists, so users can decode AMR-WB
  83. without this library.
  84. @c man end AUDIO DECODERS