doc/swresample.txt

   1     The official guide to swresample for confused developers.
   2    =========================================================
   3
   4 Current (simplified) Architecture:
   5 ---------------------------------
   6                         Input
   7                           v
   8        __________________/|\___________
   9       /                   |            \
  10      /    input sample format convert   v
  11     /                     | ___________/
  12     |                     |/
  13     |                     v
  14     |         ___________/|\___________              _____________
  15     |        /            |            \            |             |
  16     |   Rematrix          |          resample <---->|   Buffers   |
  17     |        \___________ | ___________/            |_____________|
  18     v                    \|/
  19 Special Converter         v
  20     v         ___________/|\___________              _____________
  21     |        /            |            \            |             |
  22     |   Rematrix          |          resample <---->|   Buffers   |
  23     |        \___________ | ___________/            |_____________|
  24     |                    \|/
  25     |                     v
  26     |                     |\___________
  27     \                     |            \
  28      \   output sample format convert   v
  29       \_________________  | ___________/
  30                          \|/
  31                           v
  32                         Output
  33
  34 Planar/Packed convertion is done when needed during sample format convertion
  35 Every step can be skipped without memcpy when its not needed.
  36 Either Resampling and Rematrixing can be performed first depending on which
  37 way its faster.
  38 The Buffers are needed for resampling due to resamplng being a process that
  39 requires future and past data, it thus also introduces inevitably a delay when
  40 used.
  41 Internally 32bit float and 16bit int is supported currently, other formats can
  42 easily be added
  43 Externally all sample formats in packed and planar configuration are supported
  44 Its also trivial to add special converters for common cases
  45 If only sample format and or packed/planar convertion is needed it
  46 is performed from input to output directly in a single pass with no intermediates.