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documentation of similarities and (noteworthy) differencies between Unix systems git clone https://hacktivis.me/git/cross-unix-documentation.git

au.5x (2371B)

    

  1. .\" This file is part of Cross Unix Documentation
  2. .\" Copyright © 2019-2021 Haelwenn (lanodan) Monnier <contact@hacktivis.me>
  3. .\" SPDX-License-Identifier: CC-BY-4.0
  4. .Dd 2021-03-12
  5. .Dt AU 5x
  6. .Os
  7. .Sh PROLOG
  8. This manual page is part of
  9. .Lk https://hacktivis.me/git/cross-unix-documentation "Cross-Unix Documentation"
  10. which is an attempt to provide documentation of similarities and (noteworthy) differencies between Unix-like systems.
  11. To be used as an addition to the POSIX standard.
  12. .Sh NAME
  13. .Nm au
  14. .Nd AU/.snd Audio Format
  15. .Sh DESCRIPTION
  16. .Nm
  17. is a simple Audio Format that came from Sun/NeXT, it is widely supported on Unix systems.
  18. .Ss Header
  19. All fields are 32-bits (so 4 octets) unsigned big-endian integers.
  20. .Bl -tag -width Ds
  21. .It magic
  22. Always equal to 0x2E736E64 (".snd")
  23. .It header size
  24. number of octets the header contains; 24 if no further info was added
  25. .It data size
  26. number of octets the data contains; 0 or 0xFFFFFFFF for undefined
  27. .It encoding
  28. refer to codecs section
  29. .It sample rate
  30. number of samples per seconds (aka Hz). Common ones are 8000, 11025, 16000, 22050, 32000, 44100, and 48000 Hz.
  31. .It channels
  32. Number of interleaved channels. 1 for mono, 2 for stereo, ...
  33. .El
  34. .Pp
  35. You may append information after the header in multiple of 8 octets that is terminated and filled with NULL octets.
  36. Pure ASCII is the strongly suggested usage but it seen as implementation defined.
  37. .Ss Codecs
  38. .Bl -tag -width Ds
  39. .It 01
  40. 8-bit G.711 µ-law
  41. .It 02
  42. unsigned 8-bit linear PCM
  43. .It 03
  44. 16-bit linear PCM
  45. .It 04
  46. 24-bit linear PCM
  47. .It 05
  48. 32-bit linear PCM
  49. .It 06
  50. 32-bit IEEE floating point
  51. .It 07
  52. 64-bit IEEE floating point
  53. .It 23
  54. 4-bit CCITT G.721 ADPCM
  55. .It 25
  56. CCITT G.723 3-bit ADPCM
  57. .It 27
  58. 8-bit G.711 A-law
  59. .El
  60. .Pp
  61. Note: Linear PCM data is signed and zero-centered.
  62. .Sh SOURCE
  63. .Bl -bullet -compact
  64. .It
  65. .Lk https://code.9front.org/hg/plan9front/file/default/sys/src/cmd/audio/sundec 9front's /sys/src/cmd/audio/sundec
  66. .It
  67. .Lk https://wiki.multimedia.cx/index.php/Au/snd Au/snd - MultimediaWiki
  68. .It
  69. .Lk https://pubs.opengroup.org/external/auformat.html AU - Audio File Format © Sun Microsystems 1992
  70. .It
  71. .Lk http://sox.sourceforge.net/AudioFormats-11.html#ss11.2
  72. .It
  73. .Xr audio_filehdr 3 ,
  74. .Xr audio_hdr 3
  75. .It
  76. .Lk https://docs.python.org/3/library/sunau.html Python3 sunau module documentation
  77. .El
  78. .Sh AUTHORS
  79. .An Haelwenn (lanodan) Monnier Aq Mt contact+c-u-d@hacktivis.me