logo

cross-unix-documentation

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