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/ IRIX Base Documentation 2002 November / SGI IRIX Base Documentation 2002 November.iso / usr / share / catman / p_man / cat3dm / audiofile / AFgetchannels.z / AFgetchannels
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Text File  |  2002-10-03  |  5.0 KB  |  67 lines
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  4. aaaaffffGGGGeeeettttCCCChhhhaaaannnnnnnneeeellllssss((((3333ddddmmmm))))                                          aaaaffffGGGGeeeettttCCCChhhhaaaannnnnnnneeeellllssss((((3333ddddmmmm))))
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  8. NNNNAAAAMMMMEEEE
  9.      afGetChannels, afGetVirtualChannels - get the number of interleaved track
  10.      / virtual channels from an AAAAFFFFffffiiiilllleeeehhhhaaaannnnddddlllleeee structure for an audio track
  11.  
  12. SSSSYYYYNNNNOOOOPPPPSSSSIIIISSSS
  13.      ####iiiinnnncccclllluuuuddddeeee <<<<ddddmmmmeeeeddddiiiiaaaa////aaaauuuuddddiiiiooooffffiiiilllleeee....hhhh>>>>
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  15.      iiiinnnntttt aaaaffffGGGGeeeettttCCCChhhhaaaannnnnnnneeeellllssss((((AAAAFFFFffffiiiilllleeeehhhhaaaannnnddddlllleeee ffffiiiilllleeee,,,, iiiinnnntttt ttttrrrraaaacccckkkk))))
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  17.      iiiinnnntttt aaaaffffGGGGeeeettttVVVViiiirrrrttttuuuuaaaallllCCCChhhhaaaannnnnnnneeeellllssss((((AAAAFFFFffffiiiilllleeeehhhhaaaannnnddddlllleeee ffffiiiilllleeee,,,, iiiinnnntttt ttttrrrraaaacccckkkk))))
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  19. PPPPAAAARRRRAAAAMMMMEEEETTTTEEEERRRR
  20.      _f_i_l_e    is an AAAAFFFFffffiiiilllleeeehhhhaaaannnnddddlllleeee structure, previously created by a call to
  21.              aaaaffffOOOOppppeeeennnnFFFFiiiilllleeee(3dm).
  22.  
  23.      _t_r_a_c_k   is an integer which identifies the audio track in the file.
  24.              Since all currently supported file formats allow at most one
  25.              audio track per file, the constant value AAAAFFFF____DDDDEEEEFFFFAAAAUUUULLLLTTTT____TTTTRRRRAAAACCCCKKKK should
  26.              always be used for this argument.
  27.  
  28. RRRREEEETTTTUUUURRRRNNNN VVVVAAAALLLLUUUUEEEE
  29.      aaaaffffGGGGeeeettttCCCChhhhaaaannnnnnnneeeellllssss(((()))) and aaaaffffGGGGeeeettttVVVViiiirrrrttttuuuuaaaallllCCCChhhhaaaannnnnnnneeeellllssss(((()))) return a nonnegative integer
  30.      value if successful, or -1 on failure.
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  32. DDDDEEEESSSSCCCCRRRRIIIIPPPPTTTTIIIIOOOONNNN
  33.      aaaaffffGGGGeeeettttCCCChhhhaaaannnnnnnneeeellllssss(((()))) returns the number of interleaved channels in the
  34.      specified audio track in the file represented by the AAAAFFFFffffiiiilllleeeehhhhaaaannnnddddlllleeee
  35.      argument.
  36.  
  37.      For example, the audio track in a stereo AIFF-C file contains 2
  38.      interleaved channels.  The audio track in a mono AIFF-C file contains 1
  39.      channel.
  40.  
  41.      aaaaffffGGGGeeeettttVVVViiiirrrrttttuuuuaaaallllCCCChhhhaaaannnnnnnneeeellllssss(((()))) returns the number of virtual interleaved channels
  42.      in the specified audio track represented by the AAAAFFFFffffiiiilllleeeehhhhaaaannnnddddlllleeee argument, as
  43.      set by the most recent call to aaaaffffSSSSeeeettttVVVViiiirrrrttttuuuuaaaallllCCCChhhhaaaannnnnnnneeeellllssss(3dm).  The default
  44.      value is the number of channels in the _t_r_a_c_k's underlying file.  See
  45.      aaaaffffIIIInnnnttttrrrroooo(3dm) for an explanation of virtual format.
  46.  
  47. CCCCAAAAVVVVEEEEAAAATTTTSSSS
  48.      aaaaffffGGGGeeeettttCCCChhhhaaaannnnnnnneeeellllssss(((()))) may return any number of channels, even for AIFF/AIFF-C
  49.      files.  Be sure to check the number of channels of any file opened for
  50.      reading and make sure your program can handle that number.  See
  51.      aaaaffffSSSSeeeettttVVVViiiirrrrttttuuuuaaaallllCCCChhhhaaaannnnnnnneeeellllssss(3dm) for a technique for dealing with files with
  52.      unexpected numbers of channels in a simple and clean way.
  53.  
  54. SSSSEEEEEEEE AAAALLLLSSSSOOOO
  55.      aaaaffffOOOOppppeeeennnnFFFFiiiilllleeee(3dm), aaaaffffRRRReeeeaaaaddddFFFFrrrraaaammmmeeeessss(3dm), aaaaffffIIIInnnniiiittttCCCChhhhaaaannnnnnnneeeellllssss(3dm),
  56.      aaaaffffSSSSeeeettttVVVViiiirrrrttttuuuuaaaallllCCCChhhhaaaannnnnnnneeeellllssss(3dm)
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  63.                                                                         PPPPaaaaggggeeee 1111
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