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/ IRIX Base Documentation 2001 May / SGI IRIX Base Documentation 2001 May.iso / usr / share / catman / p_man / cat3dm / audiofile / afGetFrameSize.z / afGetFrameSize
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Text File  |  1998-10-20  |  5.9 KB  |  133 lines
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  4. aaaaffffGGGGeeeettttFFFFrrrraaaammmmeeeeSSSSiiiizzzzeeee((((3333ddddmmmm))))                                        aaaaffffGGGGeeeettttFFFFrrrraaaammmmeeeeSSSSiiiizzzzeeee((((3333ddddmmmm))))
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  8. NNNNAAAAMMMMEEEE
  9.      afGetFrameSize, afGetVirtualFrameSize - get the track / virtual frame
  10.      size in bytes for a specified audio track from an AAAAFFFFffffiiiilllleeeehhhhaaaannnnddddlllleeee structure
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  12. SSSSYYYYNNNNOOOOPPPPSSSSIIIISSSS
  13.      ####iiiinnnncccclllluuuuddddeeee <<<<ddddmmmmeeeeddddiiiiaaaa////aaaauuuuddddiiiiooooffffiiiilllleeee....hhhh>>>>
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  15.      iiiinnnntttt aaaaffffGGGGeeeettttFFFFrrrraaaammmmeeeeSSSSiiiizzzzeeee((((AAAAFFFFffffiiiilllleeeehhhhaaaannnnddddlllleeee ffffiiiilllleeee,,,, iiiinnnntttt ttttrrrraaaacccckkkk,,,, iiiinnnntttt eeeexxxxtttteeeennnndddd3333ttttoooo4444))))
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  17.      iiiinnnntttt aaaaffffGGGGeeeettttVVVViiiirrrrttttuuuuaaaallllFFFFrrrraaaammmmeeeeSSSSiiiizzzzeeee((((AAAAFFFFffffiiiilllleeeehhhhaaaannnnddddlllleeee ffffiiiilllleeee,,,, iiiinnnntttt ttttrrrraaaacccckkkk,,,, iiiinnnntttt eeeexxxxtttteeeennnndddd3333ttttoooo4444))))
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  19. PPPPAAAARRRRAAAAMMMMEEEETTTTEEEERRRR
  20.      _f_i_l_e         is an AAAAFFFFffffiiiilllleeeehhhhaaaannnnddddlllleeee structure, previously created by a call
  21.                   to aaaaffffOOOOppppeeeennnnFFFFiiiilllleeee(3dm).
  22.  
  23.      _t_r_a_c_k        is an integer which identifies an audio track in _f_i_l_e.
  24.  
  25.      _e_x_t_e_n_d_3_t_o_4   is a integer boolean value (i.e., 0 or 1) indicating whether
  26.                   the routine should extend the value of the frame size for
  27.                   24-bit uncompressed data out to 32 bits.
  28.  
  29.                   Since all currently supported file formats contain exactly
  30.                   one audio track per file, the constant AAAAFFFF____DDDDEEEEFFFFAAAAUUUULLLLTTTT____TTTTRRRRAAAACCCCKKKK
  31.                   should always be used here for now.
  32.  
  33. RRRREEEETTTTUUUURRRRNNNN VVVVAAAALLLLUUUUEEEE
  34.      aaaaffffGGGGeeeettttFFFFrrrraaaammmmeeeeSSSSiiiizzzzeeee(((()))) returns the size in bytes of a sample frame in the file
  35.      referenced by _t_r_a_c_k.  aaaaffffGGGGeeeettttVVVViiiirrrrttttuuuuaaaallllFFFFrrrraaaammmmeeeeSSSSiiiizzzzeeee(((()))) returns size in bytes of a
  36.      sample frame in the audio buffer as specified by the current virtual
  37.      format.  See aaaaffffIIIInnnnttttrrrroooo(3dm) for an explanation of virtual format.
  38.  
  39.      In case of error, -1 is returned.
  40.  
  41. DDDDEEEESSSSCCCCRRRRIIIIPPPPTTTTIIIIOOOONNNN
  42.      aaaaffffGGGGeeeettttFFFFrrrraaaammmmeeeeSSSSiiiizzzzeeee(((()))) returns the size of a sample frame in an audio track in
  43.      the file represented by the AAAAFFFFffffiiiilllleeeehhhhaaaannnnddddlllleeee argument.
  44.  
  45.      aaaaffffGGGGeeeettttVVVViiiirrrrttttuuuuaaaallllFFFFrrrraaaammmmeeeeSSSSiiiizzzzeeee(((()))) does the same for the virtual format for the
  46.      given _t_r_a_c_k, as set by any combination of calls to
  47.      aaaaffffSSSSeeeettttVVVViiiirrrrttttuuuuaaaallllSSSSaaaammmmpppplllleeeeFFFFoooorrrrmmmmaaaatttt(3dm) and aaaaffffSSSSeeeettttVVVViiiirrrrttttuuuuaaaallllCCCChhhhaaaannnnnnnneeeellllssss(3dm).
  48.  
  49.      For monaural data, a sample frame consists of a single audio sample.  For
  50.      stereo data, a sample frame consists of a <left, right> stereo sample
  51.      pair.
  52.  
  53.      The _e_x_t_e_n_d_3_t_o_4 allows the application to choose, in the case where 24-bit
  54.      uncompressed data is present in the file associated with _t_r_a_c_k, whether
  55.      to return the actual size in bytes of a frame of data in that track (3 *
  56.      number_of_channels) or the size of the frames which will be presented to
  57.      the user (since this will _a_l_w_a_y_s be 4-byte sign-extended integer).  The
  58.      former is useful for informational purposes, but the latter is necessary
  59.      for determining the size of the audio buffer to be handed to
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  63.                                                                         PPPPaaaaggggeeee 1111
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  70. aaaaffffGGGGeeeettttFFFFrrrraaaammmmeeeeSSSSiiiizzzzeeee((((3333ddddmmmm))))                                        aaaaffffGGGGeeeettttFFFFrrrraaaammmmeeeeSSSSiiiizzzzeeee((((3333ddddmmmm))))
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  73.  
  74.      aaaaffffRRRReeeeaaaaddddFFFFrrrraaaammmmeeeessss(3dm).  Note that _e_x_t_e_n_d_3_t_o_4 only applies to 24-bit sample
  75.      width.  It is ignored in all other cases.
  76.  
  77. SSSSEEEEEEEE AAAALLLLSSSSOOOO
  78.      afWriteFrames(3dm), afReadFrames(3dm), afGetChannels(3dm),
  79.      afGetVirtualChannels(3dm), afSetVirtualSampleFormat(3dm)
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  129.                                                                         PPPPaaaaggggeeee 2222
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