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/ IRIX Base Documentation 2002 November / SGI IRIX Base Documentation 2002 November.iso / usr / share / catman / p_man / cat3dm / audiofile / afSetTrackPCMMapping.z / afSetTrackPCMMapping
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Text File  |  2002-10-03  |  5.5 KB  |  133 lines
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  4. aaaaffffSSSSeeeettttTTTTrrrraaaacccckkkkPPPPCCCCMMMMMMMMaaaappppppppiiiinnnngggg((((3333ddddmmmm))))                            aaaaffffSSSSeeeettttTTTTrrrraaaacccckkkkPPPPCCCCMMMMMMMMaaaappppppppiiiinnnngggg((((3333ddddmmmm))))
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  8. NNNNAAAAMMMMEEEE
  9.      afSetTrackPCMMapping - override the current PCM mapping values associated
  10.      with a given track in an AAAAFFFFffffiiiilllleeeehhhhaaaannnnddddlllleeee
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  12. SSSSYYYYNNNNOOOOPPPPSSSSIIIISSSS
  13.      ####iiiinnnncccclllluuuuddddeeee <<<<ddddmmmmeeeeddddiiiiaaaa////aaaauuuuddddiiiiooooffffiiiilllleeee....hhhh>>>>
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  15.      iiiinnnntttt aaaaffffSSSSeeeettttTTTTrrrraaaacccckkkkPPPPCCCCMMMMMMMMaaaappppppppiiiinnnngggg((((AAAAFFFFffffiiiilllleeeehhhhaaaannnnddddlllleeee ffffiiiilllleeee,,,, iiiinnnntttt ttttrrrraaaacccckkkk,,,,
  16.                                  ddddoooouuuubbbblllleeee ssssllllooooppppeeee,,,, ddddoooouuuubbbblllleeee iiiinnnntttteeeerrrrcccceeeepppptttt,,,,
  17.                                  ddddoooouuuubbbblllleeee mmmmiiiinnnncccclllliiiipppp,,,, ddddoooouuuubbbblllleeee mmmmaaaaxxxxcccclllliiiipppp))))
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  19. PPPPAAAARRRRAAAAMMMMEEEETTTTEEEERRRR
  20.      _f_i_l_e        is an AAAAFFFFffffiiiilllleeeehhhhaaaannnnddddlllleeee structure, previously created by a call to
  21.                  aaaaffffOOOOppppeeeennnnFFFFiiiilllleeee(3dm) or its equivalent.
  22.  
  23.      _t_r_a_c_k       is an integer which identifies an audio track in _h_a_n_d_l_e.
  24.  
  25.                  Since all currently supported file formats contain only one
  26.                  audio track, the value AAAAFFFF____DDDDEEEEFFFFAAAAUUUULLLLTTTT____TTTTRRRRAAAACCCCKKKK should always be used
  27.                  here for now.
  28.  
  29.      _s_l_o_p_e       is a double precision floating point value which specifies an
  30.                  amplitude scaling factor for the waveform to be associated
  31.                  with _t_r_a_c_k.
  32.  
  33.      _i_n_t_e_r_c_e_p_t   is a double precision floating point value indicating the
  34.                  audio waveform vertical midpoint ( zero-crossing) value for
  35.                  the audio data associated with _t_r_a_c_k
  36.  
  37.      _m_i_n_c_l_i_p     is a double precision floating point value indicating the
  38.                  minimum or most negative audio data sample value to be read.
  39.                  Any value less than this will be set to _m_i_n_c_l_i_p
  40.  
  41.      _m_a_x_c_l_i_p     is a double precision floating point value indicating the
  42.                  maximum or most positive audio data sample value to be read.
  43.                  Any value greater than this will be set to _m_a_x_c_l_i_p
  44.  
  45. DDDDEEEESSSSCCCCRRRRIIIIPPPPTTTTIIIIOOOONNNN
  46.      aaaaffffSSSSeeeettttTTTTrrrraaaacccckkkkPPPPCCCCMMMMMMMMaaaappppppppiiiinnnngggg(((()))) allows an application to override the default PCM
  47.      mapping values associated with a track.  This causes the Audio File
  48.      Library to reinterpret the sample data loaded by aaaaffffRRRReeeeaaaaddddFFFFrrrraaaammmmeeeessss(3dm)
  49.      according the the new mapping.
  50.  
  51. CCCCAAAAVVVVEEEEAAAATTTTSSSS
  52.      PCM mapping is only useful for modifying frames as they are read into or
  53.      written out from a buffer via aaaaffffRRRReeeeaaaaddddFFFFrrrraaaammmmeeeessss(3dm) or aaaaffffWWWWrrrriiiitttteeeeFFFFrrrraaaammmmeeeessss(3dm).
  54.      None of the currently supported file formats have the capability to store
  55.      this information, even though the actual mapping can and will be applied
  56.      to the frames stored in those files.  Therefor, it is important to be
  57.      careful what values you specify.  In general, all two's complement and
  58.      floating point sample formats are expected to be symmetrical about zero,
  59.      i.e., the iiiinnnntttteeeerrrrcccceeeepppptttt will be 0.0 and _m_i_n_c_l_i_p and _m_a_x_c_l_i_p will be negative
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  63.                                                                         PPPPaaaaggggeeee 1111
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  70. aaaaffffSSSSeeeettttTTTTrrrraaaacccckkkkPPPPCCCCMMMMMMMMaaaappppppppiiiinnnngggg((((3333ddddmmmm))))                            aaaaffffSSSSeeeettttTTTTrrrraaaacccckkkkPPPPCCCCMMMMMMMMaaaappppppppiiiinnnngggg((((3333ddddmmmm))))
  71.  
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  73.  
  74.      and positive N, where N is some non-zero positive value.
  75.  
  76. SSSSEEEEEEEE AAAALLLLSSSSOOOO
  77.      afInitPCMMapping(3dm), afSetVirtualPCMMapping(3dm),
  78.      afGetVirtualPCMMapping(3dm), afReadFrames(3dm)
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  129.                                                                         PPPPaaaaggggeeee 2222
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