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/ IRIX Base Documentation 2002 November / SGI IRIX Base Documentation 2002 November.iso / usr / share / catman / p_man / cat3dm / audiofile / AFgetframecnt.z / AFgetframecnt
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Text File  |  2002-10-03  |  6.0 KB  |  133 lines
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  4. aaaaffffGGGGeeeettttFFFFrrrraaaammmmeeeeCCCCoooouuuunnnntttt((((3333ddddmmmm))))                                      aaaaffffGGGGeeeettttFFFFrrrraaaammmmeeeeCCCCoooouuuunnnntttt((((3333ddddmmmm))))
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  8. NNNNAAAAMMMMEEEE
  9.      afGetFrameCount, AFgetframecnt, afGetTrackBytes, afGetDataOffset - get
  10.      the total sample frame count / data bytes / data offset for a specified
  11.      audio track from an AAAAFFFFffffiiiilllleeeehhhhaaaannnnddddlllleeee structure
  12.  
  13. SSSSYYYYNNNNOOOOPPPPSSSSIIIISSSS
  14.      ####iiiinnnncccclllluuuuddddeeee <<<<ddddmmmmeeeeddddiiiiaaaa////aaaauuuuddddiiiiooooffffiiiilllleeee....hhhh>>>>
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  16.      AAAAFFFFffffrrrraaaammmmeeeeccccoooouuuunnnntttt aaaaffffGGGGeeeettttFFFFrrrraaaammmmeeeeCCCCoooouuuunnnntttt((((AAAAFFFFffffiiiilllleeeehhhhaaaannnnddddlllleeee ffffiiiilllleeee,,,, iiiinnnntttt ttttrrrraaaacccckkkk))))
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  18.      AAAAFFFFffffiiiilllleeeeooooffffffffsssseeeetttt aaaaffffGGGGeeeettttTTTTrrrraaaacccckkkkBBBByyyytttteeeessss((((AAAAFFFFffffiiiilllleeeehhhhaaaannnnddddlllleeee ffffiiiilllleeee,,,, iiiinnnntttt ttttrrrraaaacccckkkk))))
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  20.      iiiinnnntttt aaaaffffGGGGeeeettttDDDDaaaattttaaaaOOOOffffffffsssseeeetttt((((AAAAFFFFffffiiiilllleeeehhhhaaaannnnddddlllleeee ffffiiiilllleeee,,,, iiiinnnntttt ttttrrrraaaacccckkkk))))
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  22. PPPPAAAARRRRAAAAMMMMEEEETTTTEEEERRRR
  23.      _f_i_l_e    is an AAAAFFFFffffiiiilllleeeehhhhaaaannnnddddlllleeee structure, previously created by a call to
  24.              aaaaffffOOOOppppeeeennnnFFFFiiiilllleeee(3dm).
  25.  
  26.      _t_r_a_c_k   is an integer which identifies an audio track in _f_i_l_e.
  27.  
  28.              Since all currently supported file formats contain exactly one
  29.              audio track per file, the constant AAAAFFFF____DDDDEEEEFFFFAAAAUUUULLLLTTTT____TTTTRRRRAAAACCCCKKKK should always
  30.              be used here.
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  32. RRRREEEETTTTUUUURRRRNNNN VVVVAAAALLLLUUUUEEEE
  33.      aaaaffffGGGGeeeettttFFFFrrrraaaammmmeeeeCCCCoooouuuunnnntttt(((()))) returns the total number of sample frames in _t_r_a_c_k.
  34.      aaaaffffGGGGeeeettttTTTTrrrraaaacccckkkkBBBByyyytttteeeessss(((()))) returns the total number of bytes of audio data in
  35.      _t_r_a_c_k.  aaaaffffGGGGeeeettttDDDDaaaattttaaaaOOOOffffffffsssseeeetttt(((()))) returns the offset in bytes to the beginning of
  36.      the audio data in _t_r_a_c_k.
  37.  
  38.      In case of error, -1 is returned by all of these routines.
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  40. DDDDEEEESSSSCCCCRRRRIIIIPPPPTTTTIIIIOOOONNNN
  41.      aaaaffffGGGGeeeettttFFFFrrrraaaammmmeeeeCCCCoooouuuunnnntttt(3dm) returns the current total number of sample frames in
  42.      an audio track in the file represented by the AAAAFFFFffffiiiilllleeeehhhhaaaannnnddddlllleeee argument.
  43.  
  44.      In general, each sample frame in a given track consists of n samples,
  45.      where n is the value returned by aaaaffffGGGGeeeettttCCCChhhhaaaannnnnnnneeeellllssss(3dm) for track.  For
  46.      monaural data, a sample frame consists of a single audio sample.  For
  47.      stereo data, a sample frame consists of a <left, right> stereo sample
  48.      pair.
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  50.      aaaaffffGGGGeeeettttTTTTrrrraaaacccckkkkBBBByyyytttteeeessss(((()))) returns the total number of bytes of raw audio data
  51.      (i.e., prior to decompression) in _t_r_a_c_k.  This is useful for determining
  52.      raw file seek points, etc.
  53.  
  54.      The return types AAAAFFFFffffrrrraaaammmmeeeeccccoooouuuunnnntttt and AAAAFFFFffffiiiilllleeeeooooffffffffsssseeeetttt are large enough to hold
  55.      the maximum possible frame count value  and maximum possible byte size,
  56.      respectively, for the current file system.
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  63.                                                                         PPPPaaaaggggeeee 1111
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  70. aaaaffffGGGGeeeettttFFFFrrrraaaammmmeeeeCCCCoooouuuunnnntttt((((3333ddddmmmm))))                                      aaaaffffGGGGeeeettttFFFFrrrraaaammmmeeeeCCCCoooouuuunnnntttt((((3333ddddmmmm))))
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  74. CCCCAAAAVVVVEEEEAAAATTTTSSSS
  75.      This routine may not function correctly if the user changes the file
  76.      position on the file descriptor for the AFfilehandle being manipulated.
  77.      See the section _C_A_V_E_A_T_S _F_O_R _U_S_I_N_G _T_H_E _H_A_N_D_L_E'_S _F_I_L_E _D_E_S_C_R_I_P_T_O_R in
  78.      aaaaffffIIIInnnnttttrrrroooo(3dm) for some important information about how to deal with this
  79.      situation.
  80.  
  81. SSSSEEEEEEEE AAAALLLLSSSSOOOO
  82.      afOpenFile(3dm), afWriteFrames(3dm), afReadFrames(3dm),
  83.      afGetChannels(3dm).  afGetVirtualChannels(3dm), afSetVirtualChannels(3dm)
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  129.                                                                         PPPPaaaaggggeeee 2222
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