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/ IRIX Base Documentation 2002 November / SGI IRIX Base Documentation 2002 November.iso / usr / share / catman / p_man / cat3dm / audiofile / AFseekframe.z / AFseekframe
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Text File  |  2002-10-03  |  5.3 KB  |  133 lines
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  4. aaaaffffSSSSeeeeeeeekkkkFFFFrrrraaaammmmeeee((((3333ddddmmmm))))                                              aaaaffffSSSSeeeeeeeekkkkFFFFrrrraaaammmmeeee((((3333ddddmmmm))))
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  8. NNNNAAAAMMMMEEEE
  9.      afSeekFrame, afTellFrame - move logical file read pointer for a specified
  10.      audio track to a desired sample frame location / retrieve current value
  11.      of file read or write pointer.
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  13. SSSSYYYYNNNNOOOOPPPPSSSSIIIISSSS
  14.      ####iiiinnnncccclllluuuuddddeeee <<<<ddddmmmmeeeeddddiiiiaaaa////aaaauuuuddddiiiiooooffffiiiilllleeee....hhhh>>>>
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  16.      AAAAFFFFffffrrrraaaammmmeeeeccccoooouuuunnnntttt aaaaffffSSSSeeeeeeeekkkkFFFFrrrraaaammmmeeee((((ccccoooonnnnsssstttt AAAAFFFFffffiiiilllleeeehhhhaaaannnnddddlllleeee ffffiiiilllleeee,,,, iiiinnnntttt ttttrrrraaaacccckkkk,,,,
  17.                               AAAAFFFFffffrrrraaaammmmeeeeccccoooouuuunnnntttt ffffrrrraaaammmmeeeeooooffffffffsssseeeetttt))))
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  19.      AAAAFFFFffffrrrraaaammmmeeeeccccoooouuuunnnntttt aaaaffffTTTTeeeellllllllFFFFrrrraaaammmmeeee((((ccccoooonnnnsssstttt AAAAFFFFffffiiiilllleeeehhhhaaaannnnddddlllleeee ffffiiiilllleeee,,,, iiiinnnntttt ttttrrrraaaacccckkkk))))
  20.  
  21. PPPPAAAARRRRAAAAMMMMEEEETTTTEEEERRRR
  22.      _f_i_l_e     is an AAAAFFFFffffiiiilllleeeehhhhaaaannnnddddlllleeee structure, previously returned by
  23.               aaaaffffOOOOppppeeeennnnFFFFiiiilllleeee(3dm), aaaaffffOOOOppppeeeennnnFFFFDDDD(3dm), or aaaaffffOOOOppppeeeennnnNNNNaaaammmmeeeeddddFFFFDDDD(3dm).
  24.  
  25.      _t_r_a_c_k    is an integer which identifies an audio track within a file
  26.               which is open for read access.
  27.  
  28.               Since all currently supported file formats contain one audio
  29.               track per file, the constant value AAAAFFFF____DDDDEEEEFFFFAAAAUUUULLLLTTTT____TTTTRRRRAAAACCCCKKKK should
  30.               always be used here for now.
  31.  
  32.      _f_r_a_m_e_o_f_f_s_e_t
  33.               is a sample frame location of type AFframecount with a value
  34.               between 0 and the total number of sample frames in the _t_r_a_c_k
  35.               minus one.  If frameoffset is set to -1, aaaaffffSSSSeeeeeeeekkkkFFFFrrrraaaammmmeeee(((()))) will
  36.               return the current location in the file.
  37.  
  38. RRRREEEETTTTUUUURRRRNNNN VVVVAAAALLLLUUUUEEEE
  39.      On successful completion, aaaaffffSSSSeeeeeeeekkkkFFFFrrrraaaammmmeeee(((()))) returns the new file pointer
  40.      location measured in sample frames from the beginning of the audio track.
  41.      aaaaffffTTTTeeeellllllllFFFFrrrraaaammmmeeee(((()))) returns the current pointer location.  On an error, a
  42.      negative value is returned.  The return type AFframecount is large enough
  43.      to hold the maximum possible frame offset.
  44.  
  45. DDDDEEEESSSSCCCCRRRRIIIIPPPPTTTTIIIIOOOONNNN
  46.      aaaaffffSSSSeeeeeeeekkkkFFFFrrrraaaammmmeeee(((()))) repositions the logical audio sample read pointer to _o_f_f_s_e_t
  47.      sample frames from the beginning of the _t_r_a_c_k. A call to
  48.      aaaaffffRRRReeeeaaaaddddFFFFrrrraaaammmmeeeessss(3dm) following a call aaaaffffSSSSeeeeeeeekkkkFFFFrrrraaaammmmeeee(((()))) will return sample data
  49.      beginning at the updated file pointer location.  aaaaffffTTTTeeeellllllllFFFFrrrraaaammmmeeee(((()))) is used to
  50.      query the current value, and functions identically to the call
  51.      afSeekFrame(_f_i_l_e, _A_F__D_E_F_A_U_L_T__T_R_A_C_K, -_1);
  52.  
  53. EEEEXXXXAAAAMMMMPPPPLLLLEEEE
  54.      To seek to the 10000th <left, right> sample pair in a stereo AIFF-C file,
  55.      call aaaaffffSSSSeeeeeeeekkkkFFFFrrrraaaammmmeeee(((()))) with _o_f_f_s_e_t set to 10000.
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  63.                                                                         PPPPaaaaggggeeee 1111
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  70. aaaaffffSSSSeeeeeeeekkkkFFFFrrrraaaammmmeeee((((3333ddddmmmm))))                                              aaaaffffSSSSeeeeeeeekkkkFFFFrrrraaaammmmeeee((((3333ddddmmmm))))
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  74. SEE ALSO
  75.      afOpenFile(3dm), afReadFrames(3dm), afSaveFilePosition(3dm)
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  129.                                                                         PPPPaaaaggggeeee 2222
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