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Text File  |  2002-10-03  |  6.2 KB  |  133 lines

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  4. ddddmmmmGGGG777722226666DDDDeeeeccccooooddddeeee((((3333ddddmmmm))))                                            ddddmmmmGGGG777722226666DDDDeeeeccccooooddddeeee((((3333ddddmmmm))))
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  8. NNNNAAAAMMMMEEEE
  9.      dmG726Decode - implements ITU (International Telecommunication Union)
  10.      Recommendation G.726 ADPCM decompression for input compressed bit stream
  11.      of 40, 32 ,24, or 16 kbit/s and output data of 64 kbit/s A-law, mu-law,
  12.      or linear PCM.  G.726 replaced G.721 and G.723.
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  15. SSSSYYYYNNNNOOOOPPPPSSSSIIIISSSS
  16.      ####iiiinnnncccclllluuuuddddeeee <<<<ddddmmmmeeeeddddiiiiaaaa////ddddmmmm____aaaauuuuddddiiiioooouuuuttttiiiillll....hhhh>>>>
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  18.      DDDDMMMMssssttttaaaattttuuuussss ddddmmmmGGGG777722226666DDDDeeeeccccooooddddeeee((((DDDDMMMMGGGG777722226666ddddeeeeccccooooddddeeeerrrr hhhhaaaannnnddddlllleeee,,,,
  19.                            uuuunnnnssssiiiiggggnnnneeeedddd cccchhhhaaaarrrr ****iiiinnnnBBBBuuuuffffffffeeeerrrr,,,,
  20.                            vvvvooooiiiidddd ****oooouuuuttttBBBBuuuuffffffffeeeerrrr,,,,
  21.                            iiiinnnntttt nnnnuuuummmmSSSSaaaammmmpppplllleeeessss))))
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  24. PPPPAAAARRRRAAAAMMMMEEEETTTTEEEERRRR
  25.      _h_a_n_d_l_e    DDDDMMMMGGGG777722226666ddddeeeeccccooooddddeeeerrrr structure, created by ddddmmmmGGGG777722226666DDDDeeeeccccooooddddeeeerrrrCCCCrrrreeeeaaaatttteeee((((3333ddddmmmm)))),
  26.                specifies the signal processing parameters.
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  29.      _i_b_u_f      pointer to input compressed data buffer, an array of bytes. The
  30.                data format is unsigned char (8-bit).  The input bitstrem
  31.                buffer consists of a multiple of 1, 3, 1, or 5 bytes, for
  32.                operations at 16, 24, 32, or 40 kbit/s respectively.
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  35.      _o_b_u_f      pointer to output sample data buffer, an array of short (16
  36.                bits) for linear output or unsigned char for A-law or mu-law
  37.                output.  For linear output, samples are assumed to be two's
  38.                complement.  Data buffer must be a multiple (the same multiple
  39.                as that of input bitstrem buffer) of 4, 8, 2, or 8 for
  40.                operations at 16, 24, 32, or 40 kbit/s respectively.  This
  41.                assumes the sampling rate of 8 kHz.
  42.  
  43.  
  44.      _n_u_m_S_a_m_p_l_e_s
  45.                number of samples to be processed. it must always be a multiple
  46.                of 4, 8, 2, or 8 for operations at 16, 24, 32, or 40 kbit/s
  47.                respectively.
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  50. RRRREEEETTTTUUUURRRRNNNNEEEEDDDD VVVVAAAALLLLUUUUEEEE
  51.      Returns DDDDMMMM____FFFFAAAAIIIILLLLUUUURRRREEEE or DDDDMMMM____SSSSUUUUCCCCCCCCEEEESSSSSSSS.
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  54. DDDDEEEESSSSCCCCRRRRIIIIPPPPTTTTIIIIOOOONNNN
  55.      ddddmmmmGGGG777722226666DDDDeeeeccccooooddddeeee((((3333ddddmmmm)))) implements the ITU G.726 decompression.  G.726
  56.      decompression decompresses 2, 3, 4, or 5 bits to generate one output
  57.      sample for 16, 24, 32, or 40 kbit/s operations respectively. 16, 24, 32,
  58.      or 40 kbit/s operation is indicated by setting parameter DDDDMMMM____AAAAUUUUDDDDIIIIOOOO____BBBBIIIITTTTRRRRAAAATTTTEEEE
  59.      to 16000, 24000, 32000, or 40000 using DMparams and passed to
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  63.                                                                         PPPPaaaaggggeeee 1111
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  70. ddddmmmmGGGG777722226666DDDDeeeeccccooooddddeeee((((3333ddddmmmm))))                                            ddddmmmmGGGG777722226666DDDDeeeeccccooooddddeeee((((3333ddddmmmm))))
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  74.      ddddmmmmGGGG777722226666DDDDeeeeccccooooddddeeeerrrrSSSSeeeettttPPPPaaaarrrraaaammmmssss((((3333ddddmmmm)))).  Output format is indicated by setting
  75.      DDDDMMMM____GGGG777722226666____NNNNAAAATTTTIIIIVVVVEEEE____FFFFOOOORRRRMMMMAAAATTTT to AAAAUUUUDDDDIIIIOOOO____EEEENNNNCCCCOOOODDDDIIIINNNNGGGG____UUUULLLLAAAAWWWW, AAAAUUUUDDDDIIIIOOOO____EEEENNNNCCCCOOOODDDDIIIINNNNGGGG____AAAALLLLAAAAWWWW, or
  76.      AAAAUUUUDDDDIIIIOOOO____EEEENNNNCCCCOOOODDDDIIIINNNNGGGG____LLLLIIIINNNNEEEEAAAARRRR, respectively for outputting mu-law, A-law, or
  77.      linear PCM data, using DMparams and passed to
  78.      ddddmmmmGGGG777722226666DDDDeeeeccccooooddddeeeerrrrSSSSeeeettttPPPPaaaarrrraaaammmmssss((((3333ddddmmmm)))).  If output mode is AAAAUUUUDDDDIIIIOOOO____EEEENNNNCCCCOOOODDDDIIIINNNNGGGG____LLLLIIIINNNNEEEEAAAARRRR,
  79.      the PCM data type will be short.  Otherwise, the PCM data type will be
  80.      unsigned char.  Therefore, obuf is void in the function prototyping.
  81.  
  82.  
  83. NNNNOOOOTTTTEEEE
  84.      G.726 algorithm was developed for sampling rate of 8 kHz, but could be
  85.      used from 8 kHz to 48 kHz.
  86.  
  87.  
  88. SSSSEEEEEEEE AAAALLLLSSSSOOOO
  89.      dmG726DecoderCreate(3dm), dmG726DecoderSetParams(3dm),
  90.      dmG726DecoderDestroy(3dm), dmG726Encode(3dm), ITU (International
  91.      Telecommunication Union) Recommendation G.726.
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  129.                                                                         PPPPaaaaggggeeee 2222
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