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/ IRIX Base Documentation 2002 November / SGI IRIX Base Documentation 2002 November.iso / usr / share / catman / p_man / cat3dm / dmedia / dmFS1016Decode.z / dmFS1016Decode
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Text File  |  2002-10-03  |  7.1 KB  |  133 lines
  1.  
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  4. ddddmmmmFFFFSSSS1111000011116666DDDDeeeeccccooooddddeeee((((3333ddddmmmm))))                                        ddddmmmmFFFFSSSS1111000011116666DDDDeeeeccccooooddddeeee((((3333ddddmmmm))))
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  8. NNNNAAAAMMMMEEEE
  9.      dmFS1016Decode - implements the US Federal Standard 1016 4800/7200/9600
  10.      bits/s CELP (Code Excited Linear Predictive) Voice Coder.
  11.  
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  13. SSSSYYYYNNNNOOOOPPPPSSSSIIIISSSS
  14.      ####iiiinnnncccclllluuuuddddeeee <<<<ddddmmmmeeeeddddiiiiaaaa////ddddmmmmeeeeddddiiiiaaaa....hhhh>>>>
  15.      ####iiiinnnncccclllluuuuddddeeee <<<<ddddmmmmeeeeddddiiiiaaaa////ddddmmmm____ppppaaaarrrraaaammmmssss....hhhh>>>>
  16.      ####iiiinnnncccclllluuuuddddeeee <<<<ddddmmmmeeeeddddiiiiaaaa////ddddmmmm____aaaauuuuddddiiiioooouuuuttttiiiillll....hhhh>>>>
  17.  
  18.      DDDDMMMMssssttttaaaattttuuuussss ddddmmmmFFFFSSSS1111000011116666DDDDeeeeccccooooddddeeee((((DDDDMMMMFFFFSSSS1111000011116666ddddeeeeccccooooddddeeeerrrr hhhhaaaannnnddddlllleeee,,,,
  19.                           uuuunnnnssssiiiiggggnnnneeeedddd cccchhhhaaaarrrr ****iiiibbbbuuuuffff,,,, sssshhhhoooorrrrtttt ****oooobbbbuuuuffff,,,, iiiinnnntttt nnnnssssaaaammmmpppplllleeeessss))))
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  22. PPPPAAAARRRRAAAAMMMMEEEETTTTEEEERRRR
  23.      _h_a_n_d_l_e    DDDDMMMMFFFFSSSS1111000011116666ddddeeeeccccooooddddeeeerrrr structure, created by
  24.                ddddmmmmFFFFSSSS1111000011116666DDDDeeeeccccooooddddeeeerrrrCCCCrrrreeeeaaaatttteeee((((3333ddddmmmm)))), specifies the signal processing
  25.                parameters.
  26.  
  27.  
  28.      _i_b_u_f      pointer to input compressed data buffer. The data format is
  29.                unsigned char (8-bit).  This bitstream buffer must consist of a
  30.                multiple of 18 bytes.
  31.  
  32.  
  33.      _o_b_u_f      pointer to output sample data buffer.  The data format is short
  34.                (16-bit).  The samples are assumed to be two's complement.  The
  35.                sampling rate must be 8 kHz.
  36.  
  37.  
  38.      _n_s_a_m_p_l_e_s  number of sample in the output buffer to be generated.  The
  39.                value of nsamples passed to the FS1016 decode/decode routines
  40.                must always be a multiple of 240, 160, or 120 for operations of
  41.                4800, 7200, or 9600 bits/s respectively.
  42.  
  43.  
  44. RRRREEEETTTTUUUURRRRNNNNEEEEDDDD VVVVAAAALLLLUUUUEEEE
  45.      Returns DDDDMMMM____FFFFAAAAIIIILLLLUUUURRRREEEE or DDDDMMMM____SSSSUUUUCCCCCCCCEEEESSSSSSSS.
  46.  
  47.  
  48. DDDDEEEESSSSCCCCRRRRIIIIPPPPTTTTIIIIOOOONNNN
  49.      ddddmmmmFFFFSSSS1111000011116666DDDDeeeeccccooooddddeeee((((3333ddddmmmm)))) implements the Federal Standard 1016 decompression.
  50.      The uncompressed data sampling rate is 8000 Hz. The compression bitrate
  51.      and modes for decoding operation can be
  52.  
  53.      DDDDMMMM____FFFFSSSS1111000011116666____4444888800000000____BBBBIIIITTTTSSSS
  54.      DDDDMMMM____FFFFSSSS1111000011116666____7777222200000000____BBBBIIIITTTTSSSS
  55.      DDDDMMMM____FFFFSSSS1111000011116666____9999666600000000____BBBBIIIITTTTSSSS
  56.  
  57.      DDDDMMMM____FFFFSSSS1111000011116666____PPPPOOOOSSSSTTTTFFFFIIIILLLLTTTTEEEERRRRIIIINNNNGGGG____YYYYEEEESSSS
  58.      DDDDMMMM____FFFFSSSS1111000011116666____PPPPOOOOSSSSTTTTFFFFIIIILLLLTTTTEEEERRRRIIIINNNNGGGG____NNNNOOOO
  59.  
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  62.  
  63.                                                                         PPPPaaaaggggeeee 1111
  64.  
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  70. ddddmmmmFFFFSSSS1111000011116666DDDDeeeeccccooooddddeeee((((3333ddddmmmm))))                                        ddddmmmmFFFFSSSS1111000011116666DDDDeeeeccccooooddddeeee((((3333ddddmmmm))))
  71.  
  72.  
  73.  
  74.      and
  75.  
  76.      DDDDMMMM____FFFFSSSS1111000011116666____HHHHIIIIGGGGHHHHPPPPAAAASSSSSSSS____YYYYEEEESSSS
  77.      DDDDMMMM____FFFFSSSS1111000011116666____HHHHIIIIGGGGHHHHPPPPAAAASSSSSSSS____NNNNOOOO
  78.  
  79.  
  80.  
  81.      that select a decoder with or without postfiltering and highpass
  82.      filtering.  Cautious application of postfiltering at the decoder's output
  83.      is recommended.  The human ear's masking properties are exploited to
  84.      trade off speech distortion vs. quantizing noise.  In tandem coding
  85.      scenarios, only one stage of postfiltering is recommended and multiple
  86.      stages should be avoided.  The bitrate and decode mode are set by a call
  87.      to ddddmmmmFFFFSSSS1111000011116666DDDDeeeeccccooooddddeeeerrrrSSSSeeeettttPPPPaaaarrrraaaammmmssss((((3333ddddmmmm)))). Without calling
  88.      ddddmmmmFFFFSSSS1111000011116666DDDDeeeeccccooooddddeeeerrrrSSSSeeeettttPPPPaaaarrrraaaammmmssss((((3333ddddmmmm)))), decoder sets defaults to
  89.      DDDDMMMM____FFFFSSSS1111000011116666____4444888800000000____BBBBIIIITTTTSSSS, DDDDMMMM____FFFFSSSS1111000011116666____PPPPOOOOSSSSTTTTFFFFIIIILLLLTTTTEEEERRRRIIIINNNNGGGG____YYYYEEEESSSS, and
  90.      DDDDMMMM____FFFFSSSS1111000011116666____HHHHIIIIGGGGHHHHPPPPAAAASSSSSSSS____NNNNOOOO.
  91.  
  92.  
  93.      see DESCRIPTION in ddddmmmmFFFFSSSS1111000011116666EEEEnnnnccccooooddddeeee((((3333ddddmmmm)))) for the discussion of
  94.      decompression of a part of compressed bit stream beginning in the middle
  95.      of a compressed data file.
  96.  
  97.  
  98. NNNNOOOOTTTTEEEE
  99.      FS1016 algorithm was developed for sampling rate of 8 kHz.
  100.  
  101.  
  102. SSSSEEEEEEEE AAAALLLLSSSSOOOO
  103.      dmFS1016DecoderCreate(3dm), dmFS1016DecoderDestroy(3dm),
  104.      dmFS1016Encode(3dm), dmFS1016DecoderSetParams(3dm), Federal Standard
  105.      1016.
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  128.  
  129.                                                                         PPPPaaaaggggeeee 2222
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