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Text File  |  2002-10-03  |  8.1 KB  |  133 lines
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  4. ddddmmmmMMMMPPPPEEEEGGGG1111AAAAuuuuddddiiiiooooEEEEnnnnccccooooddddeeee((((3333ddddmmmm))))                                ddddmmmmMMMMPPPPEEEEGGGG1111AAAAuuuuddddiiiiooooEEEEnnnnccccooooddddeeee((((3333ddddmmmm))))
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  8. NNNNAAAAMMMMEEEE
  9.      dmMPEG1AudioEncode - Compresses a single block of audio data using MPEG1
  10.      audio compression algorithm.
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  13. SSSSYYYYNNNNOOOOPPPPSSSSIIIISSSS
  14.      ####iiiinnnncccclllluuuuddddeeee <<<<ddddmmmmeeeeddddiiiiaaaa////ddddmmmmeeeeddddiiiiaaaa....hhhh>>>>
  15.      ####iiiinnnncccclllluuuuddddeeee <<<<ddddmmmmeeeeddddiiiiaaaa////ddddmmmm____aaaauuuuddddiiiioooouuuuttttiiiillll....hhhh>>>>
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  17.      DDDDMMMMssssttttaaaattttuuuussss ddddmmmmMMMMPPPPEEEEGGGG1111AAAAuuuuddddiiiiooooEEEEnnnnccccooooddddeeee((((DDDDMMMMMMMMPPPPEEEEGGGG1111aaaauuuuddddiiiiooooeeeennnnccccooooddddeeeerrrr eeeennnnccccooooddddeeeerrrr,,,,
  18.                                          sssshhhhoooorrrrtttt ****ssssaaaammmmppppBBBBuuuuffff,,,,
  19.                                          uuuunnnnssssiiiiggggnnnneeeedddd cccchhhhaaaarrrr ****oooouuuuttttppppuuuutttt,,,,
  20.                                          iiiinnnntttt ****ffffrrrraaaammmmeeeeBBBByyyytttteeeessss))))
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  23. PPPPAAAARRRRAAAAMMMMEEEETTTTEEEERRRR
  24.      _e_n_c_o_d_e_r   DDDDMMMMMMMMPPPPEEEEGGGG1111aaaauuuuddddiiiiooooeeeennnnccccooooddddeeeerrrr structure, created by
  25.                ddddmmmmMMMMPPPPEEEEGGGG1111AAAAuuuuddddiiiiooooEEEEnnnnccccooooddddeeeerrrrCCCCrrrreeeeaaaatttteeee((((3333ddddmmmm)))), specifies and stores the signal
  26.                processing parameters.  It describes the kind of compression to
  27.                perform, and holds the between-block state of the compressor.
  28.                It is initially generated and processed by calls to
  29.                ddddmmmmMMMMPPPPEEEEGGGG1111AAAAuuuuddddiiiiooooEEEEnnnnccccooooddddeeeerrrrCCCCrrrreeeeaaaatttteeee((((3333ddddmmmm)))) and
  30.                ddddmmmmMMMMPPPPEEEEGGGG1111AAAAuuuuddddiiiiooooEEEEnnnnccccooooddddeeeerrrrSSSSeeeettttPPPPaaaarrrraaaammmmssss((((3333ddddmmmm)))), and is modified on each
  31.                call.
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  34.      _s_a_m_p_B_u_f   pointer to input sample data buffer.  The data format is short
  35.                (16-bit).  The samples are assumed to be two's complement.  The
  36.                block of audio data is understood to be
  37.                DDDDMMMM____AAAAUUUUDDDDIIIIOOOO____CCCCOOOODDDDEEEECCCC____FFFFRRRRAAAAMMMMEEEESSSS____PPPPEEEERRRR____BBBBLLLLOOOOCCCCKKKK sample frames long, where this
  38.                is a symbol, which value is returned by
  39.                ddddmmmmMMMMPPPPEEEEGGGG1111AAAAuuuuddddiiiiooooEEEEnnnnccccooooddddeeeerrrrGGGGeeeettttPPPPaaaarrrraaaammmmssss((((3333ddddmmmm)))).  For each call to
  40.                ddddmmmmMMMMPPPPEEEEGGGG1111AAAAuuuuddddiiiiooooEEEEnnnnccccooooddddeeee((((3333ddddmmmm)))), DDDDMMMM____AAAAUUUUDDDDIIIIOOOO____CCCCOOOODDDDEEEECCCC____FFFFRRRRAAAAMMMMEEEESSSS____PPPPEEEERRRR____BBBBLLLLOOOOCCCCKKKK sample
  41.                frames long data must be provided in the buffer.
  42.  
  43.  
  44.      _o_u_t_p_u_t    pointer to output data buffer, an array of bytes.  The data
  45.                format is unsigned char (8-bit).  It points to a pre-allocated
  46.                byte block into which ddddmmmmMMMMPPPPEEEEGGGG1111AAAAuuuuddddiiiiooooEEEEnnnnccccooooddddeeee((((3333ddddmmmm)))) will write the
  47.                compressed data for this block.  The block must be at least
  48.                DDDDMMMM____AAAAUUUUDDDDIIIIOOOO____CCCCOOOODDDDEEEECCCC____MMMMAAAAXXXX____BBBBYYYYTTTTEEEESSSS____PPPPEEEERRRR____BBBBLLLLOOOOCCCCKKKK bytes long, where this is
  49.                also a symbol, which value is also returned by
  50.                ddddmmmmMMMMPPPPEEEEGGGG1111AAAAuuuuddddiiiiooooEEEEnnnnccccooooddddeeeerrrrGGGGeeeettttPPPPaaaarrrraaaammmmssss((((3333ddddmmmm)))).
  51.  
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  53.      _f_r_a_m_e_B_y_t_e_s
  54.                pointer to an integer return value; indicates the actual number
  55.                of compressed bytes written into the data structure (which will
  56.                be less than or equal to DDDDMMMM____AAAAUUUUDDDDIIIIOOOO____CCCCOOOODDDDEEEECCCC____MMMMAAAAXXXX____BBBBYYYYTTTTEEEESSSS____PPPPEEEERRRR____BBBBLLLLOOOOCCCCKKKK).
  57.                It is the value returned by the function.  In the case of some
  58.                error occuring such as an unrecognized encoder structure, this
  59.                value is zero.
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  63.                                                                         PPPPaaaaggggeeee 1111
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  70. ddddmmmmMMMMPPPPEEEEGGGG1111AAAAuuuuddddiiiiooooEEEEnnnnccccooooddddeeee((((3333ddddmmmm))))                                ddddmmmmMMMMPPPPEEEEGGGG1111AAAAuuuuddddiiiiooooEEEEnnnnccccooooddddeeee((((3333ddddmmmm))))
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  74. RRRREEEETTTTUUUURRRRNNNNEEEEDDDD VVVVAAAALLLLUUUUEEEE
  75.      Returns DDDDMMMM____FFFFAAAAIIIILLLLUUUURRRREEEE or DDDDMMMM____SSSSUUUUCCCCCCCCEEEESSSSSSSS.
  76.  
  77.  
  78. DDDDEEEESSSSCCCCRRRRIIIIPPPPTTTTIIIIOOOONNNN
  79.      ddddmmmmMMMMPPPPEEEEGGGG1111AAAAuuuuddddiiiiooooEEEEnnnnccccooooddddeeee((((3333ddddmmmm)))) implements MPEG1 audio compression.
  80.  
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  82. NNNNOOOOTTTTEEEE
  83.      compression/decompression delay will be caused by filter operations that
  84.      convolve a N past input samples with a filter M-coefficient array to
  85.      create N+M-1 output samples.  The filtered signal contains more samples
  86.      than the unfiltered signal. the output signal is offset by
  87.      DDDDMMMM____AAAAUUUUDDDDIIIIOOOO____CCCCOOOODDDDEEEECCCC____FFFFIIIILLLLTTTTEEEERRRR____DDDDEEEELLLLAAAAYYYY samples from the first sample thus omits the
  88.      last DDDDMMMM____AAAAUUUUDDDDIIIIOOOO____CCCCOOOODDDDEEEECCCC____FFFFIIIILLLLTTTTEEEERRRR____DDDDEEEELLLLAAAAYYYY samples from the output file.
  89.  
  90.  
  91. SSSSEEEEEEEE AAAALLLLSSSSOOOO
  92.      dmMPEG1AudioEncoderCreate(3dm), dmMPEG1AudioEncoderSetParams(3dm),
  93.      dmMPEG1AudioEncoderGetParams(3dm), dmMPEG1AudioEncoderDestroy(3dm),
  94.      dmMPEG1AudioDecode(3dm).
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  129.                                                                         PPPPaaaaggggeeee 2222
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