interpretor/libsndfile-1.0.25/src/G72x/g72x_priv.h

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  26
  27 #ifndef G72X_PRIVATE_H
  28 #define G72X_PRIVATE_H
  29
  30 #ifdef __cplusplus
  31 #error "This code is not designed to be compiled with a C++ compiler."
  32 #endif
  33
  34 /*
  35 ** The following is the definition of the state structure used by the
  36 ** G.721/G.723 encoder and decoder to preserve their internal state
  37 ** between successive calls.  The meanings of the majority of the state
  38 ** structure fields are explained in detail in the CCITT Recommendation
  39 ** G.721.  The field names are essentially identical to variable names
  40 ** in the bit level description of the coding algorithm included in this
  41 ** Recommendation.
  42 */
  43
  44 struct g72x_state
  45 {       long  yl;       /* Locked or steady state step size multiplier. */
  46         short yu;       /* Unlocked or non-steady state step size multiplier. */
  47         short dms;      /* Short term energy estimate. */
  48         short dml;      /* Long term energy estimate. */
  49         short ap;       /* Linear weighting coefficient of 'yl' and 'yu'. */
  50
  51         short a[2];     /* Coefficients of pole portion of prediction filter. */
  52         short b[6];     /* Coefficients of zero portion of prediction filter. */
  53         short pk[2];    /*
  54                                         ** Signs of previous two samples of a partially
  55                                         ** reconstructed signal.
  56                                         **/
  57         short dq[6];    /*
  58                                         ** Previous 6 samples of the quantized difference
  59                                         ** signal represented in an internal floating point
  60                                         ** format.
  61                                         **/
  62         short sr[2];    /*
  63                                         ** Previous 2 samples of the quantized difference
  64                                         ** signal represented in an internal floating point
  65                                         ** format.
  66                                         */
  67         char td;        /* delayed tone detect, new in 1988 version */
  68
  69         /*      The following struct members were added for libsndfile. The original
  70         **      code worked by calling a set of functions on a sample by sample basis
  71         **      which is slow on architectures like Intel x86. For libsndfile, this
  72         **      was changed so that the encoding and decoding routines could work on
  73         **      a block of samples at a time to reduce the function call overhead.
  74         */
  75         int             (*encoder) (int, struct g72x_state* state) ;
  76         int             (*decoder) (int, struct g72x_state* state) ;
  77
  78         int             codec_bits, blocksize, samplesperblock ;
  79 } ;
  80
  81 typedef struct g72x_state G72x_STATE ;
  82
  83 int     predictor_zero (G72x_STATE *state_ptr);
  84
  85 int     predictor_pole (G72x_STATE *state_ptr);
  86
  87 int     step_size (G72x_STATE *state_ptr);
  88
  89 int     quantize (int d, int    y, short *table, int size);
  90
  91 int     reconstruct (int sign, int dqln,        int y);
  92
  93 void update (int code_size, int y, int wi, int fi, int dq, int sr, int dqsez, G72x_STATE *state_ptr);
  94
  95 int g721_encoder        (int sample, G72x_STATE *state_ptr);
  96 int g721_decoder        (int code, G72x_STATE *state_ptr);
  97
  98 int g723_16_encoder     (int sample, G72x_STATE *state_ptr);
  99 int g723_16_decoder     (int code, G72x_STATE *state_ptr);
 100
 101 int g723_24_encoder     (int sample, G72x_STATE *state_ptr);
 102 int g723_24_decoder     (int code, G72x_STATE *state_ptr);
 103
 104 int g723_40_encoder     (int sample, G72x_STATE *state_ptr);
 105 int g723_40_decoder     (int code, G72x_STATE *state_ptr);
 106
 107 void private_init_state (G72x_STATE *state_ptr) ;
 108
 109 #endif /* G72X_PRIVATE_H */