ld8k.h

这是G.723和G.729的音频编解码的源代码

/* Version 2.0    Last modified: 6/30/95 */

/*--------------------------------------------------------------*
 * LD8K.H                                                       *
 * ~~~~~~                                                       *
 * Function prototypes and constants use in the ITU 8kb/s coder.*
 *                                                              *
 *--------------------------------------------------------------*/

/*--------------------------------------------------------------------------*
 *       Codec constant parameters (coder, decoder, and postfilter)         *
 *--------------------------------------------------------------------------*/

#define  L_TOTAL      240     /* Total size of speech buffer.               */
#define  L_WINDOW     240     /* Window size in LP analysis.                */
#define  L_NEXT       40      /* Lookahead in LP analysis.                  */
#define  L_FRAME      80      /* Frame size.                                */
#define  L_SUBFR      40      /* Subframe size.                             */
#define  M            10      /* Order of LP filter.                        */
#define  MP1          (M+1)   /* Order of LP filter + 1                     */
#define  MM1          (M-1)   /* Order of LP filter - 1                     */
#define  PIT_MIN      20      /* Minimum pitch lag.                         */
#define  PIT_MAX      143     /* Maximum pitch lag.                         */
#define  L_INTERPOL   (10+1)  /* Length of filter for interpolation.        */

#define  PRM_SIZE     11      /* Size of vector of analysis parameters.     */
#define  SERIAL_SIZE  (80+2)  /* Bits per frame + bfi+ number of speech bits*/

#define SHARPMAX  13017   /* Maximum value of pitch sharpening     0.8  Q14 */
#define SHARPMIN  3277    /* Minimum value of pitch sharpening     0.2  Q14 */

#define L_SUBFRP1 (L_SUBFR + 1)

/*-------------------------------*
 * Mathematic functions.         *
 *-------------------------------*/

Word32 Inv_sqrt(   /* (o) Q30 : output value   (range: 0<=val<1)           */
  Word32 L_x       /* (i) Q0  : input value    (range: 0<=val<=7fffffff)   */
);

void Log2(
  Word32 L_x,       /* (i) Q0 : input value                                 */
  Word16 *exponent, /* (o) Q0 : Integer part of Log2.   (range: 0<=val<=30) */
  Word16 *fraction  /* (o) Q15: Fractionnal part of Log2. (range: 0<=val<1) */
);

Word32 Pow2(        /* (o) Q0  : result       (range: 0<=val<=0x7fffffff) */
  Word16 exponent,  /* (i) Q0  : Integer part.      (range: 0<=val<=30)   */
  Word16 fraction   /* (i) Q15 : Fractionnal part.  (range: 0.0<=val<1.0) */
);

/*-------------------------------*
 * Pre and post-process.         *
 *-------------------------------*/

void Init_Pre_Process(void);
void Init_Post_Process(void);

void Pre_Process(
  Word16 signal[],   /* Input/output signal */
  Word16 lg          /* Length of signal    */
);

void Post_Process(
 Word16 signal[],   /* Input/output signal */
 Word16 lg          /* Length of signal    */
);

/*----------------------------------*
 * Main coder and decoder functions *
 *----------------------------------*/

void Init_Coder_ld8k(void);

void Coder_ld8k(
 Word16 ana[],      /* output  : Analysis parameters */
 Word16 synth[]     /* output  : Local synthesis     */
);

void Init_Decod_ld8k(void);

void Decod_ld8k(
  Word16  parm[],      /* (i)   : vector of synthesis parameters
                                  parm[0] = bad frame indicator (bfi)  */
  Word16  voicing,     /* (i)   : voicing decision from previous frame */
  Word16  synth[],     /* (o)   : synthesis speech                     */
  Word16  A_t[],       /* (o)   : decoded LP filter in 2 subframes     */
  Word16  *T0_first    /* (o)   : decoded pitch lag in first subframe  */
);

/*-------------------------------*
 * LPC analysis and filtering.   *
 *-------------------------------*/

void Autocorr(
  Word16 x[],      /* (i)    : Input signal                      */
  Word16 m,        /* (i)    : LPC order                         */
  Word16 r_h[],    /* (o)    : Autocorrelations  (msb)           */
  Word16 r_l[]     /* (o)    : Autocorrelations  (lsb)           */
);

void Lag_window(
  Word16 m,         /* (i)     : LPC order                        */
  Word16 r_h[],     /* (i/o)   : Autocorrelations  (msb)          */
  Word16 r_l[]      /* (i/o)   : Autocorrelations  (lsb)          */
);

void Levinson(
  Word16 Rh[],      /* (i)     : Rh[m+1] Vector of autocorrelations (msb) */
  Word16 Rl[],      /* (i)     : Rl[m+1] Vector of autocorrelations (lsb) */
  Word16 A[],       /* (o) Q12 : A[m]    LPC coefficients  (m = 10)       */
  Word16 rc[]       /* (o) Q15 : rc[M]   Relection coefficients.          */
);

void Az_lsp(
  Word16 a[],        /* (i) Q12 : predictor coefficients              */
  Word16 lsp[],      /* (o) Q15 : line spectral pairs                 */
  Word16 old_lsp[]   /* (i)     : old lsp[] (in case not found 10 roots) */
);

void Lsp_Az(
  Word16 lsp[],    /* (i) Q15 : line spectral frequencies            */
  Word16 a[]       /* (o) Q12 : predictor coefficients (order = 10)  */
);

void Lsf_lsp(
  Word16 lsf[],    /* (i) Q15 : lsf[m] normalized (range: 0.0<=val<=0.5) */
  Word16 lsp[],    /* (o) Q15 : lsp[m] (range: -1<=val<1)                */
  Word16 m         /* (i)     : LPC order                                */
);

void Lsp_lsf(
  Word16 lsp[],    /* (i) Q15 : lsp[m] (range: -1<=val<1)                */
  Word16 lsf[],    /* (o) Q15 : lsf[m] normalized (range: 0.0<=val<=0.5) */
  Word16 m         /* (i)     : LPC order                                */
);

void Int_lpc(
 Word16 lsp_old[], /* input : LSP vector of past frame              */
 Word16 lsp_new[], /* input : LSP vector of present frame           */
 Word16 lsf_int[], /* output: interpolated lsf coefficients         */
 Word16 lsf_new[], /* output: new lsf coefficients                  */
 Word16 Az[]       /* output: interpolated Az() for the 2 subframes */
);

void Int_qlpc(
 Word16 lsp_old[], /* input : LSP vector of past frame              */
 Word16 lsp_new[], /* input : LSP vector of present frame           */
 Word16 Az[]       /* output: interpolated Az() for the 2 subframes */
);

void Reorder_lsf(
  Word16 *lsf,       /* (i/o) Q15 : vector of LSFs   (range: 0<=val<=0.5) */
  Word16 min_dist,   /* (i)       : minimum required distance             */
  Word16 n           /* (i)       : LPC order                             */
);

/*--------------------------------------------------------------------------*
 *       PWF constant parameters                                            *
 *--------------------------------------------------------------------------*/

#define A1           4567   /*  2.23   in Q11   */
#define L_B1      3271557L  /*  0.78   in Q22   */
#define A2          11776   /*  5.75   in Q11   */
#define L_B2     16357786L  /*  3.90   in Q22   */
#define A3          27443   /* 13.40   in Q11   */
#define L_B3     46808433L  /* 11.16   in Q22   */
#define SEG1         1299   /*  0.6341 in Q11   */
#define SEG2         1815   /*  0.8864 in Q11   */
#define SEG3         1944   /*  0.9490 in Q11   */

#define THRESH_L1   -3562   /* -1.74   in Q11   */
#define THRESH_L2   -3116   /* -1.52   in Q11   */
#define THRESH_H1    1336   /*  0.65   in Q11   */
#define THRESH_H2     890   /*  0.43   in Q11   */

#define GAMMA1_0    32113   /*  0.98   in Q15   */
#define GAMMA1_1    30802   /*  0.94   in Q15   */
#define GAMMA2_0_L  13107   /*  0.40   in Q15   */
#define GAMMA2_0_H  22938   /*  0.70   in Q15   */
#define GAMMA2_1    19661   /*  0.60   in Q15   */

#define ALPHA       19302   /*  6*pi   in Q10   */
#define BETA         1024   /*     1   in Q10   */


void perc_var (Word16 *gamma1, /* Bandwidth expansion parameter */
   Word16 *gamma2, /* Bandwidth expansion parameter */
   Word16 *lsfint, /* Interpolated LSP vector : 1st subframe */
   Word16 *lsfnew, /* New LSP vector : 2nd subframe */
   Word16 *r_c     /* Reflection coefficients */
   );


void Weight_Az(
  Word16 a[],      /* (i) Q12 : a[m+1]  LPC coefficients             */
  Word16 gamma,    /* (i) Q15 : Spectral expansion factor.           */
  Word16 m,        /* (i)     : LPC order.                           */
  Word16 ap[]      /* (o) Q12 : Spectral expanded LPC coefficients   */
);

void Residu(
  Word16 a[],    /* (i) Q12 : prediction coefficients                     */
  Word16 x[],    /* (i)     : speech (values x[-m..-1] are needed (m=10)  */
  Word16 y[],    /* (o)     : residual signal                             */
  Word16 lg      /* (i)     : size of filtering                           */
);

void Syn_filt(
  Word16 a[],     /* (i) Q12 : a[m+1] prediction coefficients   (m=10)  */
  Word16 x[],     /* (i)     : input signal                             */
  Word16 y[],     /* (o)     : output signal                            */
  Word16 lg,      /* (i)     : size of filtering                        */
  Word16 mem[],   /* (i/o)   : memory associated with this filtering.   */
  Word16 update   /* (i)     : 0=no update, 1=update of memory.         */
);

void Convolve(
  Word16 x[],      /* (i)     : input vector                           */
  Word16 h[],      /* (i) Q12 : impulse response                       */
  Word16 y[],      /* (o)     : output vector                          */
  Word16 L         /* (i)     : vector size                            */
);

/*--------------------------------------------------------------------------*
 *       LTP constant parameters                                            *
 *--------------------------------------------------------------------------*/

#define THRESHOLDPIT 27853 /* Threshold to favor small pitch = 0.85 in Q15 */
 /* L_inter = Length for fractionnal interpolation = nb.coeff/2 */

#define UP_SAMP      3
#define L_INTER4     4
#define FIR_SIZE_ANA     (UP_SAMP*L_INTER4+1)
#define L_INTER10   10
#define FIR_SIZE_SYN    (UP_SAMP*L_INTER10+1)


/*-----------------------*
 * Pitch functions.      *
 *-----------------------*/

Word16 Pitch_ol(       /* output: open loop pitch lag                        */
   Word16 signal[],    /* input : signal used to compute the open loop pitch */
                       /*     signal[-pit_max] to signal[-1] should be known */
   Word16   pit_min,   /* input : minimum pitch lag                          */
   Word16   pit_max,   /* input : maximum pitch lag                          */
   Word16   L_frame    /* input : length of frame to compute pitch           */
);

Word16 Pitch_fr3(    /* (o)     : pitch period.                          */
  Word16 exc[],      /* (i)     : excitation buffer                      */
  Word16 xn[],       /* (i)     : target vector                          */
  Word16 h[],        /* (i) Q12 : impulse response of filters.           */
  Word16 L_subfr,    /* (i)     : Length of subframe                     */
  Word16 t0_min,     /* (i)     : minimum value in the searched range.   */
  Word16 t0_max,     /* (i)     : maximum value in the searched range.   */
  Word16 i_subfr,    /* (i)     : indicator for first subframe.          */
  Word16 *pit_frac   /* (o)     : chosen fraction.                       */
);

Word16 G_pitch(      /* (o) Q14 : Gain of pitch lag saturated to 1.2       */
  Word16 xn[],       /* (i)     : Pitch target.                            */
  Word16 y1[],       /* (i)     : Filtered adaptive codebook.              */
  Word16 g_coeff[],  /* (i)     : Correlations need for gain quantization. */
  Word16 L_subfr     /* (i)     : Length of subframe.                      */
);

Word16 Enc_lag3(     /* output: Return index of encoding */
  Word16 T0,         /* input : Pitch delay              */
  Word16 T0_frac,    /* input : Fractional pitch delay   */
  Word16 *T0_min,    /* in/out: Minimum search delay     */
  Word16 *T0_max,    /* in/out: Maximum search delay     */
  Word16 pit_min,    /* input : Minimum pitch delay      */
  Word16 pit_max,    /* input : Maximum pitch delay      */
  Word16 pit_flag    /* input : Flag for 1st subframe    */
);

void Dec_lag3(        /* output: return integer pitch lag       */
  Word16 index,       /* input : received pitch index           */
  Word16 pit_min,     /* input : minimum pitch lag              */
  Word16 pit_max,     /* input : maximum pitch lag              */
  Word16 i_subfr,     /* input : subframe flag                  */
  Word16 *T0,         /* output: integer part of pitch lag      */
  Word16 *T0_frac     /* output: fractional part of pitch lag   */
);

Word16 Interpol_3(      /* (o)  : interpolated value  */
  Word16 *x,            /* (i)  : input vector        */
  Word16 frac           /* (i)  : fraction            */
);

void Pred_lt_3(
  Word16   exc[],       /* in/out: excitation buffer */
  Word16   T0,          /* input : integer pitch lag */
  Word16   frac,        /* input : fraction of lag   */
  Word16   L_subfr      /* input : subframe size     */
);

Word16 Parity_Pitch(    /* output: parity bit (XOR of 6 MSB bits)    */
   Word16 pitch_index   /* input : index for which parity to compute */
);

Word16  Check_Parity_Pitch( /* output: 0 = no error, 1= error */
  Word16 pitch_index,       /* input : index of parameter     */
  Word16 parity             /* input : parity bit             */
);

/*-----------------------*
 * Innovative codebook.  *
 *-----------------------*/

/*--------------------------------------------------------------------------*
 *       FCB constant parameters                                            *
 *--------------------------------------------------------------------------*/

#define DIM_RR   616
#define NB_POS   8
#define STEP     5
#define MSIZE    64
#define THRESHOLDFCB  13107        /* 0.4 in Q15 */
#define MAX_TIME   75

/*-----------------------*
 * FCB functions.        *
 *-----------------------*/

Word16  ACELP_Codebook(  /* (o)     :index of pulses positions    */
  Word16 x[],            /* (i)     :Target vector                */
  Word16 h[],            /* (i) Q12 :Inpulse response of filters  */