dcodpg.c

语音CELP压缩解压源代码（C语音)

/**************************************************************************
*
* ROUTINE
*		dcodpg.c
*
* FUNCTION
*		 Decodes all pitch gain values for a frame
*
*
* SYNOPSIS
*		subroutine dcodpg(pgbits,bitsum1,bitsum2,bitpointer,
*				  nn,stream,pgs)
*
*   formal
*
*                       data    I/O
*       name            type    type    function
*       -------------------------------------------------------------------
*	pgbits		int	i	number of bits for quantization
*	bitsum1		int	i	number of bits for odd subframes
*	bitsum2		int	i	number of bits for even subframes
*	bitpointer	int	i	number of bits used
*	nn		int	i	number of subframes/frame
*	stream		short	i	bit stream
*	pgs		float	o	vector of pitch gains
*
***************************************************************************
*
* DESCRIPTION
*
*
***************************************************************************
*
* CALLED BY
*
*       celp
*
* CALLS
*
*       pitchdecode      unpack
*
***************************************************************************
*
* REFERENCES
*
*
**************************************************************************/
dcodpg(pgbits, bitsum1, bitsum2, bitpointer, nn, stream, pgs)
int pgbits, bitsum1, bitsum2, *bitpointer, nn;
short stream[];
float pgs[];

{
  int i, pointer, index;

  pointer = *bitpointer;
  for (i = 0; i < nn; i++)
  {
    unpack(stream, pgbits, &index, &pointer);
    pitchdecode(index, &pgs[i]);
    if (i == 0 || i == 2 || i == 4)
      pointer += bitsum2 - pgbits;
    else if (i == 1 || i == 3 || i == 5)
      pointer += bitsum1 - pgbits;
    else
      printf("dcodpg:  Error in decoding pitch gain\n");
  }
  *bitpointer += pgbits;
}