dcodcbg.c

语音CELP压缩解压源代码（C语音)

/**************************************************************************
*
* ROUTINE
*		dcodcbg.c
*
* FUNCTION
*		 Decodes all code book gains for a frame
*
*
* SYNOPSIS
*		subroutine dcodcbg(cbgbits,bitsum1,bitsum2,bitpointer,
*		                   nn,stream,cbg)
*
*   formal
*
*                       data    I/O
*       name            type    type    function
*       -------------------------------------------------------------------
*	cbgbits		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/o	number of bits used
*	nn		int	i	number of subframes/frame
*	stream		short	i	bit stream
*	cbg		float	o	vector of code book indicies
*
***************************************************************************
*
* DESCRIPTION
*
*
***************************************************************************
*
* CALLED BY
*
*       celp
*
* CALLS
*
*       gaindecode	unpack
*
***************************************************************************
*
* REFERENCES
*
*
**************************************************************************/
dcodcbg(cbgbits, bitsum1, bitsum2, bitpointer, nn, stream, cbg)
int cbgbits, bitsum1, bitsum2, *bitpointer, nn;
short stream[];
float cbg[];

{
  int i, pointer, index;

  pointer = *bitpointer;
  for (i = 0; i < nn; i++)
  {
    unpack(stream, cbgbits, &index, &pointer);
    gaindecode(index, cbgbits, &cbg[i]);
    if (i == 0 || i == 2 || i == 4)
      pointer += bitsum2 - cbgbits;
    else if (i == 1 || i == 3 || i == 5)
      pointer += bitsum1 - cbgbits;
    else
      printf("dcodcbg: ***Error in decoding cbgain\n");
  }
  *bitpointer += cbgbits;
}