c_stereo_x.c

关于AMR-WB+语音压缩编码的实现代码

#include <float.h>
#include <stdlib.h>
#include <stdio.h>
#include <math.h>
#include "../include/amr_plus.h"
#include "../include/cod_hi_stereo.h"
#include "../include/cod_tcx_stereo.h"
/*-----------------------------------------------------------------*
* Funtion  init_coder_stereo                                      *
* ~~~~~~~~~~~~~~~~~~~~~~~~~~                                      *
*   ->Initialization of variables for the stereo coder.           *
*-----------------------------------------------------------------*/
void init_coder_stereo_x(Coder_State_Plus *st)
{
	init_cod_hi_stereo(st);
	init_tcx_stereo_encoder(st);
	return;
}
/*-----------------------------------------------------------------*
* Funtion coder_stereo                                            *
* ~~~~~~~~~~~~~~~~~~~~                                            *
*   ->Principle stereo coder routine (working at fs=12.8kHz).     *
*                                                                 *
* Note: HF band are encoded twice (2 channels) using 0.8kbps BWE. *
*       Usage of 2xBWE for stereo provide better time domain      *
*       stereo definition in HF without increasing the bit-rate.  *
*       Another advantage is that the stereo decoder is limited   *
*       to the lower band (fs=12.8kHz) and this reduce the        *
*       overall complexity of the AMR-WB+ codec.  Also, this      *
*       solution is not dependent of the AMR-WB+ mode where many  *
*       different sampling frequencies are used (16, 24, 32 kHz). *
*-----------------------------------------------------------------*/
void coder_stereo_x(float speech_hi[],	/* (i)	: Mixed channel, hi	*/
					float chan_hi[],		/* (i)	: Right channel, hi	*/
					float speech_2k[],	/* (i)	: Mixed channel, lo */
					float chan_2k[],		/* (i)	: Right channel, lo	*/
					float AqLF[],
					int brMode,
					int param[],			/* (o)	: Encoded parameters*/	
					int fscale,
					Coder_State_Plus *st)		/* (i/o): Encoder states	*/
{	
    int mod[4];
	int i;
	/* param */
	/*-----------------------------------------------------------------*
	* NPRM_STEREO_HI_X*NB_DIV + 4 (mode) + Rest (TCX)				   *
	*-----------------------------------------------------------------*/
	if (StereoNbits[brMode]-4 > 300)
	{
		st->filt_hi_pmsvq = &filt_hi_pmsvq7;
		st->gain_hi_pmsvq = &gain_hi_pmsvq5;
	}
	else {
		st->filt_hi_pmsvq = &filt_hi_pmsvq4;
		st->gain_hi_pmsvq = &gain_hi_pmsvq2;
	}
	/* encode the high band */
	cod_hi_stereo(speech_hi,chan_hi,AqLF,param,st);  /* 64 echantillon look-ahead */
	/* encode the low band */
	cod_tcx_stereo(speech_2k,chan_2k,param+4+NPRM_STEREO_HI_X*NB_DIV,brMode,mod,fscale,st);
	/* transmitt the mode in the parameters buffer*/
	for(i=0;i<4;i++){
		param[i+NPRM_STEREO_HI_X*NB_DIV] = mod[i];
	}
	return;
}
static int unpack4bits_d(int nbits, int *prm, short *ptr)
{
	int i;
	i=0;
	while (nbits > 4)
	{
		int2bin(prm[i], 4, ptr);
		ptr += 4;
		nbits -= 4;
		i++;
	}
	int2bin(prm[i], nbits, ptr);
	i++;
	return(i);
}
void enc_prm_stereo_x(int param[],       /* (i) : parameters                       */
					  short serial[],    /* (o) : serial bits stream               */
					  int nbits_pack,     /* (i) : number of bits per packet of 20ms*/
					  int nbits_bwe,	/* (i) : number of BWE bits per 20ms  */
					  int brMode
					  )
{
	int nbits, *prm;
	int k,j;
	short *ptr;
	int i;
	int mod[NB_DIV],nbits_AVQ[NB_DIV];
	int mode,n_pack;
	int prm_AVQ[(NBITS_MAX/4)+N_PACK_MAX];
	int hf_bits=0;
      int hiband_mode;
	/*----------------------------------------------------------*
	* Set number of bits used for stereo (per packet of 20 ms) *
	* When stereo is transmitted, the bit ordering is:         *
	* serial: mode (2bits), core, stereo, 2xBWE(2x16bits)      *
	*----------------------------------------------------------*/
	nbits = (StereoNbits[brMode] + (2*nbits_bwe))/4;
    hiband_mode = 0;
    if (StereoNbits[brMode]-4 > 300) {
		hiband_mode = 1;
	}
   /*----------------------------------------------------------*
	* Encode the high band parameters	 		   *
	*----------------------------------------------------------*/
	for(k=0;k<NB_DIV;k++) {
		prm = param + k*NPRM_STEREO_HI_X;
		ptr = serial + (k+1)*nbits_pack - nbits;
		if(hiband_mode == 0) {
			int2bin(prm[0],4, ptr); ptr += 4;
			int2bin(prm[1],2, ptr); ptr += 2;
		}
		else {
			int2bin(prm[0],4, ptr); ptr += 4 ;
			int2bin(prm[1],3, ptr); ptr += 3 ;
			int2bin(prm[2],5, ptr); ptr += 5 ;
		}		
	}
		if(hiband_mode == 0)
		{
			hf_bits = 4+2;
		}
		else
		{
			hf_bits = 7+5;
		}
		/*----------------------------------------------------------*
		* Encode the low band parameters							*
		*----------------------------------------------------------*/
		/* fill up the mode */
		for(i=0;i<NB_DIV;i++) 
		{
			mod[i]=param[i+NPRM_STEREO_HI_X*NB_DIV];
		}
		k = 0;
		while (k < NB_DIV)
		{	
			mode = mod[k];
			/* set pointer to parameters */
			prm = (param +4+NPRM_STEREO_HI_X*NB_DIV)+ (k*NPRM_DIV_TCX_STEREO);
			if ((mode == 1) || (mode == 0)){
				/* encode 20ms TCX */
				n_pack = 1;
				nbits_AVQ[0] = ((StereoNbits[brMode]-4)/4)-7-2-7-hf_bits;
				AVQ_encmux(n_pack, prm+2, prm_AVQ, nbits_AVQ, TOT_PRM_20/8);
				/* set pointer to bit stream */
				ptr = serial + (k+1)*nbits_pack - nbits + hf_bits;
				/* encode the mode */
            *ptr = 0;                  ptr += 1;
				int2bin(mode, 2, ptr);       ptr += 2;
				int2bin(prm[0], 7, ptr);     ptr += 7;
				int2bin(prm[1], 7, ptr);     ptr += 7;
				unpack4bits_d(nbits_AVQ[0], prm_AVQ, ptr);
				ptr += nbits_AVQ[0];
				k++;
			} /* end of mode 0/1 */
			else if (mode == 2) {																				
				/* encode and multiplex 40ms TCX */
				n_pack = 2;
				nbits_AVQ[0] = ((StereoNbits[brMode]-4)/4)-2-7-hf_bits;
				nbits_AVQ[1] = ((StereoNbits[brMode]-4)/4)-2-7-hf_bits;
				AVQ_encmux(n_pack, prm+2, prm_AVQ, nbits_AVQ, TOT_PRM_40/8);
				/* set pointer to bit stream */
				ptr = serial + (k+1)*nbits_pack - nbits + hf_bits;
				/* encode first 20 ms frame */
            *ptr = 0;                  ptr += 1;
				int2bin(mode, 2, ptr);     ptr += 2;
				int2bin(prm[0], 7, ptr);     ptr += 7;
				j= unpack4bits_d(nbits_AVQ[0], prm_AVQ, ptr);
				/* set pointer to bit stream */
				ptr = serial + (k+2)*nbits_pack - nbits + hf_bits;
				/* encode second 20 ms frame */
            *ptr = 0;                  ptr += 1;
				int2bin(mode, 2, ptr);     ptr += 2;
				int2bin(prm[1], 7, ptr);     ptr += 7;
				unpack4bits_d(nbits_AVQ[1], prm_AVQ+j, ptr);
				k+=2;
			} /* end of mode 2 */
			else if (mode == 3) {
				/* encode and multiplex 80ms TCX */
				n_pack = 4;
				nbits_AVQ[0] = ((StereoNbits[brMode]-4)/4)-7-2-hf_bits;
				nbits_AVQ[1] = ((StereoNbits[brMode]-4)/4)-2-hf_bits;
				nbits_AVQ[2] = ((StereoNbits[brMode]-4)/4)-7-2-hf_bits;
				nbits_AVQ[3] = ((StereoNbits[brMode]-4)/4)-2-hf_bits;
				AVQ_encmux(n_pack, prm+2, prm_AVQ, nbits_AVQ, TOT_PRM_80/8);
				/* set pointer to bit stream */
				ptr = serial + (k+1)*nbits_pack - nbits + hf_bits;
				/* encode first 20 ms frame */
            *ptr = 0;                  ptr += 1;
				int2bin(mode, 2, ptr);     ptr += 2;
				int2bin(prm[0], 7, ptr);     ptr += 7;
				j= unpack4bits_d(nbits_AVQ[0], prm_AVQ, ptr);
				/* set pointer to bit stream */
				ptr = serial + (k+2)*nbits_pack - nbits + hf_bits;
				/* encode second 20 ms frame */
            *ptr = 0;                  ptr += 1;
				int2bin(mode, 2, ptr);     ptr += 2;
				j += unpack4bits_d(nbits_AVQ[1], prm_AVQ+j, ptr);
				/* set pointer to bit stream */
				ptr = serial + (k+3)*nbits_pack - nbits + hf_bits;
				/* encode third 20 ms frame */	
            *ptr = 0;                  ptr += 1;
				int2bin(mode, 2, ptr);     ptr += 2;
				int2bin(prm[1], 7, ptr);     ptr += 7;
				j += unpack4bits_d(nbits_AVQ[2], prm_AVQ+j, ptr);
				/* set pointer to bit stream */
				ptr = serial + (k+4)*nbits_pack - nbits + hf_bits;
				/* encode forth 20 ms frame */
            *ptr = 0;                  ptr += 1;
				int2bin(mode, 2, ptr);     ptr += 2;
				unpack4bits_d(nbits_AVQ[3], prm_AVQ+j, ptr);
				k+=4;
			}  /* end of mode 3 */
		} /* end of while k < NB_DIV */
	return;
}