/*2.4 kbps MELP Proposed Federal Standard speech coderversion 1.2Copyright (c) 1996, Texas Instruments, Inc.  Texas Instruments has intellectual property rights on the MELPalgorithm.  The Texas Instruments contact for licensing issues forcommercial and non-government use is William Gordon, Director,Government Contracts, Texas Instruments Incorporated, SemiconductorGroup (phone 972 480 7442).*//*    Name: melp_chn_write, melp_chn_read    Description: Write/read MELP channel bitstream    Inputs:      MELP parameter structure    Outputs:       updated MELP parameter structure (channel pointers)    Returns: void*/#include <stdio.h>#include <math.h>#include "melp.h"#include "vq.h"#include "melp_sub.h"/* Define number of channel bits per frame */#define NUM_CH_BITS 54#define ORIGINAL_BIT_ORDER 0  /* flag to use bit order of original version */extern float msvq_cb[];extern float fsvq_cb[];/* Define bit buffer */static unsigned int bit_buffer[NUM_CH_BITS];#if (ORIGINAL_BIT_ORDER)/* Original linear order */static int bit_order[NUM_CH_BITS] = {0,  1,  2,  3,  4,  5,6,  7,  8,  9,  10, 11,12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23,24, 25, 26, 27, 28, 29,30, 31, 32, 33, 34, 35,36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53};#else/* Order based on priority of bits */static int bit_order[NUM_CH_BITS] = {0,  17, 9,  28, 34, 3, 4,  39, 1,  2,  13, 38,14, 10, 11, 40, 15, 21,27, 45, 12, 26, 25, 33,20, 24, 23, 32, 44, 46,22, 31, 53, 52, 51, 7,6,  19, 18, 29, 37, 30,36, 35, 43, 42, 16, 41, 50, 49, 48, 47, 8,  5};#endifstatic int sync_bit = 0; /* sync bit */void melp_chn_write(struct melp_param *par){    int i, bit_cntr;    unsigned int *bit_ptr;         /* FEC: code additional information in redundant indeces */    fec_code(par);        /*	Fill bit buffer	*/    bit_ptr = bit_buffer;    bit_cntr = 0;    pack_code(par->gain_index[1],&bit_ptr,&bit_cntr,5,1);        /* Toggle and write sync bit */    if (sync_bit)	sync_bit = 0;    else	sync_bit = 1;    pack_code(sync_bit,&bit_ptr,&bit_cntr,1,1);    pack_code(par->gain_index[0],&bit_ptr,&bit_cntr,3,1);    pack_code(par->pitch_index,&bit_ptr,&bit_cntr,PIT_BITS,1);    pack_code(par->jit_index,&bit_ptr,&bit_cntr,1,1);    pack_code(par->bpvc_index,&bit_ptr,&bit_cntr,NUM_BANDS-1,1);        for (i = 0; i < par->msvq_stages; i++)       pack_code(par->msvq_index[i],&bit_ptr,&bit_cntr,par->msvq_bits[i],1);        pack_code(par->fsvq_index[0],&bit_ptr,&bit_cntr,	      FS_BITS,1);        /*	Write channel output buffer	*/    for (i = 0; i < NUM_CH_BITS; i++) {	pack_code(bit_buffer[bit_order[i]],&par->chptr,&par->chbit,		  1,CHWORDSIZE);	if (i == 0)	    *(par->chptr) |= 0x8000; /* set beginning of frame bit */    }}int melp_chn_read(struct melp_param *par, struct melp_param *prev_par){    int erase = 0;    int i, bit_cntr;    unsigned int *bit_ptr;     /*	Read channel output buffer into bit buffer */    bit_ptr = bit_buffer;    for (i = 0; i < NUM_CH_BITS; i++) {	erase |= unpack_code(&par->chptr,&par->chbit,&bit_buffer[bit_order[i]],			     1,CHWORDSIZE,ERASE_MASK);	bit_ptr++;    }    /*	Read information from  bit buffer	*/    bit_ptr = bit_buffer;    bit_cntr = 0;    unpack_code(&bit_ptr,&bit_cntr,&par->gain_index[1],5,1,0);        /* Read sync bit */    unpack_code(&bit_ptr,&bit_cntr,&i,1,1,0);    unpack_code(&bit_ptr,&bit_cntr,&par->gain_index[0],3,1,0);    unpack_code(&bit_ptr,&bit_cntr,&par->pitch_index,PIT_BITS,1,0);        unpack_code(&bit_ptr,&bit_cntr,&par->jit_index,1,1,0);    unpack_code(&bit_ptr,&bit_cntr,&par->bpvc_index,			 NUM_BANDS-1,1,0);        for (i = 0; i < par->msvq_stages; i++)       unpack_code(&bit_ptr,&bit_cntr,&par->msvq_index[i],			   par->msvq_bits[i],1,0);    unpack_code(&bit_ptr,&bit_cntr,&par->fsvq_index[0],			 FS_BITS,1,0);        /* Clear unvoiced flag */    par->uv_flag = 0;        erase = fec_decode(par,erase);        /* Decode new frame if no erasures occurred */    if (erase) {		/* Erasure: frame repeat */			/* Save correct values of pointers */	prev_par->chptr = par->chptr;	prev_par->chbit = par->chbit;	*par = *prev_par; 			/* Force all subframes to equal last one */	for (i = 0; i < NUM_GAINFR-1; i++) {	    par->gain[i] = par->gain[NUM_GAINFR-1];	}    }    else {		/* Decode line spectrum frequencies	*/	vq_msd2(msvq_cb,&par->lsf[1],(float*)NULL,(float*)NULL,par->msvq_index,		par->msvq_levels,par->msvq_stages,LPC_ORD,0);	i = FS_LEVELS;	if (par->uv_flag)	  fill(par->fs_mag,1.,NUM_HARM);	else	  {		      /* Decode Fourier magnitudes */	      vq_msd2(fsvq_cb,par->fs_mag,(float*)NULL,(float*)NULL,		      par->fsvq_index,&i,1,NUM_HARM,0);	  }	/* Decode gain terms with uniform log quantizer	*/	q_gain_dec(par->gain, par->gain_index,GN_QLO,GN_QUP,GN_QLEV);	/* Fractional pitch: */	/* Decode logarithmic pitch period */	if (par->uv_flag)	  par->pitch = UV_PITCH;	else 	  {	      quant_u_dec(par->pitch_index,&par->pitch,PIT_QLO,PIT_QUP,			  PIT_QLEV);	      par->pitch = pow(10.0,par->pitch);	  }	/* Decode jitter and bandpass voicing */	quant_u_dec(par->jit_index,&par->jitter,0.0,MAX_JITTER,2);	q_bpvc_dec(&par->bpvc[0],&par->bpvc_index,par->uv_flag,		   NUM_BANDS);    }    /* Return erase flag */    return(erase);}