melp.c

2400bps MELP语音编解码源程序。

/*

2.4 kbps MELP Proposed Federal Standard speech coder

Fixed-point C code, version 1.0

Copyright (c) 1998, Texas Instruments, Inc.  

Texas Instruments has intellectual property rights on the MELP
algorithm.  The Texas Instruments contact for licensing issues for
commercial and non-government use is William Gordon, Director,
Government Contracts, Texas Instruments Incorporated, Semiconductor
Group (phone [phone]).

The fixed-point version of the voice codec Mixed Excitation Linear
Prediction (MELP) is based on specifications on the C-language software
simulation contained in GSM 06.06 which is protected by copyright and
is the property of the European Telecommunications Standards Institute
(ETSI). This standard is available from the ETSI publication office
tel. [phone]. ETSI has granted a license to United States
Department of Defense to use the C-language software simulation contained
in GSM 06.06 for the purposes of the development of a fixed-point
version of the voice codec Mixed Excitation Linear Prediction (MELP).
Requests for authorization to make other use of the GSM 06.06 or
otherwise distribute or modify them need to be addressed to the ETSI
Secretariat fax: [phone].

*/
/*                                                                  */
/*  melp.c: Mixed Excitation LPC speech coder                       */
/*                                                                  */

/*  compiler include files  */
#include	<stdio.h>
#include "melp.h"
#include "spbstd.h"
#include "mat.h"

/*  compiler constants */
#define ANA_SYN 0
#define ANALYSIS 1
#define SYNTHESIS 2

/* note: CHSIZE is shortest integer number of words in channel packet */
#define CHSIZE 9
#define NUM_CH_BITS 54

/* global variables for fixed-point library */
int complexity, saturation = 0;
int max_complexity = 0;

/*  external memory */
Shortword melpmode = ANA_SYN;
char in_name[80], out_name[80];

void main(int argc, char **argv)

{
    void parse(int argc, char **argv);

    Shortword i;
    Longword length, frame;
    Shortword eof_reached;
    Longword num_frames = 0;
    Shortword speech_in[FRAME];
    Shortword speech_out[FRAME];
    static struct melp_param melp_par;      /* melp parameters */
    UShortword chbuf[CHSIZE];
    unsigned int tempbuf[CHSIZE];
    FILE *fp_in, *fp_out;

    /* Print user message */
    printf("\n2.4 kb/s Federal Standard MELP speech coder\n");
    printf("  Fixed-point C simulation, version 1.0\n\n");

    /* Get input parameters from command line */
    parse(argc, argv);

    /* Open input, output, and parameter files */
    if (( fp_in = fopen(in_name,"rb")) == NULL ) {
	printf("  ERROR: cannot read file %s.\n",in_name);
	exit(1);
    }
    if (( fp_out = fopen(out_name,"wb")) == NULL ) {
	printf("  ERROR: cannot write file %s.\n",out_name);
	exit(1);
    }

    /* Check length of channel input if needed */
    if (melpmode == SYNTHESIS) {
	fseek(fp_in,0L,2);      /* go to end of input file */
	length = ftell(fp_in);
	rewind(fp_in);

	num_frames = (Longword)(0.5 + length * (8.0/NUM_CH_BITS) * (6.0/32));
	
    }

    /* Initialize MELP analysis and synthesis */
    if (melpmode != SYNTHESIS)
      melp_ana_init();
    if (melpmode != ANALYSIS)
      melp_syn_init();

    /* Run MELP coder on input signal */
    frame = 0;
    melp_par.chptr = chbuf;
    melp_par.chbit = 0;
    eof_reached = 0;
    while (eof_reached == 0) {

#if (COMPLEXITY_COUNT)
	complexity_reset();
#endif

	/* Perform MELP analysis */
	if (melpmode != SYNTHESIS) {
	    /* read input speech */
	    length = readbl(speech_in,fp_in,FRAME);
	    if (length < FRAME) {
		v_zap(&speech_in[length],(Shortword)(FRAME-length));
		eof_reached = 1;
	    }

	    /* Run MELP analyzer */
	    if (melpmode == ANA_SYN) {
		/* reset pointers to short channel buffer */
		melp_par.chptr = chbuf;
		melp_par.chbit = 0;
	    }

	    melp_ana(speech_in,&melp_par);
 
	    /* Write channel output if needed */
	    if (melpmode == ANALYSIS && melp_par.chbit == 0) {
	        for (i = 0; i < CHSIZE; i++)
		    tempbuf[i] = (int)chbuf[i];
		fwrite((void *) tempbuf,sizeof(int),
		       melp_par.chptr-chbuf,fp_out);

		/* reset pointer to short channel buffer */
		melp_par.chptr = chbuf;
	    }

	    if (melp_par.chptr >= &chbuf[CHSIZE] && melp_par.chbit > 0) {
		printf("\nERROR: Ran out of channel buffer memory.\n");
		exit(1);
	    }

	}          

	/* Perform MELP synthesis (skip first frame) */
	if (melpmode != ANALYSIS) {

	    if (melpmode == ANA_SYN) {
		/* reset pointers to short channel buffer */
		melp_par.chptr = chbuf;
		melp_par.chbit = 0;
	    }

	    /* Read channel input if needed */
	    if (melpmode == SYNTHESIS && melp_par.chbit == 0) {
		fread((void *) tempbuf,sizeof(int),CHSIZE,fp_in);
		for (i = 0; i <CHSIZE; i++)
		  chbuf[i] = (Shortword)tempbuf[i];

		/* reset pointer to short channel buffer */
		melp_par.chptr = chbuf;
	    }

	    melp_syn(&melp_par,speech_out);
	    if (frame > 0)
	      writebl(speech_out,fp_out,FRAME);
	}
	frame++; 
	if (melpmode == SYNTHESIS) {
	    if (frame >= num_frames)
	      eof_reached = 1;
	}
    }
 
    /* Write channel output if needed */
    if (melpmode == ANALYSIS) {
      if (melp_par.chbit > 0) {
	  for (i = 0; i < CHSIZE; i++)
	      tempbuf[i] = (int)chbuf[i];
	  fwrite((void *) tempbuf,sizeof(int),melp_par.chptr-chbuf+1,fp_out);
      }
      else {
	  for (i = 0; i < CHSIZE; i++)
	      tempbuf[i] = (int)chbuf[i];
	  fwrite((void *) tempbuf,sizeof(int),melp_par.chptr-chbuf,fp_out);
      }
    }

#if (COMPLEXITY_COUNT)
    complexity_print();
#endif

    fclose(fp_in);
    fclose(fp_out);
}

void parse(int argc,char **argv){

    int error_flag;

    error_flag = 0;
    if (argc < 2)
      error_flag = 1;
    melpmode = ANA_SYN;
    while ((--argc>0) && ((*++argv)[0] == '-')){
	switch ((*argv)[1]){
	  case 'a':
	    melpmode=ANALYSIS; break;
	  case 's':
	    melpmode=SYNTHESIS; break;
	  case 'i':
	    sscanf(*++argv,"%s",in_name); --argc; break;
	  case 'o':
	    sscanf(*++argv,"%s",out_name); --argc; break;
	  default:
	    error_flag = 1;
	    break;
	}
    }

    if (error_flag == 1) {
	fprintf(stderr,"Usage:\n\n"); 
	fprintf(stderr,"Analysis/synthesis: melp -i infile -o outfile\n");
	fprintf(stderr,"Analysis only:  melp -a -i infile  -o bitfile\n"); 
	fprintf(stderr,"Synthesis only: melp -s -i bitfile -o outfile\n");
        exit(1);
    }
    if (melpmode == ANA_SYN)
      printf(" MELP analysis and synthesis \n");
    else if (melpmode == ANALYSIS)
      printf(" MELP analysis \n");
    else if (melpmode == SYNTHESIS)
      printf(" MELP synthesis \n");

    printf("   input from %s\n   output to %s.\n",in_name, out_name);

}