io-sparc.c

16kb/s Low Delay CELP 算法

/*************************************************************************/
/*                                                                       */
/*                            LD-CELP  G.728                             */
/*                                                                       */
/*    Low-Delay Code Excitation Linear Prediction speech compression.    */
/*                                                                       */
/*    Code edited by Michael Concannon.                                  */
/*    Based on code written by Alex Zatsman, Analog Devices 1993         */
/*                                                                       */
/*************************************************************************/

#include <fcntl.h>
#include <stdio.h>
#include "common.h"
#include "prototyp.h"

extern int fprintf();
extern void audio_read_filehdr();
extern int read(int, char*, int);
real rscale=0.125;  /* Scaling factor for input */


char * xfile_name;
#ifdef CODER

int oxfd = 0; /* output file (codebook indices) */
int ifd  = 1; /* input file */

char *ifile_name;

void
init_input()
{
    if ((ifd=open(ifile_name, O_RDONLY)) < 0) {
	(void) fprintf(stderr, "Can't open \"%s\"\n", ifile_name);
	exit(1);
    }
    if ((oxfd=open(xfile_name, O_WRONLY | O_CREAT | O_TRUNC, 0644)) < 0) {
	(void) fprintf(stderr, "Can't open \"%s\"\n", xfile_name);
    }
}

void
put_index(int x)
{
    short sx = x;
    write(oxfd, &sx, 2);
}

#endif

#ifdef DECODER
char * ofile_name;

static int ofd=1; /* Outpu file */
static ixfd = 0; /* Input file (codebook indices) */
int sound_overflow = 0;

void init_output()
{
    sound_overflow = 0;
    if ((ofd=open(ofile_name, O_WRONLY|O_CREAT|O_TRUNC, 0644)) < 0) {
	extern  int errno;
	extern char *sys_errlist[];
	int ee = errno;
	(void) fprintf(stderr, "Can't open \"%s\" for output\n", ofile_name);
	printf(sys_errlist[ee]);
	exit(1);
    }
    if ((ixfd = open(xfile_name, O_RDONLY)) < 0) {
	(void) fprintf(stderr, "Can't open \"%s\"\n", xfile_name);
	exit(3);
    }
}

int get_index()
{
    short sx;
    if (read(ixfd, (char*)&sx, sizeof(sx)) < sizeof(sx))
	return -1;
    return (int)sx;
}
#endif

/* Return Number of Samples Read */

#ifdef CODER

int read_sound_buffer(int n, real buf[])
{
    short s;
    int i, c=0;
    
    for (i=0; i<n && read(ifd, &s, 2) > 0; i++) {
      buf[c++] =  rscale * (real) s;
    }
    return c;
}
#endif

#ifdef DECODER
int
write_sound_buffer(int n, real buf[])
{
    int i;
    short s;
    float xx;

    for (i=0; i<n; i++) {
	xx = buf[i]/rscale;
	if (xx > 0.0)
	  if (xx > 32767.0)
	    xx = 32767.0;
	  else
	    xx += 0.5;
	else
	  if (xx < -32768.0)
	    xx = -32768.0;
	  else
	    xx -= 0.5;
	s = (short) xx;
	write(ofd, &s, 2);
    }
    return 0;
}
#endif