复件 sndtools.c

声音信号的采集和回放

/****************sndtools.h*****************************/
#ifndef SNDTOOLS_H
#define SNDTOOLS_H
                                                                               
#include<linux/soundcard.h>
                                                                               
#define FMT8BITS AFMT_S8_LE
#define FMT16BITS AFMT_S16_LE
                                                                               
#define FMT8K 8000
#define FMT16K 16000
#define FMT22K 22000
#define FMT44K 44000
                                                                               
#define MONO 1
#define STERO 2
                                                                               
#ifndef VAR_STATIC
extern int devfd;
extern int CapMask;
#endif //ifndef VAR_STATIC
                                                                               
//Open sound device,return 1 if open success
//else return 0
int OpenSnd();
                                                                               
//Close sound device
int CloseSnd();
                                                                               
//Set record or playback format,return 1 if success
//else return 0
int SetFornat(int bits,int hz);
                                                                               
//Set record or playback channel, return 1 if success
//else return 1
int SetCheannel(int chn);
                                                                               
//Record
int Record(char *buf,int size);
                                                                               
//Playback
int Play(char *buf,int size);
                                                                               
#endif//ifndef SNDTOOLS_H
                                                                               
/*****************sndtools.c************************/
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <string.h>

#define VAR_STATIC

#include "sndtools.h"

int devfd=0;

/*
Open Sound device
Return 1 if success,else return 0
*/
int OpenSnd(/*add by new version*/int nWhich)
{
if(devfd>0)
close(devfd);

devfd=open("/dev/dsp",O_RDWR);

if(devfd<0)
return 0;
return 1;
}
/*Close Sound device
return 1 if success, else return 0
*/
int CloseSnd(/*add by new version*/int nWhich)
{
close(devfd);
devfd=0;
return 1;
}


/*
Set Record an Playback format
return 1 if success,else return 0
bits--FMT8BITS(8bits),FMT16BITS(16bits)
hz--FMT8K(8000Hz),FMT16K(16000Hz),FMT22K(22000Hz),FMT44K(44000Hz)
*/

int SetFormat(int bits,int hz)
{
int tmp=bits;

if(-1==ioctl(devfd,SNDCTL_DSP_SETFMT,&tmp))
{

#ifdef DEUG_WARN
printf("Set fmt to s16_little faile:%d\n",nWhich);
#endif

return 0;
}
tmp=hz;
if(-1==ioctl(devfd,SNDCTL_DSP_SPEED,&tmp))
{
#ifdef DEBUG_WARN
Printf("Set speed to %d:%d\n",hz,nWhich);
#endif
return 0;
}

return 1;
}
/*Set Sound Card Channel
return if success,else return 0
chn--MONO,STERO
*/
int SetChannel(int chn)
{
int tmp=chn;

if(-1==ioctl(devfd,SNDCTL_DSP_CHANNELS,&tmp))
{

#ifdef DEBUG_WARN
printf("Set Audio Channel faile:%d\n",nWhich);
#endif

return 0;
}
return 1;
}
/*
Record
return numbers of byte for read.
*/
int Record(char *buf,int size)
{
return read(devfd,buf,size);
}
/*
Playback
return numbers of byte for write
*/
int Play(char *buf,int size)
{
return write(devfd,buf,size);
}
//A sample to test record and playback.
#include <stdio.h>
#include<stdlib.h>
#include <unistd.h>
#include"sndtools.h"
int main()
{
char *buf;
int dwSize;
int i;
if(!OpenSnd(devfd))
{
printf("Open sound device error!\n");
exit(-1);
}
SetFormat(FMT16BITS,FMT8K);
SetChannel(MONO);

buf=(char*)malloc(320);
if(buf==NULL)
exit(-1);
//int i;
for( i=0;i<1000;i++)
{
dwSize=Record(buf,640);
dwSize=Play(buf,dwSize);
}
exit(1);
}