pcm.cpp

Linux下的.wav文件播放示例

#include <unistd.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <linux/soundcard.h>

#define OPEN_DSP_FAILED     0x00000001      /*打开  dsp 失败!*/
#define SAMPLERATE_STATUS     0x00000002    /*samplerate status failed*/
#define SET_SAMPLERATE_FAILED  0x00000003   /*set samplerate failed*/
#define CHANNELS_STATUS       0x00000004    /*Channels status failed*/
#define SET_CHANNELS_FAILED    0x00000005   /*set channels failed*/
#define FMT_STATUS       0x00000006        /*FMT status failed*/
#define SET_FMT_FAILED     0x00000007       /*set fmt failed*/
#define OPEN_FILE_FAILED        0x00000008    /*opem filed failed*/

int P8100_Audio_Play(char *pathname,int nSampleRate,int nChannels,int fmt)
{
int dsp_fd,mix_fd,status,arg;
dsp_fd = open("/dev/dsp" , O_RDWR);   /*open dsp*/
if(dsp_fd < 0)
{
  return  OPEN_DSP_FAILED;
}
arg = nSampleRate;
status = ioctl(dsp_fd,SOUND_PCM_WRITE_RATE,&arg); /*set samplerate*/
if(status < 0)
{
  close(dsp_fd);
  return SAMPLERATE_STATUS;
}
if(arg != nSampleRate)
{
  close(dsp_fd);
  return SET_SAMPLERATE_FAILED;
}
arg = nChannels;  /*set channels*/   
status = ioctl(dsp_fd, SOUND_PCM_WRITE_CHANNELS, &arg);
if(status < 0)
{
  close(dsp_fd);
  return CHANNELS_STATUS;
}
if( arg != nChannels)
{
  close(dsp_fd);
  return SET_CHANNELS_FAILED;
}
arg = fmt; /*set bit fmt*/
status = ioctl(dsp_fd, SOUND_PCM_WRITE_BITS, &arg);
if(status < 0)
{
  close(dsp_fd);
  return FMT_STATUS;
}
if(arg != fmt)
{
  close(dsp_fd);
  return SET_FMT_FAILED;
}/*到此设置好了DSP的各个参数*/            
FILE *file_fd = fopen(pathname,"r");
if(file_fd == NULL)
{
  close(dsp_fd);
  return OPEN_FILE_FAILED;
}
int num = 3*nChannels*nSampleRate*fmt/8;
int get_num;
char buf[num];
while(feof(file_fd) == 0)
{
  get_num = fread(buf,1,num,file_fd);
  write(dsp_fd,buf,get_num);
  if(get_num != num)
  {
   close(dsp_fd);
   fclose(file_fd);
   return 0;
  }
}
close(dsp_fd);
fclose(file_fd);
return 0;
}
/*
*test
*/
int main()
{
int value;

value = P8100_Audio_Play("/windows/C/WINDOWS/Media/Windows Startup.wav",44100,2,16);//注意播放文件的路径哦！！
fprintf(stderr,"value is %d",value);
return 0;
}