sound.c

linux声卡编程 可以播放.wav格式的音乐。

/***************************************************************************
 *   Copyright (C) 2008 by root   *
 *   [e-mail]   *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 *   This program is distributed in the hope that it will be useful,       *
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
 *   GNU General Public License for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this program; if not, write to the                         *
 *   Free Software Foundation, Inc.,                                       *
 *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
 ***************************************************************************/


#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

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


#define LENGTH 3
#define RATE 44100
#define SIZE 16
#define CHANNELS 2

//unsigned char buf[LENGTH*RATE*SIZE*CHANNELS/8];

int main(int argc, char *argv[])
{
 	int fd1,fd2;
	int arg;
	int status;
	unsigned char* buf=NULL;
	struct stat stat_buf;

	//打开声音设备
	fd1=open("/dev/dsp",O_RDWR);
	
	if(fd1<0){
		perror("cannot open /dev/dsp device");
		return 1;
	}


	/*==一下设置声卡参数 ==*/
	
	//设置采样的量化位数
	arg=SIZE;
	status=ioctl(fd1,SOUND_PCM_WRITE_BITS,&arg);	
	if(status==-1){
		perror("error");
		return 1;
	}
	
	//设置采样声道数目
	arg=CHANNELS;
	status=ioctl(fd1,SOUND_PCM_WRITE_CHANNELS,&arg);
	if(status==-1){
		perror("error");
		return 1;
	}

	//设置采样频率
	arg=RATE;
	status=ioctl(fd1,SOUND_PCM_WRITE_RATE,&arg);
	if(status==-1){
		perror("error");
		return 1;
	}

	//打开声音文件
	fd2=open("/root/bgm_013.wav",O_RDONLY);
	if(fd2<0)
		printf("error fd2");
	//把声音文件的信息保存到stat结够体中
	if(fstat(fd2,&stat_buf)){
		close(fd2);
		printf("error");
		return 1;
	}
	
	buf=malloc(stat_buf.st_size);
	if(!buf){
		close(fd2);
		printf("error");
		return -1;
	}
		
	
	if(read(fd2,buf,stat_buf.st_size)<0){
		free(buf);
		printf("error");
		close(fd2);
  		return -1;
	}
	
	
	status =write(fd1,buf,stat_buf.st_size);
		if(status !=sizeof(buf)){
			perror("wrote wrong number of bytes");
		}
	
	
	free(buf);
	close(fd1);
	close(fd2);
	return 0;
}