#include

#include

#include

#include

#include

#include

#include

/* 下面的三个参数是跟具体文件相关

* cmd： file 音频文件

* [file pass.wav] =>> pass.wav: RIFF (little-endian) data, WAVE audio, Microsoft PCM, 16 bit, mono 44100 Hz

*　　1. 16位

*　　2. mono为当声道=1, Stereo为立体声=2

*　　3. 44100HZ为频率这个大家都知道，及一秒钟采集或者播放音频的bit数量。

*/

#define RATE 44100

#define SIZE 16

#define CHANNELS 1 // 1表示单声道，2为立体/* 缓冲区 */

unsigned char buff[RATE * SIZE * CHANNELS / 8]; //buff里面正好放一秒钟的音频

int main()

{

int fd;

int wavfd; /* wav文件的描述符 */

int arg; /* ioctl参数 */

int ret; /* 返回值 */

/* 打开dsp音频设备 */

fd = open("/dev/dsp", O_WRONLY);

if (fd < 0) {

printf("open of /dev/dsp failed");

exit(1);

}

wavfd = open("pass.wav",O_RDONLY);

if (wavfd < 0) {

printf("open of wav failed");

close(fd);

exit(1);

}

/* 设置bit */

arg = SIZE;

ret = ioctl(fd, SOUND_PCM_WRITE_BITS, &arg);

if (ret == -1)

perror("SOUND_PCM_WRITE_BITS ioctl failed");

if (arg != SIZE)

perror("unable to set sample size");

/* 设置channels */

arg = CHANNELS;

ret = ioctl(fd, SOUND_PCM_WRITE_CHANNELS, &arg);

if (ret == -1)

perror("SOUND_PCM_WRITE_CHANNELS ioctl failed");

if (arg != CHANNELS)

perror("unable to set number of channels");

/* 设置rate */

arg = RATE;

ret = ioctl(fd, SOUND_PCM_WRITE_RATE, &arg);

if (ret == -1)

perror("SOUND_PCM_WRITE_WRITE ioctl failed");

/* 从wav文件中读buff大小的内容，然后写入/dev/dsp中，直到文件结束 */

/* Q：这里我试验时播放了两次，不知道啥情况，如果大家也遇到了请指教。*/

while ((ret = read(wavfd, buff, sizeof(buff))) > 0) {

//printf("read size = %d\n", ret);

write(fd, buff, sizeof(buff));

/* 下面的代码用于在更改播放文件的参数时，播放掉缓冲区内的内容 */

ret = ioctl(fd, SOUND_PCM_SYNC, 0);

if (ret == -1)

perror("SOUND_PCM_SYNC ioctl failed");

}

close(fd);

close(wavfd);

}

下面是封装的接口可以直接拿过来使用：

void play_audio(int rate, int bits, int channels, char *filename)

{

int fd;

int wavfd; /* wav文件的描述符 */

int arg; /* ioctl arg */

int ret; /* return value */

unsigned char buff[rate * bits * channels / 8]; //buff里面正好放一秒钟的音频

/* open device */

fd = open("/dev/dsp", O_WRONLY);

if (fd < 0) {

printf("open of /dev/dsp failed");

exit(1);

}

wavfd = open(filename, O_RDONLY);

if (wavfd < 0) {

printf("open of wav failed");

close(fd);

exit(1);

}

/* set bits */

arg = bits;

ret = ioctl(fd, SOUND_PCM_WRITE_BITS, &arg);

if (ret == -1)

perror("SOUND_PCM_WRITE_BITS ioctl failed");

if (arg != SIZE)

perror("unable to set sample size");

/* set channels */

arg = channels;

ret = ioctl(fd, SOUND_PCM_WRITE_CHANNELS, &arg);

if (ret == -1)

perror("SOUND_PCM_WRITE_CHANNELS ioctl failed");

if (arg != CHANNELS)

perror("unable to set number of channels");

/* set rate */

arg = rate;

ret = ioctl(fd, SOUND_PCM_WRITE_RATE, &arg);

if (ret == -1)

perror("SOUND_PCM_WRITE_WRITE ioctl failed");

/* 从wav文件中读buff大小的内容，然后写入/dev/dsp中，直到文件结束 */

while ((ret = read(wavfd, buff, sizeof(buff))) > 0) {

printf("read size = %d\n", ret);

write(fd, buff, sizeof(buff));

/* 下面的代码用于在更改播放文件的参数时，播放掉缓冲区内的内容 */

ret = ioctl(fd, SOUND_PCM_SYNC, 0);

if (ret == -1)

perror("SOUND_PCM_SYNC ioctl failed");

}

close(fd);

close(wavfd);

}