播发minimad的解码声音

播放minimad的解码声音

网上有篇利用libao结合minimad的播放mp3程序,试用发现电流声过大,而且又要调用libao还不如直接对声卡编程。将minimad解码声音用以下命令写入一个文件中，$./minimad <丁香花.mp3 1>temp然后用程序播放即可，命令如下：$./a.out temp在virtual pc下还有略微的电流声而在另外一台redhat9中速度过快，有些变调，暂时还不知道怎么调节。播放的实质其实关键是要调节几个参数。 

#include <stdio.h>#include <stdlib.h>#include <unistd.h>#include <fcntl.h>#include <sys/ioctl.h>#include <sys/soundcard.h>int main(int argc, char *argv[]){int id,fd,i;char buf[4096];int rate; /* 采样频率 44.1KHz*/int format; /* 量化位数 16*/int channels; /* 声道数 2*/int setting; /* 高16位标明分片最大序号,低16位标明缓冲区的尺寸*/if (argc != 2){fprintf (stderr, "usage: %s <filename>!\n", argv[0]);exit ( -1 ) ;}if ( ( fd = open (argv[1],O_RDONLY))<0){fprintf ( stderr, " Can't open sound file!\n");exit (-1 );}if ( ( id = open ( "/dev/dsp", O_WRONLY) ) < 0 ){fprintf (stderr, " Can't open sound device!\n");exit ( -1 ) ;}/* 此项在Virtual PC中可减少电流声 */setting = 0x0002000F;ioctl(id, SNDCTL_DSP_SETFRAGMENT, &setting);rate = 441000;ioctl(id, SNDCTL_DSP_SPEED, &rate);format = AFMT_S16_LE;ioctl(id, SNDCTL_DSP_SETFMT, &format);channels = 2;ioctl(id, SNDCTL_DSP_CHANNELS, &channels);while((i = read(fd,buf, sizeof(buf)))>0){write(id,buf,i);}close(fd);close(id);exit(0);}

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