在程序中,很有可能会涉及到播放一些音频文件(比如:.wav文件)和音频数据,这个问题怎么解决呢?VC++中想要播放一个音频文件(.wav)是很容易的,只要调用WIndows API函数PlaySound()就可以了,但是,如果您想播放自己在程序中产生的一段音频数据,就不是那么简单了,需要利用WIndows wave I/O API的几个函数来实现。
下面结合实例来说明(完整实例可在我的CSDN资源中下载:http://download.csdn.net/detail/margin1988/3677328,该例子利用WIndows wave I/O API 函数,实现了播放自定义的一段音频数据(通过sin()函数产生);并且使用了PlaySound()函数播放“250.wav”文件):
//需包含的头文件
#include <MMSystem.h>
#pragma comment(lib,"winmm.lib")
//PlaySound()函数和其他WIndows wave I/O API 函数的使用
#include "math.h"//sin()函数的使用
1.播放文件:
CString path;
path.Format("%s250.wav",g_BasePath);
//g_BasePath的取值不用多说,前面已详细介绍了。
PlaySound(_T(path),0,SND_FILENAME|SND_ASYNC);
2.播放数据:
(1)确定音频数据的格式及内容:
int rate=1000; //刺激率
int sampleRate = 44100; //采样率
const int NUMPTS = (int) (44100 * 0.5); // 0.5s
short int waveOut[NUMPTS];//音频数据
//内容
for (int i=0;i<NUMPTS;i++)
{
waveOut[i] = (short int)ceil(sin(2*3.1415926*rate*i/sampleRate)*20000);
}
//格式
WAVEFORMATEX pFormat;
pFormat.wFormatTag=WAVE_FORMAT_PCM;
//simple,uncompressed format
pFormat.nChannels=1;//1=mono, 2=stereo
pFormat.nSamplesPerSec=sampleRate; // 44100
pFormat.nAvgBytesPerSec=sampleRate*2;
// = nSamplesPerSec * n.Channels * wBitsPerSample/8
pFormat.nBlockAlign=2; // = n.Channels * wBitsPerSample/8
pFormat.wBitsPerSample=16;
//16 for high quality, 8 for telephone-grade
pFormat.cbSize=0;
(2)打开一个给定的波形音频输出装置:
HWAVEOUT hWaveOut;
WAVEHDR WaveOutHdr;
MMRESULT result;
result = waveOutOpen(&hWaveOut, WAVE_MAPPER,&pFormat,0L, 0L, WAVE_FORMAT_DIRECT);
if (result)
{
MessageBox(_T("Failed to open waveform output device."));
return;
}
(3)准备波形数据块:
WaveOutHdr.lpData = (LPSTR)waveOut;
WaveOutHdr.dwBufferLength = NUMPTS*2;
WaveOutHdr.dwBytesRecorded=0;
WaveOutHdr.dwUser = 0L;
WaveOutHdr.dwFlags = 0L;
WaveOutHdr.dwLoops = 0L;
waveOutPrepareHeader(hWaveOut, &WaveOutHdr, sizeof(WAVEHDR));
(4)向给定音频媒体中输出波形数据块:
result = waveOutWrite(hWaveOut, &WaveOutHdr, sizeof(WAVEHDR));
if (result)
{
MessageBox(_T("Failed to play sound"));
return;
}
(5)清除准备:
// Wait until finished sound play
do {} while (waveOutUnprepareHeader(hWaveOut, &WaveOutHdr, sizeof(WAVEHDR))==WAVERR_STILLPLAYING);
(6)关闭给定音频媒体:
waveOutClose(hWaveOut);