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):
1 //需包含的头文件
2 #include <MMSystem.h>
3 #pragma comment(lib,"winmm.lib")
4 //PlaySound()函数和其他WIndows wave I/O API 函数的使用
5 #include "math.h"//sin()函数的使用
1.播放文件:
1 CString path; 2 path.Format("%s250.wav",g_BasePath); 3 //g_BasePath的取值不用多说,前面已详细介绍了。
4 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:
1 int rate=1000; //刺激率
2 int sampleRate = 44100; //采样率
3 const int NUMPTS = (int) (44100 * 0.5); // 0.5s
4 short int waveOut[NUMPTS];//音频数据 5
6 //内容
7 for (int i=0;i<NUMPTS;i++) 8 { 9 waveOut[i] = (short int)ceil(sin(2*3.1415926*rate*i/sampleRate)*20000); 10 } 11 //格式
12 WAVEFORMATEX pFormat; 13 pFormat.wFormatTag=WAVE_FORMAT_PCM; 14 //simple,uncompressed format
15 pFormat.nChannels=1;//1=mono, 2=stereo
16 pFormat.nSamplesPerSec=sampleRate; // 44100
17 pFormat.nAvgBytesPerSec=sampleRate*2; 18 // = nSamplesPerSec * n.Channels * wBitsPerSample/8
19 pFormat.nBlockAlign=2; // = n.Channels * wBitsPerSample/8
20 pFormat.wBitsPerSample=16; 21 //16 for high quality, 8 for telephone-grade
22 pFormat.cbSize=0;
2)打开一个给定的波形音频输出装置:
1 HWAVEOUT hWaveOut; 2 WAVEHDR WaveOutHdr; 3 MMRESULT result; 4 result = waveOutOpen(&hWaveOut, WAVE_MAPPER,&pFormat,0L, 0L, WAVE_FORMAT_DIRECT); 5 if (result) 6 { 7 MessageBox(_T("Failed to open waveform output device.")); 8 return; 9 }
(3)准备波形数据块:
1 WaveOutHdr.lpData = (LPSTR)waveOut; 2 WaveOutHdr.dwBufferLength = NUMPTS*2; 3 WaveOutHdr.dwBytesRecorded=0; 4 WaveOutHdr.dwUser = 0L; 5 WaveOutHdr.dwFlags = 0L; 6 WaveOutHdr.dwLoops = 0L; 7 waveOutPrepareHeader(hWaveOut, &WaveOutHdr, sizeof(WAVEHDR));
(4)向给定音频媒体中输出波形数据块:
1 result = waveOutWrite(hWaveOut, &WaveOutHdr, sizeof(WAVEHDR)); 2 if (result) 3 { 4 MessageBox(_T("Failed to play sound")); 5 return; 6 }
(5)清除准备:
1 // Wait until finished sound play
2 do {} while (waveOutUnprepareHeader(hWaveOut, &WaveOutHdr, sizeof(WAVEHDR))==WAVERR_STILLPLAYING);
(6)关闭给定音频媒体:
1 waveOutClose(hWaveOut);