如何用directsound实现音量调节

sweetpea

如何用directsound实现音量调节 [复制链接]

如题。期待高手指点！

yangwm

1. if (S_OK == CoInitializeEx(NULL, COINIT_MULTITHREADED))
   
2.         {
   
3.                 RETAILMSG(DBGMSGON, (_T("\n\tInitializes the Component Object Model (COM)...OK\n")));
   
4.         }
   
5.         if(MMSYSERR_NOERROR == waveOutSetVolume(0, 0xffffffff))
   
6.         {//设置系统音量
   
7.                 RETAILMSG(DBGMSGON, (_T("MySystem Volume set...ok\n")));
   
8.         }
   
9.         if (S_OK == CoCreateInstance(CLSID_FilterGraph, NULL, CLSCTX_INPROC, IID_IGraphBuilder, (void **)&pGraph))
   
10.         {
    
11.                 RETAILMSG(DBGMSGON, (_T("\tCoCreateInstance ...OK\n\n")));
    
12.         }
    
13.         else
    
14.         {
    
15.                 RETAILMSG(DBGMSGON, (_T("\tCoCreateInstance ...failed\n\n")));
    
16.                 return FALSE;
    
17.         }
    
18.         if(pGraph->QueryInterface(IID_IMediaControl, (void **)&pMediaControl) != NOERROR)
    
19.         {
    
20.                 RETAILMSG(DBGMSGON, (_T("QueryInterface IMediaControl failed")));
    
21.                 return FALSE;
    
22.         }
    
23.         if(pGraph->QueryInterface(IID_IBasicAudio, (void **)&m_pBA) != NOERROR)
    
24.         {//
    
25.                 RETAILMSG(DBGMSGON, (_T("QueryInterface IBasicVideo failed")));
    
26.                 return FALSE;
    
27.         }
    
28.         if(pGraph->QueryInterface(IID_IMediaEventEx, (void **)&m_pME) != NOERROR)
    
29.         {
    
30.                 RETAILMSG(DBGMSGON, (_T("QueryInterface IMediaEvent failed")));
    
31.                 return FALSE;
    
32.         }
    
33.         m_pBA->put_Volume(lVolume);//-10000...0
    
34.         m_pBA->put_Balance(lBalance);//-10000...0...10000
    

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省略了很多

mhlllf

如何拖动滑块，改变音量呢？

wmj0402

有点难度哦