播放mp3文件时如何控制音量？ [英] how to contorl the volume when playing mp3 file?

问题描述

我使用SndPlaySync播放mp3文件，我的问题是：如何调整音量？waveOutSetVolume似乎只在hwo设置为WAVE_MAPPER时才有效，如果设置为设备句柄，则无法正常工作。我只想更改应用程序的卷，不要影响整个系统。有没有办法做到这一点？谢谢。

I use SndPlaySync to play mp3 file, my question is: how to adjust the volume? waveOutSetVolume seems only work when hwo is set to WAVE_MAPPER, if set to the device handle, it's not working. I want to only change the volume for the application and don't affect the whole system. Is there a way to do that? Thanks.

推荐答案

您可能需要使用Windows Media Player界面。
希望这有助于

You may need to use Windows Media Player interface.
Hope this helps

	HRESULT					lHRes = E_FAIL;



	CComPtr<IWMPPlayer>		lPlayerPtr;



	CComPtr<IWMPSettings>	lPlayerSettingsPtr;



	LONG					lOldVolStatus = 0;



	CoInitializeEx(NULL,COINIT_MULTITHREADED);



	lHRes = lPlayerPtr.CoCreateInstance(__uuidof(WindowsMediaPlayer));



	if(SUCCEEDED(lHRes) && (IWMPPlayer *)NULL != lPlayerPtr)



	{



		lPlayerPtr->get_settings(&lPlayerSettingsPtr);



		if((IWMPSettings *)NULL != lPlayerSettingsPtr)



		{



			lHRes = lPlayerSettingsPtr->get_volume(&lOldVolStatus);



			lHRes = lPlayerSettingsPtr->put_volume(100L);






		}



         lPlayerPtr.Release();



        }



        CoUninitialize();

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