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序号：50470 发表者：vivid 发表日期：2003-08-21 12:54:26
<br>主题：帮忙看看这段程序，thx
<br>内容：我再网上copy了这样一段程序，然后新建了一个win32 console application的工程，但是运行以后得到的结果不是播放视频文件，而是出来一个黑屏：press any key to continue.这是怎么回事啊？<BR>#include <dshow.h><BR><BR>#pragma comment(lib,"Strmiids.lib")<BR>#pragma comment(lib,"Quartz.lib")<BR><BR>void main(void)<BR>{<BR>IGraphBuilder *pGraph;<BR>IMediaControl *pMediaControl;<BR>IMediaEvent *pEvent;<BR>CoInitialize(NULL);<BR><BR>// 创建过滤通道管理器，并引出其接口<BR>CoCreateInstance(CLSID_FilterGraph, NULL, CLSCTX_INPROC_SERVER, <BR>IID_IGraphBuilder, (void **)&pGraph);<BR>pGraph->QueryInterface(IID_IMediaControl, (void **)&pMediaControl);<BR>pGraph->QueryInterface(IID_IMediaEvent, (void **)&pEvent);<BR><BR>// 为指定文件建立通道<BR>// 注意：此处的文件名字符串依照自己要播放的文件而定<BR>// 注意：L"字符串"是一个把ANSI字符串转换为UNICODE字符串的宏<BR>pGraph->RenderFile(L"C:\\Example.avi", NULL);<BR><BR>// 运行此通道<BR>pMediaControl->Run();<BR><BR>// 等待播放完毕或停止 <BR>long evCode;<BR>pEvent->WaitForCompletion(INFINITE, &evCode);<BR><BR>// 释放所有接口<BR>pMediaControl->Release();<BR>pEvent->Release();<BR>pGraph->Release();<BR>CoUninitialize();<BR>}<BR><BR>
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<font color=red>答案被接受</font><br>回复者：绍辉 回复日期：2003-08-27 21:47:46
<br>内容：CoCreateInstance(CLSID_FilterGraph, NULL, CLSCTX_INPROC_SERVER, <BR>IID_IGraphBuilder, (void **)&pGraph);<BR>该语句有误，IID_IGraphBuilder应该是IID_IFilterGraph，且pGraph的类型应该为<BR>IFilterGraph。<BR>然后通过pGraph->QueryInterface(IID_IGraphBuilder, (void **)&pBuilder);得到<BR>IGraphBuilder类型的pBuilder，最后调用 pBuilder->RenderFile(L"C:\\Example.avi", NULL);<BR> <BR><BR>
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回复者：微笑的撒旦 回复日期：2003-08-27 23:28:35
<br>内容：源程序是这样的<BR>#include <dshow.h><BR>void main(void)<BR>{<BR> IGraphBuilder *pGraph = NULL;<BR> IMediaControl *pControl = NULL;<BR> IMediaEvent *pEvent = NULL;<BR><BR> // Initialize the COM library.<BR> HRESULT hr = CoInitialize(NULL);<BR> if (FAILED(hr))<BR> {<BR> printf("ERROR - Could not initialize COM library");<BR> return;<BR> }<BR><BR> // Create the filter graph manager and query for interfaces.<BR> hr = CoCreateInstance(CLSID_FilterGraph, NULL, CLSCTX_INPROC_SERVER, <BR> IID_IGraphBuilder, (void **)&pGraph);<BR> if (FAILED(hr))<BR> {<BR> printf("ERROR - Could not create the Filter Graph Manager.");<BR> return;<BR> }<BR><BR> hr = pGraph->QueryInterface(IID_IMediaControl, (void **)&pControl);<BR> hr = pGraph->QueryInterface(IID_IMediaEvent, (void **)&pEvent);<BR><BR> // Build the graph. IMPORTANT: Change this string to a file on your system.<BR> hr = pGraph->RenderFile(L"C:\\Example.avi", NULL);<BR> if (SUCCEEDED(hr))<BR> {<BR> // Run the graph.<BR> hr = pControl->Run();<BR> if (SUCCEEDED(hr))<BR> {<BR> // Wait for completion.<BR> long evCode;<BR> pEvent->WaitForCompletion(INFINITE, &evCode);<BR><BR> // Note: Do not use INFINITE in a real application, because it<BR> // can block indefinitely.<BR> }<BR> }<BR> pControl->Release();<BR> pEvent->Release();<BR> pGraph->Release();<BR> CoUninitialize();<BR>}<BR><BR>这是Directx Show的SDK文档上的例子，在DirectShow->Getting Started->How to play a file。在学习之前先看文档啊，会了解得跟全面。
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回复者：vivid 回复日期：2003-08-28 09:37:20
<br>内容：一楼的shaohui 朋友，我按照你说的修改了原来的程序，但是不能运行，说应用程序错误，不知道怎么回事：（
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回复者：绍辉 回复日期：2003-08-28 12:28:52
<br>内容：我刚才试了一下，其实你开始的程序是正确的，我更改的也是正确的，都可以播放。是不是在你的C盘下没有文件Example.avi，所以不能播放？如果是这样的话在RenderFile中指定一个存在的媒体文件。<BR><BR>我更改的如下：<BR>void main(void)<BR>{<BR> IFilterGraph *pGraph;<BR> IGraphBuilder *pBuilder;<BR> IMediaControl *pMediaControl;<BR> IMediaEvent *pEvent;<BR> CoInitialize(NULL);<BR> <BR> // 创建过滤通道管理器，并引出其接口<BR> CoCreateInstance(CLSID_FilterGraph, NULL, CLSCTX_INPROC_SERVER, <BR> IID_IFilterGraph, (void **)&pGraph);<BR><BR> pGraph->QueryInterface(IID_IGraphBuilder, (void **)&pBuilder);<BR><BR><BR> pGraph->QueryInterface(IID_IMediaControl, (void **)&pMediaControl);<BR> pGraph->QueryInterface(IID_IMediaEvent, (void **)&pEvent);<BR> <BR> // 为指定文件建立通道<BR> // 注意：此处的文件名字符串依照自己要播放的文件而定<BR> // 注意：L"字符串"是一个把ANSI字符串转换为UNICODE字符串的宏<BR> pBuilder->RenderFile(L"F:\\Out2.dat", NULL);<BR> <BR> // 运行此通道<BR> pMediaControl->Run();<BR> <BR> // 等待播放完毕或停止 <BR> long evCode;<BR> pEvent->WaitForCompletion(INFINITE, &evCode);<BR> <BR> // 释放所有接口<BR> pMediaControl->Release();<BR> pEvent->Release();<BR> pGraph->Release();<BR> CoUninitialize();<BR>}<BR>
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