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序號：62208 發表者：nbm 發表日期：2003-11-25 12:16:01
<br>主題：奇怪，我抓的圖為什么上面有三分之一是黑的？
<br>內容：我抓的圖上面有三分之一是黑的，所以抓的圖就少了三分之一，不知道為什么？程序如下：<BR>抓圖部分：<BR>&nbsp;&nbsp;&nbsp;&nbsp;HRESULT hr;<BR><BR>&nbsp;&nbsp;&nbsp;&nbsp;m_pGB-&gt;QueryInterface(IID_IBasicVideo, (void **)&amp;pibv);<BR>&nbsp;&nbsp;&nbsp;&nbsp;long* image = NULL; <BR><BR>&nbsp;&nbsp;&nbsp;&nbsp;pibv-&gt;GetVideoSize(&amp;lWidth, &amp;lHeight); <BR><BR>&nbsp;&nbsp;&nbsp;&nbsp;// determine size <BR>&nbsp;&nbsp;&nbsp;&nbsp;pibv-&gt;GetCurrentImage(&amp;size,image); <BR><BR>&nbsp;&nbsp;&nbsp;&nbsp;buffer = new char[size]; <BR><BR>&nbsp;&nbsp;&nbsp;&nbsp;hr = pibv-&gt;GetCurrentImage(&amp;size,(long*)buffer); <BR><BR>&nbsp;&nbsp;&nbsp;&nbsp;lpbi = (LPBITMAPINFOHEADER)buffer; <BR>寫文件部分：<BR>&nbsp;&nbsp;&nbsp;&nbsp;HANDLE&nbsp;&nbsp;fh;<BR>&nbsp;&nbsp;//創建位圖文件&nbsp;&nbsp;&nbsp;&nbsp;<BR>&nbsp;&nbsp;&nbsp;&nbsp;fh = CreateFile(&#34;h:\\b.bmp&#34;, GENERIC_WRITE, <BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 0, NULL, CREATE_ALWAYS,<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; FILE_ATTRIBUTE_NORMAL | FILE_FLAG_SEQUENTIAL_SCAN, NULL);<BR><BR>&nbsp;&nbsp; if (fh == INVALID_HANDLE_VALUE)<BR>&nbsp;&nbsp; {<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;AfxMessageBox(&#34;error&#34;);<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;return ;<BR>&nbsp;&nbsp;&nbsp;&nbsp;}<BR><BR>&nbsp;&nbsp;&nbsp;&nbsp;DWORD dwWritten;<BR>&nbsp;&nbsp; // 寫入位圖文件頭<BR>&nbsp;&nbsp; WriteFile(fh, lpbi, sizeof(BITMAPFILEHEADER), &amp;dwWritten, NULL);<BR><BR>&nbsp;&nbsp; // 寫入位圖文件其余內容<BR>&nbsp;&nbsp; WriteFile(fh, (LPSTR)buffer, size,&nbsp;&nbsp;&amp;dwWritten, NULL);<BR>&nbsp;&nbsp; <BR>&nbsp;&nbsp; //消除內存分配&nbsp;&nbsp;<BR>&nbsp;&nbsp; CloseHandle(fh);<BR>
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<font color=red>答案被接受</font><br>回復者：DickieX 回復日期：2003-11-25 17:22:43
<br>內容：BITMAPFILEHEADER里面的值要設定吧.
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回復者：nbm 回復日期：2003-11-25 17:35:27
<br>內容：謝謝，我的問題已經解決了，你知不知道如何從某一幀開始播放，并能把該幀取出來存成BMP?<BR>
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回復者：donly 回復日期：2003-11-26 23:31:46
<br>內容： IMediaSeek接口有：可以設置播放的位置！<BR>hr = m_pMS-&gt;SetPositions(&amp;pos, AM_SEEKING_AbsolutePositioning ,<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; NULL, AM_SEEKING_NoPositioning);<BR><BR>其實Directshow的IMediaDet里面已經提供了保存BMP的方法，直接用該函數就可以了<BR>hr=m_pMD-&gt;WriteBitmapBits(dCurTime,m_lWidth,m_lHeight,wsFilename);<BR>&nbsp;&nbsp;&nbsp;&nbsp;if (FAILED(hr))&nbsp;&nbsp;return FALSE;<BR><BR>查看一下幫助什么都有^_^
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