directshow视频裁剪过滤器

Question

我想在directshow中创建一个过滤器，将o/p视频剪裁到某个感兴趣的区域。 [GetMediaType（int iPosition，CMediaType * pMediaType）“]我通过使用[DIBSIZE]更改[biWidth，biHeight和biSizeImage]指定指针指向pMediatype的视频标题，详情如下：

// pvih is a pointer to pMediaType->pbFormat of type videoheader 
//pInVh is a pointer to CurrentMediaType().pbFormat of the i/p of type videoheader 
pvih->rcSource = pInVh->rcSource; 
pvih->rcTarget = pInVh->rcTarget; 
//bitmap settings 
pvih->bmiHeader.biWidth = _Width;//width of region of interest 
pvih->bmiHeader.biHeight = _Height;// height of region of interest 
m_Width=pInVh->bmiHeader.biWidth; 
m_Height=pInVh->bmiHeader.biHeight; 
pvih->bmiHeader.biSize = sizeof(BITMAPINFOHEADER); 
pvih->bmiHeader.biPlanes = 1;    //1 image plane 
pvih->bmiHeader.biBitCount = 24;   //24bit 
pvih->bmiHeader.biCompression = BI_RGB; //simply three values 
pvih->bmiHeader.biSizeImage = DIBSIZE(pvih->bmiHeader); 


//mediatype settings 
pMediaType->majortype = MEDIATYPE_Video; //a video stream 
pMediaType->subtype = MEDIASUBTYPE_RGB24; //24bit rgb samples 
pMediaType->bFixedSizeSamples = true;  //no varying size 
pMediaType->bTemporalCompression = false; //no compression 
pMediaType->formattype = FORMAT_VideoInfo; //VIDEOINFOHEADER 
pMediaType->lSampleSize = pvih->bmiHeader.biWidth * pvih->bmiHeader.biHeight * pvih- >bmiHeader.biBitCount/8; //size of one sample in bytes 
pMediaType->cbFormat = sizeof(VIDEOINFOHEADER); //additiona format setting 

但是当我用原始帧的样本填充裁剪框架时，o/p视频是垃圾，我也试着用常量颜色填充它，o/p不正确，不知道如何解决这个问题？

Answer 1

这是任何帮助： http://videoprocessing.sourceforge.net/#crop

还有就是源代码可用。