WPF MediaKit low frame rate for large display with VMR9

Question

I am using WPF MediaKit to render a directshow graph. The display framerate is fine if the wpf D3DRender is small. If I increase the size of the display (the control that is), the framerate drops significantly.

How do I prevent the drop in framerates? My display will need to occasional display the graph full screen, which causes the framerates to drop to an unacceptable value.

I heard the EVR (Enhanced Video Render) is much better than the VMR9. Will the EVR maintain the framerates when increasing the size of the display?

Answer 1

You should specify video compression codec (MediaSubType) when initializing directshow graph. I had the same problem when trying to capture video from web camera using default compression (in my case it was YUY2).

Example:

/// <summary>
/// Configures the DirectShow graph to play the selected video capture
/// device with the selected parameters
/// </summary>
private void SetupGraph()
{
    ...

    if (UseYuv && !EnableSampleGrabbing)
    {
        /* Configure the video output pin with our parameters and if it fails
         * then just use the default media subtype*/
        if (!SetVideoCaptureParameters(graphBuilder, m_captureDevice, MediaSubType.YUY2))
            SetVideoCaptureParameters(graphBuilder, m_captureDevice, Guid.Empty);
    }
    else
        /* Configure the video output pin with our parameters */
        SetVideoCaptureParameters(graphBuilder, m_captureDevice, MediaSubType.MJPG); // Change default compression to MJPG.

    ...
}

Example can be found in WPFMediaKit.DirectShow.MediaPlayers.VideoCapturePlayer.