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How can I ensure the correct frame rate when recording animations using DirectShow?

I am trying to write an animation (computer graphics, not video) to a WMV file using DirectShow. Setup:

  • A Push source that uses a bitmap in memory containing an animation frame. Each time FillBuffer () is called, the bitmap image data is copied to the sample, and the sample has a time stamp with the start time (frame number * frame length) and duration (frame length). The frame rate in the filter is set to 10 frames per second.

  • ASF Writer Filter. I have a custom profile file that sets a video at 10 frames per second. Its video filter, so there is no sound.

The ligaments are connected, and when the graph starts, a wmv file is created. But...

The problem is that DirectShow outputs data from the Push source at a speed of more than 10 FPS. Thus, the wmv result, reproduced and containing the correct animation (as well as a message about the correct FPS), plays the animation several times too slowly, because too many frames were added during recording. That is, a 10-second video in 10 FPS should have only 100 frames, but about 500 are recorded in the video, as a result of the video lasts 50 seconds.

My initial attempt at a solution was only to slow down the call to FillBuffer () by adding sleep () by 1/10 of a second. And it really more or less works. But it seems hacky, and I doubt it will work well at higher FPS.

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:

DateTime start=DateTime.Now;
int frameCounter=0;
while (wePush)
{
    FillDataBuffer(...);
    frameCounter++;
    DateTime nextFrameTime=start.AddMilliseconds(frameCounter*100);
    int delay=(nextFrameTime-DateTime.Now).TotalMilliseconds;
    Sleep(delay);
}

EDIT:

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