Re: Live Video preview dropping frames in XP verses 98SE

Tech-Archive recommends: Repair Windows Errors & Optimize Windows Performance

From: The March Hare \(MVP\) (phil_at_ndsm.maps)
Date: 04/20/04 

Date: Mon, 19 Apr 2004 20:15:04 -0600

"Tom" <anonymous@discussions.microsoft.com> wrote in message
news:A2097AC6-63A1-43B3-9378-829492D021CF@microsoft.com...
>
> I used graph edit and built a graph with the VMR render(preview pin was
YUY2 format) and one with the standard render with an overlay mixer. Both
graphs had the same problem of looking like frames where dropped when the
system was busy doing other video tasks ( I have a test app displaying
various bitmaps and fonts.)

This is expected, especially on the older hardware you quoted.

> In graphedit I checked the properties of the VMR render and it never
showed any dropped frames but the standard render did not display any
Quality data ( I assume because the overlay was used). When I ran the test
load app the frame rate of the Render would decrease a little but no dropped
frames even though the video preview window look jerky as if frames were
being dropped.
>
> So if the render is not dropping frames then where is the data being lost?
Could it be the Video capture filter?

Yes. See CBaseVideoRenderer docs. "Cumulative frames that have been
dropped in the renderer since streaming started. Frames can also be dropped
upstream without the renderer recognizing them."

> Can I check if the video data is being transfer directly from the video
chip to the Display overlay surface or does Directshow not do this?

What video chip? The capture board?

> Any debug or performance tools I can run to debug this issue?

What is the issue? If there isn't enough CPU/GPU you will drop frames.
VMR9 isn't suited to older hardware because it is based on D3D.

See if your capture graph supports IAMDroppedFrames.

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