Weird timing problem with some mpegs...

Factual Questions
1

I downloaded a 100MB mpeg file and used Windows Media Player (WMP) 8 to view it. The video file is at least 30 minutes long. But the WMP timing slider moves very fast and reaches the right side of the slide after about 1 minute!

After that point, the mpeg video stutters for the next 29 minutes.

When I move the slider back to any point on the slide, the mpeg begins to play at the accurate point in the video. But then it quickly moves to the right and movies begins to stutter again.

I tried to search Google for help, but because I’m not even sure how to describe the problem and I lack the technical vocabulary, my search was in vain.

Please, Straight Dopers, help me! (Assuming you can userstand my question!)

2

Upgrade to WMP9, maybe? It sounds like a codec problem, and since (at least some) new codecs come with 9, that might help.

3

Thanks for the suggestion. I actually did update to WMP 9 yesterday and it does the same thing.

I should also point out that this only seems to happen with longer mpeg files and not with other video file types or even short mpegs.

Still looking for suggestions!