I've recently noticed a problem playing MPEG-1 video files in Windows Media Player 9 and Real Player 10.

The video doesn't play at all (i.e. the screen is blank) but the audio plays OK, and sometimes (but not always) after a few seconds more also stops.

If I manually advance the progress marker along the timeline, the video then starts playing but it is out of sync with the audio.

MPEG-2 video's play just fine.

I'm not experienced at this sort of thing, but I thought it must be a codec issue, but running the AVI Codec tool on my computer says the following for an MPEG-1 video:

V. Codec Name: MPEG 1 (VCD)
A.1 Codec Name: Mpeg-1 audio Layer 2 [0xc0]
V.codec vendor: Supported

So I assume I have the necessary codecs installed. What is most puzzling to me about this (as a novice) is that if I play the same video in PowerDVD 5 it works just fine. I can also produce MPEG-1 videos in Pinnacle Studio 9.

I think you can tell by now that I am confused. Please help!