7 minute .mp4 file opens in MPC with HOURS listed as length.

I recorded a 7 minute .mp4 piece of game footage with my new HD PVR Gaming Edition. I try to open it in Media Player Classic, which tells me the video is 39:56:24 in length, and stops me being able to skip around the file using seek bar.

Windows Media Player seems to play the video fine though.

 

What happens if you play it in VLC?

Might be a weird codec issue or something.