weird .mpg problem

corona_799

Guest

It’s hard to describe, but I’ll try anyway.

I have a mpeg file that is around 20 mins long, but when I open it, the player shows that it is only about 2:14. If I leave it like that, the video ends there, but if I move around the time bar, it jumps to different scenes that are supposed to come later. Also, jumping back and forth between the same times result in different scenes each time I do so.

Hope I’ve explained it clearly enough. Anyone help?

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Joined: 20 Nov 2004
Posts: 1,286

I presume you mean MPEG-1. If you’re unsure, feed the file into gspot to find out.

That’s usually the symptom of a truncated or corrupt file. If it’s a file you downloaded off the net, chunks are likely missing in the middle of the file (if you look with a hex editor you may see long strings of 0’s), so the timestamps are messed up. You can still see parts, or jump, but it’s not particularly dependable.
A very reliable way to diagnose this is to use VirtualDub (I know it’s a tool for AVI files, but it has an excellent MPEG-1 parser). If you open the file in VirtualDub, and it’s as I think it is, you’ll see a popup with messages like “MPEG anachronistic or discontinuous timestamp found”.

You may be able to fix the issue by rebuilding the mpeg file. You won’t be able to recover the missing chunks in the middle though.
I can’t remember on top of my head what the procedure is using TMPGEnc. I think it’s under File, MPEG Tools, Merge & Cut, then you add a file and browse for an output, when you click run it should automatically correct the file (easy way to check is feed output into VirtualDub). (The free version of TMPGEnc can be found here - after you pick your language, the download button is at the top of the page).

Append: A google search also turned up “mpeg corrector”, so you could try that. Before you use mpeg corrector, should you choose to do so, be sure to make a backup copy of the original.