Fixing defective .MPG file

[Seeker47]

Not sure if this is the most appropriate forum, but here goes. What sort of defect accounts for an .MPG video that plays just fine in current GOM on the computer (though not in recent VLC), but when it plays on a standalone player, it is not searchable or fast-forwardable, freezes and dies within the first two minutes of its 25 min. running time ? And what does one use to attempt to repair it ? My search in the Tools forum brings up this

https://www.videohelp.com/tools?toolsearch=repair+mpeg&Submit=Search&s=&orderby=Name&hi...uthorfeatures=

but neither sounds all that on-target. The clip is not VCD, and not in HD. I can run it through GSpot or MediaInfo, if more specific codec info is required to answer this. It would be nice if there was a (preferably free) diagnostic utility that could tell you just what was wrong with a given video.

[poisondeathray]

Sometimes the index is broken or the .mpg is corrupt, I don't think there are any diagnostic utilities that are remotely accurate

Sometimes you can fix it with the "quickstream fix" option in videoredo ($)

I've had some luck with PVAStrumento (free), using the "make ps" option - it basically re-packages the .mpg

[Seeker47]

Sometimes the index is broken or the .mpg is corrupt, I don't think there are any diagnostic utilities that are remotely accurate

Sometimes you can fix it with the "quickstream fix" option in videoredo ($)

I've had some luck with PVAStrumento (free), using the "make ps" option - it basically re-packages the .mpg

Thanks for those suggestions. I'm wondering how it is that these .MPG files may be corrupt, damaged, lost their index or whatever, and yet on-the-computer players like VLC or Gom (perhaps not both players for a given file, but definitely one or the other of them) can still play the file in a seemingly normal way ? By this I mean no evident glitches, with the file still searchable or fast-forward / reversible from the player controls ?

[redwudz]

Not so complicated. VLC and some other software players can ignore errors. But re-encoding may fail because of those same errors as that needs a 100% error free file. That's just part of digital video. My guess is that the index is trashed. And there may be some discontinuities in the file itself.

Try opening it in VirtualDub Mod. I suspect it will only open part of the video and stall at the problem section. But it may give you some info on the errors. VD Mod won't be able to fix them in MPEG format, though.

Another option is to open it in VLC and see if it can transcode it to a different file.

Generally, I haven't had much luck with 'fixer' programs with MPEG files that are really messed up.

[Soopafresh]

Gspot capture would be great to see.

[Seeker47]

Not so complicated. VLC and some other software players can ignore errors. But re-encoding may fail because of those same errors as that needs a 100% error free file. That's just part of digital video. My guess is that the index is trashed. And there may be some discontinuities in the file itself.

Try opening it in VirtualDub Mod. I suspect it will only open part of the video and stall at the problem section. But it may give you some info on the errors. VD Mod won't be able to fix them in MPEG format, though.

I've now tried poisondeathray's suggestion for PVASTRUMENTO, since that one was free, did not need any real installation, and seemed pretty accessible (even though I can't say I really understand what it does, other than the demux option). The PS option tried to do its thing, then basically said "Can't Sync. Not enough data." There was some header type info missing, and it complained about the audio portion, although the audio is there when played on the PC.

Another option is to open it in VLC and see if it can transcode it to a different file.

Since VLC is already present, I should be able to try that shortly.

Generally, I haven't had much luck with 'fixer' programs with MPEG files that are really messed up.

Does that mean that VideoRedo (poisondeathray's other suggestion) is unlikely to succeed where PVAS failed ? I was probably going to buy VDR sooner or later anyway -- either that or Womble, or maybe TME. I don't know how limited their Trial versions may be.

Gspot capture would be great to see.

I'll try to have that to post later on.

[redwudz]

I'd give it a try with VideoReDo. Most times if you can get a video to open in a editor, you can fix it. VLC's transcode feature is a bit limited, but I have had success a few times with a damaged MPEG.

I've had a lot more success fixing damaged AVI type files than with MPEG types.

[Seeker47]

I'd give it a try with VideoReDo. Most times if you can get a video to open in a editor, you can fix it. VLC's transcode feature is a bit limited, but I have had success a few times with a damaged MPEG.

I've had a lot more success fixing damaged AVI type files than with MPEG types.

If I can attempt that with the Trial version (as opposed to those program trial versions that don't let you write the results to disk), that would be great.

When you say "transcode", I take it that means some loss of quality, even if successful ? And that would apply to the VLC procedure as well ? (I take it that way because on VH folks always seem to be looking for tools that process something without transcoding, so as to avoid loss of video quality.) My recollection is that a lot of the non-player functions or controls of VLC are not all that easy to find. In that case, I might as well ask for some quick directions, re the VLC procedure being referred to above.

[Seeker47]

I'd give it a try with VideoReDo. Most times if you can get a video to open in a editor, you can fix it. VLC's transcode feature is a bit limited, but I have had success a few times with a damaged MPEG.

I installed the trial version of VideoRedo, and so far it is 2 for 2 on repairing damaged MPEG files, however on one of those it lopped off 10 minutes from a 25 minute video, reducing it to 15 min.s that play fine. (What's up with that ?) I've also noticed something odd with those and a few other files, after I've let ConvertX adapt them for standalone player playback: on my Pioneer DVDR, the audio portion is turning out like something from Alvin & the Chipmunks (!) . . . but the DVD sounds normal if played on the Oppo. Weird. Normally, I don't play more than brief spot sections on the Pioneer -- for checking purposes -- because I save its' burner almost exclusively for recording. I'll have to try a couple other standalone players, to see if this occurs anywhere else.

I've had a lot more success fixing damaged AVI type files than with MPEG types.

What do you use for that, or for damaged WMV files ?

Gspot capture would be great to see.

This will be much easier, now that it seems I've got that computer working properly again, for the first time in a long time. I'm going to guess that you're mostly interested in that "checkerboard" display from Gspot ? The report should be very different, as between the VideoRedo-fixed and the original versions of a bad MPG file ? Now I need to find that guide on uploading images here. I'd rather not bother with one of those file-host services.