GOP errors - what's the answer?

[Radixmind]

hi guys,

so, what's the solution, then? GOP errors in mpeg2 files can be pretty frustrating - i have some tv shows taken from DVD recorder discs that Cuttermaran warns have GOP errors, and most of the DVD authoring tools i use dont like them at all.

so, aside from reencoding the whole thing, what can be done?

people have suggested restream, which is a fine tool, but which hasnt helped me in this case - unless i'm doing it wrong of course.

similarly, the videohelp panacea, virtualdubmpeg has been suggested - but i dont see how i can get my original mpeg stream back out of it without making a MASSIVE avi file.

GOP errors have to be a pretty common problem - i imagine mine were a result of either the writing stage or the ripping stage (i used dvd decrypter). a quick fix should exist, surely?

anybody - what do you use? any replies gratefully accepted.

PS. apologies if i put this in the wrong forum.

[MOVIEGEEK]

I think the problem is your standalone recorder.
If they are VOB's you can try FixVTS,it won't fix GOP errors but it will fix navigation errors.If you want VOB->MPEG-2 try VOB2MPG.

[Radixmind]

thanks for replying, moviegeek.

i know where the problem lies. after about 50 re-recordings my DVD+RW's tend to get a bit flaky - i replace them pretty soon after that.

but that still leaves me with the occasional ripped file that has GOP errors. they're ripped as elementary streams, not VOB's. i'd still like to find a way to make them author-able.

the stupid thing is, the files alone play OK, not perfect, the point where the video recording screws up, the video 'skips' a bit, but recovers. but i cant get these files onto a dvd because i cant find software that will handle them.

as an aside, i tried creating a divx of the episode a few days ago, and that file messed up at the GOP error too - the audio stopped working.

it seems that these GOP errors are predominantly creating problems associated with muxing the audio back with the video, is that a fair assessment, people? when i was trying to work out why i couldnt author these, i originally thought the faulty file was the AC3 file, as the error messages i kept getting would only tell me the audio wasnt correct. i checked and reprocessed the audio several times before realising it was the video file.

[jimmalenko]

Maybe try MPEG-VCR's GOP fixer ?

[Radixmind]

thanks for the reply Jimmalenko,

unfortunately, i'm a bit of a wuss when it comes to installing software that i might ultimately not want to buy. i know Mpeg-VCR has a 30-day trial, but it might not do what i want, and these things rarely uninstall cleanly, i've found. perhaps there's someone out there who has used this program for this or similar, with good results. if so, post and let me know.

[Radixmind]

just to give some positive feedback here, i finally found a way to resolve my faulty GOP problem, using cuttermaran and tmpgenc (you could use any encoder really).

first, i identified the part of the file with the problem. this was easy for me as it was the point at which Cuttermaran stopped creating a new file in my failed cut - basically about 25 minutes in. thankfully there was only one real GOP problem - the file turned to garbage for about 4 seconds.

i then loaded the file into tmpgenc and used the 'select range' to choose only the bit of video garbage where the GOP error occurs. best way to set it is to choose clean action cuts in the show as edit points. then reprocess that section only, using identical processsing settings as the original.

you can now recompose these elements in Cuttermaran. if you use 'processing mode' it will cut frame accurately, so the video and audio will remain in sync. (best to remove any audio elements for the recomposing, and use your original audio file)

what you have then is a video file identical to the original, but which will author and playback without GOP errors, with the minimum of reprocessing. sure, it has a bit of visual garbage in it, but thats better than an unplayable file.

hope this workaround will be of help to others.

[jimmalenko]

unfortunately, i'm a bit of a wuss when it comes to installing software that i might ultimately not want to buy. i know Mpeg-VCR has a 30-day trial, but it might not do what i want, and these things rarely uninstall cleanly, i've found. perhaps there's someone out there who has used this program for this or similar, with good results. if so, post and let me know.

I have used this program to fix open GOPs with good results. That's why I recommended it.