GOP errors

markayates

New member
When I try burning the saved mpeg2s to a DVD using DVD Lab Pro I get warning messages that the mpeg2s are not correct due to GOP issues. When they are burned to DVD they then have problems when being played.
The GOP error means that when I skip from 1 video to the next it gets completely confused play freezes, sound from other files plays, picture blocking errors.
Has anyone else experienced this? Is this a fault in Video ReDo's editing of mpeg2 files?
My mpeg2s are sourced from a TV based HDD recorder in mpeg2. I use Video Redo to strip the file down to a pure mpeg2.
 

Anole

Moderator
Well, DVD Labs is overbearing, complicated, non-intuitive, and intimidating to use the first time.
Do you have experience using it?
Have you made good discs with it before, from other source material?

Is the error message from DVD Labs that you have open GOPs ?
If so, this can be ignored.
The worst that will happen is that your chapter marks might be off a few frames.

You talk about using "saved Mpeg2's" for source material.
Could you elaborate on your "TV based HDD recorder" ?
And what format are they in?
Load one into VideoReDo , press Ctrl-L, and post that info.
The GOP error means that when I skip from 1 video to the next it gets completely confused play freezes, sound from other files plays, picture blocking errors.
I build multi-episode or multi-movie discs all the time with DVD Labs and VideoReDo, and never have such a problem.
Is this a possible problem with the player?
You seem to suggest it's a source problem...

There are a lot of unknowns... I guess the best way to narrow down the problem is this:
Do each of the files/movies/episodes/shows play okay for you on your computer in VideoReDo?
Have you tried making a DVD with just a single one of your shows, and if so, how does it play?

We'll zero in on your problem, and get you fixed right up! ;)
 
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laserfan

New member
markayates said:
I get warning messages that the mpeg2s are not correct due to GOP issues.
It's possible (likely?) that the "GOP issues" are that your GOPs are too long, and thus are out-of-DVD-spec.

Try switching on the GOP length option when you save out of VRD, and set it to 18 or less. If your files are e.g. Tivo files, VRD may have to make many hundreds of re-encoded GOPs in order to create a DVD-compliant output file.
 

TimA-C

Member
TMPGenc's DVd Author 2 (previously Pro) won't accept many things I've recorded from the E4/More4 Freeview channels unless I save from VRD with the GOP set to 15. (It may accept other values, but my understanding was that 15 was the correct size for PAL DVDs). If VRD does have to change the GOP size then it will dramatically increase the time to save an edited file. (An episode of Hill St. Blues would often take getting on for 20mins when changing the GOP size compared with maybe 3-4 mins when it didn't)
 

Anole

Moderator
Yes, GOP length may be one component of the problem.
I don't want to jump on that bandwaggon as the likely/only cause just yet.

However, I've done some saves of Dish satellite output with various GOP settings, including 10, 18, 24, 36, 40, and 48.
You'd be surprised how long some of these GOPs are!
I've posted in other threads that I am concerned that GOP length may be a contributing factor to some of the problems we see.
And I've certainly found that there are outrageously long GOP runs, as DanR has suggested!

As for the time it takes to save, yes, it may go from two minutes to 20 ... or worse.
And doing experiments with different GOP sizes then becomes a real labor.
It's not a universal cure for what ails you.
But when it is a component of the cure, the long save times could make the difference between a working DVD and one that fails.
 

TimA-C

Member
Anole said:
As for the time it takes to save, yes, it may go from two minutes to 20 ... or worse.
And doing experiments with different GOP sizes then becomes a real labor.
It's not a universal cure for what ails you.
But when it is a component of the cure, the long save times could make the difference between a working DVD and one that fails.
Anole, I'm not complaining about the extra time it takes to rearrange the GOP sequences, just warning that it could take quite a bit longer than normal, in case somebody thinks that VRD has locked up or something.
 
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