How to change PGC starting point and playing time?

[FredThompson]

I've got a PGC for which I'd love to "crop" off the start and end by changing the pointer to the start of the video and the playing time.

PgcEdit has a nice interface which makes it easy to pick starting and stopping points but no way to edit that particular information. IfoEdit allows raw edit but I keep missing something as I twiddle bits to calculate the proper pointer and length.

I've used DVDStripper which frequently is able to kernalize things enough that little pieces can be removed. In this case, the junk is in the piece with the video I want. It's like a sandwich where the bread is the junk and the inside is what I want kept.

How can this be done?

[2COOL]

I think Vobblanker might be your answer.

[r0lZ]

It is illegal to change the start or end point of a cell. Some players will crash when trying to play such modified cells. This is why I doesn't allow to edit these values in PgcEdit.

VobBlanker is able to remove properly the beginning or end of a cell.

[pilotsnipes]

It is illegal to change the start or end point of a cell. Some players will crash when trying to play such modified cells. This is why I doesn't allow to edit these values in PgcEdit.

VobBlanker is able to remove properly the beginning or end of a cell.


Yes but to do so takes AGES to process the whole DVD again in VOBBLANKER, for the sake of the few minutes at the start of the movie.. If I go into IFOedit, i can changed the start time of the PCG in a few seconds.

I nearly do this on every DVD, because I HATE watching all that intro stuff (you know, the movie studio logos such as the circular flying stars, boys fishing from the moon, a big mountain, Warner Brothers studio symbol).....I mean, it can last up to 2mins before you even see the first shot of the movie. That sucks!!

Please r0lZ, if you can find it in your heart (!), please create a (secret?) option that warns us that changing the entry point is not safe (to keep all the other users away from it), but then enables us to do it. It works perfectly on my standalone.....and that's all I care about, I'm prepared to take the hit if it doesn't work elsewhere. Just like everyone else too I'd bet!

Please.

Oh and this isn't a suck up, but along with DVD shrink/DVD Decrypter, I think Pgcedit is phenomenal. Well done and thank you, you've saved me hours of work and it's appreciated.

[r0lZ]

Thanks. But I'm still not sure I will add this option. Wait and see.

[FredThompson]

@pilotsnipes,

You do know you can use the "kill playback" option of the right-click menu to prevent playback, yes?

VOBBlanker will run quite a bit faster if source and destination are on different drives. You can also use DVD Shrink with manual compression levels. Set the stuff you don't want to be a still image, run shrink, then use the kill playback function. DVDShrink won't parse those items which are set for no compression which means it will be faster than VOBBlanker. Granted, there will be a little bit of wasted space but not much.

[pilotsnipes]

@Fredthompson

Oh I don't think I expained that very well.

Bypassing FBI, Trailers, intros extras etc etc is no sweat, either by Killing the PGC playback, or if they're (ie extras) all in one video set, by "Blank out all VTST Titles".

Piece of cake,

Now for the anal part......you know when you click play on your movie, and as the movie starts you see the intro, it's usualy a movie company logo, followed by things like:

Columbia Pictures presents
In association with Blah blah studios
A really cool movie
It's going to appear soon
Yes we know this is annoying
But we need to pad this total time out
So here it is
That movie we talked about
(It's going to get really good reviews)
Just one more black screen with white writing on it.
We're presenting:
<pause>
Opening scene.


I think you get my drift, well normally all of that is in the first cell of the movie PGC...along with maybe the first 10mins of the movie, so you can't strip it away fastly (at least not with my experience of VOBblanker - it has to write all the massive VOB files again for the removal of 1min of video), nor do I need to.

All I wanted was to be able to edit the "Cell entry point sector" and change it from the original value of in and around 0 to the point where the movie starts.

Now this is definately not an overly recommended feature because it MIGHT POSSIBLY cause your standalone DVD player to choke on this new start sector and start at cell 2 instead.

I know from experience that my standalone does accept it, and I'm prepared to take the risk!

I'm anal I suppose :) Or did I just pick your reply up wrong!?

@r0lZ - Thankyou for at least considering it and having the courtesy to reply.

[FredThompson]

Take a look at DVDStripper. The vast majority of the time it can do what you want.

[Surf]

lmao @pilot's

Columbia Pictures presents
In association with Blah blah studios
A really cool movie
It's going to appear soon
Yes we know this is annoying
But we need to pad this total time out
So here it is
That movie we talked about
(It's going to get really good reviews)
Just one more black screen with white writing on it.
We're presenting:
<pause>
Opening scene.

Just sometimes, you can blank the 1st cell(maybe 2) of the movie with PgcEdit, provided it contains exactly what you described above.

If you want the anal way then I'm afraid you need VobBlanker's famous chop-chop method. I'm guessing that you don't have a 2nd hdd? I bought one just for vobblanking purpose and have nooooo regrets since! Lightning fast!

[pilotsnipes]

Just sometimes, you can blank the 1st cell(maybe 2) of the movie with PgcEdit, provided it contains exactly what you described above.


Only if you're lucky! I've found through experience that more than 80% of DVD have most of the first scene in Cell 1 along with all the intro stuff.

Having said that last night I did 2 DVD's BOTH of which had cell 1 exclusively used for the intro, and cell 2 onwards for the movie. Just the way I like it :)


If you want the anal way then I'm afraid you need VobBlanker's famous chop-chop method. I'm guessing that you don't have a 2nd hdd? I bought one just for vobblanking purpose and have nooooo regrets since! Lightning fast!


Hehe...yeah...well I'm not that Anal about it to be honest, it was just another idea I had seeing as I was already in PGCEDIT for 99% of my DVD editing time and thought it would be nice not to have to open IFOEDIT all the time.

It's funny how things change, I remember when I first saw PGCEDIT for the first time last year, I though "Ugh, don't like the look of that....IFOEDIT is much easier".....how times have changed. Couldn't do without PGCEDIT now!

[blutach]

Here's what I do sometimes:

1. Use DVD Shrink's re-author function to chop start and end bit that I don't want. You don't need compression at this point so just do it uncompressed and it will fly. But if you want to compress and strip streams, you can.

2. Use VobBlanker to replace the title. See guide on VobBlanker site - how to add menus back to DVD Shrink re-authored DVDs.

Regards

[jeanl]

pilotsnipes, I feel the same way you do. I wish there was an easy way to edit that entry point. my standalone does not mind it, so I sometimes do it by hand in IfoEdit, it takes 1 minute and I'm happy... Of course, as all of you have stated, there's many "more legit" ways to do that, but they don't take 1 minute...
I'm still not entirely clear why it's illegal to have that pointer start in the middle of a cell. As long as it points to a NavPack, I would imagine the player would be fine... The only difference is that the cell elapsed time isn't 0 (but why would that really matter). I don't see why a player could choke on that... but that's probably just my limited understanding.
jeanl
P.S. If that were legit, that would be an easy way to split a cell in half (for example to add a chapter point in the middle of an existing cell)... But apparently, this isn't legit either...

[mpucoder]

There are many things wrong with that, but here's one you can demonstrate (provided the operation isn't prohibited). Start one of your movies that has its start altered in just the PGC cell table, then press reverse .

[pilotsnipes]

pilotsnipes, I feel the same way you do. I wish there was an easy way to edit that entry point. my standalone does not mind it, so I sometimes do it by hand in IfoEdit, it takes 1 minute and I'm happy...Of course, as all of you have stated, there's many "more legit" ways to do that, but they don't take 1 minute...

Yeah, I mean that's the crux of the point there. I'm only interested in doing this because it takes just 1 min. If I have to take longer it's not worth it! Seeing as there were so many options in PGCedit that I can't even pronounce never mind grasp, I was just hoping that r0lZ would add this one in for us! Hopefully those who didn't understand it would either

a) Not click the option allowing us to use it or
b) Be scared away with the message that said, "By enabling this, you very likely will break your DVD backup (!)".


@mpucoder
There are many things wrong with that, but here's one you can demonstrate (provided the operation isn't prohibited). Start one of your movies that has its start altered in just the PGC cell table, then press reverse

Ugh....don't make me run downstairs to see what happens... OK here goes.

Right back again. My standalone handels this perfectly.

From the main menu, I press on the play movie button. The movie starts, in the middle of the first cell (around 1min:12sec) at the "proper" opening scene, not the crap at the start.

If I then press rewind, it goes all the way back to 0min0secs and I can stop and view anything between 0 and 1min 12sec. No problems. If I rewind all the way to 0 and keep it going, the movie restarts itself and begins again at 1min 12sec.

Now I don't know about other machines, but for me this is 100% how I wanted it!

[mpucoder]

OK - I thought some people doing this might not want that happening.

[jeanl]

mpucoder, can you see a reason why doing something like this would actually break something? A chapter point is supposed to be at the start of a cell, but what is different about the first navpack of a cell, and another navpack further down that could break playback? That totally baffles me!
On the other hand, I can totally see why things would break if your start sector does not point to a navpack of course, if the player isn't very careful about it (mine does not seem to care, though!)... I truly think that the reports of things breaking when you adjust this pointer were caused by the fact that the people who did it weren't careful to point to a navpack... I'm convinced that if they had adjusted the start lba to point to a navpack, things would have worked just fine...
I know that r0lZ's Sony for example, is finnicky about this start pointer. I wonder if it complains if you make it point to a navpack.

As we all know, the specs are what they are (and few of us actually know what they are), but what really matters is what actual players can do, that's the real specs if you ask jsoto, r0lZ and the others.
jeanl

[mpucoder]

Well, it's not as bad as some other hacks, like marking PAL as NTSC. The difference between the first NAV pack and others is the SRI pointers. Because they still point back to previous parts of the cell it is possible to view the video in reverse to before the new beginning. I don't think this technique will break anything in the sense that a player will refuse to play it. But unless you know that it was modified this way you might be puzzled by the way the DVD acts.

The only real problem I see is the effect this has on any program trying to edit the DVD afterwards. If you're certain you never want to do that, then no problem. But you can certainly see how confused a program could become when the PGC disagrees with VTS_C_ADT about where the cell begins.

As for specs, it is probably no secret that I believe conformance to the specs is the greatest assurance of compatability. This is why there are specs. And if a compliant DVD doesn't play as expected on a certain player, then at least you know it is not the fault of the DVD. Conversely, if something works on a limited number of players that is no guarantee that it will work on all players.

I don't want people feeling I'm anal about this, though. But I feel it my duty from time to time to remind people that a certain method is bending the rules, and that there is a better way. It may not be as quick, but cell splitting is not very difficult (my mindless DVR can do it). And reauthoring is becoming very fast (here's a quote from d3s7 about the next Big3/Muxman combination "Spiderman, with all 13,000 [subpictures] ... took under 10min to mux the entire DVD")

[r0lZ]

I know that r0lZ's Sony for example, is finnicky about this start pointer. I wonder if it complains if you make it point to a navpack.When I have tested this method with my Sony, I have -of course- used a nav pack sector to point to. It's the minimum we can do to ensure some compatibility. In some cases, the player doesn't complain. But generally, it hangs, displaying an error code in the led display. I don't know why, but it's a fact.

[jeanl]

Well, that's a fact! So too bad for that idea...
jeanl

[pilotsnipes]

I'm still not entirely clear why it's illegal to have that pointer start in the middle of a cell. As long as it points to a NavPack,

<Looking sheepish>

OK - Would you explain to me how I can find out where the navpack is? Currently I just preview the PGC with ifoedit, drag the slider along until I get to the frame I want to start on and note this frame number down (LDA I think it's called?).

Then I go into the VTS_PGCITI select the right PGC and edit the cell 1 entry point sector.

By the sounds of it.....this ain't what I should be doing (even though I shouldn't be doing it at all!)

[r0lZ]

<Looking sheepish>

OK - Would you explain to me how I can find out where the navpack is? Currently I just preview the PGC with ifoedit, drag the slider along until I get to the frame I want to start on and note this frame number down (LDA I think it's called?).

Then I go into the VTS_PGCITI select the right PGC and edit the cell 1 entry point sector.

By the sounds of it.....this ain't what I should be doing (even though I shouldn't be doing it at all!)The image number is not directly related to the sector number.

You can find all VOBU sectors in the VTS_VOBU_ADMAP table (for title VOBs) and VTSM_VOBU_ADMAP or VMGM_VOBU_ADMAP (for menu VOBs).
You will have to process by trial and errors, as you cannot guess easily at which VOBU your frame number belongs.
There is another method using DVD2AVI's preview explained in a guide (probably by 2COOL), but I don't remember where this guide is located.

[jeanl]

PgcEdit's preview only shows I-frames, and 99% of the time, there's a navpack right before it (because there's usually only 1 GOP - group of picture, starting with an I-frame - per VOBU, and a VOBU starts and ends with a NavPack). So, there's a very good chance that the navpack is LBA(image)-1.
But the safest way is to look in VobEdit, then you'll know for sure. Find the image LBA, then open vobedit, use the goto button to go to the desired LBA, then go up to the next navpack (they're easy to see in vobedit).
jeanl

[pilotsnipes]

Thank you! I'll look at the this the next time I'm doing a disk!

[jeanl]

Guys,
I'm not giving up with this idea for quickly adding a chapter to an existing PGC by inserting a cell whose start LBA points to a VOBU somewhere in the middle of the existing VOB cell. Mpucoder thinkgs this is beinding the rule, and I must say I had never seen a commercial DVD with this kind of authoring (a pgc cell whose start lba does not correspond to the start lba of the vob cell), BUT recently, we saw the Seinfeld 4th season DVD that has exactly that structure!
I'm thinking that if we find a commercial DVD that does this kind of stuff, it can't really be considered illegal. Now the problem is, why does r0lZ's DVD player crash when he does this kind of stuff, but not when he plays the Seinfeld DVD?

I agree with mpucoder that there's a legit way to do it, which includes changing a few things in the VOB, but if there's a quick and dirty way that does not require that, I think it would be pretty cool. The only affordable soft that allows you to do that, that I know of, is DVD Remake.... And I do think it's doing it the "right way" (the legit way).

jeanl

[pilotsnipes]

Well I appreciate you resurrecting this old thread with some positive news. As much as I would sincerely like to help in the debugging of why one disk might work and another crash, my expertise on DVD structures is abysmal to say the least! Well I appreciate you resurrecting this old thread with some positive news.

As much as I would sincerely like to help in the debugging of why one disk might work and another crash, my expertise on DVD structures is abysmal to say the least!

Thanks for yourl help.