PGCedit Seamless layer break discussion..

[jamos]

I am a bit confused. looking at the dual layer images created from PGCedit 7.0 it seems the discontinuty flag is not set. Is this normal as I see other programs such as nero sets it?
Image of a iso from PGCedit
http://img242.imageshack.us/img242/449/duallayer8uo.png (http://imageshack.us)

note: I can manually set the discontnuity flag, but that kind of defeats the purpose of letting PGCedit choose the layer break doesn't it or does it really not matter?

[blutach]

The STC discont does not need to be set unless there is an actual discon in the system time clock. You would typically see this happen when a VOB ID changes (cell 36 should have been a 10), and in other cases.

For the LB, it is important that the cell is marked as seamless. I would suspect that the orig LB was on 36 but you manually moved it to 34. It is correctly set up to break at cell 34.

As for Ner0, I wouldn't trust it at all.

Regards

[jamos]

The STC discont does not need to be set unless there is an actual discon in the system time clock. You would typically see this happen when a VOB ID changes (cell 36 should have been a 10), and in other cases.

For the LB, it is important that the cell is marked as seamless. I would suspect that the orig LB was on 36 but you manually moved it to 34. It is correctly set up to break at cell 34.

As for Ner0, I wouldn't trust it at all.

Regards
Thanks, that makes much sense!

No the reason 36 is not a chapter cell is because this is a merged DVD I get this because of the extra vobs it adds when I merge them (ie start of a new vob has to be a new cell) I did not know that it should be a 10 though I manually changed it back to 8 guess I should of left it a 10 (although it plays fine so maybe I am ok).

[r0lZ]

I suppose that, theoretically, it is better to have a STC discontinuity in the VOB files at the LB. But if you select a cell that has not the STCD flag set, I don't think it's a good idea to force it, since it will not reflect the reality. Anyway, I haven't read reports on playback problems when the STCD flag is not set. Maybe the pause is a little bit longer to let the player resynchronize the audio and the video?

[jamos]

I suppose that, theoretically, it is better to have a STC discontinuity in the VOB files at the LB. But if you select a cell that has not the STCD flag set, I don't think it's a good idea to force it, since it will not reflect the reality. Anyway, I haven't read reports on playback problems when the STCD flag is not set. Maybe the pause is a little bit longer to let the player resynchronize the audio and the video?
In all the pressed dvds that I have looked at the flag is not set at the layer break, it looks like the above screen shot. As far as the pause I have not noticed any difference either way. I would say unless the break is at the starting cell of a new VOB that it should not be set.

[r0lZ]

Thanks. That confirms what I've seen, and that PgcEdit is not faulty.

[jamos]

Thanks. That confirms what I've seen, and that PgcEdit is not faulty.
Don't you love when I answer my own questions..:p

[r0lZ]

Yeah! :goodpost: :p

[jamos]

Also looking at the Phantom Menace DVD they have a layer break on a new VOB cell. Discontinuity is set at the layer break. I would assume that is the best way to do a layer break as Frank stated. But, for a break that is NOT the first cell of a VOB, discontinuity should be set off.

[r0lZ]

Yes, it's a good method, also recommended by mpucoder.

Though it is true that a cell at the beginning of a new VOB must have the STC flag set, I'm not sure a cell that is not at the beginning of a new VOB cannot have the STC discontinuity (and its flag.)

[mpucoder]

Just look at the SCR values, if they do not reset (or change by a large amount in either direction) then the flag should not be set - and is unaffected by the layer break. In general cells within a vob are continuous and seamless, a new vob should reset the clock (and may be seamless or not).
I've been researching the "seamless layer break" and seen recomendations to make the layer break either between cells of the same vob or between seamlessly joined vobs to yield a smooth playback. Jim Taylor, in DVD Demystified, says "A cell cannot be spread across both layers of a disk. This rule is also supposed to apply to a pair of cells intended to play seamlessly, but so-called seamless layer changes can be made by violating this rule." (2nd ed, p 264)
I believe he is trying to say that the rule is "a pair of cells intended to be played backed seamlessly should not be spread (or split?) across both layers" and that by violating this rule, ie making the layer break between 2 cells intended to be played back seamlessly, a seamless layer break will result.

[r0lZ]

Great info, mpucoder!

So, it should be possible to leave the seamless flag set on the LB cell! Do you think this rule violation is compatible with all players, or is it a risk of crash/freeze, especially with old standalone players? I thought the player need some time to switch from a layer to the other one...
I might add an option to leave the seamless flag on the LB in the burn setup dialog of PgcEdit. Is it safe?

[bigotti5]

http://forum.doom9.org/showthread.php?t=102185

[r0lZ]

Thanks, bigotti5. So, it appear that this seamless LB technique requires a special muxing. Difficult for PgcEdit to analyse the VOB file to be sure the seamless flag can be set. Pity! :(

[jamos]

Well so far out of 15 pressed dvds I have never seen the seamless flag set (several had a discontinuity flag set because its break was at the start of the first cell of a VOB). So I am guessing that even if there is a standard to set seamless and multiplex it, it is rarely done. Maybe with older dvds setting seamless was done more often as the older dvd players took more time on layer breaks?

pressed dvd with discontinuity at start of new VOB:
http://img81.imageshack.us/img81/1783/pressed1cg.png (http://imageshack.us)
pressed dvd with discontinuity not set (not at new VOB):
http://img270.imageshack.us/img270/7001/disnotset5mu.png (http://imageshack.us)

[bigotti5]

take a look at Superbit DVD (http://www.sonypictures.com/cthe/superbit/)

[r0lZ]

Thanks, Jamos.
BTW, your second screenshot is a good example of several cells that are not used for chapter points. In this case, it is difficult for PgcEdit to guess which cell was used for the LB (unless the seamless flag is left unchanged during the rip.)

@bigotti5
I haven't analysed a superbit DVD yet.
Do you think superbit really offers a better quality than a good traditional DL DVD? Unless the movie is really long or full of action scenes, I think a perfect quality can be archived without having to use the full DVD size for the main movie. Anyway, the bitrate is limited by the standard. Is it true that the main movie occupies (almost) the full space of the DL DVD?
Honestly, I suspect a commercial trick instead of a real improvement.

[bigotti5]

Perfect quality imo is always subjectively.
I have only one Superbit DVD ("Das Boot") in my Collection and I have not compared with other releases of this movie.

It is the seamless layer change that initiates me drawing attention to Superbit, not the quality (quality is good though).

[blutach]

I don't think I will ever use the seamless layer change - it's just too risky ATM. Many studios are getting smarter about where they put the LB so it is aesthetically pleasing (a scene which fades to black for example, or one where there is no audio or movement for a couple of seconds).

I do like superbit - I have one or 2 (Hannibal I think is one) and it is very good - avergae BR is very high around 7-8Mbps (which doesn't give much room for low BRs - it is almost like CBR encoding). And, r0lZ, the movie occupies ALL the DVD, there are no extras just wasting space.

In any event, as we know, it is a "psychvisual" experience r0lZ, as "perfect quality" is in the eye (literally) of the beholder.

Regards

[r0lZ]

And, r0lZ, the movie occupies ALL the DVD, there are no extras just wasting space.
I know there are no extras. But that doesn't mean that the main movie occupies the whole DVD. Have you verified that the VOB files of the main movie are really around 7GB?

[bigotti5]

I don't think I will ever use the seamless layer change - it's just too risky ..

As mpucoder stated, seamless layer change requires especially muxing, imo no available authoring soft is capable of doing this

[mpucoder]

I gotta find my notes, apparently back in November I knew of an example. There are two issues - seamless and bitrate. Two cells of the same vob will be seamless. You can also join two vobs seamlessly in many authoring programs, including MuxMan 0.17
And being seamless should work in the majority of players. At worst it will still pause while the laser refocuses due to buffer depletion. It won't crash or stop, being seamless makes it easier to play, not harder.
Lowering the mux bitrate helps the buffer depletion problem. Notice this is the mux bitrate, not the combined bitrate, a slightly different aspect of program streams. The normal mux rate is 10.08 and the lower rate for interleaving is 8.0 It may seem as though it wouldn't matter if the combined rate is low there will be less data to handle and the buffers can fill up before the layer change. But the lower mux rate signals to the player that something is going to happen that requires cramming the buffers full (usually angle or story skipping)
Even so, a combined bitrate of 8.0 or less should also work in modern players which have buffers many times larger than the target decoder model.

[jamos]

I gotta find my notes, apparently back in November I knew of an example. There are two issues - seamless and bitrate. Two cells of the same vob will be seamless. You can also join two vobs seamlessly in many authoring programs, including MuxMan 0.17
And being seamless should work in the majority of players. At worst it will still pause while the laser refocuses due to buffer depletion. It won't crash or stop, being seamless makes it easier to play, not harder.
Lowering the mux bitrate helps the buffer depletion problem. Notice this is the mux bitrate, not the combined bitrate, a slightly different aspect of program streams. The normal mux rate is 10.08 and the lower rate for interleaving is 8.0 It may seem as though it wouldn't matter if the combined rate is low there will be less data to handle and the buffers can fill up before the layer change. But the lower mux rate signals to the player that something is going to happen that requires cramming the buffers full (usually angle or story skipping)
Even so, a combined bitrate of 8.0 or less should also work in modern players which have buffers many times larger than the target decoder model.
So are you saying if I split a cell in a vob, added the layer break to the new cell and was Able to set the flag to seemless (which you cannot do now with pgcedit on layer breaks) without remuxing it would work better (ie buffer would be full still) on the break or not?

[r0lZ]

... and was Able to set the flag to seemless (which you cannot do now with pgcedit on layer breaks) ...
If you want to test it, you can set the seamless flag this way: start PgcEdit's burn function, but abort the ISO creation. Change the seamless flag and save. Create the ISO with ImgTool Classic or launch the MakeISO.bat file created by PgcEdit in your %TEMP% directory. However, I'm not sure ImgBurn will let you burn the image without resetting the seamless flag. Also, if you want, I can do a version which doesn't clear the seamless flag on demand.

[mpucoder]

That would be really great if you could burn with the seamless flag set, it would answer some questions. And while you are working on that, I am working on another mux directive for MuxMan that will allow changing the mux rate. With both changes we should be able to duplicate what superbit and others are doing.

[jamos]

If you want to test it, you can set the seamless flag this way: start PgcEdit's burn function, but abort the ISO creation. Change the seamless flag and save. Create the ISO with ImgTool Classic or launch the MakeISO.bat file created by PgcEdit in your %TEMP% directory. However, I'm not sure ImgBurn will let you burn the image without resetting the seamless flag. Also, if you want, I can do a version which doesn't clear the seamless flag on demand.
I can try this.

Edit: ok I created the iso with no layer break the old layer break set to seemless..

Now I get this when trying to burn with IMGburn
http://img139.imageshack.us/img139/3743/imgburn7px.jpg (http://imageshack.us)

Maybe a modified version of PGCedit that allows both the layer break set and the seemless flag set could be done and sent to me? Then I could try imgburn again.

[mpucoder]

Start with a cell or vob that already is seamless. Setting the flag when the mux is not seamless only results in a hang on my Sony players.

[bigotti5]

I am working on another mux directive for MuxMan that will allow changing the mux rate. With both changes we should be able to duplicate what superbit and others are doing.

Great - muxman is overtaking scenarist, seamless multistory, seamless layer change, multiangles, seamless b*****...... ;)

[r0lZ]

Jamos, you're right. You have to change the seamless flag with IfoEdit (w/o Get VTS Sectors!) If you save the modified DVD with PgcEdit, it will recompute the VTS sector pointers as for a single layer DVD.

Anyway, I'll do the modification in PgcEdit...

[jamos]

Start with a cell or vob that already is seamless. Setting the flag when the mux is not seamless only results in a hang on my Sony players.
I did pick a seemless cell I think the problem is that pgcedit clears the layer break when I do this.

[jamos]

Jamos, you're right. You have to change the seamless flag with IfoEdit (w/o Get VTS Sectors!)
what cell value would I change this to other than 8?

I really think if the flag is anything but 2 or 0 that IMGburn will not work.

[r0lZ]

Forget it, and download PgcEdit_winexe_7.0.1_beta1.zip (http://www.videohelp.com/~r0lZ/pgcedit/beta/PgcEdit_winexe_7.0.1_beta1.zip). Change the Seamless LB state in Options -> Input/Output, and create the ISO normally.

However, I'm pretty sure ImgBurn will clear the seamless flag before burning the image. Maybe you have to use the good old DVD Decrypter? PgcEdit should still support DVDD. Just configure it in the burn setup dialog. Or launch it manually, and configure the LB LBA in its setup dialog.

I haven't a DL DVD to test, so, let me know if ImgBurn or DVDD works.

[r0lZ]

Just fixed a last minute little bug! If you have already downloaded the beta, please download it again!

[jamos]

OK burning with decrypter now manually set the layer break to what pgcedit said it was at. When I look at the image with pgcedit (mounted with dameon tools) it shows no layer break.

[jamos]

Looks like a sucess layer break still marked 8 on finished disk. Though maybe you could show the layer break cell when i reopen it with pgcedit as a 8 with the layer break marked?

[jamos]

Playback on my Sony Home player is now Flawless at the layer break no pauses or skips with the new disk.:D

Now the question is: does burning with decrypter and setting the layer break manually do a better job than imgburn and is what is causing the no pause? So I guess I would need to test decrypter with the layer break set to non seamless as in the old PGCedit version to truly test if it is the seamless that is doing this or just decrypter burns layer breaks better than the latest version of imgburn.

p.s. just bought 10 more dual layer disks at newegg :p


mkisofs log for DVD
From:
DVD-TEXT General Name: ""
Provider ID: "IFOEDIT BY DERROW"
Number of VTS: 1
Output file:
Volume label:
Running under windows (OS type: Windows NT)

mkisofs 2.01-bootcd.ru (i686-pc-mingw32)
Layer break is at absolute sector 2077232. (Offset in L0 is 68576.)
Layer break cell:
2008656: VTST 1 , 1 TTN 1 (4:26:24) Title 1 Cell 41 (00:08:55.08), V/CID: 5/37
EXPERIMENTAL: The seamless flag is set on the LB cell!

The pad was 68592 for file VIDEO_TS.IFO
Total translation table size: 0
Total rockridge attributes bytes: 0
Total directory bytes: 4248
Path table size(bytes): 42
4154455 extents written (8114 MB)

ISO created OK.

[blutach]

Very interesting thread. Might be a bit hit and miss with some players though.

Regards

[jamos]

It is not Decrypter, i reburned the same dvd with its layer break set to 0. Small pause at layer break. So it does look like setting the layer break seemless works (at least with my sony homeplayers). Now we just need imgburn to support this type of break:p

[jamos]

Very interesting thread. Might be a bit hit and miss with some players though.

Regards
try it and see if it works for you, if you have any dual layers blu. Maybe older players will have issues (but they have issues with burned dual layers anyways).

[dirio49]

However, I'm pretty sure ImgBurn will clear the seamless flag before burning the image. Maybe you have to use the good old DVD Decrypter? PgcEdit should still support DVDD. Just configure it in the burn setup dialog. Or launch it manually, and configure the LB LBA in its setup dialog.

I haven't a DL DVD to test, so, let me know if ImgBurn or DVDD works.

Can't you do the same thing with imgburn?

Settings-->Write-->Layer Break--->Change from calculate optimal to User specified.
shouldn't that work the same as DVDD.;)

P.S.
Do you people think that LUK would be interested in this discussion?

Peace out.

[jamos]

Can't you do the same thing with imgburn?

Settings-->Write-->Layer Break--->Change from calculate optimal to User specified.
shouldn't that work the same as DVDD.;)

P.S.
Do you people think that LUK would be interested in this discussion?

Peace out.
I do not think it is the manually setting the layer break that is the issue (which you have to do with decrypter to keep it at the correct position), it is that imgburn will report a error or force the layer break into a 2 or 0 (non-seamless breaks) is what we are worried about. But, yes LUKs input on what imgburn will do to the layer break would be appreciated as I do not want to use another disk to test his program with this without confirmation.

[jamos]

2nd title flawless, no skip at layer break using seamless break;) and decrypter to burn.

[jamos]

Third title tested no pauses at layer break :)

[jamos]

4th DVD tested no pause at layer break..looks like it works well.

[r0lZ]

Thanks for your tests, jamos.

Could you specify if the LB in your tests was set at the original LB location, or at the start of a VOB (where the VOB ID changes)?

[r0lZ]

Looks like a sucess layer break still marked 8 on finished disk. Though maybe you could show the layer break cell when i reopen it with pgcedit as a 8 with the layer break marked?I don't understand your question very well. No, the flags are always displayed as they are on disc. The layer break checkbox is just a shortcut to the seamless flag, for the newbies. (Its value is actually the inverse of the seamless flag.)

[jamos]

I don't understand your question very well. No, the flags are always displayed as they are on disc. The layer break checkbox is just a shortcut to the seamless flag, for the newbies. (Its value is actually the inverse of the seamless flag.)
My question is there is no way to look at the burned disk and tell where the layer break is at using seamless breaks with PGCedit? here is what i see from a seamless burn that I have done. Break is at chapter 30. Is there a another tool that would show this or is there no way to display this sense it is seamless?

Seamless burn:

http://img90.imageshack.us/img90/7184/duallayer8ou.png (http://imageshack.us)

P.S. I put a post in LUks forum on if there is a way to call imgburn and set the layer break position manually through a command line option, and if it will leave the layer break seamless.

[jamos]

Thanks for your tests, jamos.

Could you specify if the LB in your tests was set at the original LB location, or at the start of a VOB (where the VOB ID changes)?
Break is in the middle of the VOB on 3 cases (as in screenshot above), at the start of a VOB in one case, all no pause. All of my layer break positions are not the original positions of the layer break as these are merged DVDs. But, like I said up above using the same image and using the non-seamless flag I did get a pause, so it is the seamless flag that is making my DVD player not pause and Nothing Else (IE burn or burner as I tried several different burners (my Plextor, my Liteon and my Pioneer) and they all worked perfectly with seamless).

[r0lZ]

In fact, by looking at the IFOs, it is impossible to know for sure where the layer break was, even if there is a cell with the seamless flag clear. The non-seamless cell can be there for different purposes (though, generally, in a feature movie, it's the layer break.)
You can try to guess where it was, by looking at the VOB ID change, or by searching an unique cell that is not used as a chapter point. The presence of the STC discontinuity flag is also a good indication.
If you burn with the seamless flag set, it is even more difficult to loacte the original LB cell, since this indication is lost.

[r0lZ]

All of my layer break positions are not the original positions of the layer break as these are merged DVDs.OK. Then, I reformulate my question: did you use the merge point for the layer break?

But, like I said up above using the same image and using the non-seamless flag I did get a pause, so it is the seamless flag that is making my DVD player not pause and Nothing Else (IE burn or burner as I tried several different burners (my Plextor, my Liteon and my Pioneer) and they all worked perfectly with seamless).I understand that. I just wan to know if something special exists in the muxing of those LB cells (as explained by mpucoder), or if the trick works with all cells. In the latter case, that would be really great!
I need this info to know if I can safely add the "Seamless layer break" option in PgcEdit, or if I still have to display a warning, or even to suppress it.

I have also PMed LUK! I hope he will reply in this thread soon...