Clarification on what the "Next" remote button does

[jeanl]

People,
Can one of you knowledgeable poeple clarify exactly what the "Next" or "Previous" button on a DVD remove do? (I mean the next chapter, or the "+" buttons).
Here's my best guess, but I'm not sure at all:
- If in the middle of a multi-program PGC, it goes to the next program ?
- If in the last program of the PGC, it goes to the next PGC (as specified in the IFO file)?

Are the cell commands executed (I don't think so), are the post-commands executed?

Jeanl

[jeanl]

mmmm, no one out there can give me an answer on that one?
jeanl

[M7S]

I just read about that on dvd-replica. It said normally the "next" button goes to next program (I assume those players who doesn't goes to the next ppt). When it comes to the end of the pgc it jumps to the pgc that has the next chapter number (I mean if the last program in a pgc is in ppt 3 it will go to the pgc that begins with ppt 4). I could have misunderstood something though so checking with dvd-replica yourself could be a good thing.

Regards,
M7S

[jeanl]

Originally posted by M7S
I just read about that on dvd-replica. It said normally the "next" button goes to next program (I assume those players who doesn't goes to the next ppt). When it comes to the end of the pgc it jumps to the pgc that has the next chapter number (I mean if the last program in a pgc is in ppt 3 it will go to the pgc that begins with ppt 4). I could have misunderstood something though so checking with dvd-replica yourself could be a good thing.

Regards,
M7S
Thanks for the pointer to dvd-replica, I did a google seach on that site (couldn't find a search on the site itself), and I found the page (http://www.dvd-replica.com/DVD/title.php) that contains the info you mention. According to dvd-replica though, if the "Next PGC" field is non-zero, that's where you jump if you click on the next/skip button, regardless of where you are in the PGC.
I guess I'll have to experiment! Thanks for the help!
Jeanl

[r0lZ]

The next button jumps to the next program (not chapter) of the PGC.
When in the last program, it signals the end of the PGC playback, and the post commands are executed. Cell command, if any, is not executed. The next PGC Link is used only, after the post commands, if the commands are not linking to another PGC.

Similarly, the Prev button go to the prev program. If in the first program, the Prev PGC link is used.

The Return button always go to the PGC pointed to by the GoUp link, regardless of the current program you are in.
The Return button, when in title domain, may Resume to the title domain if the GoUp link is 65535.

None ot these buttons are active if the link value is 0.

[jeanl]

Thanks r0lZ, that clarifies it a bit for me!
Jeanl

[2COOL]

Just to add to this thread. Read after the illustration (http://www.dvd-replica.com/DVD/pgc.php).

[jeanl]

Thanks, 2COOL.
Jeanl

[blutach]

@2cool/rolz - who is right then? DVD replica or rolz in his earlier post?

DVD Replica implies Program 3 can't be reached by the next button as it skips to the next chapter (Program 4 = Chapter 3) even if Program 2 is playing (because Program 3 is also contained in chapter 2).

Regards

[r0lZ]

Make your own test and you'll see. ;)

[blutach]

Originally posted by r0lZ
The next button jumps to the next program of the PGC.
When in the last program, it signals the end of the PGC playback, and the post commands are executed. Cell command, if any, is not executed. The next PGC Link is used only, after the post commands, if the commands are not linking to another PGC. I have found that without the NextPGCN linked to the a PGC (usually the same one), the next button on the remote is useless in the last chapter. It just plays. That is why AddChapter was so useful.

However, if NextPGCN is the same as current PGCN, then even in a long last chapter, pressing Next on the remote will always skip to the post commands.

Getting confused now :confused:

[2COOL]

You know what? after reading DVD-Replica's page, I think there wrong. Though it says that the next button should make a jump to next program, they state it like it's jumping to next PTT. :( If i'm right, then I apologize for the link.

[blutach]

They have been known to be wrong before - on lots of occasions - as we all know.

[jeanl]

Originally posted by r0lZ
Make your own test and you'll see. ;)
I did that on a few occasions, and I was utterly confused by the results! For one thing, I was never able to make it jump to the PGC pointed to by NextPGCN, and I also noticed something similar to what Blutach described with regards to NextPGCN being set or not.
I've decided that I don't need to know until the time when I do need to know. I'm afraid it's pretty much the way it is with the whole DVD specs (or which I "know" about 0.1% at this point :( )
Jeanl

[r0lZ]

Originally posted by blutach
I have found that without the NextPGCN linked to the a PGC (usually the same one), the next button on the remote is useless in the last chapter. It just plays. That is why AddChapter was so useful.

However, if NextPGCN is the same as current PGCN, then even in a long last chapter, pressing Next on the remote will always skip to the post commands.

Getting confused now :confused:
As I said: "None ot these buttons are active if the link value is 0.".
Note: The NextPGC link must be > 0, but do not need to be equal to the current PGC number to jump to the post-commands.

And it is absolutely right that the Next and Prev buttons jumps from program to program, not chapters. But most of the time, the program and chapter numbers are the same, so, this makes no difference for the user.

[dnetzero]

The DVD specs imply skip/next/previous buttons are for PTT, not programs. The DVD consortium suggests the display on player LCD for PTT and program. However because of the complexity of the specs, many manufacturers just implemented on programs only instead of PTT. Probably due to cost, the display has only chapter information (not both PTT and PGN). Most commercial titles have only one program per PTT, so it makes no difference. The chapter display is also the program number in this case.

[blutach]

@rolz

Understood now, and thank you

[r0lZ]

Well, to clarify again, here is the normal flow of operations when reaching the last cell of a PGC:

1) The cell command, if any, is executed. If the cell command jumps to another PGC, program or cell, then continue with that PGC, program or cell.

2) If, after the cell command, the playback point is still at the end of the PGC, then execute the post-commands. If one post command jumps to another PGC, program or cell, then continue with that PGC, program or cell.

3) At this point, if the playback point is still at the end of the PGC, then the NextPGC link is used to jump to that PGC. Obviously, if the NextPGC link is the same as the current PGC, this will force the PGC to loop back at the beginning.

4) If the NextPGC link is 0, then exit playback.

If the NextPGCN is > 0, then pressing the Next Chapter button when in the last program of the PGC will interrupt the playback, and junp directly to point 2 above (skipping the Cell command).
If the NextPGCN is 0, then nothing happens.

This means that the NextPGCN is used for two purposes:
1) To enable the use of the Next button.
2) To jump to the specified PGC, if there was no cell or post commands with a jump/call or link.

[blutach]

Sorry rolz, that's not how it works on my 2 standalones. Maybe they are offspec.

If I press Next on the remote in last program (and NextPGCN = 0) they continue to play.

Regards

[jeanl]

Originally posted by blutach
Sorry rolz, that's not how it works on my 2 standalones. Maybe they are offspec.

If press Next on the remote in last program (and NextPGCN = 0) they continue to play.

Regards
Same here on PowerDVD...
Just to add to the confusion ;)
Jeanl

[r0lZ]

Originally posted by blutach
Sorry rolz, that's not how it works on my 2 standalones. Maybe they are offspec.

If press Next on the remote in last program (and NextPGCN = 0) they continue to play.

Regards Yes. NextPGCN must be > 0. (Previous post modified)

[2COOL]

I "third" the motion. ;)

[jeanl]

Originally posted by r0lZ

3) At this point, if the playback point is still at the end of the PGC, then the NextPGC link is used to jump to that PGC. Obviously, if the NextPGC link is the same as the current PGC, this will force the PGC to loop back at the beginning.
well, I was expecting that, but PowerDVD does NOT do that. I have set NextPGC to link to the current PGC, and if I press Next in the last cell, I find myself in no-man's land (the current PGC has no cell or post commands) instead of looping the beginning of the PGC. Matter of fact, I can't link to any other PGC.
But like I said, I'm not going to lose sleep over it, damit! There must be something I'm doing wrong. I'll post back if I ever figure it out.
Jeanl

[r0lZ]

Mpucoder said elsewhere that NextPGCN may link to any PGC in the menu domain, but is restricted to a PGC belonging to the same title when used in the title domain.

Are you linking to a PGC in the title domain? This is probably why PowerDVD is lost. However, it should work if you link to the same PGC, as it obviously belongs to the same title.

[EDIT:] Works fine with WinDVD.

[jeanl]

Originally posted by r0lZ
Mpucoder said elsewhere that NextPGCN may link to any PGC in the menu domain, but is restricted to a PGC belonging to the same title when used in the title domain.

Are you linking to a PGC in the title domain? This is probably why PowerDVD is lost. However, it should work if you link to the same PGC, as it obviously belongs to the same title.
Yes, I'm in the title domain, and yes, since it's the same PGC it's in the same title... How can I see whether a PGC belongs to the same title as another one PgcEdit? Do all the PGCs following a given one marked "title 1" belong to the same title? Pardon my ignorance... :(

Jeanl

[r0lZ]

All PGCs marked with the same TTN number are parts of the same title. The PGC with the Title label is the entry PGC of the title.
Anyway, all PGCs following the Title's entry PGC should belong to the same title, but it's not an obligation.

[blutach]

Originally posted by 2COOL
Just to add to this thread. Read after the illustration (http://www.dvd-replica.com/DVD/pgc.php). Just to add to the confusion...

From the very next page after your reference (http://www.dvd-replica.com/DVD/title.php) 2 paras after the diagram:

Most DVD player allows the selection of programs (commonly referred to as tracks) in a title by pressing the (Skip/Next) or (Skip/Previous) key on the remote control. If PGC 1 is playing the first cell, pressing (Skip/Next) starts the next program and the LCD display of the player still shows chapter 1 (it was a 2 program chapter). Pressing (Skip/Next) again to start program 3 and the LCD display shows chapter 2.DVD-replica contradicts itself!

This, obviously, supports rolz.