Several subpic packs with PTS in same VOBU

[jeanl]

Guys,
I'm seeing something I think for the first time (on Incredibles, R1, cell 3/2). There's several subpic packs in the VOBU that have PTS information. I'm used to seeing only the first one with PTS info (for a given stream) then all subsequent ones simply with subpic data. But this is different. In addition, the second PTS is different from the first one, and matches another I-frame that's also present in that VOBU.

Is it fairly standard, or is it unusual? Is it a requirement that the PTS of a subpic pack be equal to the PTS of the previous I-frame, even it the subpic pack is really the continuation of a subpic stream?

I'm a bit confused...
Jeanl

[mpucoder]

The first pack of a SPU will have its pts. A SPU is all the information for one 4-color image and the commands to present it. What you are used to seeing is just one SPU per vobu, fairly normal for dialog or menu SPUs.
But there can be as many SPUs as there are display frames (if done properly), and each will have a pts value.
SPUs are not tied to an I frame - you've been looking at menus too long, jean.:p

[jeanl]

Originally posted by mpucoder
The first pack of a SPU will have its pts. A SPU is all the information for one 4-color image and the commands to present it. What you are used to seeing is just one SPU per vobu, fairly normal for dialog or menu SPUs.
But there can be as many SPUs as there are display frames (if done properly), and each will have a pts value.
SPUs are not tied to an I frame - you've been looking at menus too long, jean.:p
you can say that again! Yes, I suspected that you could have more than 1 SPU per vobu, but the thing that's surprising is the first pack does not seem to be self contained (although I didn't check carefully, but for example, there's no padding stream, but OK OK, it's still possible it could be self contained and have the commands at the end of the pack, I need to check that)...
Thanks a bunch anyway!
Jeanl

[mpucoder]

I would be suspicious, too, if there was no padding stream - what are the odds? about 1 out of 256 will need no padding.

[jeanl]

OK I was wrong. They are indeed self-contained, so this is exactly what you describe: several SPUs in the same VOBU, the first pack of each has its own PTS. mmm this is going to complicate things a bit for MenuShrink, if by any chance this is combined with "stop commands" in the subpics (not the case here, but I'm sure it will happen, eventually)! Oh well....

Thanks a bunch mpucoder. (as usual!)
jeanl