DVD NAV packet times differ from the mpeg pts times?

[rogerdpack]

Hello all.
Possibly common knowledge, but couldn't seem to find an answer on the forum here.

I've noticed, using mplayer to play DVD's (for example Sintel), that

1) the internal mpeg stream's first video packet seems to typically come not at second 0.00 but at second 0.28

2) the DVD NAV packets seem to not quite match the underlying mpeg stream. They seem to think that DVD started at second 0.18. And they're 30 fps instead of 29.97 fps. Anybody know what's up there, or any resources I could investigate? huh?

Thanks!
-roger-

[rogerdpack]

My only guess for this is maybe there's some spec that says "when you switch VOBU's don't feed us any video frames too quickly, to prevent a pause" or what not, for slow DVD players. I guess. I don't get it, and it varies, some start at 0.30, some start at 0.07 or what not. Weird.

This could be corroborated by the fact that when you switch VOBU's, mplayer displays timestamps like


A:3498.3 V:3498.32 A-V: -0.040 ct: -0.248 58/ 55 21% 5% 35.5% 0 0
A:3498.3 V:3498.36 A-V: -0.031 ct: -0.251 59/ 56 20% 5% 34.9% 0 0
A:3499.3 V: 0.00 A-V:3499.321 ct: -0.247 0/ 0 ??% ??% ??,?% 0 0
A: -0.7 V: 0.04 A-V: -0.728 ct: -0.247 1/ 1 ??% ??% ??,?% 0 0
A: -0.6 V: 0.04 A-V: -0.608 ct: -0.247 1/ 1 ??% ??% ??,?% 0 0
A: -0.4 V: 0.04 A-V: -0.468 ct: -0.247 1/ 1 ??% ??% ??,?% 0 0
A: -0.3 V: 0.04 A-V: -0.298 ct: -0.247 1/ 1 ??% ??% ??,?% 0 0
A: -0.1 V: 0.04 A-V: -0.128 ct: -0.247 1/ 1 ??% ??% ??,?% 0 0
A: 0.1 V: 0.04 A-V: 0.032 ct: -0.247 1/ 1 ??% ??% ??,?% 0 0
A: 0.2 V: 0.04 A-V: 0.132 ct: -0.243 1/ 1 ??% ??% ??,?% 0 0
A: 0.2 V: 0.08 A-V: 0.151 ct: -0.239 2/ 2 ??% ??% ??,?% 0 0
A: 0.3 V: 0.13 A-V: 0.139 ct: -0.235 3/ 3 ??% ??% ??,?% 0 0
A: 0.3 V: 0.17 A-V: 0.107 ct: -0.231 4/ 4 ??% ??% ??,?% 0 0
A: 0.3 V: 0.21 A-V: 0.106 ct: -0.226 5/ 5 ??% ??% ??,?% 0 0
A: 0.4 V: 0.25 A-V: 0.114 ct: -0.222 6/ 6 ??% ??% ??,?% 0 0
A: 0.4 V:3498.69 A-V:-3498.298 ct: -0.226 7/ 7 ??% ??% ??,?% 0 0
A: 0.4 V:3498.73 A-V:-3498.310 ct: -0.231 8/ 8 ??% ??% ??,?% 0 0
A: 0.5 V:3498.78 A-V:-3498.281 ct: -0.235 9/ 9 ??% ??% ??,?% 0 0
A: 0.5 V:3498.82 A-V:-3498.273 ct: -0.239 10/ 10 ??% ??% ??,?% 0 0
A: 0.6 V:3498.86 A-V:-3498.275 ct: -0.243 11/ 11 103% 30% 253.1% 0 0
A: 0.6 V:3498.90 A-V:-3498.297 ct: -0.247 12/ 12 95% 28% 235.1% 0 0
A: 0.7 V:3498.94 A-V:-3498.289 ct: -0.251 13/ 13 89% 26% 218.5% 0 0
A: 0.7 V:3498.98 A-V:-3498.312 ct: -0.256 14/ 14 83% 25% 204.1% 0 0
A: 0.8 V:3499.03 A-V:-3498.272 ct: -0.260 15/ 15 78% 24% 193.2% 0 0
A: 0.8 V:3499.07 A-V:-3498.254 ct: -0.264 16/ 16 74% 23% 187.0% 0 0
A: 0.9 V:3499.11 A-V:-3498.256 ct: -0.268 17/ 17 70% 22% 180.1% 0 0
A: 0.9 V:3499.15 A-V:-3498.267 ct: -0.272 18/ 18 67% 21% 171.1% 0 0
A: 0.9 V:3499.19 A-V:-3498.259 ct: -0.276 19/ 19 64% 20% 163.4% 0 0
A: 1.0 V:3499.23 A-V:-3498.271 ct: -0.281 20/ 20 61% 19% 155.6% 0 0
A: 1.0 V:3499.28 A-V:-3498.242 ct: -0.285 21/ 21 58% 19% 151.3% 0 0
A: 1.1 V:3499.32 A-V:-3498.234 ct: -0.289 22/ 22 56% 18% 146.8% 0 0
A: 1.1 V:3499.36 A-V:-3498.236 ct: -0.293 23/ 23 54% 17% 140.9% 0 0
A: 1.2 V:3499.40 A-V:-3498.238 ct: -0.297 24/ 24 52% 17% 135.5% 0 0
A: 1.2 V:3499.44 A-V:-3498.239 ct: -0.301 25/ 25 51% 16% 130.5% 0 0
A: 1.3 V:3499.49 A-V:-3498.231 ct: -0.306 26/ 26 49% 16% 126.9% 0 0
A: 1.3 V: 0.25 A-V: 1.073 ct: -0.301 27/ 27 48% 15% 124.5% 0 0
A: 1.4 V: 0.29 A-V: 1.061 ct: -0.297 28/ 28 46% 15% 122.3% 0 0

So there's some overlap.

[Midzuki]

I think you should ask a moderator to move this thread to a "more-appropriate" forum:

http://forum.doom9.org/forumdisplay.php?f=15

Hopefully Reimar will want to answer your question =^.^=