Extension and user data in group_of_pictures_header()

[Trahald]

I was wondering why the call for extension_and_user_data(); was commented out at the end of group_of_pictures_header() function.. i was messing around with having raw format close caption data saved during .d2v save. i put in the code and was wondering why it was never being called. hehe. any help would be great.

[Guest]

There is no extension data that directly follows a GOP header. I also don't know of any user data following a GOP header; in any case, DGIndex isn't interested in user data.

Usually, per-picture user data, such as closed captioning, follows a picture header.

[Trahald]

ahh.. i see.. so basically its just not needed when closed caption (or user data in general) isnt an issue.. so far in the streams ive looked at , cc user_data is coming up at gop headers ( ive only tested a few streams however)

[McPoodle]

It sort of goes both ways, actually.

DVD closed captions are per-GOP, and appear between the GOP header and the first (I frame) picture header.

On the other hand, some of the DVB captions formats, such as various ReplayTV formats, are per-frame, and the user data packet appears between the picture header and the first slice packet.