View Single Post
Old 10th January 2012, 05:42   #11  |  Link
hello_hello
Registered User
 
Join Date: Mar 2011
Posts: 4,823
Quote:
Originally Posted by gaelsano View Post
I did some tests on BBC DVDs and yes, Not only do they use 16 out of 720 pixels for padding, they also use ITU ratios. The grandfather clock in Fawlty Towers is a prime example. I made some fresh pics.
I have no doubt what you're saying is true. There are ITU DVDs out there and the older the DVD, probably the greater the chances are it'll be ITU. For all I know every BBC DVD ever produced may be ITU, but I wouldn't take it for granted that just because one is, they all must be.
If ever you get around to seeing if you can work out the correct aspect ratios for newer DVDs such as Doctor Who, I'd be interested to know what results you come up with.

Quote:
Originally Posted by gaelsano View Post
Thanks for the remarks and info. I'm getting more and more curious about sequence display extension. The most recent version of GSpot is not reporting any sequence_display_extension and in fact is showing a DAR of 5:4, but I do see MPC-HC and VLC respecting some sort of non 4:3 DAR or some sort of sequence_display_extension.
As far as I'm aware the sequence_display_extension is optional so if GSpot isn't reporting it maybe the video doesn't contain it? Or are you saying an older version of GSpot will report one when for the same file the latest version won't?

As far as I know the sequence_display_extension defines a "windowed area" for display. For instance when displaying a 16:9 image on a 4:3 screen the sequence_display_extension can be used to specify which part of encoded frame to use, but I'm not really knowledgeable on what the various headers specify so I could be completely wrong.
I didn't think software players paid any attention to that sort of thing but from your observations I guess they might, however I still don't think any headers contain information which define the resize method used to obtain a particular aspect ratio, even if an aspect ratio is specified. If you discover anything interesting though, please enlighten us.

Maybe we'll get lucky and someone who understand the various types of headers will come along and explain them.
hello_hello is offline   Reply With Quote