You wrote:
> Most video quality is average, so the higher density
> would only provide questionable special features
> space for now.
First, I am in FULL agreement that most video quality these days is only average. However I strongly DISAGREE with your conclusion that higher density would only result in adding more special features.
Fact of the matter is that DVD video quality is poor for the same reason that many MP3's don't sound as good as the original CD.
Please forgive a short technical detour. When a film is very first produced, it's actual resolution is equivelant (sp?) to many megabytes per frame. Multiply that by 24 to 30 frames per second, times the number of seconds in the whole movie, and you get a value that is 10's, even 100's of gigs worth of video data.
The majority of videos stored on DVD are in one or another of the 'lossy' compression formats. Current video/audio compression technology has its roots back in the 'old' days when we were using 24k modems, and 80 Megabytes was a LOT of space. So, to get the absolute maximum compession possible, these programs literally 'threw out' large parts of the information. In theory, the parts that got thrown out were parts that the human ear/eye would never notice. I haven't kept up with the actual compression formats used in the past few years, but their basic function is still the same as those old days.
When movies get pressed to DVD, the amount of data lost is quite high. I'm certain someone will correct me on this, but I think the number is something like 66-75% of the original video data is lost in the current compression formats. And I don't care how good a program is at decoding the data, when you lose that much of the original, you WILL suffer a very noticeable loss in quality. Hence MP3's that are recorded at too low a bit rate sound tinny, and DVD's can look little better than video tape.
SO, my point is that when there is more available space on a disk, then compression programs will not need to throw out so much of the video information. And the more original data that is kept, then the better the quality of the picture on your screen. So, while there will probably still be a second disk thats just filled with oodles of special features, it should also be true that the first disk will be filled with more video data, and thus (in theory) have vastly superior video quality than the 'only average' we see on current DVD's.
Hope this helps clarify.
Ima Sloetyper