Quote:
Originally Posted by
dfiler 
Resolution isn't the only consideration either.
All DVDs use interlaced video and there isn't a great way to quantitatively compare that to a non-interlaced video mastered from film. Some people are very susceptible to interlacing artifacts while others will never be able to tell the difference.
There are also the issues of color space and frame rate. It would be interesting to know how apple is producing these files. I doubt an actual DVD is anywhere in the production chain. Or at least I hope not.

I've often wondered the same about iTunes. Audio CDs are much lower fidelity than the original production. It is possible that Apple has been ripping from the original, highest-def source, rather than re-down-sampling from the already down-sampled consumer release.
What I'm getting at is, I suspect that the Apple's rips (should) look and sound better than is possible when ripping from DVDs or CDs.
Don't forget that film itself isn't projected the way it is shot.
Film is shot at 24 fps, but projected back at 48 fps with two identical frames presented one after the other to reduce flicker.
Color space has to match the much narrower space of Tv. That's been changing over the years, but not in a standard way. Tv, any older standard, has about 1 million colors possible. HD, in theory, allows for 16.7 million, but I doubt most Tv's can reproduce it, except for a very few models. The HDMI 1.3 spec allows for "deep color". We'll have to see how that works out.
The question of CD quality is argued back and forth. Considering that the mics, mixers, and associated equipment is no better than, or of lower fidelity than the CD itself, it's an interesting argument.
Quality is always better when moving from the original source.
An interesting aside about this. When my company began producing graphics and video for the internet from clients content, we found that content shot on Betacam always looked better than content shot on lesser machines—even when what we had to produce was 320 x 240 with 16 bit color, rather than 24, and high compression rates.
Higher quality original material ALWAYS produces better end quality because it handles the downsampling, and high compression better!