Originally Posted by Favelle
I don't understand how that is possible? Aren't DVD's still red-laser and maxed out on bitrate at like 8mbps?? How can you get 40+mbps to play off of a red-lasered DVD?
You're thinking of these bit rates incorrectly. You have to separate the concept between the encoded bitrate and the transfer rate that a medium can provide.
With DVDs, MPEG2 compression is used and is at around 8mbps (as you said). With HD-DVDs, VC1, H264, or MPEG2 is used with bit rates as high as 40mbps (as you also said). So, we have established that these are data rates.
Since a DVD is merely a disc with some data on it, we can put anything we want on it. This includes movies authored as DVD, HD-DVD, and even Blu-Ray. The medium just needs to provide enough bandwidth for the movie to play smoothly. A DVD drive reading at 4x or higher should be able to provide 40mbps for data transfer. Or, if you authored a small amount of HD material that can fit on a CD, you need a CD drive that can provide at least 36x speed.