Just noticed in your Ultimate Guides, glossary of terms under bit-rates. You state dvd has a maximum bit-rate of 5Mbit/s and blu-ray has a maximum of 40Mbit/s. This is incorrect for dvd, 5Mbit/s is often quoted as the typical average bit-rate, it is not the maximum. Bit-rates for dvds are adaptive and typically average around 4000kbps to 5000kbps with peaks of 7000kbps to 8000kbps for action scenes (the theoretical maximum is 9800kbps but that is without any audio).