Dvd quality nowadays have improved since the introduction of bluray.
DVD releases improved even before the official introduction of Blu-ray. But it's true that Blu-ray had something to do with it. They started minting high definition masters in anticipation of the introduction of HD DVD and Blu-ray.
Rumor has it that
The Godfather Trilogy has been remastered in high def --- not just 1080p, but in 4K (4096 x 2048 resolution). If this is true, then the studios are probably getting ready for the 4k home video format. (See my Red-Ray post:
http://pinoydvd.com/board/index.php?topic=70470.msg800025#msg800025 )
I think the dvds now are bluray ripped so the Pq is excellent plus the AQ is dts certified.
The standard DVD was authored directly from the high-definition master, not ripped from the Blu-ray disc.
Today, a master for home video is usually made in high definition. From that hi def master, they encode both a standard DVD version and Blu-ray version.
Take
Con Air for example. The old DVD version was very good at the time it was released. But today, it's a blurry, non-anamorphic antique.
They made a new anamorphic master in hi def, then released a new standard DVD version. From the same high def master, they released a Blu-ray version:
It's unlikely that the new standard DVD version was ripped from Blu-ray for the following reasons:
(a) The
Con Air Blu-ray version was released on January 8, 2008; the latest standard DVD version was released much earlier, on May 6 2006;
(b) The first Blu-ray discs, encoded in MPEG-2, were released on June 20, 2006; the first AVC and VC-1 encodes were released in September 2006.
Con Air Blu-ray is encoded in AVC, so it's unlikely that Buena Vista already had the AVC encode at the time the latest DVD version was released in May 2006.
(c) The latest
Con Air standard DVD is an unrated extended cut (122 mins.); the Blu-ray version is a theatrical cut (115 mins.)
The DVDs ripped from Blu-ray are the fakes. Since they were encoded by pirates, encoding errors are common --- average bitrates are usually 9+ to 11+ Mbps, way higher than the DVD spec of 6 to 8 max. ave., and 9.8 max. peak. Excessively high bitrates cause judders, skips and pauses on many players.
The orig is still the best.