I get the impression the dvd portion of many bluray players, were added in as an afterthought. I wouldn't be surprised if they were the exact same circuit designs used in a particular manufacturer's older dvd player models from many years ago. For example, I have a bluray player and an older dvd player both manufactured by Toshiba. It turns out on the known problematic dvds I have, both Toshiba players freeze and/or skip at exactly the same places on a particular disk. Using another dvd or bluray player manufactured by a different company, I've noticed the freezing and/or skipping behavior on these same problematic disks is typically different.