I have a similar complaint about transfer quality. I have noticed this issue with DVDs from almost every adult studio. (Every title that I have seen from Digital Playground has had great picture quality.)
I was recently disappointed in the transfer quality of Flesh for Fantasy, starring Rebecca Lord. The cover indicates that it was shot on film. Two minutes into it and you realize that it's obviously a poor transfer from VHS.
Unfortunately this is normal for most adult titles. There are a few studios that take the time to digitally remaster on a frame-by-frame basis. Most of the Cal Vista stuff from Metro is done this way. New Wave Hookers 5 is picture perfect as well.
Another common complaint about transfers from VHS libraries is that many times scenes are deleted. I wish someone from the studios could explain this one.

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