Not sure what your mean by "PC DVDs". The way the content is recorded on DVD is the same no matter what device reads it.
How it is displayed depends upon the output device.
DVD content is almost always progressive, the exception being TV Episodes which are most often interlaced.
All modern CRTs and LCDs displays are progressive, non-HDTVs are interlaced, all HDTV's support progresive inputs, but many of the CRT based ones still interlace their output anyway.
Those TVs that support progressive inputs can only do so using Component, DVI and HDMI inputs, RF, Coax, RCA, SVIDEO inputs only allow interlaced signals.