I know that with dvd players the quality of the upconversion of a sd dvd it related to the vp in the player or external vp such as the dvdo VP50, which I have. I am currently using a G5 dual 2.0ghz. If I just set the display preference to 1080i on the G5 and then connect that to the VP50 the picture is not nearly as sharp as when I go from my sdi modded Denon 3910 into the VP50. I have tried setting the display preference to 480i but then all of the menu's become huge. So I am wondering if maybe swithres might help or maybe just getting a better video card? I am assuming that it is the video card in macs that determines the quality of the upcoversion then is it the software used to play back the dvd's that controls the deinterlacing?

I know that with dvd players the quality of the upconversion of a sd dvd it related to the vp in the player or external vp such as the dvdo VP50, which I have. I am currently using a G5 dual 2.0ghz. If I just set the display preference to 1080i on the G5 and then connect that to the VP50 the picture is not nearly as sharp as when I go from my sdi modded Denon 3910 into the VP50. I have tried setting the display preference to 480i but then all of the menu's become huge. So I am wondering if maybe swithres might help or maybe just getting a better video card? I am assuming that it is the video card in macs that determines the quality of the upcoversion then is it the software used to play back the dvd's that controls the deinterlacing?

What version of OS X are you using? From what I've read, the DVD Player application on 10.4 (Tiger) does not handle the video processing very well. DVD Player for 10.5 (and presumably 10.6) is supposed to be much much better.

If that doesn't work, you could try using VLC to play back DVDs. There are many many more settings that you can play with on VLC to tweak your picture.

I am using 10.5.6. I have vlc but from what I have seen it will only play the movie and does not let you have access to the dvd menu structure?

...maybe just getting a better video card? I am assuming that it is the video card in macs that determines the quality of the upcoversion then is it the software used to play back the dvd's that controls the deinterlacing?
This is actually a good question. For sure the transition from Tiger to Leopard for the Apple DVD Player was a huge improvement.

But the question remains: does the video card matter at all and if so how much? Would switching to a fancier video card on a Mac Pro improve picture quality for HT purposes at 1080P with sources such as DVDs or EyeTV?