It looks similar because it is. DVDs use MP2 lossy compression.
There are a lot of variables at work here. CRT I assume that this is an analog SD TV VRS your 46" HDTV.
DVDs are 720x480(ED) or so pixels, the analog TV is somewhat less than that, the DVD player has to down scale the video and convert to analog to view on your CRT-TV.
For the HDTV are you using component cables or HDMI???
Anyway the DVD will send the 720x480 MP2 to the HDTV, the HDTV will rescale this to it's native resoultion of 1280x720 or 1920x1080, to do this is uses dithering.
Some HDTVs do a good job of this and some don't. Many are using a upscaling DVD player to help out with this problem. John