I'm not really sure... but I suspect using the uncompressed digital interface of your DVD player that supports up converting to 720p/1080i will result with an improved picture being rendered from your Pioneer DV-79AVi to your Panasonic TH-42PWD6UY.
Hopefully I will be testing the same with an OPPO OPDV971H and my TH-50PX50U sometime today.
Hopefully I will be testing the same with an OPPO OPDV971H and my TH-50PX50U sometime today.