320x240 is already VERY low quality, so when you expand it to a DVD compliant resolution you're going to lose quality. I would recommend running it thru an encoder with ghost and noise reduction, and maybe use a 2 pass encode, it will take a while but it will ensure the least loss of quality. Also, as far as resolution, if you're putting it onto a dvd-video (assuming you are since it's dvd-video authoring forum) then you need to use a standard resolution, which for an NTSC DVD is 720x480.
TMPGEnc has "ghost" and noise reduction settings under "other settings' tab....but it will take your 320x240 SIF video and "pad" around it to make up 720x480 standard framesize...which is good & bad depending on how you look at it...you'll end up with a large filesize(mostly black video arould your SIF) which will mean you won't be able to stuff as many vids on the same dvd, but the quality will be much better that trying to blow up a 320x240 to 720x480..you're need to check under advanced setings..go down to Video Arrange Method select(center, maintain aspect ratio)the make sure it still shows 320x480 in the framesize box below that(you'll end up with a 720x480 video with your SIF in the middle(but you've just increased your filesize. Or, if you're going with a DVD Authoring program that allows non-standard and more flex that supports SIF, SAT...like DVD_Lab_Pro....you could just stick with your ImTOO encoder and keep the framesize at 320x240! No padding, All depends on the tools you have. but be warned...the dvd with 320x240 framesize...might not play in every dvd player.
