is it better archiving HD video at full res, max compression or lower res, less compression, for same filesize

Question

for example, if one were trying to take a raw 1080i or 720p file of 15 gb and wanted to fit it onto a DVD or, worse a CD, would it better to compress the original resolution (eg, 1280x720) agressively, or to resize it to 720x480 but use a less agressive compression?

Answer 1

Always start with a resize. It just makes the work of the encoder much easier and you will have fewer coding artifacts.