Supposing constant quality, how much smaller is an h264 file than a DiVX/XViD one?

[b0mbrman]

Keeping quality constant, about what fraction of the size of comparable DiVX files do you find the size of your h264 files to be?

 

[b0mbrman]

...and as a corrolary, relative to the original DVD image, what percentage of the original file size do you find 100% (video) quality to be at?

For h264 and DiVX...