mpeg and mpeg2 macroblock question

[Die*wrek*show]

In this (http://forum.doom9.org/showthread.php?threadid=63849) thread they're talking about how its better to have a resolution that is a multiple of 16 or 8 for mpeg4. Here's my question, what about mpeg1 and mpeg2? Do they compress badly with a resolution that has a multiple of 8? The reason I ask is because sometimes I use crop(8,8,-8,-8) or similar scripts.

[killingspree]

hi,
well honestly i didn't know, but could look it up :) this page (http://icsl.ee.washington.edu/~woobin/ti/overview.html) states, that mpeg1 video is encoded in 8x8 blocks or 16x16 macroblocks. so as the same that was said for mpeg4 also counts for mpeg1: Do not go below modulation 16, if you want to have best results, go for mod 32!

hth
steVe

[Lord of the Discs]

I had troubles with full-screen playback of "8x"-mpegs, i.e.
360x288, so I always go for 16.

When you cut 8 pixels from both sides, you´re still in "16x"-range.

[Sulik]

All MPEG video codecs only accept resolutions that are a multiple of 16 (Every macroblock is 16x16).
If you choose a resolution that's not a multiple of 16, it will be encoded as the nearest next multiple of 16. For interlaced content, the vertical resolution should actually be a multiple of 32 (as each field should be a multiple of 16), though most decoder will work fine if it's not a multiple of 32.

HDTV 1920x1080 is actually encoded as 1920x1088, though the bottom 8 lines are never displayed.