Please see my earlier "discussion" at this link:
I think my final question got lost in the main discussion. So this thread is to ask for any good links links that wil explain Gobs, P frames etc, in relation to Premiere Pro (CS4).
That ought to get you started. For more background on temporal compression, read here:
Those same principles apply to today's more advanced codecs, too.
PS - it's GOPs (Group Of Pictures), not Gobs.
If you mean GOP, then maybe this ARTICLE will give you a background. Also, Jeff's links will contain much more detail. Mine is very simple, but with all of the possibilities, will stop short.