last night i tried to export demos to AVI with quake 4’s demo system…. it’s a nightmare:
you cannot directly export netdemos (demos you recorded during multiplayer matches), you have to record your netdemo to a renderdemo (best explained as singleplayer/localhost demo) first and than you can export the video to TGA screenshots.
but even there seem to be nasty bugs with the renderdemos: they slow down and speed up from time to time, often it looks like your player is out of sync with the rest of the "world" (like playing with ping >500) and projectiles and explosions are NOT shown.
also the promised audio export is not working correctly (it exports only a 16kb wav file).
i hope raven will fix this in one of the next patches. i would really like to create movies out of quake 4 content.