Slow playback in sequencer...

When loading video files around 200-300 mb in the Video Sequencer, I get extremely slow playback. Apparently someone edited a 2hr movie, how on earth could they do this!! I heard that it was something to do with the “MEM Cache Limit” or something, but I’m not sure what setting it was meant to be at. Somebody please help!

System Spec:
Windows XP
AMD Athlon XP 2200+, 1.8GHz
512Mb RAM

EDIT: Ok, I’ve kindof sorted it by pressing the “Sync” button in the Anim/Playback buttons. This only solves the issue of synching the video with audio - the video is still very choppy, but surely it must be possible to play the video in realtime, as Premiere Elements 1.0 does on my 866 Mhz pc and Avid Free DV on this 1.8 Ghz pc?

is anti-aliasing turn on? if it is, and the video resolution is not the same as the final render resolution, blender will attempt to scale down the video nicely using a brillinear method, which will slow it down considerably.

The fix is (obviously) to disable Anti-aliasing until you are ready to render the video.

btw, what resolution is the video and what format is it in?

Wow, that worked! I just realised the output render controls were set to 800x600 and the input video was PAL 720x576 (avi). I think a nice feature would be if blender automatically detected the resolution of the input vid and set that as the output res ( although this could be a bit annoying if you wanted to render at a different res I guess).