COD4 DEMO RECORDING HELP!

Ok so i know how to record the demos /record and /stoprecord. Then i open them up in Cod4 but when i watch them whenever i turn or move my person twitches or lags. Is there a way to fix this??

But when i go into my own private match and i record in there and play it there is no twitching or lag if you want to see a clip heres a link. Tell me if you see the twitching too. Thanks

http://www.filefront.com/15382277/Wallbang.dm_1/

And I have a iMac so i cant use cod4 player or any exe. files.. i know gay right.

But if you guys know how to fix this please tell me!

THANK YOU !!!!!

edited 2010-01-19 08:49:35