[redstrike]

have you tried this video on other web server like apache?

this will give us more info.

update:
I tried this video on LAN with 256K Outbound Bandwidth (bytes/sec) limit, and JWPlayer 5.7(http://developer.longtailvideo.com/t...fl5/player.swf), seek working fine.
not sure if the file name will cause any problem, I renamed it to video.mp4 before testing.

No. I don't use Apache. Seeking time is ok, but the video's frame starting lagging, not smooth. i have tried to rename the file for long time ago but it's not working. Can you show me your mp4 link?

I had same problem on KVM, under OpenVZ everything was fine. Are you using any sort of virtualisation?

I am using a VPS with 768 MB RAM. Is it the bottleneck? But another videos work correctly (after seek time, it's play normally, not lag in frame). Maybe, i don't know which virtualization software is used by my VPS provider, but it can be KVM.