Video lag in preview window

MemoriesFX wrote on 7/19/2009, 4:11 PM
My video lags in the preview window when editing. It happens often when combining video with still images. The preview window skils some of the images so I cannot see the effects like pan and zoom or transitions clearly. I need to to a pre-render to preview my work. Is this noraml?
Can it be the speed of my system? I am storing my files on an external hard drive that plugs nto my duo core laptop through USB. My computer has 2 gigs of RAM and a 1.6 gHz processor, which should be enough.

Steve

Comments

Ivan Lietaert wrote on 7/19/2009, 9:59 PM
What you describe is very normal. With Vegas, it is the raw power of the processor that is the main factor for fps in preview. Vegas will run on your machine, but preview will be slow, aspecially with transitions and (some) effects.
Also the format of the video file is a factor: the 'old' dv-avi format, captured from minidv tapes, will play at a much higher frames per second ( fps) in preview, compared to the latest avchd files, which will make even a recent machine play them at low fps.
Don't forget you can set the quality of the preview screen: normal setting is 'preview<auto'. This will give a much better fps than 'best<full'.
MemoriesFX wrote on 7/20/2009, 12:42 PM
Thanks, I have tried the auto setting and it does work better but still laggs greatly on the still images I am using for transitions between videos. Is this problem similar with outher editing software? This is the first program I am using for more advanced editing features.

Steve
ritsmer wrote on 7/20/2009, 2:10 PM
Check this about preview speed http://eugenia.gnomefiles.org/2008/12/19/sony-vegas-hints-and-tips/
Besides a single 1.6 processor is very, very small for editing.
I still see a little lagging with 2 x quad Xeons at 2.8 GHz and 8 GB.

Also keep your stills small i.e. at or only a little over project size.
rrrrob wrote on 7/20/2009, 11:13 PM
one thing that has helped me is to unplug/disable other USB devices (printers, other external drives, etc.)...sometimes multiple USB devices will slow the speed of data transfer between your external drive and your PC drive. Keep this in mind also if you have multiple drives and are saving portions of your projects on different drives...try to get them all on the same hard drive when possible to reduce the USB load so that you have as few hard drives hooked up as possible. For smaller renderings, try using only your PC main hard drive when feasible.

Also, i have noticed that if I play the same clip over a few times, the software seems to build up some sort of buffer to allow for a smoother framerate to see your transitions and whatnot at a smoother pace.