Preview window video jerky

riredale wrote on 11/6/2007, 11:24 PM

This issue has me stumped.

I'm playing with V8. In the preview window I can never get 29.97 playback, even if I make the window tiny and/or change the quality to Draft. If I switch to full mode the frame rate drops to 5 or so.

With HDV clips the preview/auto frame rate is about 27 at best. This is with a 360x270 preview window. For DV clips the frame rate is even worse, about 20. The whole time my AMD x2 processor says it's only working at about 20% of max.

Everything else on my PC seems to run fine. WinDVD plays back DVDs with fluid motion. But for some reason, V8 can't give me 29.97 in the preview window, and as a result, all the video is very choppy.

Any ideas?

Comments

farss wrote on 11/7/2007, 12:27 AM

Is this just a problem in V8, like was V7 OK or have you always had this problem?
If it's just a V8 problem you're not using 32bit mode are you?

Although if the CPUs are only running at 20% I'd suspect it's a disk i/o problem.

Bob.

jrazz wrote on 11/7/2007, 7:07 AM

I am experiencing this on my editing machine but not on my laptop (with lower specs). I only experience it with Vp8- 7 played back fine. I did have issues with 5 doing this but that was on another system and if I took the focus off the preview window and placed it on the timeline it would play smooth but if I placed the focus back on the preview window it would be jerky again. That was in V5 though.

I was rendering to a USB2 external from a Firewire external and then I switched to two internal sata drives and that did not fix the problem, but I can go back into 7 and all is well.

j razz

riredale wrote on 11/7/2007, 7:55 AM

V7 works fine, with 29.97 on playback after stumbling for maybe the first half-second.

Also, the hard drive light flickers on playback, implying that disk access is happening maybe half the time. Disks are all running DMA. Video scopes have no effect, since they don't operate while clip is playing, and the issue exists even if the scopes are removed. The 3800x2 processors are running overclocked at 2.6GHz and the system is very stable and all other voltages and freqs are within specs.

So the processors aren't the bottleneck, nor the disks.

What is especially surprising is that something within V8 is laboring just to show a DV clip in the Preview window, no matter the window size. My guess would be that there is some accidental loop, or a conflict with some other codec. One thing I can try is to do a completely clean install of XP and V8, and see how that goes. But not now; I have a big project to do and I know V7 can do it.