Non-repeatable, real-time preview problems

johnmeyer wrote on 4/29/2005, 9:26 AM

I put ten medium res (1600x1200) still images on the timeline. Vegas preferences set for 3.5 seconds, with a one second disolve. I playback in Preview Full mode (720x480x32). I have no keyframes, so the images aren't moving (yet), just the disolves.

Everything plays smoothly until a certain point when suddenly the display gets very jerkey. It goes to perhaps 3 frames per second. The next transition is OK, then a few more jerky ones.

I try moving images around, and some seem to work well with others, and some not. I start saving various test cases. Later, I go back and open one of the test VEG files and playback one of the problem transitions.

It plays back perfectly!

I start a new project and put the same files on the timeline in the same order and go to the problem spot. It plays perfectly. I then start scrubbing elsewhere on the timeline, and eventually the problem starts again.

I am doing a huge project that involves almost a dozen separate "music videos" that involve lots of stills and this has been driving me crazy all week. I am still using Vegas 5.0d. It appears that there is some sort of memory leak or bug. I have tried different "Dynamic RAM Preview" sizes, even though I am not prerendering. I have tried different preview sizes, going down to 360x240, but once the problem happens, this doesn't help.

I am stumped and more than a little desparate because what I am really trying to do is set some pretty complex moves using keyframes, and with 2-3 fps preview I can't tell what is going on. I don't remember whether I had this problem before. I did recently upgrade from 5.0b to 5.0d.

Any ideas?

Comments

johnmeyer wrote on 4/29/2005, 9:44 AM

Update:

I rolled back to 5.0b. No change.

Another bit of information: If I do a RAM pre-render (Shift-B), the preview goes smoother, but there is still some jerkiness. My understanding is that this should give me perfectly smooth playback.

JJKizak wrote on 4/29/2005, 9:45 AM

When you select a tranisiton and play it looped does it correct itself after about 3 or 4 passes?
If it does it's memory, not enough.

JJK

johnmeyer wrote on 4/29/2005, 10:15 AM

When you select a tranisiton and play it looped does it correct itself after about 3 or 4 passes?

Sometimes it does get better on subsequent plays if I repeat, but sometimes not. I agree it sounds like a memory issue, but I don't think it is simply how much memory. I have 1 Gbyte of RAM, plenty of disk space, and a big pagefile. I'm not running any other programs (including nothing in the background - no anti-virus or anything else). I've checked the task manager and looked at the processes that are running, and I'm familiar with each of the 3-4 processes that are running.

I am currently updating to the latest DirectX to see if I can clean out any garbage that may have accumulated there.

rmack350 wrote on 4/29/2005, 11:34 AM

My understanding of the way Vegas caches to RAM is that it just grabs enough frames to make things play smoothly. How it determines that, I don't know. But i'd bet that it's just not calculating it's needs all that well.

But, what to do about it... Maybe this is a case where you're going to have to do actual prerenders (knowing that you'll just be losing them in a minute).

Rob Mack

johnmeyer wrote on 4/29/2005, 11:51 AM

I have done more testing on this in the past hour. It is too long to detail, but basically, the problem comes and goes. Once Vegas is in a "state" where it doesn't want to display smoothly, I can't get it to change. If I quite Vegas, then immediately re-start it, load the project, and go immediately to the point on the timeline where the video was playing jerkily, it now plays smoothly. Eventually, the problem returns. I have contacted Sony to see if I can get a response, but I don't know whether they have the bandwidth to handle a 5.0d question given their priorities to get Vegas 6 smoothed out.