Rendering gets progressively slower.

wm_b wrote on 5/17/2010, 1:19 PM
I am rendering for 60 minutes of video for DVD. When the rendering first starts it goes very quickly. I would say it's nearly 200% of normal speed. After a few minutes the rendering seems to slow. Let's say it's about 5 minutes in the 60 minute timeline. By this time its noticeably slower. Now it's 33% complete after 3 hours and saying there are 6 more to go. Presently it's processing about 2.5 frames per second by my estimate. This video is straight from the camera. Color correction is applied.

I am redering to mpeg2 with mainconcept encoder. My settings are DVD architect widescreen. Default parameters.

I am using Vegas 9e 64bit
Windows 7
i7 920 cpu
12 gigs ram

My current memory usage is 8 gigs and CPU usage is 16%. Maybe I am doing something wrong because it seems unusual that the performance would be non-linear.

I have been using FCP to do this job and was trying to save time by using vegas. The initial prep is quicker because vegas can read the MTS files right off the card but the render is ridiculous. FCP requires me to log and transfer the card which takes about an hour but the render is much quicker.

Any suggestions?

Comments

wm_b wrote on 5/17/2010, 2:35 PM
Deciding that 9 hours to render a 60 minute DVD was too much I canceled the job to regroup. I went to preferences in the options menu and selected Default on the editing tab. I think I had changed my ram preview to several gigs when I first set things up. I left everything else unchanged.

I rebooted the computer and started the render job again. Now things are trucking along for a much faster job. It's holding an average of 20.5 fps as measured with my eye and a stopwatch for over 1000 frames. All 8 cores are 100% and my memory usage is down to 2.38 gigs. I guess having a huge ram preview capability is messing up the render times.

I hope the output looks as good as it does in FCP. If I can do this job in vegas I can turn these weekly lectures around in a 2.25 hour period of time. The same output in FCP is about 5 hours total time with importing, slight color correction/chapter markers and exporting to DVD.

it's 17 minutes in with about 109 to go. This figures in with my 90 minute calculation.
LanceMGY wrote on 7/19/2010, 6:00 PM
I wish I could reply to offer a suggestion, but I'm having that same issue as well, except I've been having blue screen crashes as well.

Right now I'm rendering a DVD Ar NTSC Widescreen 24p mpeg file from a 1920x1080 24p project (4 streams of MXF from EX-3 and Z1, in quad screen, with CC applied to all 4 clips). Since the render started, I've been having random colored lines flashing across the screen. Not sure if it's related or just coincidence.

I tried 5 times yesterday to render sections from that 1080 24p project just into simple DVD MPEG files. 4 of the times, I had blue screen crashes. The system rebooted before I had time to read, but the first two bsod's was something about memory access, and I don't remember the others offhand. I finally had to render that particular 10 minute section into HD AVI Sony codec and then create an MPEG from that.

But to your point, all these times I was rendering a section (there were 3 from that project in all), the render speed was great at first, but it got sooo slow and finally was handling about 3-6 frames at a time, every second or so. And it wasn't a steady pace...they would go quickly, then there'd be a pause.

My system is very similar to yours except I have the i7 930 and only 6GB of RAM. These issues happened in both 64bit and 32bit Vegas 9e. I'm curious what the issue is as well! After all the reboots, Vegas was the only app running. ???
rmack350 wrote on 7/19/2010, 7:14 PM
I'm not sure about your problems, tvlance, but wm_b's problems are typical of having a ram preview setting too high.

Basically, if RAM preview is set very high then there may be quite a lot of timeline stored as uncompressed rendered frames in RAM. This will render very fast but when that's used up the rest of the render happens at a more normal speed since it's all being read from disc, and all your effects need to be processed.

On top of this, in some cases a high preview RAM setting can trigger Windows to start using the page file, this can also slow down your render. Theoretically, 64-bit Vegas on a 12GB system shouldn't be running out of RAM if the RAM preview is only set to be a couple of GB, but the real proof would be to open task manager and watch the size of the page file. If it's growing then that's a sign of a problem and lowering the RAM preview setting way down to something like 0 MB, 16 MB, or 128 MB would help. A high Preview RAM setting makes that much memory unavailable for renders.

Rob Mack