28 hr render, and some ?'s and discussion

tfc wrote on 9/19/2004, 11:34 PM
I just completed a 28, yes, that 's right, 28 hour single pass render to MPEG-2 in the latest version of Vegas 5. Before this one, the longest render I previously accomplished was about 4 or 5 hours. I accomplished all of this on a relatively new computer with a 2.8G P4 CPU, 1 G RAM, two dedicated fast hard drives, etc, etc. This is by far, my most lengthy render yet. I consider myself a little more experienced than a beginner, and have done about 20 or 30 projects so far. All of my previous projects have not taken nearly this long. My questions:

1) Has anyone else experienced such a long render? What is your longest and what caused it to be so long?

2) In this project I made extensive use of "pixel redistribution" filters, i.e. -lots and lots of levels filters, with a few primary color corrector filters here and there with some minor color balancing, gamma correction and saturation increases. This was necessary because the original footage was shot on an el-cheapo Digital 8 camcorder which resulted in most of the shots being way overexposed and with many flat, unsaturated colors. I have dabbled a little bit with these filters previously, but it has never taken this long before. Does anyone think that 28 hours is a little bit excessive or is that not unrealistic in this case? Can one draw a conclusion that the farther the pixels are off from the desired tonal balance/color, the longer the render will take?

3) Does anyone know which filter or filters are typically the most CPU intensive and take the longest for V5 to render? Do the Levels F/X take the longest? Is this the reason it took so long?

4) I am very paranoid about having any other apps or programs running in the background while I render, so as to use all of the CPU's power and not have it be diverted. I do not have V5 display the video preview as it renders. I turn off my screensaver, firewall, anti-viral applications and actually physically disconnect my cable modem to prevent any unintended disruptions to the render. Is 28 hours straight too long to have a computer run? Could I have overheating issues with the CPU, the longer I render? Is this bad for my computer? What about having V5 on the screen for that long without a screensaver? I have an LCD screen, so I would think it would be less prone to "burn-in" which plagued some of the early CRT computer screens. Will any of this affect my computer or LCD screen long term down the road, if I continue doing these long renders?

Sorry for the long rambling post, I just thought it would be best to combine all of my questions into one post! I am very happy with the final render, it looks fantastic on my television! I'm just glad I didn't find any mistakes in it, as I would hate to go through all this again! Any comments, questions, or info?

Thanks a lots guys/gals, I appreciate it!

Comments

apit34356 wrote on 9/20/2004, 12:06 AM
Behind door number 2! Your item 2 and any 3d track movement is your villian. Try rendering to a new track all your color adjustments first. then apply your next adjustments that are complex to a new track, then mask off tracks or sections of tracks not needed, made sure you have a sound track for your full time line, render out with new and tracks as needed. This shortens lenght of the final render time, may or may not effect your total time on the project.
Chienworks wrote on 9/20/2004, 4:20 AM
I agree that #2 is probably your problem. Your complaint about a 28 hour render is slightly unfounded if this project is different from previous projects. Try doing a much more simple render that is representative of what you usually do and you'll find that the render time is a lot shorter.

Regarding #4, allow me to say that you're being way over paranoid. I continue happily using my computer for most other usual tasks while rendering. You will NOT affect the output of the render by doing other tasks *unless you crash your computer, of course), but i don't think that is your concern. As far as slowing the render down i think you'll find that this really isn't an issue. All the other tasks i do on my computer may occasionally max out at 10% CPU usage about 1% of the time. That means that at most i'm diverting maybe 0.1% or less of the processor cycles to programs other than Vegas. For that matter, Windows itself steals cycles to, but not enough to notice. Losing even 1% of the cycles to other processes would lengthen your render from 28 hours to 28.283 hours. This difference isn't worth worrying about.

Screen burn? This is almost nonexistant with modern CRT and LCD monitors. Plus, even if it was a problem, if you use your computer for other tasks while rendering then the display will be changing. If you aren't using it for other tasks then turn the monitor off and save electricity! This issue isn't even worth worrying about. Don't worry about having your computer on that long either. Mine is usually on 24x7. We have PCs at work that have been on for years (some of them even without reboots!) and they keep running fine. As long as the ventilation fans keep running and the room doesn't overheat you won't have any problems.

Also consider the time you waste by not accomplishing anything else during the 28 hour render. True, if you have more than one computer then you can go use the other one. However, if that's your only computer, how productive are you being during the long renders by saving a couple of minutes rendering time while not getting anything else done? Go use your computer, have fun, do work, go play ... whatever you wish. Just stop worrying about the rendering process.
johnmeyer wrote on 9/20/2004, 8:03 AM
My experience with level filters is that they don't take much time, but anything you do that involves the interaction between tracks (masking, compositing, etc.) can take a long time. Also, the amount of level adjustment should not make ANY difference in rendering time; the software just has to add or subtract a larger number, and it takes the same time to add 1+1 as it does 1+100,000.

The other thing I note is that you are encoding to MPEG-2 at the same time that you are rendering. This is perfectly OK to do, but if you really want to find out how much time the rendering is taking, you might want to render to a DV AVI file first, and then encode the MPEG-2 file. On your computer, you should be able to encode an already-rendered AVI file at pretty close to real time (i.e., one hour of footage should take one hour to encode to MPEG-2). If you find it is taking longer than this to encode, then perhaps you have changed from the standard DVD Architect MPEG templates (which I hope is what you are using). (Do NOT use the "Default" template -- it will encode faster, but the results look horrible).

If you find that most of the time is being consumed by rendering and not by MPEG-2 encoding, then you might want to consider using Network Rendering. It is of limited value for "garden variety" rendering, like transitions and title overlays, but when you start using motion blur, compositing, bezier curves, etc., the rendering times can really shoot up, and the overhead in setting up the Network Render, and the unecessary "stitch" times in the current implementation are more than offset by the reduction in time in having two or three computers share the rendering load.

You should also make sure that you didn't accidentally "nudge" one of the track level controls, or the opacity levels for any of your events. This will needlessly lengthen the rendering, as well as subtly degrade your video.

Sony, it sure would be nice to have Vegas create a summary dialog that lists each fX used in the project, along with a column that shows the total duration to which this fX is applied. This could either be done as a "log" file, or it could be done as a pop-up at the current cursor location where you could get a quick readout of everything that will be done to the video at that instant in time.
apit34356 wrote on 9/20/2004, 10:24 AM
Johnmeyer, a while ago, I ran a series of tests on identical machines, using different filters, track motion small and large, 24p, 30p, 60i with avi only, avi with stills. 6 basic tracks with 100 different run modes, to build a math model, the last six months of updates have changed results, so I've been curious to see if anyone else has been testing vegas. My focus is on large project management for rendering similar to C4d.network jobs. Mirroring the raw footage is not a problem when done ahead of time. so the science is breaking up the veg into subunits. Sony vegas builds sound ptrs files, this approach for video would be big leap for fast networking.
tfc wrote on 9/20/2004, 12:15 PM
Chienworks: "Regarding #4, allow me to say that you're being way over paranoid. I continue happily using my computer for most other usual tasks while rendering. You will NOT affect the output of the render by doing other tasks *unless you crash your computer, of course), but i don't think that is your concern. As far as slowing the render down i think you'll find that this really isn't an issue. All the other tasks i do on my computer may occasionally max out at 10% CPU usage about 1% of the time. That means that at most i'm diverting maybe 0.1% or less of the processor cycles to programs other than Vegas."

Yes, you are correct, I guess I am being paranoid. I didn't realize it had that little of an effect. I thought it would really sap the CPU's resources. Thanks for the info. It was really tough not using my computer for that long. I will now start using it!

Johnmeyer: "My experience with level filters is that they don't take much time, but anything you do that involves the interaction between tracks (masking, compositing, etc.) can take a long time. Also, the amount of level adjustment should not make ANY difference in rendering time; the software just has to add or subtract a larger number, and it takes the same time to add 1+1 as it does 1+100,000........You should also make sure that you didn't accidentally "nudge" one of the track level controls, or the opacity levels for any of your events. This will needlessly lengthen the rendering, as well as subtly degrade your video."

I guess I thought that the levels would have more of an effect than they did. I had literally hundreds and hundreds of Levels keyframes in this project. I guess I forgot to mention that I had numerous tracks and lots of composite, and opacity envelopes as well. It sounds like these are what really ate up the rendering time!

Johnmeyer: "The other thing I note is that you are encoding to MPEG-2 at the same time that you are rendering. This is perfectly OK to do, but if you really want to find out how much time the rendering is taking, you might want to render to a DV AVI file first, and then encode the MPEG-2 file. On your computer, you should be able to encode an already-rendered AVI file at pretty close to real time (i.e., one hour of footage should take one hour to encode to MPEG-2). If you find it is taking longer than this to encode, then perhaps you have changed from the standard DVD Architect MPEG templates (which I hope is what you are using). (Do NOT use the "Default" template -- it will encode faster, but the results look horrible). "

Yes, John, true I am both encoding and rendering at the same time. I did NOT render to an .AVI first prior to encoding. I usually don't do this, unless it is an exceedingly complicated project. I remember reading here on this forum, that one will get a higher quality final output with colors closer to the original footage if one does NOT render to .AVI first. I'm not really concerned all that much with exactly how long my rendering took, as much as I am trying to find out specifically what aspect, i.e. Levels, Composite Envelope, etc, was the main culprit in adding so much to my render time. You are correct about the encoding from a previously rendered .AVI file, it is very close to real time. Thanks for the warning about the default templates in the MPEG-2 menus. I fortunately found out about this little "gotcha" when I first started. FWIW, the only 3 variables I change are the rendering to "Best", the quality slider to 31, and the bit rate to a constant fixed 8,000,000. I don't mess with the rest of the stuff. You're right about the default setting ! This is definitely setting up a beginner for failure. Like you, I am surprised that Sony would default these values to such a crappy setting. I wonder if they have those same default values in the Vegas Lite edition, otherwise known as Movie Studio. I wonder how many potential followers of Vegas they lose when newbies use those settings and get frustrated on the results and give up!

Thanks for the comments everyone, anyone else?



B.Verlik wrote on 9/20/2004, 12:24 PM
How long is a DVD made with a constant bit rate of 8,000,000? Maybe I should say, how long can it be?
jetdv wrote on 9/20/2004, 12:39 PM
about 70 minutes.