Rendering times

djmd wrote on 8/28/2002, 1:02 PM
Just wondering if there's anywhere on the net anyone knows of that has rendering times in vegas on different systems and codecs? I just put together an Athlon XP 2200+ system and can do and hour of SVCD Mpeg-2 in about 95 minutes. That's about twice as fast as my t-bird 1200. I'd love to compare my results to others to see if I need to do some tweaking with the settings in the bios.

Just curious...


djmd wrote on 8/28/2002, 9:37 PM
I need to clarify my original post. I meant to say I rendered 30 minutes into SVCD mpeg-2 and it took 95 minutes to render.
BillyBoy wrote on 8/28/2002, 10:10 PM
If you PC is running up to specs there isn't much you can do to speed up rendering which is mostly dependant on CPU speed. Having no other applications running will help a slight amount. Overclocking with get you faster rendering, but do you really want to overclock an already fast chip? More RAM won't help enough to be worth the investment.
djmd wrote on 8/28/2002, 10:47 PM
Well I understand that... I guess what I really meant to find out was what margains of increase in rendering speed are provided against processor speed... and I know RAM won't do anything for rendering once you've gone past 256 meg, maybe even 128.
BillyBoy wrote on 8/28/2002, 11:13 PM
I don't think I understand what you're asking as you phrased it. As you've seen rendering times go down in direct proportion to increased CPU speed. It isn't linear, but roughly you can expect a 1,000 Mhz CPU to be render in half the time as a 500 Mhz CPU takes and so on.

There are a heck of a lot of bits being manipulated which requires raw horsepower, or CPU speed. The more filters you add, the more transations, rescaling frame size etc., all takes a lot of work and therefore processor cycles. So until computers really pick up at more muscle than they have now, rendering is going to remain a slow process. If you're getting 8 to 1 maybe 6 to 1, ratios you're doing about as well as can be expected with today's hardware.
Arty wrote on 9/12/2002, 4:16 PM
Although it's a pity that when VV3 renders it doesn't use both CPUs in a dual system. I have a dual P3 1GHz system and renders only use half of the available power which really is a crying shame.
SonyDennis wrote on 9/12/2002, 11:21 PM
> Although it's a pity that when VV3 renders it doesn't use both CPUs in a dual system.

Vegas does use two CPUs during rendering, and during playback. Audio FX are rendered in separate threads, and DV compression is done in a separate thread. We're I/O bound most of the time, not CPU bound, so you're never going to see 100% on both CPUs during rendering.

Have you timed it with one CPU vs. two?

Arty wrote on 9/13/2002, 7:18 AM
Yeah I have timed it, using a credit roll on black not in PAL DV, 10 second clip.
Single CPU = 1 minute 15
Dual CPU = 1 minute 6

so throwing an additional P3 1Ghz at it only shaves off 9 seconds.

It does use the CPUs more during playback but is hardly making the most of 2 CPUs during render time and disk access isn't an issue at all.

I'm not worried about it not getting 100% CPU usage but something above 60% would be nice.
RBrandt wrote on 9/13/2002, 10:44 AM
For my understanding, VV only uses multiple processors when rendering in DV. The options have to be selected just right to get it. Using the Main Concept codecs uses only one processor. That is according to conversations I have had with SF tech support so tell me if I'm incorrect. I just rendered a 58 minute video into DV (avi) and my CPU utilization was varying between 65 and 80% with 2 P4 1.5GHz processors. It took 76 minutes to complete.

As far as RAM affecting rendering speed, you have to have enough to keep the system from going to a disk cache. 128MB is certainly not enough and 256 is right on the edge. I have 512MB and have about a 128MB cushion.
wcoxe1 wrote on 9/13/2002, 11:46 AM
You mentioned earlier that you normally were I/O bound, not limited by the CPU.

How can we plan ahead to minimize being I/O bound in our next computer setup?
JJKizak wrote on 9/13/2002, 1:29 PM
A 1.5 hr video in my computer (1gig, 786ram) takes 11 hrs. to render.
Be thankful that yours is that fast.

James J. Kizak
jjyoung wrote on 9/18/2002, 11:06 AM
I have a 900M system with 256M ram and am rendering a 2 hour video with just about no edits into DVD format. The estimate time to completion is about 28 hours! Doesn't this sound a bit over the top. I've changing my destination drive to a different disk to try to reduce the I/O bounding, but it doesn't appear to have an effect. I've also changed where my temp files reside, also to no effect.

Is this render time typical?
BillyBoy wrote on 9/18/2002, 11:17 AM
Rendering times are proportional to your CPU processing speed. By today's standards a 900 Mhz system is "slow" so the time you are seeing while long are on the high side of normal. Generally RAM beyond a certain point (256/516MB) won't have any noticeable effect. The more complex your project, if or not your change frame size, use lots of filters, multiple tracks, transititions, all impact on how long the render takes.
jjyoung wrote on 9/20/2002, 11:08 AM
Well, I just realized that I hadn't upgraded my Desktop ti VV 3.0, and was still using the encoder from VV 2.0. I guess that explains my long encode times, duh...
Work's MUCH better now. 6.5 hours to encode a 2 hour MPEG2 file.
wcoxe1 wrote on 9/20/2002, 3:37 PM
Are there any ways to plan a machine so that one is NOT I/O bound? Specific suggestions, number of drives, kinds, etc?
avgeek wrote on 9/20/2002, 4:49 PM
I ran across a similar topic about a week or two ago and we've started rendering everything to a video only Mpeg2 stream (an M2v) file and a separate 48Khz wav file. We then combine the two in DVDit and we're off. This approach has also dramatically decreased my burn times when making a DVD.
SonyDennis wrote on 9/23/2002, 5:40 PM

> Are there any ways to plan a machine so that one is NOT I/O bound? Specific suggestions, number of drives, kinds, etc?

Just the usual stuff: fast drives, fast interface. Keep your media on a different drive than your OS and swap file. If you're doing a lot of audio tracks, multiple physical drives (spindles). Vegas' audio engine uses async I/O so it can be waiting for multiple drives at the same time, and take the data in any order that it arrives, instead of asking for it one piece at a time.

vicmilt wrote on 9/23/2002, 6:24 PM
I've been working on a project with loads of special effects. What I'm doing now is dividing the project up into separate Vegas files, and prerendering there to new tracks, which I am importing into the main show.
If I'm rendering a number of different VV projects at the same time, will additional memory help, or is it still a matter of processor speed. Also, will twin processors make a difference?