Preview speed w/Dual-Core CPU on V6/V7

gbohn wrote on 10/12/2006, 6:50 AM
Hi;

I just downloaded the V7.0b trial (to see what had changed from V6), and was hoping that the ‘preview’ would have been enhanced to make better use of Multi-cores. I was disappointed to see that this doesn’t seem to be the case (at least when using Preview and Track FX).

Let me describe what I see, and maybe someone can let me know if this is the best I can expect, or if I’m missing some option, etc. I’m also confused by something I see which makes me think that they already have the ability to do more acceleration than they seem to be using.

I set up an NTSC DV project (720x480 at 29.97 FPS) and dropped a DV ‘.AVI’ on the timeline. I set my preview to ‘Full/Best’ (720x480x32). I set the preview to use an external monitor connected (by Firewire port) to a Canopus ADV-100 DV/Analogue converter. The Computer monitor Preview window is ‘docked’ in the lower right hand corner, and only shows about 1/4 the image area with this setting, but I normally look at the external monitor which shows the full image area.

Without any ‘Track FX’ specified, I can preview the Timeline at a full 29.97 FPS. (I can turn on or off the Computer monitor Preview (so that only the external monitor is used) and this doesn’t make much if any difference to the preview speed).

If I add ‘Color Correction’ and ‘Quick Blur’ Track FX, the preview speed drops to about 9.5 – 10.5 FPS. During preview I noticed that the Win XP ‘Task Manager’ window only shows about 54% CPU use.

With my Dual-Core AMD X2 4400+ system, this means each of the two cores is only about half used. So, there would seem to be room for improvement.

If I mark a 20 second section on the timeline and perform ‘Build Dynamic Ram Preview’, this pushes the system to 100% CPU use, and completes in about 32.6 seconds. This would seem to be about an 18.4 FPS conversion rate. (I set about 900 MB of my 2GB RAM for Vegas use in the Vegas preferences).

The kicker is that during the ‘Build Preview’ time, my external monitor and local desktop preview both seem to be playing, and playing faster than they were when just playing the timeline!

So, to the casual observer, it seems like they could actually use both cores for faster preview speed (since they are able to do this for Build Dynamic RAM Preview which seems to be performing a preview as it runs…).

Is there some setting I’m missing that would allow Vegas to make better use of both cores (for Preview and effects)?

Using the Build Ram preview is helpful, but the most I can preview is about 20 seconds (since the process seems to be very 'piggy' in memory use) and it would be much more convienient to have Vegas just use all the CPU respources it can.

Vegas 6 and Vegas 7 seem to be about the same in this regard as far as I can tell, with Vegas 6 maybe a little faster…

Thanks;

-Greg

Comments

gbohn wrote on 10/12/2006, 7:14 AM
> The kicker is that during the ‘Build Preview’ time, my external monitor and local
> desktop preview both seem to be playing, and playing faster than they were when
> just playing the timeline!

I just wanted to clarify that by 'faster' I meant FPS wise... The Build Dynamic Ram Preview seems to be able to use both cores more fully (while it's rendering) to get more rendered FPS than I see when just playing from the timelime.

(Even if the normal preview 'drops frames' during display to 'keep up' and the Build RAM preview seems to show them all, albeit at a less than a real-time rate).

I'm just hoping to be able to use both cores fully, when possible.

-Greg
Rosebud wrote on 10/12/2006, 8:52 AM
Hi,

In the Internal Preferences, we can find a field named “Enable Multi-core rendering for play…”.
By default, the value is "False".
I’m curious to know if preview speed is better when this value is "True" ?

To access the Internal Preference press ‘Shift’ & Options > Preferences > Internal

TIA
gbohn wrote on 10/12/2006, 3:00 PM
If I set “Enable Multi-core rendering for play…” to TRUE, this seems to produce 'variable results'.

When I set the Multi-core setting to TRUE, and use the two Video FX plugins I previously mentioned (Quick Blur + Color Correction) it increases the reported CPU use (up to 100%), but actually reports a slower FPS playback rate.

I quickly tried a few combinations (of Video FX Plug-in Active/disabled) and got the approximate FPS rates:


Vegas 7.0b
Enable Multicore Enable Multicore playback
Plug-In Active TRUE FALSE
-----------------------------------------------------------------------------------------------------------
Quick Blur Only: 15-24 FPS 16-17 FPS
Color Corrector Only: 26-29.97 23.9-26
QB+CC: 6.6-6.7 10.2-10.5
No Plug-In: 29.97 29.97

So, it looks like a little faster (and more variable) for one plug-in, and slower for the two plug-ins.

-Greg