Rendering slow down Vegas 10 v s Premier Pro

[Rob Franks]

A faster cpu. Vegas (with exception to avc rendering) is completely dependent on cpu power. However P Pro 5 or better is pretty hard to beat in terms of speed.

[Dave Haynie]

If your overall CPU usage drops much below 90-95%, you have a problem. Make sure you’re looking at total system performance, since Vegas breaks things up into different processes during render, not just threads.

I can believe Premiere CS5.5 might be a bit faster. In an AVCHD to DV/MPEG-2 render, assuming no effetcs, the most CPU intensive part of the rendering pipeline will be the AVCHD decode. And the latest Premiere is probably using the GPU to do that decode, Vegas is not.

But such a low CPU use should be a big red flag. And while it’s true that a faster CPU will be faster for siure, its not true that 20% of a faster CPU will be faster than 90-100% of what you have right now.

I would double check that I’m not using any plug-ins, first of all. Try a braand new Vegas session, drop in your AVCHD and render to DVD, changing nothing. Make sure you have Vegas set to use multiple rendering threads, and that you have enough RAM for this — no disc thrashing for VM, etc. Make sure your’re rendering to the normal MainConcept MPEG CODEC, and no possible other weirdness, from CODEC packs or other evils that might mess with Vegas.

-Dave

[Stephen Mann]

Check the affinity. If your process affinity is not using all cores, you will see low processor utilization.

Low processor utilization can also mean a hardware I/O bottleneck.
High processor utilization means that the processor may be your limiting part of the program. (If you’re frequently seeing 100%, then you definitely need a faster processor).

Steve Mann
MannMade Digital Video
http://www.mmdv.com

[Larry Rantapaa]

Thanks for the input. My cpu is not accelerated at 3.4 ghz. The windows 7 rating is 5.9 due to disk IO. All 8 threads start out working and continue but slow down. The ram usage is strange. I have 12 gb and it seems to want to use it all. I came from a 2.8 ghz duo core 3.4 gb usable ram with XP. I will do more checking and post the results.

Larry

[Dave Haynie]

There’s always one bottleneck in any render. The value of looking for 95-100% CPU is because the CPU ought to be your bottleneck. At least, as long as you’re using normal video files (not some crazy number of RAW files or something that really demand a high-end SAN on Infiniband or some-such), with or without plug-ins, the act of rendering something like HDV or AVC to any output format is, at best, going to show a CPU bottleneck. On any CPU ever made.

If you don’t see 90-100% CPU, there’s something in the system that can probably be fixed, for free. The only way to go faster when you see nearly 100% CPU is, as you say, a faster CPU. But once you add that faster CPU, you should still see near 100% CPU.

The reason is simple: every other thing in the system will only be a bottleneck if not optimized. For example, hard disc. Typical video runs 24Mb/s for AVC, 25Mb/s for HDV or DV, 28Mb/s for AVCHD 2.0 compliant 1080/60p, 35-50Mb/s for some pro or digital still camera formats, 100Mb/s for Cineform, 144Mb/s for DNxHD, and, well, you probably don’t run into higher bitrates on a regular basis.

A plain old fairly modern hard drive ought to deliver at least 50MB/s, and probably more like 100MB/s… that’s an order of magnitude faster than your video input. You get into trouble if you’re reading too many files at once from the same drive — not because the drive’s too slow per se, but because the drive is thrashing (unfortunately, Vegas doesn’t let you set disc buffer sizes to help minimize this). Easy solution: use other drives. Your USB 2.0 drives, your C: drive, etc. Direct output to a flash drive, even. Pretty easy to solve… and yeah, I ran into this myself, with only one stream of HDV, but many, many 6-8Mpixel photos, on a project many moons ago. Shuffling assets between two drives, and rendering to my desktop, solved the problem completely.

Adding plug-ins only increases the appetite for CPU. The only big problem is that you have to watch for the occasional plug-in that might be single threaded.

Video decoding can also be very CPU intensive… a very fast modern PC is lucky to be able to decode two or three AVCHD streams in realtime. Naturally, when a video editor is rendering, that’s just one piece of the whole compositing puzzle. So actually, additional AVC layers in general may slow down your overall render, but push it even more toward the CPU bottleneck. You can probably speed things up a bit rendering out AVCHD files to some intermediate format (at least until you make HDD the bottleneck), or rendering out pieces of a project as subprojects. I’ve had a few 1-3 minute animations that technically take hours each to fully render, but the top level will rendering under 1/2 hour (most of that’s due to compositing layers — the CPU is pegged, even with a few short raw video tracks here and there).

Modern Intel CPUs have hyperthreading — each CPU core can appear to the system as two CPUs, with the provision that each pair is going to be locked to the same thread. Ideally, this makes things faster. And you might expect that with video rendering, given that much of the inner loop for things like AVC and MPEG output fit entirely in cache, with both register sets in a pair can access without thrashing. Data, on the other hand, has to move faster. Overloading a CPU due to cache thrashing in hyperthreading mode probably still looks like the CPU being pegged — if I had that kind of CPU (Intel i7 these days for sure), I’d do some benchmarks with Vegas to see which mode really produces the faster render.

And there’s some indication that a slow GPU can become a bottleneck for Sony AVC output. If so, this is easily fixed by editing the output preset to run on the CPU only, not the GPU.

-Dave

[Larry Rantapaa]

The problem seems to be with my Vegas setup. If my cpu or disc io were to blame it would seem to affect P Pro also. Vegas acts like it has to reprocess what it has already done from the beginning after it processes a little bit more of the file. This is a simple avchd or mts ,1920 by 1080i, file from my Sony HDR AX2000 which includes video and audio. Render this to DVD NTSC ,720 by 480i, with audio. No filters , adjustments. I just drop the file imported from the SDHC card into the HD onto the timeline and render to a new track.

If anybody else does this type render could you tell me how your Vegas 10e,64bit is setup. Perhaps I am unknowingly selecting options in Vegas that contribute to the problem. I built this new computer to handle the avchd files faster so I am a little frustrated that it seems to choke on the files.

mb ASUS P8 z68-V Pro
cpu Quadcore 3.40 gigahertz Intel Core i7-2600K
12 gb ram
video NVIDIA GeForce GTX 560 Ti with dual monitor
Black Magic decklink hdmi out

One other item. Vegas quit on me, just shut down while I was editing added audio to another avchd clip. I was adding small clips of audio on a separate track.

[Larry Rantapaa]

Solution found!! I reduced the number of rendering threads from the default of 16 to 8 and set the dynamic ram to 0. Setting the dynamic ram to 0 without reducing the number of threads did not do the trick.

CPU usage fluctuates between 65 and 75%, ram usage is less than 3 gig, render times are 50% actual. This corresponds favorably with Prem Pro.

Hope this helps someone else.

Thank you all for the input.

Larry

[Dave Haynie]

It’s all about keeping the CPU busy. If you allocate two much memory, you get memory faults and paging in the virtual memory system. Each rendering thread is going to take memory, and of course, the RAM preview buffer is by all accounts a static allocation only ever used for RAM preview (you’d think, during rendering, this could be de-allocated or re-purposed, since it’s a big waste, but that’s not what Vegas does).

-Dave

[Larry Rantapaa]

Another tweak to the solution. Setting Ram preview at 1024 MB let the horses run full out at over 95%. The things you did not learn in kindergarten.

Larry