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Will Radeon 6970 Improve Render Time vs. Radeon 7850

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Mike Kerr
Will Radeon 6970 Improve Render Time vs. Radeon 7850
on Mar 16, 2015 at 4:20:14 pm
Last Edited By Mike Kerr on Mar 16, 2015 at 4:59:30 pm

I've been reading through many of the topics related to render performance and codec quality vis-à-vis MainConcept, and I gather the following:

- MainConcept codec AVC is better quality than Sony AVC
- Newer GPUs are not really supported for OpenCL

I thought I had understood most of the discussions and then the question of Render vs. Preview came up and one used GPU and the other didn't, and I got all confused again.

My CPU is an AMD FX 9370 and my GPU is a Radeon HD 7850. All of my rendering is for YouTube, and on most of them I have several clips with transitions and brightness enhancements. A 20-minute video will usually take 50+ minutes. I understand MC does not support newer radeon cards for OpenCL after the 6k series, so if I were to purchase a Radeon 6970 as a second GPU, if I were to use that GPU for Rendering would it render faster and better quality than the 7850?

I am less concerned with preview (though that would be nice). My main concern is cutting down my render time. Most of my videos are 20-30 minutes, so for me it's worth it if I can cut render times down to 30-40 mins, and realize the improved quality of using MC AVC than Sony AVC.

But with recent stuff I've been reading, I'm not sure if there would be a render improvement, and that the improvement would only come in the preview. Confused...help!


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Dave Osbun
Re: Will Radeon 6970 Me vs. Radeon 7850
on Mar 16, 2015 at 4:56:35 pm

Your CPU is what is slowing your render speeds down. AMD has never been known as a 'great' CPU for video editing.

Latest Intel i7 (even previous model) will give you much better results.

Dave


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Mike Kerr
Re: Will Radeon 6970 Me vs. Radeon 7850
on Mar 16, 2015 at 5:08:28 pm

So if I get a radeon 6970 and use GPU for rendering, which MC AVC supports, it won't make a difference?


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Norman Black
Re: Will Radeon 6970 Improve Render Time vs. Radeon 7850
on Mar 16, 2015 at 7:06:39 pm
Last Edited By Norman Black on Mar 16, 2015 at 7:09:53 pm

Mainconcept AVC will support AMD 5xxx and 6xxx GPUs for encoding via their OpenCL encoder. 7xxx and newer are not supported by MC AVC but the Vegas video engine itself still works very well with newer GPUs.

GPU encoder algorithms are not typically at the quality level of CPU encoders. It all depends on the bitrate you are encoding to and the source material. Really, unless bitrates are low and you pixel peep you are not likely to notice. Do your own tests.


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Mike Kerr
Re: Will Radeon 6970 Improve Render Time vs. Radeon 7850
on Mar 16, 2015 at 8:14:41 pm

The bitrates I'm using I believe are 20k if I recall. If I had a card that MC supported, I'd be happy to do my own testing and share it. Unfortunately I only have the card I have, the 7850, which is why I'm asking if I did buy the 6970 for $100 if it would make a difference.

I'm not spending $100+ to perform a test... I know what I see right now, and if you're telling me that I'd barely notice any quality drop-off with GPU encoding, then that's good. But should I expect a render speed increase?


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Norman Black
Re: Will Radeon 6970 Improve Render Time vs. Radeon 7850
on Mar 16, 2015 at 9:28:39 pm

By 20K, I believe you mean 20 megabits. That is a very high bitrate for HD material. Most every encoder should look the same at that level. This includes MC AVC versus Sony AVC and even those versus x264. Sure PSNR and/or SSIM will show some differences, but the human eye at frame rate, I doubt it.

I once compared MC AVC OpenCL GPU versus my GoPro 1080p30 source file. Both 20Mbit. Pixel peeping a still frame between source and the re-encode was nearly identical. I had to toggle to see any pixel difference.

Back then I had an AMD 5850 GPU. These days I have an AMD 7950 GPU and so MC AVC is no longer an interest to me and I render using x264 via frameserving and encoding is the least of my worries as editing takes all my time.


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Stefan Jovanovic
Re: Will Radeon 6970 Improve Render Time vs. Radeon 7850
on Mar 17, 2015 at 7:50:22 am

Could you please explain this part "and I render using x264 via frameserving"?
I'm just trying to figure out what it means.


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Scott Francis
Re: Will Radeon 6970 Improve Render Time vs. Radeon 7850
on Mar 17, 2015 at 2:27:26 pm

I am interested in what you mean by that as well!! "and I render using x264 via frameserving"?

Xavier (Scott) Francis
Mind's Eye Audio/Video Productions


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Norman Black
Re: Will Radeon 6970 Improve Render Time vs. Radeon 7850
on Mar 17, 2015 at 7:29:17 pm

[Stefan Jovanovic] "Could you please explain this part "and I render using x264 via frameserving"?
I'm just trying to figure out what it means."


I use the "Debugmode Frameserver" utility render driver.
Then one installs Avisynth, or Avisynth+ into the system.
Then I use ffmpeg as the receiver of this whole process. ffmpeg directly support access to Avisynth.

Avisynth is the frameserver. Debugmode framserver is a go between between Vegas and Avisynth and ffmpeg is the encoder which basically receives from Avisynth.

With ffmpeg one can render whatever your heart desires. AVC/H.264 (via x2564), DNxHD, ProRes, XDCAM, Xvid and more. In whatever container file format you want. ffmpeg is a command line tool and not terribly easy to use.

I really only encode AVC for my use. x264 is the best quality and fastest encoder out there for AVC. In its superfast modes it is as fast as GPU encoders at similar quality and in its slower modes it generates better quality. Your choice.

Here is an example of my command script which executes ffmpeg. It is a slower quality encode.


@echo off

title encode crf25

cd d:\renders
d:

REM output the AviSynth commands
echo AviSource("server.avi") > server.avs
echo ConvertToYUY2(matrix="rec709") >> server.avs
REM echo ConvertToYUY2(matrix="PC.709") >> server.avs

c:\systools\ffmpeg32\bin\ffmpeg.exe -threads 0 -i server.avs -c:v libx264 -preset medium -profile:v high -me_method umh -crf 25 -colorspace bt709 -color_primaries bt709 -color_trc bt709 -pix_fmt yuv420p -bufsize 40M -maxrate 40M -c:a libmp3lame -qscale:a 2 -chunk_size 64K output.mp4

pause

del server.avs

REM saved commands for alternate audio output formats and bitrates
REM (mp3 160k vbr) -c:a libmp3lame -qscale:a 4
REM (mp3 192k vbr) -c:a libmp3lame -qscale:a 2
REM (aac 192k vbr) -strict experimental -c:a aac -q:a 2.4
REM (aac 192k) -strict experimental -c:a aac -b:a 192k


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Dave Osbun
Re: Will Radeon 6970 Improve Render Time vs. Radeon 7850
on Mar 17, 2015 at 3:29:52 pm

The improvement, if there is any at all, will be minimal. Replacing your current GPU isn't really a fix when you have a system bottleneck (the AMD CPU).


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Sorin Nicu
Re: Will Radeon 6970 Improve Render Time vs. Radeon 7850
on Mar 17, 2015 at 10:54:26 pm

[Mike Kerr] "I'm not spending $100+ to perform a test..."
Well... you could first sell your video card on eBay and make those $100.
Although, I wonder... you paid $600 for the editing software and you have no extra $100 for a video card?


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Mike Kerr
Re: Will Radeon 6970 Improve Render Time vs. Radeon 7850
on Mar 17, 2015 at 11:27:55 pm

No, I am using Sony Vegas 13 Platinum.

Perhaps I'm too noob or don't understand something. A lot of what has been posted in this thread is above my head. I found my way here through google several days ago trying to find out ways to improve render times in Vegas for YouTube, which consensus seems to indicate we should use the Main Concept AVC codec. I have a newer Radeon card not supported by MC, and (IMO) a fairly decent CPU. Unfortunately there does not seem to be any insightful discussion anywhere else on this topic.

I just want to know if putting in an older series card that is supported will render faster using GPU than right what I'm using now (a newer card and CPU).

So far I understand half of what people have graciously taken their time to respond with, and a recommendation to upgrade my CPU (which would require a motherboard upgrade and re-installing my entire system). If what I'm trying to ask is more complicated than a yes/no, or if I'm asking the wrong question, then just let me know and I'll move along.


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John Rofrano
Re: Will Radeon 6970 Improve Render Time vs. Radeon 7850
on Mar 18, 2015 at 2:15:02 am

[Mike Kerr] "I just want to know if putting in an older series card that is supported will render faster using GPU than right what I'm using now (a newer card and CPU)."
I believe the answer is YES. The MainConcept AVC encoder gave me a 3.6x improvement in performance with my AMD Radeon HD 5870 GPU. Here is a thread with all the details:

"New" graphics card

I assume an AMD Radeon HD 6xxx series card would do even better. The 6000 series is the last one supported my MainConcept AVC.

~jr

http://www.johnrofrano.com
http://www.vasst.com



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Dave Haynie
Re: Will Radeon 6970 Improve Render Time vs. Radeon 7850
on Mar 21, 2015 at 3:50:45 am

Ok, first, let's deal with the details:

* MainConcept AVC will probably deliver a better result than Sony AVC at lower bitrates. MainConcept can also do VBR encoding, Sony can't. So there are some advantages to MainConcept. At higher bitrates, there's not likely much difference.

* MainConcept has very good GPU acceleration that they won't enable if your GPU basically isn't on their internal list. There's no good reason for that aside from pressuring Sony to upgrade, but since they stopped doing upgrades (MainConcept has been a division of several different companies), that's what we're stuck with. GPU rendered AVC isn't quite as high quality as CPU rendered AVC, due to the differences in algorithm. Maybe some day, but probably not from MainConcept. The HD6970 -- my GPU, BTW -- is the fastest card for MainConcept support, far as I know.

*All newer GPUs support OpenCL just dandy -- the MainConcept problem is something different (they reject GPUs hard coded in their driver, kind of doing an end run around the very concept of OpenCL).

So, OpenCL is also used by Vegas itself. Some plug-ins use it, the compositing engine uses it for some work, etc. Basically, you refer to "preview" acceleration, but truthfully, anything that speeds up preview using the GPU can also speed up any render to any CODEC.

So the real questions to answer: [a] will the HD6970 speed up your MainConcept AVC renders, and [b] will the HD6970 at least not slow down your system in any other way, in order to make [a] worthwhile.

Ok, so as far as speeding up your system, yes, it will. My old system was based on an AMD 1090T processor, a 6-way "Phenom II" processor. There are a few architectural advantages in Phenom over the Piledriver architecture in your CPU, the idea of two integer CPUs sharing one FPU and L2 caches, but the extra cores and clock speed means your chip should edge out my old one, but probably not enough to change basic system behavior.

Given that, the HD6970 was a dramatic speed improvement for MainConcept rendering on my old system, so probably on yours, too. I didn't find that specific benchmark, but it was a solid increase. In fact, I bought both the HD6970 and the price-parity nVidia, GTX580 maybe, and ran the Sony benchmark and other tests. The nVidia went back. And Vegas 12 improved the rendering performance, mostly due to Vegas itself using the GPU, not just the MainConcept plug-in. That benchmark is around somewhere.

Here's a thread with the results on my current system (Intel i3930K)... best speedup is about 6x using GPU vs no-GPU. That is significant.
https://forums.creativecow.net/thread/24/973364#973581

You can see that the GPU helps preview and rendering. But anything that's speeding up the preview will speed up that same work, compositing and all, that's needed for the final render.

Now, about that [b] part -- it's technically possible that the speed boost from a more modern GPU would run the Vegas accelerations so much faster than an older GPU, that this would offset the MainConcept improvements. And those would be enjoyed by the Sony CODEC and any other output rendering you do. However, checking on the available benchmarks, it looks like the HD6970 is faster than your HD7850 at many graphics benchmarks and OpenCL, but they're not far apart even when the HD7850 wins. So you would get a speedup buying the HD6970. Makes some sense -- they're only one generation apart. That said, the HD6970's peak power consumption is around 260W... twice that of the HD7850 -- they got a die shrink from 40nm to 28nm in there as well. So make sure your PSU can handle it.

-Dave


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