Red 8k performance in Davinci

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AndreasOberg

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Red 8k performance in Davinci

PostSun Nov 11, 2018 12:43 am

Hi,

I'm having problems with playback of red files from Helium in Davinci.
What makes it worse is that it seems to change. I remember being able to playback files a few days ago but now one of my projects struggles even with 1/8 debayer and I have not even started grading.
Another project can playback in full debayer if I use half resolution mode.

Are there any special settings I need to setup? I cannot find any clear differences.

First, I'm using latest Davinci 15.1.2
Windows 10
2x14 Core 2.6GHz Xeon running at steady 3.1GHz
Geforce 1080 Ti 11GB
Geforce Titan X 12GB (previous generation so the 900 serie)
128GB Ram
8x8 RAID disk that delivers between 400-800MB/s

Also the CPU load in Davinci when I playback is very low. Usually around 30%
Redcine X can playback full debayer in 8k with a bit of buffer time.
/Andreas
Consulting Lead VFX Microsoft Games/Rare Ltd
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MishaEngel

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Re: Red 8k performance in Davinci

PostSun Nov 11, 2018 1:27 am

Your Titan is ~ 6 Tflops fp32 and the 1080 ti is ~ 11 Tflops fp32.

With only 1 1080ti it will be faster.

Turn off Hyper Threading.
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AndreasOberg

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Re: Red 8k performance in Davinci

PostSun Nov 11, 2018 10:33 pm

Hi Misha. I sit fp32 that Davinci uses for all its operations?

I turned off Hyperthreading in bios and half res seems to be faster. CPU load is 100% and I can playback in halfres fine.
However full res has CPU jumps between 8-100% and stutters all the time.
I tried using only the 1080 Ti and together with the Titan X. But I could not see any difference in performance.

On another note I remember the performance mode in the settings would drop to one step lower in debayer, but that does not seem to happen any more. I liked that before you could have full res when the image was still and when you would play it would go to half debayer.

Best,
Andreas
Consulting Lead VFX Microsoft Games/Rare Ltd
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MishaEngel

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Re: Red 8k performance in Davinci

PostSun Nov 11, 2018 10:48 pm

AndreasOberg wrote:Hi Misha. I sit fp32 that Davinci uses for all its operations?

I turned off Hyperthreading in bios and half res seems to be faster. CPU load is 100% and I can playback in halfres fine.
However full res has CPU jumps between 8-100% and stutters all the time.
I tried using only the 1080 Ti and together with the Titan X. But I could not see any difference in performance.

On another note I remember the performance mode in the settings would drop to one step lower in debayer, but that does not seem to happen any more. I liked that before you could have full res when the image was still and when you would play it would go to half debayer.

Best,
Andreas


Davinci Resolve uses fp32 for debayering.
Your CPU's are fast enough to handle the .R3D because you can playback 1/2 res, so the GPU is the limiting(around 20 fps) factor in full-res.

What compression ratio are you using and how many fps?
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AndreasOberg

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Re: Red 8k performance in Davinci

PostSun Nov 11, 2018 11:04 pm

Hiya Misha.
It is the full 8k helium sensor in 25fps in 13:1. Normally we record in 60fps 8k.

So if the CPU can handle half res it will automatically handle full res? How does that work? (just curious)

So if I had 2x1080 Ti cards would it playback i realtime?
I have another card on another computer (that has 2x10 3.1GHz core) that I could grab.

My plan was to get a 2080 GTX and use together with the 1080 Ti on this machine.
/Andreas
Consulting Lead VFX Microsoft Games/Rare Ltd
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MishaEngel

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Re: Red 8k performance in Davinci

PostSun Nov 11, 2018 11:29 pm

AndreasOberg wrote:Hiya Misha.
It is the full 8k helium sensor in 25fps in 13:1. Normally we record in 60fps 8k.

So if the CPU can handle half res it will automatically handle full res? How does that work? (just curious)

So if I had 2x1080 Ti cards would it playback i realtime?
I have another card on another computer (that has 2x10 3.1GHz core) that I could grab.

My plan was to get a 2080 GTX and use together with the 1080 Ti on this machine.
/Andreas


The CPU's handle the decrypt/decode/decompress of the .R3D so it doesn't matter if it is full, 1/2 or 1/4 res. The GPU handles the de-bayer process, here it does matter what the resolution and the quality is that you want to display. 2x 1080ti's should be able to display around 40 fps in 8k 444 at maximum quality (when you lower the quality and/or the resolution, 60 fps is easy).
Just don't edit on full res, highest quality settings.

RTX2080 only has 8 GByte so it is not suited for 8k(you will run out of memory all the time).

2 VEGA FE's would be the best option (when you can still get them), they have 16 GB of memory and when those are full, it swaps it to system memory. An other good option is the WX9100 but this one costs around 1500 pound each (or $1400).
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AndreasOberg

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Re: Red 8k performance in Davinci

PostMon Nov 12, 2018 12:02 am

MishaEngel wrote:
AndreasOberg wrote:Hiya Misha.
It is the full 8k helium sensor in 25fps in 13:1. Normally we record in 60fps 8k.

So if the CPU can handle half res it will automatically handle full res? How does that work? (just curious)

So if I had 2x1080 Ti cards would it playback i realtime?
I have another card on another computer (that has 2x10 3.1GHz core) that I could grab.

My plan was to get a 2080 GTX and use together with the 1080 Ti on this machine.
/Andreas


RTX2080 only has 8 GByte so it is not suited for 8k(you will run out of memory all the time).


Just to clarify. I meant the Ti that has 11GB of memory. I never ran out of memor on the Titan X that has 12GB. You still think 11GB would not be enough?
Consulting Lead VFX Microsoft Games/Rare Ltd
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MishaEngel

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Re: Red 8k performance in Davinci

PostMon Nov 12, 2018 1:05 am

AndreasOberg wrote:Just to clarify. I meant the Ti that has 11GB of memory. I never ran out of memor on the Titan X that has 12GB. You still think 11GB would not be enough?


When you do enough effects like TNR you will run out of memory quick enough, Phil Holland got 2 P6000's with 24 GByte each for a reason.

The good thing about the NVidia consumer cards is that they are pretty fast, the bad thing is that they lack the memory for lots of 8k work. An almost similar priced WX9100 is a bit slower (around 10%) in 8K but won't run out of memory.

https://www.pugetsystems.com/labs/articles/DaVinci-Resolve-15-NVIDIA-GeForce-RTX-2070-Performance-1264/ the VEGA 64 is the consumer version with 8 GByte of the WX9100 which has 16 GByte.

Maybe it's an idea to shoot 7k with an Abt-speedbooster, you gain almost a stop of light and you have 23.4% less data to be handled by the GPU's. Your equivalent pixel size will rise from 3.65 um to (3.65/0.72) = 5.07 mm. Only a few(OTUS 85 at F4 and some master primes at T4) current day lenses available for mortals can handle 8k with such small pixels. https://www.lensrentals.com/blog/2017/10/the-8k-conundrum-when-bad-lenses-mount-good-sensors/

From a 6K bayer sensor you can get a perfect 4k RGB delivery signal, just ask James Cameron he is shooting the new Avatars on 6k bayer sensors. With 7K you still have room for image stabllization and/or cropping for 4k delivery
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Marc Wielage

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Re: Red 8k performance in Davinci

PostMon Nov 12, 2018 1:15 am

MishaEngel wrote:From a 6K bayer sensor you can get a perfect 4k RGB delivery signal, just ask James Cameron he is shooting the new Avatars on 6k bayer sensors. With 7K you still have room for image stabllization and/or cropping for 4k delivery

I think this is very good advice. To me, 8K is one of those issues where "just because you can do something doesn't mean you should do something."

I think there are good reasons to shoot 6K for a 4K extraction, but the reality is that 8K is very, very tough in terms of workflow. This is one of those things that you really need to rigorously test prior to the shoot, just to make sure the workflow will be practical on down the line. Given infinite time and money, of course, anything could be done. But in the real world, it's going to be trying, especially with a 2GPU system and anything but the best CPUs in the world. Transcoding might be a better option for many projects -- and bear in mind quite a few major Hollywood blockbusters routinely transcode everything to DPX or EXR for the final. You don't necessarily see 5K/6K/8K Raw being used in those setups.
marc wielage, csi • VP/color & workflow • chroma | hollywood
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AndreasOberg

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Re: Red 8k performance in Davinci

PostMon Nov 12, 2018 6:29 pm

8k is an interesting debate. I agree it is very demaning on storage and CPU/GPU for playback.
Most of the time we shot in 7.5k because we use the Canon CN20x50 which vignettes at 8K. It cannot use a speed booster but our canon lenses can of course.

The only strong reason I see for 8k for wildlife is that you can zoom in. For some shots you can actually zoom in 2x and still get a quite sharp 4k out. Most of the time the focus will be a bit off though so I would maybe only zoom in 1.5x.

Interesting with the AMD 9100 cards. You are right that they have tons more memory and also cost about the same as 2080 Ti. I am a bit hesitant to use AMD cards. I remember there was poor OpenCL supprort back in the days, but today is of course very different. I wonder if it is only 10% slower also in other programs? What are the features that takes the most memory. Is there anyway I can push the system?

For noise reduction I always use Neat Video currently which takes forever, but creates very good results. It is painful to use, but superiour results. Helium has quite a bit of noise. I do use up to 30-40 nodes but have not run into memory issues yet but it would of course NOT be good to if I do after upgrading to 2080 Ti cards.

One point with resolution. Shooting with 8k Helium will generate considerably less noise than 6k. Also at 8k resolution you begin pushing the quality of your lenses so it is quite easy to see artifacts. Downsampling from 8k of course reduces this a lot.

Interesting input!
Andreas
Consulting Lead VFX Microsoft Games/Rare Ltd
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MishaEngel

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Re: Red 8k performance in Davinci

PostMon Nov 12, 2018 10:19 pm

To me the most sensible upgrade in your case would be to add another 1080ti.

RTX2080ti is still on 12nm, not much faster than a 1080ti and way to expensive.
Since you have never run into memory problems so far this would be the the most cost effective way to upgrade your system. 7nm is on it's way from both NVidia and AMD.

You mentioned that you can shoot 7.5k with your Canon 20x50, this would mean that it has an image circle of atleast 31.74 mm. When you put a speedmount on your camera with this lens you will still have an image circle of 31.74mmx(31.1/43.3)=22.8 mm which is 5.5k WS and 5.5k HD that will give you an almost perfect de-bayer for UHD RGB delivery and you gain almost a stop of light hence less noise.

Spend your money wisely, a $500.000 Ferrari is not 10 times faster than a $50.000 BMW.
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Dermot Shane

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Re: Red 8k performance in Davinci

PostMon Nov 12, 2018 10:40 pm

one thing is to set your timeline and monitoring to match your deliverables

if delivering UHD, then timeline and monitor UHD.... not 8k
if delivering HD, then timeline and monitor HD.... not 8k

i'm gradeing a film shot on Helium a 8k today, my timeline is UHD, my monitor is UHD, the caches are DNxHR444_HDR and it's running trouble free all day long - 2x2697v2 / 2x 1080Ti / 128g /SAS array / Decklink4kPro, hyperthreading turned on, and all 48 threads are sparking

the deliverables are UHD, HD and DCi_2k_flat

why on earth would i run a 8k timeline? makes less than zero sense
why on earth would i use the computer's resources to debayer on the fly over and over for no purpose (or gain)?
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AndreasOberg

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Re: Red 8k performance in Davinci

PostMon Nov 12, 2018 11:06 pm

Dermot Shane wrote:
why on earth would i run a 8k timeline? makes less than zero sense
why on earth would i use the computer's resources to debayer on the fly over and over for no purpose (or gain)?


Hi Dermot, just to be clear. I'm using an UHD timeline, not 8k. But I need to inspect at 8k level if it is actually in focus and we often zoom in the image when editing as well.

We do not edit so complex material so can usually do a rough cut using Red RAW files, and then when the edit needs to tighten up then I would transcode into DNxHR media for the media that I use.
With neat video so far i have cached the node, but it is not working so great (often the cache has to be remade for no reason, and sometimes they do not work at all) so I think I will begin transcoding the whole clip every time I use Neat Video.

/Andreas
Consulting Lead VFX Microsoft Games/Rare Ltd

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