Blackmagic Forum

Hello

I am having some issues playing back real time on my system and I am looking for some suggestions.

current specs are:

Intel Core i9-7980X
GIGABYTE X299 DESIGNARE EX
Samsung 960 PRO Series 512 for OS and 2TB for cache
128gb DDR4 3000
2 x titan x GPU
External black magic decklink 4k through th8underbolt 3
Win 10 pro
10GBE Nic
Qnap 8x8TB in raid 5

I cannot achieve realtime playback even with no effects on the video.

The footage is UHD canon clog from a c300 mk2 and pro res 444 from Alexa.

I must be doing something wrong. There is no issue playing back the files in a regular media player or Premiere.

None of the components are being topped out in any way.

No matter what cache settings I try there does not seem to be a way to achieve realtime playback, even when the clips are seemingly cached. They should play back from an NVME drive no problem.

Any thoughts would be really appreciated.

Cheers

Ian

Try disabling one of the Titans and see what happens.

Can you monitor HD from a UHD timeline? What happens if you switch the timeline to HD?

I have seen 18-core processors similar to yours play back in real-time with no problem. Heck, my Trashcan Mac can play back 4K in a 4K timeline provided I don't have anything going on in the node window.

Put 4K ProRes into your M.2 and simply try to play it. Plays or not?
Your system is definitely powerful enough- there has to be some fundamental issue.

Thanks all. Putting the the media on the NVME drive makes no difference.

I will try disabling a titan.

I should clarify that I am talking about the Color page not the Edit page.

Do you have a frame delay set for the viewer? I found that a 12 frame delay brought my system to a crawl. Setting it to 0 made everything run well again.


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Thanks again all.

Frame delay is set to 0. If you are referring to the options under play out in Capture and Playback.

Physically taking out a GPU makes no difference.
Switching them makes no difference.
Switching for a GTX 1080 makes no difference.

I understand that different aspects of the program are driving playback depending on what window you are in.

MEDIA, EDIT, COLOR. But are people getting full frame rate playback on the COLOR window?

Is it normal to switch to the edit window every time you want to play back the shot at full frame rate?

Playback in the Color page may be worse than is seen on Edit, since Edit (unless otherwise instructed) will drop frames to maintain audio and may *appear* to be real time, when it isn't.

However, your system should be capable of real-time playback on the Color page. What is the timeline resolution? What is the monitoring resolution? What's the resolution of the footage?

John Paines wrote:Playback in the Color page may be worse than is seen on Edit, since Edit (unless otherwise instructed) will drop frames to maintain audio and may *appear* to be real time, when it isn't.

However, your system should be capable of real-time playback on the Color page. What is the timeline resolution? What is the monitoring resolution? What's the resolution of the footage?

All res is set to 3840 x 2160. Output is also UHD to an external LG monitor through a decklink 4k.

If I switch everything to 1080 it plays back just fine.

Also regardless of effects the frame rate is a steady 12.5-13fps. If i disable all effects there is no change. All NR on, its the same as with it off.

I assume this is GPU driven and so I should be looking closely at the GPU's.

We have a system here with a couple of TITAN Xp's. I am going to give it a try on that and see what happens.

1080 is not ideal as it seems that certain effects and such are not scaled properly. Grain and noise reduction seems to look entirely different at these reduced resolutions.

Perhaps there is a setup that works that I am missing. Any advice is really appreciated.

Do you have your UI monitor or monitors connected to just one GPU?

Which nvidia and which CUDA driver are you using?

Is your output res set to the same rate as you monitor res?

V15 Studio version?

Ian Duncan wrote:Frame delay is set to 0. If you are referring to the options under play out in Capture and Playback.

No, I mean in DaVinci Resolve's universal "User" settings.

DaVinci Resolve > Preferences > User tab > UI Settings > "Delay viewer display by _ frames"

Is that set to 0?

Have you tried setting your video output to 8 bit?

I've also found that using a display LUT in resolve can slow things down a little bit.

Peter Chamberlain wrote:Do you have your UI monitor or monitors connected to just one GPU?

Which nvidia and which CUDA driver are you using?

Is your output res set to the same rate as you monitor res?

V15 Studio version?

Yes just one gpu, and the GPUS are in SLI

My output monitor is DCI and the output res is the same as the footage which is UHD. The scaling is set to center with no scaling.

14.3.00.14 version - 15 is currently unusable for us, but awesome none the less to have Fusion.

Seth Goldin wrote:

Ian Duncan wrote:Frame delay is set to 0. If you are referring to the options under play out in Capture and Playback.

No, I mean in DaVinci Resolve's universal "User" settings.

DaVinci Resolve > Preferences > User tab > UI Settings > "Delay viewer display by _ frames"

Is that set to 0?

The box is not checked.

Checking it, leaving it at 0 and restarting resolve and playing the clip seems to make no difference.

Resolve doesn't like SLI, try and deactivate it.

Plus, UHD and DCI 2K are not the same…

bruce alan greene wrote:Have you tried setting your video output to 8 bit?

I've also found that using a display LUT in resolve can slow things down a little bit.

I have the video output set to 8 bit.

Unfortunately I am running into this problem even if the disable all effects button is toggled. So no luts of effects.

Just playing back the log footage is not possible realtime.

I am also noticing a lot of frame tearing on the external monitor during play back. Is that normal?

Is this a custom-built PC? Are your fans all working? I once had the fan to cool my PCIe slots die, and when my DeckLink started melting I got all sorts of crazy artifacts. Resolve can be quite resource intensive and if you’re not dissipating the heat properly, this can cause all sorts of otherwise hard-to-diagnose problems.


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Seth Goldin wrote:Is this a custom-built PC? Are your fans all working? I once had the fan to cool my PCIe slots die, and when my DeckLink started melting I got all sorts of crazy artifacts. Resolve can be quite resource intensive and if you’re not dissipating the heat properly, this can cause all sorts of otherwise hard-to-diagnose problems.


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Yes its custom. It's properly cooled. Not a heat problem. Also the decklink is external via TB3.

Thanks for the feedback.

I think the issue has to do with OFX and nodes that are pre and post group not caching. This seems to be the way resolve works.

Uli Plank wrote:Resolve doesn't like SLI, try and deactivate it.

Plus, UHD and DCI 2K are not the same…

Interesting. Does not like SLI. How did you discover this? If online can you point me to where you read it or have you done some testing yourself? Please share if so.

When I said DCI i meant 4096 x 2160. So 4k DCI not 2k DCI.

Thanks for all your help everyone.


It's really nice to get so much feedback.

I think the issue has to do with OFX and nodes that are pre and post group not caching. This seems to be the way resolve works.

Ian Duncan wrote:
Interesting. Does not like SLI. How did you discover this? If online can you point me to where you read it or have you done some testing yourself? Please share if so.

Resolve support multi-GPU systems well, but SLI is not used. To figure out where your performance is bottlenecked, check your CPU, GPU, and storage utilization during playback.

viewtopic.php?f=21&t=62702#p355489

Actually, I wanted to write that UHD and 4K DCI are not the same. Tearing might have to do with that.
What about frame rates in the TL and for output?

Dont use SLI.
We have a lot better low level control of the GPUs.
After removing that review status of a clip with no effects. Then add.

Thanks everyone so much. I really cant believe how helpful the forum is. It probably the best experience I have had on a forum. A testament to the users and the devs.

I was able to solve my problem.


Cheers all.

Now to make it all work in Linux...

Peter Chamberlain wrote:Dont use SLI.
We have a lot better low level control of the GPUs.
After removing that review status of a clip with no effects. Then add.

Thanks so much for the info.

I an not clear as to what you mean by that last part.

"After removing that review status of a clip with no effects. Then add."

Ian Duncan wrote:Thanks everyone so much. I really cant believe how helpful the forum is. It probably the best experience I have had on a forum. A testament to the users and the devs.

I was able to solve my problem.


Cheers all.

Now to make it all work in Linux...

How about posting what you did to help others with similar problem?

Frank Wylie wrote:

Ian Duncan wrote:Thanks everyone so much. I really cant believe how helpful the forum is. It probably the best experience I have had on a forum. A testament to the users and the devs.

I was able to solve my problem.


Cheers all.

Now to make it all work in Linux...

How about posting what you did to help others with similar problem?

I think the issue has to do with OFX and nodes that are pre and post group not caching. This seems to be the way resolve works.

I could not achieve real time playback with these nodes turned on. A bummer.