Blackmagic Forum

Hello,

Upgraded 17.b9 to 17.1. 17.b9 was removed from the system before installing.

Now, in 17.1 GPU is not used in case of H265 clips, as 17.b9 did. But for H264 clips Resolve still uses the GPU.

Reinstalled 17.b9, found out, comparing both versions, that under preferences ticking/unticking the box 'decode' has no effect in 17.1. In 17.b9 it does. GPU is effectively always switched off in 17.1, apparently for H.265 clips only.

Task manager confirms GPU GPU is not used in these cases.

Is there a fix, did I overlook something else?

regards, Tamis

I wonder if you installed the Free version of 17.1 by mistake, which won't include GPU decoding.

Thanks for the suggestion but no, I checked, installed the Studio version 17.1

OK.

Testing it here in Studio 17.1 for Windows, the GPU is doing the decoding.

GTX 1070 8GB

Added new information (into the original post): the problem appears only with H265 clips; H264 clips work normally. Are you able to check H265 also? Thanks

Yes, H.265 was the clip I tested.

I can't get the GPU to do decoding on 17.1 studio either (non beta)

Windows 10
NVIDIA 1070 Ti

Which NVIDIA driver are you using? Please update to the latest.

Thanks Rohit,

Updated NVidia driver from 456.71 to 461.72 (dated 23-2-2021)
Re-downloaded Resolve files
Removed current installation, re-installed Resolve 17.1
Opened new project, imported original H264 and H265 files

No change.

Put H265 clips and H264 clips into one timeline. On playback Task manager shows no GPU activity on the H265 clips; (see attachment).

Hope this helps.

updated to driver 461.92 (10-3-2021), no change

Tamis Kwikkers wrote:Task manager shows no GPU activity

I've never found that to be an accurate 'measure' of NLE's GPU usage.

Do you see a performance difference turning the option on/off?

Perhaps task manager is not very accurate, but is shows on/off clearly.

There is certainly a performance change.
H.265 clip plays 50 fps in 17beta9, less than 10 fps in 17.1.
H.264 clip plays 50 fps in both 17 beta9 and 17.1.
17.1: H.264 and H.265 in one timeline one can see GPU decoding kicking in for H,264 clip, switching off at H.265.
17 beta9: GPU decodes both clips.
See example screen shots in earlier post.

Switching decode on/off in preferences does have effect in 17 beta9, not in 17.1 for H.265
Switching decode on/off in preferences does have effect in 17.1 and 17 beta9 for H.264

OK.

Can you share one of the problem H.265 clips for us to look at?

Herewith the link to two of my files, one H265 and one H264: https://we.tl/t-Kop4ex8m1Y
I tried to install an older driver but that did not help.


On my laptop (1165G7/IrisXE) no problem.

Thank you for your interest.

They both play smoothly on all three machines here.

Uli, thanks you for trying.

So no problem on Mac systems and on Iris GPU systems.

However, a friend of mine has a GTX 1650, uses driver 461.92 and he has exactly the same issue as I described. We may expect the issue to be related to NVIDIA GPU's and/or drivers in combinatio with a change between Resolve 17beta9 and 17.1.

I hope this information is useful, and BMD is working on this.

I tested on two machines, one with a 4GB GTX 960 and one with an 8GB GTX 1070.

On the 960 machine, there was no performance difference with GPU decoding on or off. It does look like the CPU was doing the work in both cases.

On the 1070 machine, there was a marked performance difference with GPU decoding on, so the GPU is doing the work.

The 960 used Studio driver 461.40.
The 1070 uses Gaming driver 461.92.

The issue was solved with the update 17.1.1. Thank you BMD!