Color app Shows wrong image in viewer window

[Joseph Owens]

[Peter Robertson] “my timeline contains many video formats : HD Prores 422, 4k mp4 and 8k mp4. That all works on my new 27 inch iMac i7”

Not sure what “works on my… iMac” means, but

First thing that comes to mind is that possibly the Long-GOP mp4 high-resolution clips may be overtaxing your system’s cache/buffer/CPU/UI display buss when being decoded in Resolve. Its image engine is not the same as the playback-only function of most Quicktime-like applications.

jPo, CSI

\”I always pass on free advice — its never of any use to me\” Oscar Wilde.

[Peter Robertson]

Thanks Joseph
In the timeline (Edit) I can play the mixture of clips (except the 8k slows down and is jerky).
In the Color tool I can just click from one clip to another but the images shown do not always match (thumbnails with the large viewer window).
I have 40 Gigs of memory.
Thanks
Peter

[Joseph Owens]

[Peter Robertson] “I have 40 Gigs of memory.”

Is far more motherboard memory than Resolve15 will ever use — it is GPU/VRAM that is critical. That your 8K “slows down” is a red flag. Not knowing much more about your platform, you should look into the recommended hardware config that Black Magic publishes — its on their website in the Support column.

jPo, CSI

\”I always pass on free advice — its never of any use to me\” Oscar Wilde.

[Marc Wielage]

[Peter Robertson] “I have to say the my timeline contains many video formats : HD Prores 422, 4k mp4 and 8k mp4. That all works on my new 27 inch iMac i7.”
I would convert everything to a simpler codec, like ProRes 422 or ProRes 444 (whatever is most appropriate for the source material), and see what that does.

iMacs to me are not heavy-duty enough to handle 8K and highly-compressed codecs. They’re going to get stressed out and slow down, no matter what you do. You can either get a much more powerful machine, or use much less-stressful codecs — it’s your choice for the workflow.

[Peter Robertson]

Thanks to all for the advice.
Yes I should really convert the 8k to ProRes 422. I was trying to take a short cut. However I still managed to grade all the clips in the timeline without the conversion of the 8k mp4.
Thanks
Peter