Foreground movement distorting background

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jgugenheim

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Foreground movement distorting background

PostThu Jul 22, 2021 6:37 pm

I have some odd artefacts going on that I don't think I've seen before... The Q1 BRAW and GH5 Vlog footage in the Multicam clip when opened in the timeline does not have them, but they exist in the timeline where the Multicam clip is used in the film edit - and so also in the delivered footage. I have attached two screenshots from the film timeline and one from the Multicam timeline - I chose the GH5 examples as it is noticeably worse!
Screenshot 2021-07-22 at 19.07.39.png
Just before distortion
Screenshot 2021-07-22 at 19.07.39.png (691.98 KiB) Viewed 736 times

Two frames later:
Screenshot 2021-07-22 at 19.07.55.png
Two frames later
Screenshot 2021-07-22 at 19.07.55.png (593.8 KiB) Viewed 736 times

And then finally, the same frame from the Multicam timeline:
Screenshot 2021-07-22 at 19.30.07.png
From Multicam timeline
Screenshot 2021-07-22 at 19.30.07.png (585.43 KiB) Viewed 736 times

I'm slightly confused that they don't look like the same frame - shot at 25fps and timeline is 25fps, no proxy in use. I did start the timeline at 24fps and then converted to 25, this problem has existed throughout the lifetime of the project.
I figure I've selected something daft in the project settings, though I'm not sure what is different from previous projects?
Any help would be greatly appreciated!
JG

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Hendrik Proosa

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Re: Foreground movement distorting background

PostThu Jul 22, 2021 7:10 pm

Looks like optical flow retiming artifacts, check your frame rates again.
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jgugenheim

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Re: Foreground movement distorting background

PostThu Jul 22, 2021 9:27 pm

Yes, you’re right, indeed it does - I’ll check again.

Many thanks
JG

15" Macbook Pro, 2.9GHz 6c i9, 32GB RAM, Vega 20 4GB
Vega 56 8GB in a Core X eGPU cage
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jgugenheim

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Re: Foreground movement distorting background

PostFri Jul 23, 2021 10:18 am

Well, I created a new project, set to 25fps. Opened both the new and old projects using dynamic project switching. Copied the media and timelines across. No difference! I don't get long to check though because Resolve crashes after 10-20 seconds, even if I don't do anything, so I've obviously done something wrong in the copy.

I've gone back to the original project.

I have deleted all proxies, created new proxies and optimised media, I've tried creating a new timeline with selected clips and decomposed, I've tried creating a new timeline and copied and pasted all clips (both deselecting "use project settings and choosing 25fps).

Creating a new empty 25fps timeline and putting the Multicam into it works fine. Is there a way of refreshing the clips in the timeline, reconforming them to their source Multicams? Otherwise I'll have to recreate the whole edit!
JG

15" Macbook Pro, 2.9GHz 6c i9, 32GB RAM, Vega 20 4GB
Vega 56 8GB in a Core X eGPU cage
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Resolve Studio for Mac and iPad + Speed editor
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Jim Simon

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Re: Foreground movement distorting background

PostFri Jul 23, 2021 1:36 pm

The Multicam clips will also have to be at 25. So if they were created at 24, you'll have to scrap them, recreate them, and yes...redo the edit.
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Sander de Regt

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Re: Foreground movement distorting background

PostFri Jul 23, 2021 1:40 pm

I am not sure if that applies in this case, but I think that in the inspector you can choose to override the time interpolation method. So if it's set to optical flow in general, you can change it to something else there. You may get stuttering or something like that, but since you're working with mixed frame rates, something's gotta give anyway.
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jgugenheim

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Re: Foreground movement distorting background

PostSat Jul 24, 2021 10:40 pm

Thanks for the replies, I think I need to clarify something - only the project was set to 24fps, all the footage was shot at 25 (there is an embarrassing reason for this).

Having rebuilt all the proxies I right clicked on one of the offending clips in the timeline and hit “conform to proxy” (sorry, not in front of my computer just now, but it was something like that) and the distortion went away. What I’m not sure about until I can test it tomorrow is if this has broken the link to the original clip - which will obviously then affect the delivery.

On the “redo the edit” front, if the above does not turn out to be the solution, might I be able to export the XML and then import it into a new project with identical media? Surely the EDL will be fps independent?

A word of explanation - I came to Resolve from FCPX which is blissfully agnostic about fps and resolution - you can mix and match with very little damage indeed.
JG

15" Macbook Pro, 2.9GHz 6c i9, 32GB RAM, Vega 20 4GB
Vega 56 8GB in a Core X eGPU cage
Laptop + 2x2k & 1x4k display
iPad + 4k display
Resolve Studio for Mac and iPad + Speed editor
BMPCC4k & BMPCC6k Pro

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