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Random Black Frames in Fusion 9

PostPosted: Mon May 14, 2018 3:01 pm
by Jeff McGuire
Hey guys,

Has anyone encountered random black frames in Fusion 9 comps.

All Loaders display every frame of animation, but when I ram preview the comp it displays black on this one specific frame. It appears to be arbitrary. It's driving me insane. I've tried to replace loaders and merges etc. This happens in both HiQ and Proxy and purging the cache doesn't solve the problem.

Any thoughts?

Thanks,

Jeff

Re: Random Black Frames in Fusion 9

PostPosted: Mon May 14, 2018 3:05 pm
by Sander de Regt
Are you using paint tools in combination with the planar tracker by any chance?

Re: Random Black Frames in Fusion 9

PostPosted: Mon May 14, 2018 6:00 pm
by Jeff McGuire
No, just straight Loaders and Merges with Blurs and Glows.

If I preview the loaders, the "missing" frame is there. Sometimes when I scrub the Blur amount I can see the result, but once I let go of the slider the frame goes black. Removing the Blur doesn't appear to solve the issue either. It's very strange.

Re: Random Black Frames in Fusion 9

PostPosted: Mon May 14, 2018 8:03 pm
by Chad Capeland
Are you sure it is black and not NaN?

Re: Random Black Frames in Fusion 9

PostPosted: Mon May 14, 2018 9:15 pm
by Jeff McGuire
I'm not sure how I would get a NaN error. What would cause this?

Re: Random Black Frames in Fusion 9

PostPosted: Mon May 14, 2018 9:24 pm
by Joël Gibbs
Try turning off openCL on merges, or any other tool that doesn't need it. That gets rid of a lot of random black frames for me.
There's a tool over at steakunderwater that works well for me:
https://www.steakunderwater.com/wesuckl ... 057#p12057

Joël

Re: Random Black Frames in Fusion 9

PostPosted: Mon May 14, 2018 11:11 pm
by Jeff McGuire
Ah, the old OPENGL BS - I hadn't considered that. Thank you, I'll try and see if that solves it.

Re: Random Black Frames in Fusion 9

PostPosted: Tue May 15, 2018 2:10 am
by Jeff McGuire
This issue appears to stem from any blur or glow type node, including defocus.

Re: Random Black Frames in Fusion 9

PostPosted: Tue May 15, 2018 10:23 am
by JP Docherty
I have in the past had problems with glow nodes causing black frames and image corruption. After some trial and error I found that the glow nodes screwed up if the image was in float format and worked ok if I changed it to 16 bit integer. I also had to clear all caches as well as I found changing the bit depth did not necessarily re-render them.

This can, of course, require some thought as to where and how the glow is applied in your flow but I found that I could usually fit it in somwhere and then convert it back to float if needed, even if it meant rendering the glow over an empty frame then changing it back to float prior to merging.

This wasn't just with fu9 but with previous versions as well.

Might not be related but I thought I'd mention it . . .

Re: Random Black Frames in Fusion 9

PostPosted: Tue May 15, 2018 12:57 pm
by Chad Capeland
JP Docherty wrote: After some trial and error I found that the glow nodes screwed up if the image was in float format and worked ok if I changed it to 16 bit integer.


Integer doesn't have NaNs. If you have a float image with NaNs and convert it to integer, Fusion will set the values to 0 or 1.

JP Docherty wrote: I also had to clear all caches as well as I found changing the bit depth did not necessarily re-render them.


That's odd. Can you reproduce that?

Re: Random Black Frames in Fusion 9

PostPosted: Tue May 15, 2018 1:51 pm
by Jeff McGuire
Converting to int16 appears to have done the trick. It even got rid of these annoying black squares which would rear their ugly heads from time to time. I thought it was a Blender Cycles render error.

Is there a way to clamp values after blurring/glow/defocus to prevent this NaN issue?

Thanks for everyone's help!

Re: Random Black Frames in Fusion 9

PostPosted: Tue May 15, 2018 3:36 pm
by michael vorberg
You can always clamp your image with the brightness /contrast node. There is a checkbox to clip black/white

Maybe you have introduced negative values before you glow/blur which can lead into the black pixels
Other than that try to set the blur mode not to gaussian, this can also lead some negative values

Re: Random Black Frames in Fusion 9

PostPosted: Wed May 16, 2018 3:12 am
by Chad Capeland
michael vorberg wrote:You can always clamp your image with the brightness /contrast node. There is a checkbox to clip black/white


BC won't do that. 1.#QNAN is unchanged and 1.#INF becomes 1.#QNAN.

Re: Random Black Frames in Fusion 9

PostPosted: Wed May 16, 2018 8:59 am
by JP Docherty
JP Docherty wrote:
I also had to clear all caches as well as I found changing the bit depth did not necessarily re-render them.

Chad:That's odd. Can you reproduce that?

The comps were pretty complicated and I was under some time pressure so I wasn't able to definitely pin this down I'm afraid. It just seemed that this was the case so I started clearing caches whenever the problem arose just to be safe.