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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

Motion blur the X-track in HDRx

Christoffer Glans

Christoffer Glans

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I've posted in the DaVinci Resolve forum, but that might not be the right place.

I'm wondering if there's a way to blur the X-track while doing the HDRx merge? The reason it looks weird is because the X-track has a much higher shutter, so if we could add post motion blur to that track, it would probably look better.
 
Christoffer Glans said:
I've posted in the DaVinci Resolve forum, but that might not be the right place.

I'm wondering if there's a way to blur the X-track while doing the HDRx merge? The reason it looks weird is because the X-track has a much higher shutter, so if we could add post motion blur to that track, it would probably look better.
Click to expand...

The Foundry's Nuke + Furnace combo is perfect for dealing with this. Haven't tried any similar plugins directly for DaVinci yet...

:sifone: Peter
 
The best thing would be if wither Redcine-X could add such a feature or DaVinci. Problem is that it's a rather advanced to do true post motion blur. But I whink it would be worth it.
How does the Nuke/Furnace work with this?

A work around might be to split up the tracks and do your own post motion blur on the X-track, then merge them by overlaying the X-track with a luma key for the highlights or bright areas of the image.
 
Hi Christoffer thanks for the test ,what is the best settings for X-Track?is it 4 stop or 3 stop?what did you prefer for the best way to get HDRX ?

Thanks
Sunil Prem
 
For HDRx you need to balance amount of motion to the amount of stops. The more stops the sharper the X-track becomes (because of a higher shutter). So when blended they will look awkward when one track is sharp while the other has motion blur. The most extreme use of HDRx should only be used in a more calm shot, like someone sitting in front of a window. If you have motion, it's better to lower the stops in order to get a little more motion blur on the X-track.

This is why I'm looking into adding post motion blur to the X-track. If it's possible to blend them together with that, the motion sharpness will probably be less distracting. Right now, HDRx has been a hard sell to clients because of it.
 
Re:Vision Effects Reel Smart Motion Blur has an OFX plugin version, so it's feasible that could be implemented in Resolve for this purpose.
 
Is the Re:Vision motion blur based on shutter speeds or angles instead of just a slider? I have seen a lot of motion blur plug-ins for after effects but they are not based on the calculations you do in cinematography.
 
It's been a while since I have used it, but the pro version allows a lot more functionality than just a slider. It's not set up to simulate the terminology of the DOP, because that would be impractical as it can not mimic actual shutter angles on already shot footage perfectly. Rather it use motion vector estimation to do as near a job as it can attempt.

One thing it can do is try to apply the motion blur from one layer to another. Given that's exactly what you are trying to do with HDRX this deserves some experimentation to see how close the two layers can get.

I'd certainly imagine with creative usage and trial and error, you could get to close enough for most scenarios.
 
Craig Parkes said:
One thing it can do is try to apply the motion blur from one layer to another.
Click to expand...

Wait, what? This is exactly what is needed. If it can duplicate the motion blur from the A-track to the X-track then the image should be identical, but still retain the added stops.
This would be awesome and actually make the Epic close to the Dragon in terms of stops.
 
Peter Majtan said:
The Foundry's Nuke + Furnace combo is perfect for dealing with this. Haven't tried any similar plugins directly for DaVinci yet...

:sifone: Peter
Click to expand...
+1 ... nukex is how I do it too, mathematically there is no way of automatic doing this for all the different use cases so you need a package like nukex (adobe AE can do this and it's cheap).
 
Would be easier to do it while grading instead of round-tripping through nuke or AE. That way you could in theory shoot a whole movie with HDRx and still not be hammered by renders and other software.
 
As soon as you try to blend the HDRx track you're dealing with a VFX shot. If you're imagining it's as easy as just applying an Oflow motion blur to the x track and blending you're going to be disappointed. Optical flow motion blur is glitchy, Nuke's default oflow blur tool centers the blur which is wrong, it needs to be a forward blur to hope to match and even then, contrary to RED's mraketing, it's often slightly mismatched. All in all, I've never used HDRx on a shot that needed motion blur and didn't end up with a bunch of keys, roto shapes and paint cleanups.

If you're going to shoot a "whole movie" then I would also just go ahead and budget tens of thousands of dollars for a compositor to try and make it work. (Or alternatively you could just control your lighting).
 
The Re:Vision "ReelSmart Motion Blur" comes in three flavors. (Standard, Pro and Pro-Vector). There is motion detection available.

I use it mostly for the CG part of my work (since over a decade I guess by now), with a motion-pass from my 3D render. [Cinema 4D] (RSMB-Pro-Vector)
For difficult scenes it (Pro) has even the option to set some helper points -- animated.

I would never say that any package is able to do it completely automatically. Think for example about a shot through a dirty window, or any layered elements with a different "on-sreen-speed". You will have a hell of a roto work in front of you to get this "motion-blured".

Besides that layer problem, with glass, haze, any motion blur already in the footage puts you to the next level of trouble. Crossing motion of two objects, for example, adds to that complexity, especially in combination to all cases mentioned before. (More a CG theme: The post effect combination of shallow "Depth of Filed" and "Motion blur" is certainly the master challenge in all of that.)

In my years of "faking" motion blur, I saw not very often that the solution were "energy-conservational". Which looks, more or less, just bad, as some "drawings" that the highlights would create are not at all available. (Think of spinning chrome wheels/rims in the Sun for example).

The ability to use motion from one layer to another is based (AFAIK, and re-reading the manual) that you can use the motion of the layer to be tracked, not the motion blur directly. Which I think is a big difference. Having said that, to have a layer with motion blur already, based on up to six stops, might not work as the footage is different, but that is a guess, I would not even investigate that.

Get in contact with Jasmine, he is certainly open for this, as the user-base of RED is large. (He won an Technical Oscar btw). If you are visiting NAB next year, they are always there where all the other Ae plug-in people are.

Your millage might vary, I haven't worked with NUKE X 7 or 8, (only NUKE 4-6), nor used "Flame" which is certainly known for its motion detection/estimation.
 
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As per the above, it's not going to work perfectly or automatically at all - and as they say any HDRx shot is automatically a vfx shot for this reason. These tools could help, but they aren't miracle fixes that can backwards engineer all the optical realities of a scene from analysing a motion blurred frame.
 
Magic Motion was cancelled years ago I think.

Edit: Nope got that confused. MNMB, More natural motion blur was canceled years ago. Magic motion is fancy luma key blend.
 
Why was the more natural motion blur cancelled?
 
Don't forget that the two tracks are not photographed at the same time so there is an inevitable time offset on motion in the frame that is increased as that motion becomes faster.
 
Tom Gleeson said:
Don't forget that the two tracks are not photographed at the same time so there is an inevitable time offset on motion in the frame that is increased as that motion becomes faster.
Click to expand...

Where you got that from? Any source?
 
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