Higher resolution slow motion workaround for Raven

[Cameron McKinlay]

Hey Everyone,
So I recently completed the REDucation course at AbelCine this past week and while we were playing around with the cameras, another student in our group had the idea to shoot 4.5k or 4k at 120fps but on a 60fps timebase. Then during ingestion, use optical flow in Resolve to slow it down further to a 23.976 timebase. The result was beautiful 4k slowmotion that was slower than 120fps and a really clean image. You can further clean up the image by shooting in REDcode Burst and lowering the compression. But you don't get much shooting time with the Burst. FYI, we were only testing this theory on Epics and Weapons so I encourage the Raven Users to try it and see what results you get.
Post your results if you have time!

 

[Kabilen Mullaithilaga]

Hey Everyone,
So I recently completed the REDucation course at AbelCine this past week and while we were playing around with the cameras, another student in our group had the idea to shoot 4.5k or 4k at 120fps but on a 60fps timebase. Then during ingestion, use optical flow in Resolve to slow it down further to a 23.976 timebase. The result was beautiful 4k slowmotion that was slower than 120fps and a really clean image. You can further clean up the image by shooting in REDcode Burst and lowering the compression. But you don't get much shooting time with the Burst. FYI, we were only testing this theory on Epics and Weapons so I encourage the Raven Users to try it and see what results you get.
Post your results if you have time!

Does it give even better results than just direct 120 to 23.976 + optical flow? Instead of 120 to 60 then 23.976 + optical flow?

 

[Chris McKechnie]

Regarding trying to slow down shots in post, trying to generate/interpolate frames on complex/lots of things going on in a particular scene, presents problems for the software and you'll get weird artificting. Have a solo subject and some sky, then it's easy...but as soon as you have a lot going on, it's typically too much for the software to handle which is why it's best to acquire in the higher frame rate. Applications like Twixtor/Resolve are great for the asker shots, but again, you're stuck since it was acquired that way if the software doesn't produce the results you want.

When recording at 120fps, your red code compression drops lower, so you'd get more noise, which can be easily removed with applications like NeatVideo. Personally, I'd prefer noise over interpolation artificting. I've shot an extensive amount of 120fps content, even without black shading, and I have never noticed any noise issues that it even warranted the use of neat video or other NR software, even at 12/13:1 redcode.

It's def'n an interesting idea, and obviously some people will prefer to shoot this way, but if you're shooting it properly in the first place, noise shouldn't ever be an issue.

 

[Kabilen Mullaithilaga]

Regarding trying to slow down shots in post, trying to generate/interpolate frames on complex/lots of things going on in a particular scene, presents problems for the software and you'll get weird artificting. Have a solo subject and some sky, then it's easy...but as soon as you have a lot going on, it's typically too much for the software to handle which is why it's best to acquire in the higher frame rate. Applications like Twixtor/Resolve are great for the asker shots, but again, you're stuck since it was acquired that way if the software doesn't produce the results you want.

When recording at 120fps, your red code compression drops lower, so you'd get more noise, which can be easily removed with applications like NeatVideo. Personally, I'd prefer noise over interpolation artificting. I've shot an extensive amount of 120fps content, even without black shading, and I have never noticed any noise issues that it even warranted the use of neat video or other NR software, even at 12/13:1 redcode.

It's def'n an interesting idea, and obviously some people will prefer to shoot this way, but if you're shooting it properly in the first place, noise shouldn't ever be an issue.

For most applications 120fps is more than enough, but there are those times when you want extreme bullet-time like effects - if you can't afford to rent a phantom for those one offs... sometimes you have to look at Twixtor and the same. At which point, you really need to know its limitations and plan accordingly.

 

[Cameron McKinlay]

Does it give even better results than just direct 120 to 23.976 + optical flow? Instead of 120 to 60 then 23.976 + optical flow?

120fps is a beautiful image but for those times when you want higher fps I will definitely be using this method as 2k slow motion on the lower end RED cameras is borderline unusable IMO.

 

[Cameron McKinlay]

Regarding trying to slow down shots in post, trying to generate/interpolate frames on complex/lots of things going on in a particular scene, presents problems for the software and you'll get weird artificting. Have a solo subject and some sky, then it's easy...but as soon as you have a lot going on, it's typically too much for the software to handle which is why it's best to acquire in the higher frame rate. Applications like Twixtor/Resolve are great for the asker shots, but again, you're stuck since it was acquired that way if the software doesn't produce the results you want.

When recording at 120fps, your red code compression drops lower, so you'd get more noise, which can be easily removed with applications like NeatVideo. Personally, I'd prefer noise over interpolation artificting. I've shot an extensive amount of 120fps content, even without black shading, and I have never noticed any noise issues that it even warranted the use of neat video or other NR software, even at 12/13:1 redcode.

It's def'n an interesting idea, and obviously some people will prefer to shoot this way, but if you're shooting it properly in the first place, noise shouldn't ever be an issue.

The approach we were looking at was to get usable footage with higher frame rates and higher resolution. For most projects, 120fps will be plenty sufficient. But 4k 120fps footage on a 60p project timeline slowed to 23.976 is MUCH cleaner than 2k at 240fps on a 23.976 timeline.

 

[Nick Morrison]

The approach we were looking at was to get usable footage with higher frame rates and higher resolution. For most projects, 120fps will be plenty sufficient. But 4k 120fps footage on a 60p project timeline slowed to 23.976 is MUCH cleaner than 2k at 240fps on a 23.976 timeline.

This is an interesting approach. We'll keep it in mind!

 

[Kabilen Mullaithilaga]

The approach we were looking at was to get usable footage with higher frame rates and higher resolution. For most projects, 120fps will be plenty sufficient. But 4k 120fps footage on a 60p project timeline slowed to 23.976 is MUCH cleaner than 2k at 240fps on a 23.976 timeline.

This is very very reassuring.
Now thats given that I've been eyeing the following video for while now, which is only 1080p @ 240fps + Twixtor (from FS700):
https://www.youtube.com/watch?v=iIAmN65DvKU

 

[Kris Tait]

Please post the results and/or R3D's!!! Thanks

 

[Cameron McKinlay]

I didn't get those R3D files unfortunately. I am still waiting for my Raven. And this theory was only tested on epics and weapons so I wanted to put it out there for current raven owners

 

[Marc Hutchings]

so you have 120fps and you are using optical flow to double to 240fps? Im just trying to get my head around the benefits of the 60fps timeline is the Raven actually recording any more frame per second ?? Or are we simple talking about oflow? If 120fps at 4k is the maximum the raven can handle how does the 60fps timeline change anything?

 

[Daniel Kelly Brown]

I also can't seem to understand how 120fps shot in 60fps is any different from 120fps shot at 24fps. I thought that it might magically produce 240fps when dragged into a 24fps timeline and slowed down to 50%, but from what I can see thats not the case...it just plays out as 120fps 24fps.

 

[Anton Shavlik]

In my mind 120fps in any time base is still the same frames, I don't really understand what you gain from changing to 24 to 60.

You said you get something slower than 120fps, I assume you mean slower than 120fps at 60. You also said it's cleaner but I'm not understanding why?

 

[Cameron McKinlay]

I am new to the RED workflow so this "project timebase" is new to me and as I am still waiting for my camera, so I can only comment on what we tried in class with the weapons.
So if the fps "project timebase" doesn't affect anything....then why is it there? Seems kinda pointless if it doesn't change anything when switching from 24 to 60p.

 

[Fabio Lanzone]

So if the fps "project timebase" doesn't affect anything....then why is it there? Seems kinda pointless if it doesn't change anything when switching from 24 to 60p.

It's there because it tells your editing software how to interpret the footage. It's just metadata. Can be changed in redcinex.

 

[Marc Hutchings]

It's there because it tells your editing software how to interpret the footage. It's just metadata. Can be changed in redcinex.

exactly so 120fps in a 24 fps timeline will last for 5 seconds andin a 60fps timeline only two seconds

 

[Kabilen Mullaithilaga]

so you have 120fps and you are using optical flow to double to 240fps? Im just trying to get my head around the benefits of the 60fps timeline is the Raven actually recording any more frame per second ?? Or are we simple talking about oflow? If 120fps at 4k is the maximum the raven can handle how does the 60fps timeline change anything?

I also can't seem to understand how 120fps shot in 60fps is any different from 120fps shot at 24fps. I thought that it might magically produce 240fps when dragged into a 24fps timeline and slowed down to 50%, but from what I can see thats not the case...it just plays out as 120fps 24fps.

Now, I'm going to try to answer both of your questions, as they are similar in nature.

First and foremost, I'm not an expert at optical flow or twixtor (or anything similar in terms of software) and I do not have much proof, but theoretically, I've been educating myself on it so I can try it on my next short. So, here is my understanding of it...

Sorry... lets take a step back... because I think you will better understand it, if you have a visual representation of it, so watch the following video:
https://www.youtube.com/watch?v=FLMoJ7jl4sw&feature=related

Watch the entire thing, and you will know what I am talking about.

Okay, so that was shot on a Canon 7D DSLR at 720p with 60fps framerate (back in 2010/2011).

With Twixtor, they were able to get it down to 2000 fps.

"Wow, how did they do that?"
Or
"I'm not impressed."

In either case, if you really look at the video... the resolution degrades by doing that (cleverly hidden by VFX raindrops), and because there is a lack of frames (meaning there is a lot of software manipulation to fill 60fps to make it 2000fps) - you will see "warping," which is conveniently edited out of the video.

Here is a sample of warping (if you didn't already know):
https://www.youtube.com/watch?v=CCnYszQgieE

Okay, now... remember... that was shot at 720p with 60 fps framerate.

Think what you can do with 4.5K @ 120 fps??????

From my experience, warping still exists, but its minimalized with 120fps.

Here is a video 1080p @ 120fps with Resolve's optical flow:
https://www.youtube.com/watch?v=FySeSXyqLi8


I have no proof, as I have no footage.

But, by transforming 120fps to a 60p timeframe, then throwing that into a 24p timeframe with optical flow (or twixtor)... will reduce warping even further than just directly throwing 120fps to 24p timebase with optical flow. My theory behind that is that the footage is slowed down enough for the software to manipulate even further...

And, I should tell you guys.... this is for people that want more than just 240fps... we are looking at a theoretical 1000 fps and above.

 

[Marc Hutchings]

Ok so here's my take on it, oflow tracks pixels between two frames and interpolates to create the new frame, the speed of the timeline has no bearing on the information available to it. The more you slow it down the more inbetween frames it needs to create the higher the chance that it will interpolate wrongly and create artefacts. The only thing that helps it minimise these artefacts is clarity of the footage - busy footage with occlusions and fast moving footage will confuse and create artefacts that need to be painted out.

The chances of stretching 120fps to 1000fps aren't in your favour without substantial clean up of artefacts.

120fps to 240fps quite possibly but if you really want to go higher rent a phantom in my opinion.

 

[David Battistella]

The approach we were looking at was to get usable footage with higher frame rates and higher resolution. For most projects, 120fps will be plenty sufficient. But 4k 120fps footage on a 60p project timeline slowed to 23.976 is MUCH cleaner than 2k at 240fps on a 23.976 timeline.

what you are describing is not slow motion, but frame doubling. As in, the NLE is playing each frame back twice instead of once. With RED 240fps is 240fps, 120 fps slowed to 50% is frame doubling and can not be compared.

In terms of high frame rates 120 was about as high as you could go up to a few short years ago.

http://www.slowmotioninc.com/#!35mm-cameras/

With the day rates of film cameras i'd say raven is a bargain.



david

 

[Marc Hutchings]

glad that's cleared up I felt stupid for a minute not understanding how this could be possible, Raven is certainly a bargain there's no disputing that!