URSA 12k horizontal banding when filming LED Volume

Hi, looking for some advice!

We have a curved LED Volume that we're in the process of setting up and I've noticed that when we're filming against the screen and tilt the camera we get horizontal banding lines that appear. I've tried switching frame rates, shutter speeds/angles, Volume frame rates, Unreal Project Frame Rates, and the system is genlocked to 25hz but I've also tried at 24hz and it's produced the same issue.

I have video examples of the issue but it won't let me post them for some reason. Not sure how I can demonstrate that.

Any and all advice is very welcome! It's probably something simple but I'm still relatively new to it all so chances are I've overlooked something

Thanks!

Uhm may be a moirés problems instead of banding caused from frequency?
You told that appear only when tilt the camera, have you tried with a olfp filter on camera?


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Been shooting on LED Volumes recently as well, and have found the same issue with the Alexa 35, RED Gemini, Red Helium, etc. Still working on figuring out the right settings to get rid of it. So have mainly been working around it and using post production tools to get rid of it.

It's definitely a settings need to be right to get rid of it sort of thing. And it may apply to all cameras. Just have to find it. Will be doing more tests in the coming weeks. I've got several more projects that will be on the LED Wall in the coming months. It's now a very common tool in production. So solving is a priority for me.

Pulsed LEDs can be a major PITA and I’m not sure there’s a general solution.
If nothing is moving fast, longer exposure times and a mild speed-up in post may work.

It is normal, not suppose to keep focus on LED volumes, problem solved.
Hence, this did not happen when filming against projector background in my recent shoot no matter how much I tried to push it and test it

Yes, happens with Alexas too, recent training with EPIC and LUX Machina they also advise the same, keep LED out of focus, does not need to be much out.

Been shooting on LED Volumes recently as well, and have found the same issue with the Alexa 35, RED Gemini, Red Helium, etc. Still working on figuring out the right settings to get rid of it. So have mainly been working around it and using post production tools to get rid of it.

It's definitely a settings need to be right to get rid of it sort of thing. And it may apply to all cameras. Just have to find it. Will be doing more tests in the coming weeks. I've got several more projects that will be on the LED Wall in the coming months. It's now a very common tool in production. So solving is a priority for me.

Keep distance between talent and LED's, blur background a bit.

Hi, looking for some advice!

We have a curved LED Volume that we're in the process of setting up and I've noticed that when we're filming against the screen and tilt the camera we get horizontal banding lines that appear. I've tried switching frame rates, shutter speeds/angles, Volume frame rates, Unreal Project Frame Rates, and the system is genlocked to 25hz but I've also tried at 24hz and it's produced the same issue.

I have video examples of the issue but it won't let me post them for some reason. Not sure how I can demonstrate that.

Any and all advice is very welcome! It's probably something simple but I'm still relatively new to it all so chances are I've overlooked something

Thanks!

Try this setting, set LED to 50hz refresh rate, set your camera to 24fps, dial in shutter angle to 172.5 , set UE and genlock to 24fps.

It could be also genlock issue itself, I would test it against single user node (led screen) without genlock to confirm whether it is camera or genlock delay issue).

Been shooting on LED Volumes recently as well, and have found the same issue with the Alexa 35, RED Gemini, Red Helium, etc. Still working on figuring out the right settings to get rid of it. So have mainly been working around it and using post production tools to get rid of it.

It's definitely a settings need to be right to get rid of it sort of thing. And it may apply to all cameras. Just have to find it. Will be doing more tests in the coming weeks. I've got several more projects that will be on the LED Wall in the coming months. It's now a very common tool in production. So solving is a priority for me.

Keep distance between talent and LED's, blur background a bit.

That's definitely been one thing we've been doing. But there are the times where we need to get the wider shot to show off the set and see a bit of the background projected on the wall. So, it's definitely not always easy as saying to just throw the background out of focus.

Doing these shoots has definitely been giving me a good idea of the strengths and limitations of the LED Walls. Green screen still has its place. Location shooting still has its place. Knowing which tool to use is the most important.

Plus, the environments thrown on the wall need to be good resolution and bit depth. We've encountered some banding issues with poorly rendered Unreal Engine Environments.

And it may apply to all cameras. So solving is a priority for me.

This is the main reason I went to the Red Komodo-X camera. The global shutter solves this issue. There is a video on YouTube that talks about the best camera for volumes. If you haven't tried it yet you should.

That's definitely been one thing we've been doing. But there are the times where we need to get the wider shot to show off the set and see a bit of the background projected on the wall. So, it's definitely not always easy as saying to just throw the background out of focus.

Doing these shoots has definitely been giving me a good idea of the strengths and limitations of the LED Walls. Green screen still has its place. Location shooting still has its place. Knowing which tool to use is the most important.

Plus, the environments thrown on the wall need to be good resolution and bit depth. We've encountered some banding issues with poorly rendered Unreal Engine Environments.

Absolutely Tim, strongly agree, lots of limitations involved.
LED volumes are complex and require whole team of artists to make it work and are not feasible on smaller level productions.

4K UST HDR 12bit projectors makes things simpler and eliminates lots of weaknesses of LED wall, but comes with another set of limitations, like brightness level and screen size, as well ability to create curved environment, limiting shots choices...

And it may apply to all cameras. So solving is a priority for me.

This is the main reason I went to the Red Komodo-X camera. The global shutter solves this issue. There is a video on YouTube that talks about the best camera for volumes. If you haven't tried it yet you should.

Global shutter has advantage when it comes to camera movement, of coarse.

However, all CMOS sensors are prone to moire and banding from my understanding, and LED volumes are notorious for this.

There are numerous reason why not to focus on LED screen regardless of the camera used, like pixel pitch and density of LED as well as individual panels joints can be seen when focused on.

IMO, the most important aspect of camera used for LED wall is colour reproduction and dynamic range, challenge is to balance colours and see and match both worlds and more importantly to retain those colours at different lighting situations, Alexa is still the king here, but not the only option of course.

Here is the video I referenced earlier.

Here is the video I referenced earlier.

To call it best camera for LED volume based on global shutter advantage is silly, look at the colours on that clips Komodo vs Alexa LF Mini...I can only see 2 mushy colours on Komodo in that test.

If it was to be judged for filming live sports coverage , sure, but for narrative not so much.

They must be silly in Hollywood for shooting Barbie and Mandolorian on Alexas, I am sure they had access to Venice and Komodo.

If the global shutter is the only deciding factor, then we should all film on old used BMCC 4K and Ursa Mini 4k for less than $1000.

ICVFX is done in camera and colour grading is also done in camera in real time, there is only so much you can do later on, for this reason, when colours fall apart between real world and background game is over...Another words one should judge latitude of the camera rather than just some fast panning/tilting advantage.

I have no experience in this field at all but I would imagine that the point of a global shutter camera in this scenario isn't about panning, it's rather about how the volume screen refreshes and how that can create artefacts? So it will be different for different screen technologies.

Hi everyone, thanks for your replies (I didn't see a notification seeing people had replied until just now!)

I've got a few ideas from this that I'll try out and I'll let you know what happens.

The video examples are these (You'll have to put it after the youtube url as it wont let me post full links):
watch?v=gDgarId0Ohc
watch?v=THnm6Juj0W0

Darko, you seem to find fault with most every post in every thread from almost every person. That's OK, I guess, but it's not moving this discussion forward.

Since you have an opinion in this thread, please let me know what camera you are using for LED and green screen volume work. I would also love to see some work product as well.

For me, using the Komodo-X in both volume and green screen testing these last 2 months, I have been nothing but happy. It gives me a better image than my Blackmagic camera has, and grading both in-camera, using Ultimatte systems, and raw footage in post has been a win across all three areas. While I still have more testing to do over the next few months I can say that the Komodo-X camera makes a difference.

Also, spend some time using Brompton technology and you can find that you can focus on the volume wall. Virtual production is a very fluid space right now and there are no 100% definite answers as the technology, and people using it, are moving forward every single day. Be open to the fact that other people's experiences are not your experiences and learn from them. I do, every single day.

Darko, you seem to find fault with most every post in every thread from almost every person. That's OK, I guess, but it's not moving this discussion forward.

Not sure, where do you find this, please quote or explain, I recall answering numerous questions of yours and helping you work out your VP/ICVFX progress and shared many valuable tutorials in the past. Such statement against me is inflammatory and absolutely not called for.

Since you have an opinion in this thread, please let me know what camera you are using for LED and green screen volume work. I would also love to see some work product as well.

I shoot ICVFX workflow on Alexa Classic and Odyssey 7Q+ exclusively in ARRIRAW.
I already shown some examples here, hence I got in the trouble by admin for sharing ALEXA images, I believe I was the first one here on this forum to share working live frustum few months back and that's where I answered many of your hard trade secret questions that I had no problem to share with yourself and others here on forum.

For me, using the Komodo-X in both volume and green screen testing these last 2 months, I have been nothing but happy. It gives me a better image than my Blackmagic camera has, and grading both in-camera, using Ultimatte systems, and raw footage in post has been a win across all three areas. While I still have more testing to do over the next few months I can say that the Komodo-X camera makes a difference.

That's great that you are happy with Komodo, I also said that Alexa is not the only option, but IMO best option.

Also, spend some time using Brompton technology and you can find that you can focus on the volume wall.

I will, obviously you know something I don't as well as EPIC and Lux Machina and NEP Virtual Studio, they have been telling me lies all this time for past 6 months of the training or so. Word is that moire is an issue when focused on LED. Please enlighten me, and the rest of the Hollywood ?!

Virtual production is a very fluid space right now and there are no 100% definite answers as the technology, and people using it, are moving forward every single day. Be open to the fact that other people's experiences are not your experiences and learn from them. I do, every single day.

I totally agree, now that you called me out, please share some of your experience with VP / ICVFX work here, work samples, working VP tests, or frustums, something I did months ago, before you go out and try to take me down on live forums with all kind of false accusations ?

IMO, you did not take well my honest opinion about Komodo being far from perfect camera , which I am entitled to voice here regardless of my experience with ICVFX, my take on this is simple, latitude is more important then 5 ms delay with sensor, simple as that. When you film few stops above and below thing start to fall apart in general, let alone in ICVFX thing when you mixing different worlds.

If in the video you shared they did test or in fact if they understood importance of latitude in ICVFX set up, and Komodo proved to beat all others cameras, then I would give very positive opinion.

IMO that test is totally worthless and embarrassing, for themselves especially .
Komodo 6k - 7 stops of latitude vs ALEXA 35 almost 13 !

From CineD tests:
"So, in summary, ALEXA 35, we are getting 12 stops of exposure latitude – with some wiggle room towards 13! The ALEXA Mini LF had 10 stops, the Sony VENICE 2 had 9 stops, the FUJIFILM X-H2S gets close to 9 and most other cameras are between 7 and 8 stops of exposure latitude – just to give you some reference!"

Here are some Cinematography guidelines for volumes from recent EPIC/LUX training:

Screenshot 2023-09-11 at 1.20.06 am by Darko Djeric, on Flickr

Screenshot 2023-09-11 at 1.17.06 am by Darko Djeric, on Flickr

Screenshot 2023-09-11 at 1.16.23 am by Darko Djeric, on Flickr

Minimum distances relating to pixel pitch / density from the walls, very important, let alone moire and other issues, hence reason why you can not zoom into the wall and focus at your will:

Screenshot 2023-09-11 at 1.18.24 am by Darko Djeric, on Flickr

Screenshot 2023-09-11 at 1.19.19 am by Darko Djeric, on Flickr


Screenshot 2023-09-11 at 1.15.15 am by Darko Djeric, on Flickr
Screenshot 2023-09-11 at 1.12.25 am by Darko Djeric, on Flickr
Screenshot 2023-09-11 at 1.12.46 am by Darko Djeric, on Flickr

Hi, looking for some advice!

We have a curved LED Volume that we're in the process of setting up and I've noticed that when we're filming against the screen and tilt the camera we get horizontal banding lines that appear. I've tried switching frame rates, shutter speeds/angles, Volume frame rates, Unreal Project Frame Rates, and the system is genlocked to 25hz but I've also tried at 24hz and it's produced the same issue.

If it is banding try downsampling to 4K and see if it disappears.

If the banding is strictly horizontal then it's surely a rolling shutter artifact, moire would present itself in both the X and Y axes. I think PWM dimming is mostly a thing of the past at this point but it might depend on the LED product, in which case changing the brightness will have a larger impact than changing frame rate.

Good Luck

Those screens can show moire & banding like any other scene. I would get a RAWLITE or the Blackmagic OLPF to clear it up.

I have the RAWLITE for my UMPG2. I'll get the LED Techs together to do a test sometime. Figure out everything. Maybe we need to Genlock to the Wall. I do want to run some tests before the next project.

And to eliminate scanning issues, Sony is now making their Verona displays. “The displays also feature high-performance LED driver ICs, enabling refresh rates of up to 7,680Hz, effectively eliminating scanline artifacts on cameras.” (according to RedShark)

This sounds like a refresh rate issue.

I have shot with the 12k on volumes with Unreal without issues.

You could try shooting at 8k and see if that improves or but it really sounds to me more a config issue.

Also moire from a screen won’t be fixed by an OLPF. It’s a function of pixel size to distance.

JB

You could try shooting at 8k and see if that improves or but it really sounds to me more a config issue.

During testing I had this issue with the 12K and downsampling down to 8K you could still see it but at 4K it cleared up. Again, I went to the global shudder of the Komodo-X to remove this issue altogether.

If this is banding issue I would try this. If it's a moire issue listen to John and look for a config issue. Specifically I would look at the refresh rate of the volume to start with.

This video may be helpful:

Camera Test Video:

I think they used a Gen 1 URSA Mini Pro. So I'm curious how the G2 and 12K differ in the results. But, seeing the Alexa 35 and Mini LF have the issue in this test that I have seen in person on our shoots with the Alexa 35 does help confirm it is not only with us. And, the Red Raptor doing it too helps show why the Ranger Helium had the issue.

May have to test the new Komodo-X, which I know someone who has it, and see if that performs best.

Since you have an opinion in this thread, please let me know what camera you are using for LED and green screen volume work. I would also love to see some work product as well.

ADMIN, PLEASE DELETE IF NOT ALLOWED, ALL SHOT ON ALEXA, BUT WAS CALLED OUT .

Person who called me out is not posting any of his VP work, so I may as well answer the call.


Arri Classic (ARRIRRAW) both green screen and UE 5.2 against 4K HDR UST Projector.
Recent project, feature film in progress in Western Australia with 20 cast.

DOP-ed, Directed, Produced, currently in post.

Here is challenge for VP experts here, which scenes are green screen, which was blue screen and which was Unreal Engine Volume ???










PS. Blue & Green Screen and also UE 5.2 Volume was all projected against UST projector

Camera Test Video:

I think they used a Gen 1 URSA Mini Pro. So I'm curious how the G2 and 12K differ in the results. But, seeing the Alexa 35 and Mini LF have the issue in this test that I have seen in person on our shoots with the Alexa 35 does help confirm it is not only with us. And, the Red Raptor doing it too helps show why the Ranger Helium had the issue.

May have to test the new Komodo-X, which I know someone who has it, and see if that performs best.

I wish they used the 12k and the Production 4k (which has global shutter).

Warning: Some Strong Coarse language:

Today we did a test comparing a few of the Genlock boxes on the Arri Alexa 35 with the LED Volume.

Blackmagic Mini Converter Sync Generator - Had some issues
Aja Gen10 - Worked fine

However, we still got Horizontal Banding despite being Genlocked with the Aja Gen10.

Either way, Blackmagic probably should update their Mini Converter Sync Generator for better use with LED Volumes as it is really designed for Broadcast.

So the truth is that Blackmagic needs to build a cinema camera specifically designed to work with LED Volumes and their own new Mini Converter Sync Generator. If anything, they need to do a wireless device that can connect to the camera to untether it. It stinks running long SDI cables all over the stage because you have to keep the camera tethered to the Genlock.

Blackmagic Mini Converter Sync Generator - Had some issues

Wondering what specific issues you had with the Blackmagic Sync Generator.

Genlock isn’t a magic bullet. All genlock will do is ensure that the output of all devices is sync’d. There is no provision for capture delay on the input side, nor processor lag on the output side.

In modern systems banding is more often an artifact created by PWM dimming rather than frame rate. I shoot against LED walls daily at 60p with a variety of cameras and never see any banding (moire certainly) because the LED products we use employ voltage dimming rather than PWM. It’s the same with Macbook monitors. Shoot a Macbook monitor and you’ll never see banding, with a low end PC monitor you’ll see banding as soon as you take the brightness down from 100%.

Good Luck

If anything, they need to do a wireless device that can connect to the camera to untether it. It stinks running long SDI cables all over the stage because you have to keep the camera tethered to the Genlock.

I think the Ambient ACN-CL LockIt Wireless system is pretty close to the gold standard and it manages both timecode and genlock. That is the direction I am going with.

However that only gets rid of the genlock cable. You still have the SDI cable feeding everything that gets dragged around. However that's only one cable out and most likely another SDI cable back to the second on-board monitor, so that's nice. Unless you're using 4K Teradek systems...and that's too much money for me

If anything, they need to do a wireless device that can connect to the camera to untether it. It stinks running long SDI cables all over the stage because you have to keep the camera tethered to the Genlock.

I think the Ambient ACN-CL LockIt Wireless system is pretty close to the gold standard and it manages both timecode and genlock. That is the direction I am going with.

It provides genlock that’s frame matched to the LTC. It doesn’t jam sync genlock. The drift is <1 frame\day but that means you could easily be 100 lines out within an hour.

Good Luck

Ah...I didn't know that. Thank you Howard.

As Howard says.

Timecode means every frame has the same number.

Genlock means the PHASE of when each frame starts and finishes within that frame is also in sync.

If you think about it, a camera could be almost a full frame out of sync but still have the same frame timecode.

JB

Genlock was born out of the need for multi-camera sync to allow switching. In the days of analog, cameras (output) needed to be sync’d line for line and pixel for pixel otherwise a cut would create a jump and a dissolve would become a hot mess. If one camera is on line 100 and another is on 423 what happens when you cut between the 2?

If you sync the shutter, regardless of output, multicamera switching becomes impossible because the sync has nothing to do with the output. Genlock is what it is and serves the purpose it was designed for, which was never shutter sync. If you think about it, real time shutter sync is basically impossible because no electronics are capable of instantaneous output. A frame needs to be processed before it can be output which must necessarily be delayed.

Back in the day you had clear scan shutter where you could surf the shutter around and bury the blanking interval of a CRT but the output sync was constant.

Good Luck

Actually modern master clocks can be driven by GPS so that discrete clocks can still be in sync with each other, both TC and genlock. This is old technology at this point released the same year as the first iPhone.

https://www.tvtechnology.com/be-blogs/6211

Regardless the issues with LED walls are likely because of inexpensive products using PWM dimming. The refresh interval of quality LED products (Roe, Saco, Barco) is microseconds. You might see some flicker at 1/250 or 1/500 but at normal frame rates it will be invisible. I’m shooting a show now with no less than 5 different models of camera, some genlocked, some not, some global, some rolling shutter and there is no banding. Seriously, shoot your macbook screen, how far do you have to crank the shutter before you see artifacts?

Good Luck

Someone reading this part about genlock will see the need for a newer, more modern solution, build it, and then charge $12,000 + for it because it has to do with "virtual production".

But yes, a newer solution is needed. Until then we have the Blackmagic Mini Converter Sync Generator and the AJA Gen 10. Are there others I should be looking at?

Blackmagic Mini Converter Sync Generator - Had some issues

Wondering what specific issues you had with the Blackmagic Sync Generator.

Primarily the wall didn't seem to get Genlocked even though the camera showed Genlock.

And, Arri seems to acknowledge this in their White Paper on Page 5: https://www.arri.com/resource/blob/2335 ... i-data.pdf

In testing, we have had mixed and quite unreliable results when using a Blackmagic Mini Converter Sync Generator as a Genlock source.

Thanks for the link and your own experience!

Thanks for the link and your own experience!

You are welcome!

I'll note that the camera may have said "Genlock" but it doesn't mean it was in the correct Phase with the wall. We couldn't tell where the problem was, but it was with the BMD Mini Converter Sync Generator that this happened.

The Aja Gen10 seemed to work fine. Despite still getting some banding lines when tilting up and down.

At this stage we're not believing it to be the camera but the wall. The studio is thinking of getting an updated Graphics Card for the computer running the wall. Ultimately, there's a lot of points of failure to track in the entire system. So as a result it's not a simple "this is the cause" since there may be multiple causes.

We're about to do a full week of shooting on the Volume. I'll know more soon as we'll be using the Aja Gen10 as the Genlock box, but will be using a RED. I've gotten mixed responses on whether it's a Komodo X or if we're using a Red Gemini, so I'll know for sure tomorrow during tech prep day.

You are right with the multiple points of failure. If you are using the Komodo-X I would love an update. I bought one but have not yet tested it on a volume. I have talked to someone else who said they had zero issues with it however.

So it was a Red Gemini, and then it started not working for us today. Overheated and such. So I grabbed my URSA Min Pro G2 and that has now become the camera this week. So...

Will give input later. We got it Genlocked fine. However, I could still seeing banding when tilting. We tried a few things and there are ways that we can get rid of it via Shutter Speed and some other tricks.

I’ll share more later. But this was taken when Genlock was disconnected. Today was a gear prep day, with a focus on pre-lighting, set building, and some small LED Wall and Camera Tests. Tomorrow is continued camera tests.

But now the UMPG2 is the main A-Cam because circumstances unforeseen with regards to the Reds.


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What camera tracking system are you using?

What camera tracking system are you using?

Well, if it arrives tomorrow like planned the Valve. Previously we’ve managed to shoot without one. It’s a new studio and they’re still putting everything together.

I don’t think the tracker will solve the banding issue. But it will be worth testing.


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What camera tracking system are you using?

Well, if it arrives tomorrow like planned the Valve. Previously we’ve managed to shoot without one. It’s a new studio and they’re still putting everything together.

I don’t think the tracker will solve the banding issue. But it will be worth testing.


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Most tracking systems have genlock options. I am not familiar the the Valve tracking system however.

Have you tried shifting the GENLOCK synch, do not remember exactly but there should be some setting on the camera that refers to lines and GENLOCK.

I’ll try that today. Waiting to get into studio at moment (I’m early) and will get it set up for a test as soon as possible.


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