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Filming using LED walls as backdrops

PostPosted: Thu Aug 23, 2018 11:06 am
by najrock
Just wondering if anyone here as any experience in this type of workflow. We are using LED walls as "realtime greenscreens". Most of the work is tabletop shoots for the food industry. I am the only video engineer at the shop I am at and everyone else struggles to even really operate the cameras so to them a lot of this feels like black magic and they have brought in a parade of "experts" whom have set up up everything from a robust realtime playback computer running premier timelines to insane looking piles of computers running watchout with cables everywhere doing realtime "frame blending", stacking image pros and scan converters... ect ect. same problem on all accounts in varying degrees of intensity is scanlines when filming. I have largely kept my mouth shut as my personal opinion of the issue requires everything to be genlocked which will signifigantly increase the price.

I believe that we will need to get a processor like the Brompton and genlock our entire workflow from gpu output to camera and processing. simple as that. Currently we have very cheap nova processors and receiving cards which I do not think will ever be tricked into correctly working at base 24

any thoughts are much appreciated! :mrgreen:

Re: Filming using LED walls as backdrops

PostPosted: Fri Aug 24, 2018 7:49 am
by RGMdddd
While I hate to oversimplify the process, fundamentally you are correct: genlock is key. Initially the idea of using LED walls as "real-time" backgrounds came from the live event industry where we have to sync to cameras on every show.
You didn't mention where you are located but have a look at what https://www.luxmc.com/#home-top are doing.

Re: Filming using LED walls as backdrops

PostPosted: Fri Aug 24, 2018 9:24 pm
by doctorhandshake
I’ve always solved this by just adjusting shutter angle on a bunch of camera bodies. Last time I sent through the process we had 2/6 bodies that worked with one exposure time each, IIRC. I’d love to know a more scientific way to go about it if there is one.

Re: Filming using LED walls as backdrops

PostPosted: Thu Sep 13, 2018 1:54 pm
by nadine
Moved from Techniques to General.

Re: Filming using LED walls as backdrops

PostPosted: Sun Sep 16, 2018 11:58 pm
by oliviano
I've had good result running HD-SDI output from TouchDesigner or Premier with Genlock input on the capture card and the cameras. ( BM Quad Duo 2 )
Our projector had to be set to get their sync from SDI ( barco projectors ) everything was on sync / locked at 24.97 for a US TV series and we also did 25fps for a broadcast show.
From our R&D, dependent on film camera / broadcast camera the shutter angle can have an impact as-well.
We did another test with a led processor with GEN-LOCK input and we were good. ( nova hd i think )

HD-SDI pipeline was the easiest and cheapest to get sync out of media servers. ( sync BM SDI cards ).

cheers