DEFINITION February 2022 – Web

ADVERT I SEMENT FE ATURE . MEGAPIXEL VR

In part one of a three-part series, we get into what makes Megapixel’s HELIOS® LED Processing Platform so production-friendly for ICVFX ZERO PRODUCTION INTERFERENCE Part 1

This interference pattern is called scan lines. It’s the same phenomenon that occurs when car wheels appear as if moving backwards at high speed on video. This happens because cameras don’t capture continuous footage, but rather images per second. Our brains work to fill the void by creating an illusion of continuous movement – even if it’s not in the right direction! “It’s the single most problematic thing about pointing a camera at an LED screen, because when these artefacts occur, the only way to remove them is to rotoscope the entire scene to trace over footage and produce realistic action – and this is costly,” says Hochman. “With HELIOS, we can reduce this interference between assets and screen that’s not visible on camera. A lot of this is due to the refresh rates at which we run the panels.” THINKING OUTSIDE THE BOX Instead of just having a data processing box that sends information to the LED tiles, Megapixel also makes the magic happen on the tiles themselves. “We have mini processors, called PX1s, that go inside each individual tile – and then our HELIOS unit acts like a traffic cop, taking in all the incoming data and dispatching that over native fibre to go from tile to tile. What’s nice about this is that, rather than having a rack unit as your choke point processing tens of millions of pixels, it can take all that metadata and interpret it properly – giving you all the management and control to pass it along in little chunks, for the tiles to do their own processing.”

MEGAPIXEL’S PROPRIETARY PROCESSING technology extends from the video input, all the way to ultra-powerful tile- side processing. Leveraging sub-pixel calibration and off-axis colour metadata, coupled with the most advanced LED refresh algorithm, the patented technology allows for sophisticated virtual production stages. The HELIOS LED Processing Platform sits at the centre of the pipeline and features camera-friendly performance, cinema-grade colour accuracy, and a future-proof native 8K workflow via upgradeable and modular inputs. Starting with what makes the technology so camera-friendly for DOPs, Definition will analyse the specifics over a three-part series. But first, it’s important to recognise what makes working in a virtual production volume challenging. Megapixel CEO Jeremy Hochman explains: “Cameras capture in bursts and LEDs pulse on and off – sometimes at 1000 times per second – and if that refresh of the LED is not perfectly time-aligned to what the camera is doing, you’re going to see artefacts.” “With HELIOS, we can reduce this interference between assets and screen that’s not visible on camera... due to the refresh rates at which we run the panels”

WITH NANOSYNC

WITHOUT NANOSYNC

SYNCHRONISED OUTPUT The light from the LED is timed with the video or genlock source, and offsets can be dialled in by the nanosecond – giving the best control options

This, in turn, allows for the tiles to be run at higher refresh rates, to avoid interference. With more granularity over timings, light can be emitted from the LEDs when the camera is at full capture – and is ready to start receiving light. Using Megapixel’s groundbreaking NanoSync™ technology, this can be done down to the nanosecond, even over 10km fibre links. “I know a lot of DOPs who’ve had a poor experience working in LED volumes – because of this interference. It doesn’t matter what LED you buy. Although it may look interesting to the eye, it’s not necessarily going to work on camera without the proper processing – and we’ve got that covered,” concludes Hochman. Next month, we discuss HELIOS’ cinema-grade colour accuracy, and go into detail about benefits of storing sub-pixel colour metadata on the LED module itself.

LOOKING AHEAD Future-proof your virtual production workflow with HELIOS, using existing infrastructure – while maintaining the ability to upgrade processor inputs and LED displays

megapixelvr.com

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