3D. 4K. HFR. 8K in 60p. Increased dynamic range. The cinematic arms race is in full swing and shows no sign of abating. But while developing newer technologies at warp speed is a lot of fun (especially for us technology types to write about it), it also puts greater and greater strain on the supporting technologies that weren’t designed for it. Thank heavens that engineers have finally gotten the idea that future-proofing technologies, like HDMI, will give it legs to handle the drive over the horizon. But sometimes you have to upgrade those, and HDMI 2 will do just that, supporting 4K, HDR, and more as we move forward.
“We recognized that HDR would be a critical feature as the industry evolves. Our support for HDR enables our 800+ HDMI 2.0 Adopters to develop market-leading products that include HDR and will maintain interoperability across the entire HDMI ecosystem. Along with the publication of the CEA extensions, the HDMI Forum continues to update the HDMI Specification and remain closely aligned with leading CE standards organizations.” – Robert Blanchard, President of the HDMI Forum, Inc
Now sure, most professional grade ultra high definition camera systems rely on SDI, and that’s important. But for the emerging runner and gunner who just wants to stay within striking distance of the state of the art, SDI units are a bit out of their budget range. Unfortanately, HDMI 1.4 is about to run into a brick wall as a standard, since it can only handle about 10.2 gigbits per second across multiple channels.
SDI, by contrast, can handle three times as much data because of the speed with which it transmits the data. This is largely due, if I’m reading it right, with the fact that SDI has to have a larger pipe since it sends all the data down one 75-ohm BNC cable connection, while HDMI 1.4 breaks up the dead along three separate channels. You can already see the problem. HDMI 1.4’s three channels are smaller than the huge pipe that SDI enjoys.
So when it starts to run up against more and more bandwidth (via 4K, HFR, and HDR), you can see the backup. Fortunately, HDMI has two pipes per channel, But this “differential signalling,” is still eventually going to get overwhelmed as we continue to move forward.
“By adding HDR, the HDMI Specification continues its history of supporting the latest formats and technologies planned for Hollywood content,” said Arnold Brown, Chairman of the HDMI Forum, Inc. Board of Directors.
Enter HDMI 2.0. Adopted as a standard in 2013, HDMI 2.0 has only recently emerged on hardware thanks to advancements (and a drop in price) for 4K. Through HDMI2 (and HDMI 2.0a for high dynamic range), users can get double the bandwidth of HDMI 1.4, with 6 Gbps per channel or 18GBps second total throughput. HDMI2 also supports Rec 2020 color gamuts, ultra wide 21:9 aspect ratio, multi channel audio, high frame rate of 60 frames per second at 4K, and 3D/Sterescopic presetnations.
HDMI2 will also support high dynamic range, which is being brought about by Dolby Vision, since eventually that will trickle down to Dolby consumer products much like Atmos at Home has done for audio. This will eventually bring 48 bit color.
And while that is a huge step forward, some filmmakers – like Douglas Trumbull, James Cameron, and Peter Jackson – are already wanting frame rates up to 120 fps in 4K (or higher). HDMI won’t handle that because it would take 4 cables to handle that much bandwidth. But you can bet that engineers are already working to figure out HDMI 3.0.
But even with HDMI 2.0 finally making it into the pipeline, the issue of standards being adopted within the 4K spec is still a bit off. Yes, NAB announced a formal standard was finally being adopted, and HDMI 2.0 helped bring that to fruition, but until it’s widely adopted, we’re still stuck in the HDTV ghetto.
Hat Tip – RSN