In my Display Daily on January 28th, (See LDM for January 30, 2015) I discussed Sensio’s introduction of its new 3D/4K format. I had a chance to talk directly to Nicholas Routhier, president of Sensio, about the technology behind the 3D/4K format, which turns out to be quite simple.
The Sensio 3D/4K format is essentially a 4K frame used as a holder for four 1080p frames in quadrants. For normal 24Hz 3D content, only the top left and right quadrants are used for the left and right 1080p stereoscopic images. The bottom two quadrants are left blank. Routhier says that when this 4K frame is compressed with HEVC, these blank quadrants hardly contribute to the bit rate at all. This allows efficient streaming of the 3D/4K content over the Internet to the destination TV.
For High Frame Rate (HFR) 3D content, the lower two quadrants are populated with the next pair of images. This allows two stereoscopic frames to be packed into a single 4K frame. If the 4K frame is repeated at 24Hz, normal for most 3D content originated for the cinema, the two sets of left and right images can then produce a 48Hz HFR stream, when decoded at the 4K TV.
The Sensio system can also accommodate High Dynamic Range (HDR) content as well, e.g. Dolby Vision. This is more in the HEVC encoder/decoder than in the Sensio 3D/4K format, however. If a Codec and transmission chain can handle “ordinary” 4K HDR content, then it will be able to handle the two or four quadrants of the Sensio 3D/4K format.
Since this system basically transmits 1080p content, I asked Routhier if it was possible to display it on a 1080p TV. He said 1080p TVs do not currently have the ability to decode 4K content so he feels this is impossible now and unlikely in the future.
No TVs are currently equipped to decode the Sensio 3D/4K format, not even the LG TVs I discussed in my DD. For 2015, Routhier expects 3DGo to continue to use the previous Sensio Hi-Fi checkerboard format.
Routhier said that 3D is currently a low priority at the television makers and any 3D system that requires a special hardware design is probably a non-starter. He said that the processors in 4K TV sets all have enough horsepower to decode the Sensio 3D/4K format. For 4K 3D TVs where the firmware can be upgraded, the software to do this decoding can be added later as a firmware upgrade.
Sensio demonstrated this format in a suite and at Pepcom at CES. Routhier says he is currently busy demonstrating it to the various studios to show how their 3D movies can be streamed and has received very positive response. Still, he does not expect 3DGo to stream any 3D content using this technology before the end of 2015: all streaming this year will be in the Sensio Hi-Fi format.
When asked about UHD/4K Blu-ray 3D, Routhier said his format was probably unnecessary although it could be used. He said the Blu-ray team appears to be putting enough power and bandwidth into the next generation Blu-ray format that it will be able to handle native 4K 3D without his spatial compression scheme. – Matthew Brennesholtz
Analyst Comment
I’ve always believed that native 4K content is not needed for a viewer to benefit from the added resolution of a 4K/UHD TV. Upscaling of 2K/1080p content to 4K provides an experience at normal viewing distances that is nearly indistinguishable from native 4K. Nevertheless, I believe competitive pressure will make native 4K content inevitable. Sensio and Routhier are taking advantage of the 4K native format to provide a superior 3D experience, compared to other ways to stream 1080p 3D content to the consumer. (MB)
