SMPTE 2013 Report: HEVC, UltraHD step into the spotlight
The 2013 SMPTE Annual Technical Conference and Exhibition wrapped up yesterday in Los Angeles, giving attendees plenty to think about with respect to two key technologies, HEVC compression and “Beyond HD” TV services, that at least promise to change the relationship between content creator and viewer. The question now is whether the promise can become a reality. And with more than 2,000 executives in attendance, a nice rise from recent year, it appears that question is on a lot of people’s minds.
The next-generation HEVC compression format, for example, stepped to the fore as a means to deliver new TV services featuring higher resolution, more frames per second, and expanded colour accuracy in bandwidth levels that would have been beyond comprehension five years ago.
“HEVC is the key to deliver an enhanced viewing experience that is beyond HD,” said Sophie Percheron, Ateme, product marketing manager for Live Distribution during her presentation. “First is more resolution but beyond HD must not only be defined by resolution. Increased frame rates and wider color gamut can increase the color space to 60%, giving more accuracy to the image and higher dynamic range.”
Percheron laid out the case for HEVC with respect to new TV services, explaining that it will allow for UltraHD 4K services to be delivered between 11 and 18 Mbps, putting it in line with the requirement to deliver HD via MPEG2 in 2005.
And for those looking to move from 60 to 120 frames per second she offered even more good news: as the frame rate increases the percentage of additional bandwidth required decreases. For example, going from 25/30 to 50/60 frames per second requires between 19 and 42% additional bandwidth. But going from 60 to 120 frames per second only requires an additional 17- to 28% of bandwidth.
“You can deliver up to four channels of UltraHD per transponder with HEVC at bit-rates that are comparable to HD services today,” she added.
Yasuko Sugito of NHK’s Advanced Television Systems Research Division, meanwhile, offered up her thoughts on Super HiVision, also known as 8K. The format is taking up a large amount of NHK’s research energy as the company strives to make it a real-world production and distribution format in time for the 2020 Summer Olympics in Tokyo.
There is plenty of work to be done between now and 2020, but HEVC again is playing a major role in making production possible. “HEVC is achieving twice the compression performance than the AVC format,” she said.
In order to move real-time Super HiVision video signals each frame of video is cut into 17 strips that are each 256 pixels tall. Those 17 strips are then transported over 17 3Gbps SDI signals with a maximum combined bit-rate of 320 Mbps.
Of course, getting a 320 Mbps to a home is not, currently, possible as next-generation transmission standards like DVB-T2 currently max out at 40 Mbps. Sugito added that it will take about 10 years of development in order to get Super HiVision signals through 40 Mbps transport pipes.
Takuji Soeno of NHK also gave a presentation on multi-link 10 Gbps mapping method and interface device for 120fps UHDTV signals. This is important as the UHDTV interface, SMPTE ST 2036-3, does not support 120 fps so figuring out how to get the signals .
The requirements for interface mapping he said require support not only of 4K but also 8K. NHK’s work led to the development of a single fiber optic cable interface that can transport 8K signals at 60 fps and a 4K signal at 120 fps up to 50 meters, an important consideration given the current signal transport challenges. Up next? Work on creating an interface for 8K at 120 fps.
And Hiroshi Shimamoto of NHK and Japan Broadcasting Corporation closed out the education sessions with a presentation concerning a compact 8K camera with a 35mm PL mount lens that can shoot at 120 fps.
The camera required developing the world’s first 120 fps 8K image sensor, a 24.7mm sensor that has a bit depth of 12 as well as an RGB Bayer colour filter array. It has a single 24.7mm senor within a camera head that measures 125x125x150mm and weighs only 4.5 pounds.
One issue was that colorimetry did not match the ideal laid out in BT2020. NHK applied 3×3 linear matrix colour correction, commonly used for professional cameras.
“With linear colour correction the signal process can be real time and also has hardware simplicity,” explained Shimamoto. The result? Colour performance that Shimamoto says are nearly identical to three-chip cameras.
The camera also has the ability to output an 8K and 4K signal simultaneously, allowing an 8K image to be monitored on a 4K monitor.
He also demonstrated the camera operating on a Steadicam rig.
“It’s sufficiently light and the balance was good,” he explained. “8K is today’s technology.”