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The Continuing Evolution of HEVC - TvTechnology

The Continuing Evolution of HEVC

Compression competition hasn’t stopped development
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SEATTLE—Though the majority of video work is not done in ultra high definition yet, there are certainly plenty of solutions for acquiring and post producing in 4K. More problematic is delivering such material. If one uses the same compression codec for 4K that’s being used for good old HD video, it takes more or less four times the bitrate. When viewed by the accounts payable department, that’s four times the money to deliver UHD video.

Fortunately, forward-lookers got to work years ago on High Efficiency Video Coding (HEVC). HEVC is also known as H.265 by the ISO/IEC (Telecommunication Standardization Sector) group and as MPEG-H Part 2 by the ISO/IEC MPEG (International Organization for Standardization/International Electrotechnical Commission Moving Picture Experts Group). Those organizations were co-developers of HEVC, the first version of which was completed and published in 2013.

CHOOSING A PATH
“Customers have been interested in HEVC, evaluating HEVC as a possible replacement for current encoders that are either doing MPEG-2 or H.264,” said Abdulla Merei, director of compression systems for Evertz in Burlington, Ont. (MPEG-2 and H.264 aka MPEG-4 are long established encoding standards that provide less compression than HEVC.)

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At the 2016 IBC Show, Harmonic introduced its EyeQ software codec which brings down the bit rate of H.264 by 50 percent. Encoder makers put a lot of time and study into picking and choosing the path to HEVC encoding. “We’ve implemented and selected the codec that had the best throughput and quality and best compromise, and we’ve integrated this codec so that we can support HEVC-transcoded output,” said Matthieu Fasani, senior product manager of France-based Dalet Digital Media Systems.

Imagine Communications’ Chief Product Officer Brick Eksten said they shop for best of breed for targeted requirements. “Our philosophy on codecs, especially in the early days of any new codec, is that there’s going to be multiple vendors of technology that have specialized in different areas,” he said. “For instance, they may have focused on performance speed over quality, or vice versa. Some will have focused on live versus file, for instance.”

Telestream has integrated H.265 into its products for quite some time now, according to Paul Turner, vice president of enterprise products for the Grass Valley, Calif. -based company. “It’s been through customer demand… for the end user it’s really the only viable distribution method for getting UHD content distributed out to customers. H.264’s perfectly capable of dealing with 4K. It’s just nowhere as efficient as H.265.”

However, there’s not a big rush away from H.264, said Thierry Fautier, vice-president of video strategy at Harmonic. Harmonic does have HEVC-capable products in the market, but at the IBC Show, the San Jose, Calif.-based company introduced a new software codec called EyeQ, which brings down the bitrate of H.264 by 50 percent. “That kind of makes HEVC obsolete at this stage,” Fautier said.

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Brick Ekstein, chief product officer for Imagine CommunicationsSOFTWARE DEFINED
When encoders first hit the market many NABs ago, they were black boxes that contained each vendor’s special brew of hardware and software. Over the years, that has changed to software-defined systems, where much of the hardware is what the high-tech world calls COTS (commercial off-the-shelf) products. The economy of scale of the IT market has driven down the price of these servers and such.

Chuck Meyer, chief technical officer of production at Grass Valley, pointed to a pair of paths: software-based vs. dedicated hardware in the form of an application-specific integrated circuit (ASIC). “These things present certain tradeoffs in terms of power consumption or what kind of product can be built in terms of cost… in terms of upgradability,” he said. Upgradeability is important, Meyer added, because the H.265 codec is going to change. “Even MPEG-2 has had constant tweaks and improvements into the profiles,” he said, “the same for H.264.”

Customers rightly want to know how they get from H.264 solutions to H.265-capable equipment without sending their existing equipment off to the landfill. That is complicated by the fact that codecs are written to function in the hardware of the day. For instance, RAM was very expensive while MPEG-2 was being developed; so MPEG-2 can be encoded and decoded with relatively little RAM in the hardware.

By the time H.264 was being written, RAM was much cheaper and could be delivered in a much more dense form. H.264 requires more RAM to function, which made it difficult to use the AVC codec in hardware developed for MPEG-2. Fast forward to the requirements for HEVC coding, and the same factors are repeating themselves in upgrading legacy encoding equipment.

The modular nature of an encoding system, however, can allow upgrading pieces and parts without junking the whole system. Besides cost savings, this also means a familiar user interface and workflow can be retained.

In a half dozen or so years, this same story will be written about the successor to HEVC. But that’s then, and HEVC is now.

Meanwhile the nearly completed ATSC 3.0 standard has designated HEVC for encoding 4K content, so expect increased interest in HEVC-capable gear in the next several years as broadcasters deploy the next-gen TV standard.