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EETE JULAUG 2015

Audio & Video processing Parallel processing spawns non-MPEG Codec By Junko Yoshida What if video experts were to design a brand new video codec fit for 2015? We live in the moment of 4K Ultra High Definition (UHD) TV, with a growing number of consumers viewing video sent over unreliable and bandwidth-constrained mobile networks, while CPUs and GPUs inside their mobile devices come with multiple cores, massively parallel processing capabilities and a very large cache. And yet, we all know that no current video codec can comfortably handle 4K distribution to UHD TV at home, let alone deliver HD video to mobile devices. The new video compression algorithm, if it emerges in 2015, probably, won’t be based on MPEG, or even the brand-new H.265. A London-based startup V-Nova believes that the new video codec everyone should consider is its brainchild, called Perseus. It is designed to do hierarchical and scalable video encoding by leveraging massive parallel processing, while sidestepping the complexity of block-based compression algorithms. During the last National Association of Broadcasters (NAB) convention in Las Vegas, V-Nova showcased Perseus, which the company claims has achieved “2x – 3x average compression gains,” compared with legacy video codecs. V-Nova promises to make 4K transmission commercially viable, while enabling HD on 3G or 4G mobile network by using less power. Perseus can, in short, encode and transmit UHD quality at HD bitrates, HD at SD bitrates, and SD video at audio bitrates, explained Guido Meardi, CEO & Founder, V-Nova in a phone interview with EE Times. More importantly, with Perseus, “Service providers can upgrade their systems in software, without touching their existing delivering infrastructure or digital assets,” he added. Just as human brains function in a hierarchical manner, by first visually recognizing a human being, then, a face, then a goatee, and then, gray hairs mixed into the goatee, Perseus will provide additional details of data representation to the elementary stream of MPEG-2 or H.264, explained Meardi. V-Nova said it’s been developing and testing Perseus for more than five years, suggesting that the technology has long passed its slideware stage. The first transmission testing of Perseus was carried out by Sky Italia back in 2012. Hitachi provided Sky Italia with the first Perseus-based UHD video gateways. V-Nova has reportedly collected more than 20 global industry leaders — all working with V-Nova — in an “Open Innovation” consortium. The consortium members publicly listed in V-Nova’s press release include Broadcom, European Broadcasting Union (EBU), Hitachi Data Systems (HDS), Intel, and Sky Italia. Broadcom’s spokesperson, reached by EE Times, said, “We support V-Nova with our reference design and software environment.” Perseus implementations are being “driven by V-Nova through a software implementation of their algorithm.” Meanwhile, Broadcom’s set-top chip, currently field-deployed, can support Perseus by using its CPU power. Gary Arlen, president of Arlen Communications, a Bethesda, Maryland-based research and consulting firm, said, “The bandwidth compression Perseus claims is terrific, and its credentials – big names listed in their consortium – are impressive. But I haven’t seen their demo yet. All I can say at this point is that it (Source: V-Nova) looks promising.” To persuade U.S. operators like Comcast or AT&T to adopt Perseus, Arlen said V-Nova still has to prove itself. But if what VNova is saying today holds true, “this comes at a very interesting timing,” he added, as service operators are in the process of upgrading their infrastructure. Massively parallel processing So, how good and original is Perseus? And how do we know this isn’t yet another video codec said to be “ground-breaking to change the world forever” but never quite pans out that way? Perseus is neither a “trick” nor a tweak on the conventional MPEG standards, Meardi said. Rather, V-Nova went back to the drawing board to rethink how a video codec should work. Meardi noted that Perseus is the first video codec — designed from the ground up — to compress video by leveraging “massively parallel processing.” In contrast, legacy MPEG standards are based on a fundamentally different architecture — designed to do entropy encoding only sequentially, said Eric Achtmann, V-Nova’s executive chairman and co-founder. The difference, for instance, will result in the Perseus video codec fully running on GPU only, encoding lossless video at less than 2 milliseconds, said Meardi. “Or take an example of 20 megapixel X-ray image. It would take 14 seconds to encode it (lossless) via JPEG2000, but with Perseus, it would take only 10 milliseconds.” Since Perseus is designed to leverage multi-core CPU or GPU in a handset for parallel processing, rather than sequential processing, it is much less power-hungry compared with legacy MPEG-2 and H.264 technologies or even the newer H.265 (HEVC), according to V-Nova. By quoting data made available by a large, unnamed mobile carrier testing Perseus, Meardi said Perseus uses 15 to 30 percent less power than H.264. If a chip company like Broadcom decides to make a hardware accelerator for Perseus, power consumption on mobile turns out even lower, he explained. No more block-based coding In the course of its “rethinking” of a video codec, the V-Nova team also decided to eschew the block-based compression algorithms used in legacy codecs. “The block-based codec would only add large complexity,” said Meardi. “As blocks create artifacts, we need to de-block them, and then we also need to deal with variable block sizes.” With Perseus, V-Nova says it’s bringing fundamental change to the codec world, compared to the increments enabled by 26 Electronic Engineering Times Europe July-August 2015 www.electronics-eetimes.com


EETE JULAUG 2015
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