May 2013
www.tvbeurope.com
Every decade a new compression system heralds a new broadcasting era
TVBEurope 35 Wrap-Up Putting the squeeze on bitrates
The new H.265/HEVC compression system was getting a lot of people excited at NAB, but is all the hype justified? Part One of a two-part investigation: David Fox
EVERY DECADE a new compression system heralds a new era in broadcasting. In the mid-1990s, MPEG-2 helped make digital production practical; almost 10 years later MPEG-4/AVC/H.264 facilitated lower-cost production and HD transmission. Now HEVC (High Efficiency Video Coding), or H.265, is promised to take broadcasting beyond HD, offering the compression power to allow practical transmission of Ultra HD, as it is claimed to be up to 50% more efficient than H.264. The standard was only ratified
in January, so NAB was a first chance for vendors to show working prototypes, and several exhibited realtime encoding. “In most of the HEVC implementations we’ve seen to date, bit rate savings start at about 30-35% and then grow through optimisation,” said Keith Wymbs, VP of Marketing, Elemental. “While 50% is a target
improvement over H.264, it is expected to achieve a 30-35% performance initially for live applications,” agreed Ian Trow, senior director Emerging Technology & Strategy, Harmonic. “HEVC can achieve the 50% goal, but mature 2nd or 3rd generation encoder products are needed to achieve this.” Given that we are still seeing
improvements in compression efficiency for even MPEG-2, there will be many years of optimisation for HEVC. “The efficiency gains are initially likely to be a bit lower for ‘live’ realtime encoding than for offline file-based encoding, with the gap closing as HEVC implementations mature,” said Mike Nann, director of Marketing and Communications, Digital Rapids. “You can encode HEVC in
realtime now [which Rovi showed at NAB], but you’re not getting much extra efficiency over MPEG-4, but once you add extra [compression] features, you can see big gains,” said Eric Grab, VP Technology, Rovi Corp.
“We did exhaustive tests on
HEVC potential on various pieces of content — progressive and interlaced, sport and news content, etc. — and we can confirm that, ultimately, HEVC will bring a 50% gain compared with H.264 and even more for very large pictures like Ultra HD,” added Eric Gallier, VP Marketing, Thomson Video Networks. Motorola Mobility showed
realtime HEVC 720p30 encoding at NAB, thanks to parallel processing on its encoders. Indeed, HEVC through its new SD7000 encoder was slightly faster than its MPEG-4 encoder. “With the right hardware and right content, there shouldn’t be appreciable differences in encode times with HD. But with 4K content you are still looking at longer than realtime,” said Mike Gannon, its Home Product architect, EMEA. “At the moment 4K content is better suited to VoD-based delivery than live delivery.” At NAB, Ericsson showed
live realtime encoding and transmission of HEVC to tablets and phones, using a software encoder that Fabio Murra, its head of Portfolio Marketing, Compression, said can deliver 25-30% bandwidth savings. “In order to deliver 50% savings a hardware encoder will be needed.”
Bit by bit
Video is increasingly the major user of bandwidth on mobile and internet devices, so “if you are looking to watch video over a mobile link, HEVC is a massive advantage for the operator to reduce loading on the network,” said Gannon. It has been estimated that 1.4 billion consumer devices shipped over the past two years are HEVC playback capable with a software upgrade, with more than a billion more being sold this year. “If you have a laptop you
have enough computing power to play back HEVC,” said Grab. “But as the chips start rolling out you’ll see it everywhere.” Because over-the-top and 3G/4G-based multi-screen
H.264 and HEVC side-by-side: showing the flexibility of coding block sizes that enables the new codec to be more
Mike Nann, director of Marketing and Communications, Digital Rapids
services currently face the most pressure in terms of network/cell saturation and bandwidth cost, they will be first to switch, expects Nikos Kyriopoulos, product director, Media Excel. Key to this will be the evolution and adoption of MPEG-DASH as the preferred transport for adaptive HEVC delivery, as the end-to-end ecosystem “is quite mature”. “For OTT and mobile delivery, the emergence of HEVC is timed nicely alongside the evolution of the MPEG-DASH specification,” agreed Nann. “While there’s work to be done defining interoperability specifics of HEVC within MPEG-DASH, the DASH specification was designed with such advances in mind.” Something like MPEG-
DASH “is needed to keep a lid on the number of profiles a broadcaster needs to support,” added Trow.
On trial
Verizon in the US and Telstra in Australia are trialing HEVC to mobile applications using
Eric Gallier, Vice President Marketing, Thomson Video Networks
Ericsson equipment this year, “to provide video services in locations where there is a high concentration of users and bandwidth constraints,” said Murra. Ericsson is also working on trials with a number of European broadcasters using HEVC for broadcast and OTT applications. HEVC “is not a simple upgrade
for a lot of devices,” such as STBs, but the latest mobile devices and recent PCs can handle software decoding, he added. “The business drivers behind
bandwidth reduction [for mobile devices] will cause this to happen very quickly,” said John Pallett, director of Product Marketing, Enterprise Products, Telestream. “We anticipate that consumers will be aware of whether or not their mobile phone supports HEVC or H.265 next year; this will enable higher quality video and significantly reduce transmission costs.” Apple and Samsung have already committed to supporting HEVC decoding on new devices.
Motorola Mobility demonstrated software playback of a 1.4Mbps full HD stream on tablets at NAB, and “as there is only about 10-15% extra complexity on the decode side, tablets and mobile phones have the power to decode HEVC.” Its demonstration showed H.264 and HEVC at the same bitrate and resolution and “you could clearly see the inability of H.264 to meet the requirements of high quality video at low bitrates. Elements of the scene were too complex, but HEVC had no problems,” said Gannon. “Decoding (up to 720p, or even 1080i in some cases) can be performed by software decoders,” and “is comparable to AVC in terms of CPU utilisation due to the significantly lower bitrate of the HEVC bitstream,” added Kyriopoulos. Rovi Main Concept showed a beta HEVC encoder at NAB, which is being trialled by some 50 companies. It also announced DivX Video Service for OTT, which will support HEVC this
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