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There is a consensus that HEVC (High Efficiency Video Coding), the draft compression standard, will have a dramatic impact on the TV industry thanks to its ability to eventually halve bit rates compared to MPEG-4 AVC (H.264), the current encoding Gold Standard that it will complement but ultimately succeed. And as with all encoding, if you create sufficient extra coding efficiency to halve bit rates then you can also choose to leave bit rates the same but double picture quality, or turn the bandwidth/quality dial to any point in between. Encoder vendors are working towards deployments of the new codec as early as next year, probably starting with multi-screen TV services and fixed line IPTV.
Motorola Mobility was showing a recorded demonstration of HEVC (H.265) at IBC in September with the same HD video running at 8.8Mbps using MPEG-4 AVC and at 4.4Mbps with HEVC. “We are confident we can hit that 50% bit rate reduction in everyday usage,” noted Malcolm Latham, Marketing Manager at the company. He says HEVC will enable full resolution HD and will make it possible for all channels to go to HD. Looking ahead, ultra HD is another application. “HEVC is also
applicable to multi-screen OTT because even at lower bit rates the doubling of picture quality over a certain bandwidth can make a big difference to the user experience,” he explains.
Mobile is the immediate focus for Ericsson, which used IBC 2012 to introduce its SVP 5500 HEVC encoder, the world’s first HEVC encoder designed for the delivery of linear TV over mobile networks. The company has two customers who are ready to launch video services over LTE networks in 2013. This deployment will almost certainly combine HEVC with Ericsson’s eMBMS (evolved Multimedia Broadcast Multicast Services) technology, which introduces broadcast principles to the 4G mobile standard so that if multiple users are watching the same live video stream, for example, they can share that stream.
Describing eMBMS earlier this year (it was demonstrated at Mobile World Congress in February), Ericsson said: “This emerging broadcast technology for LTE has the potential to greatly reduce the cost for distribution of popular multimedia content, both for streaming as well as for content delivered during off-peak hours, stored in mobile device memory and accessed at a time of the user’s choosing.”
According to Fabio Murra, Head of Portfolio Marketing, Compression, Solution Area Media for Ericsson, everything points towards video over mobile broadband networks as the first application for HEVC. “There are a number of reasons for that: consumer demand for video, the refresh rates for mobile devices compared to set-top boxes and the power of those new devices, and the ability of the ecosystem to get up to speed quickly.”
Like Motorola, Ericsson was also demonstrating what HEVC can do for ‘fixed’ television, showing SD and HD video in half the bandwidth it usually requires, plus 4K ultra high-definition. “HEVC has the potential to revolutionise video delivery across all networks and services,” Murra declares. This includes DSL and digital terrestrial, both of which are bandwidth constrained. He thinks satellite operators could be the first companies to launch 4K television, while full resolution 3DTV is another possible application for the new compression technology.
“Our research says there will be benefits across the spectrum including for OTT delivery. Everyone is looking towards a new standard,” he comments. “The first implementations of HEVC clients will be in software but they may not implement the full range of tools and I suspect that like we have seen with MPEG-4 AVC, they will not achieve that promised 50% efficiency improvement on day one. There will be a learning curve and improvements over the years.”
There is widespread acknowledgement that HEVC decoding will be available first in software while the market awaits the arrival of hardware decoding on expensive and then progressively cheaper set-top boxes, which must then filter into consumer homes. Tom Lattie, VP Product Management at Harmonic, expects HEVC to be used first in the OTT arena for video delivered to smartphones and tablets with software decoding. And the impact here will be dramatic, he says.
Noting that keeping picture quality stable while halving bit rates is only one application for the codec, Lattie declares: “OTT today is half frame rate and that is okay for films but it is not pleasing for sports so you could double the frame rate and slightly reduce the bit rate. The benefits are not just increased reach on the OTT networks; you can improve the viewing experience dramatically. That is why we believe HEVC has the ability to be a game changer for some of these services.”
In the traditional television networks, IPTV providers will be big, and possibly early, beneficiaries of the new codec. “In some parts of the world IPTV operators are hampered by bandwidth limits and some telcos might think about upgrading their set-top boxes because HEVC could be a game changer for them, too, in terms of improved reach for video and improved video quality.”
Lattie points to how some cable operators are deploying home gateways with 6-8 tuners onboard and how this is going to raise expectations for multiroom viewing and how many channels you can simultaneously watch and record with a PVR. “HEVC will have more of an impact for telcos than for satellite or cable operators,” he says. Lattie also suggests that as IPTV providers often have smaller subscriber populations than other platforms they might accept the higher initial cost for early HEVC-capable set-top boxes and so deploy early. “Given their economics, the telcos might be the first to use HEVC for an STB service in the Pay TV environment,” he concludes.
Harmonic demonstrated HEVC at NAB in April and was showing the new compression technology again in September at IBC. The company believes the expectations for a 50% bandwidth reduction compared to MPEG-4 AVC are reasonable, although it could be a 35-50% range depending on the content and the use case. At IBC the company was showing SD, HD and ultra HD content that had been encoded before the show.
When it comes to ultra HD, Lattie thinks we could see some offline file transcoding for VOD content using HEVC. However, he points to the recent history of inertia surrounding 1080p60 HD for broadcasting or full frame rate 3D and predicts that ultra HD will take a long time to take off for broadcast TV, though it will be preceded by 4K VOD. He reiterates that the mass scale adoption of HEVC will be for OTT content first.
Benoit Fouchard, Chief Strategy Officer at ATEME, also believes it will be a long time before we see any broadcast 4K television to homes but there is an intermediate step to improve the HD experience we have today, namely 2K with increased frame rates. “For high motion content this will deliver a visible gain immediately,” he argues. This is viewed as a realistic use of HEVC on direct-to-home transmission networks.
ATEME is working on HEVC encoders and at IBC was demonstrating the draft compression standard with Constant Bit Rate (CBR) video encoded offline with software. Work on real-time encoding will begin in earnest next year. During the demonstration in Amsterdam it showed 4K resolution content at 60fps in 11-15Mbps depending on the content sequence.
ATEME is interested in the potential for HEVC on digital terrestrial TV, like the TNT platform in France, although this would require the introduction of new set-top boxes that can decode the new codec, of course. Fouchard makes a point about DTT that will resonate for all platform types, namely the need to avoid simulcasting new HEVC channels with what we have already. “There are no bandwidth savings unless you can turn off the existing services,” he notes.
Mobile is identified, again, as an early market for HEVC compression. ATEME expects that we will see serious testing in the first half of 2013 and commercial deployments for multi-screen viewing from 2014. “The primary reason HEVC will be used early in multi-screen is not the fact that you have software decoding but the fact that renewal cycles for those devices are much shorter,” Fouchard contends. He thinks we could see multi-screen TV offered in 1080p HD to tablets using HEVC, though he fears the effect on battery life. Lower resolutions will be delivered in MPEG-4 AVC and as more HEVC capable devices become available, the lower resolution services can start migrating to save bandwidth.
Work is underway to ensure that MPEG DASH, the standard for adaptive bit rate streaming, will support HEVC encoded video in addition to MPEG-4 AVC. Speaking in September, the Fraunhofer Heinrich-Hertz-Institute, which has been a notable contributor to the HEVC specification (as it was to AVC), was hopeful that DASH would be extended to include HEVC by April next year. During IBC the company was also showing live decoding of HEVC compressed HD content.