With Codec Chaos In The Offing MPEG Tees Up An Escape Route

Emerging LCEVC Standard Could Lend New Life to Legacy Codecs

Swimming in the alphabet soup of next-gen codecs is Low Complexity Enhancement Video Coding (LCEVC), which defines a two-layer approach to getting more out of existing MPEG codecs.

While final decisions are pending in the LCEVC spec development process, the people tasked to complete the standard by sometime next year have determined that compression enhancement technology developed by U.K. upstart V-Nova fits the bill better than anything else they’ve seen, according to multiple sources.

“V-Nova had some surprisingly strong support from some members of the (LCEVC) working group amid a lot of skepticism among others,” says a senior engineering executive involved in the deliberations, speaking on background. “So the company was invited to demonstrate their PERSEUS Plus technology under rigorous testing conditions. The results were undeniable.”

Thus, even as MPEG contributors race to complete specifications for two standards, Essential Video Coding (EVC) and Versatile Video Codec (VVC), that are meant to address market demand for a successor to HEVC, they’ve identified a solution that could enable use of a nearly universal AVC client base to leap to compression levels that match or exceed HEVC performance with far less processing density than HEVC or the successor standards require.

“Nothing is final yet,” says V-Nova CEO and co-founder Guido Meardi. “But if things work out the way it seems they will, this will be a major validation of what can be done with PERSEUS Plus.”

Indeed, he adds, because the technology is designed to work with any of the existing or emerging codecs, from MPEG varieties to Google’s VP9, the new royalty-free AOMedia Video 1 (AV1) codec and others, anyone using any of those codecs can benefit from significant performance gains by applying the processing enabled by the PESEUS Plus layer.

This leaves the basic coding intact so that any client not supplied with the downloadable lightweight PERSEUS Plus player will decode the signal in accord with the native codec parameters.

In the case of AVC, V-Nova says it has demonstrated PERSEUS Plus enables delivery of HDR-enhanced 4K UHD content at around 16 Mbps, which is on par with what can be done with HEVC. Without the enhancement layer, this rate will support AVC client decodes of full 1080p HD.

If the V-Nova technology is used with HEVC, the UHD content can be delivered at 8 Mbps, according to company documents.

In bandwidth-constrained mobile environments, PERSEUS Plus, used with AVC, enables delivery of a 720p HD signal at 300 Kbps.

As explained by Meardi, in the encoding process, rather than taking the MPEG linear macro-block approach to segmenting and encoding each frame in a video sequence, PERSEUS Plus supports a hierarchical technique using the parallel processing and scaling capabilities of today’s microprocessors to apply compression frame by frame.

This is done in a way that’s analogous to how the human visual system brings a scene into focus as attention shifts or the scene itself changes within the broader field of vision.

The PERSEUS process determines how elements in the frame need to be reconstructed in strict adherence to variations across points of greater or lesser focus as captured in the original signal.

Operating in real-time, the processing begins by specifying the gist of the information associated with any pictorial element, such as a face, and then adds additional information to reach the required quality level for that element relative to the quality reached in the uncompressed frame.

Performance gains claimed by V-Nova are confirmed by users of the technology in commercial operations at various locations around the world.

For example, Nigeria’s Pipul TV is using PERSEUS Plus to deliver a broad range of entertainment and educational services to all classes of video-capable devices in a country where mobile penetration has reached 84 percent of the population, and there is a sizeable base of IPTV subscribers as well.

Of course, any choice of bitrates for a given level of resolution depends on the level of quality the distributor wants to achieve.

With the V-Nova technology running on AVC encoders, Pipul TV is able to stream full HD in the 1 Mbps range at quality levels acceptable for mobile device viewing and to go as low as 300 Kbps with 720p resolution, says CEO Benjamin Okoroafor.

“Pipul TV is founded on a principle of delivering content with no subscriber-side data costs through agreements with local telcos, which are made feasible by the lower bitrates PERSEUS Plus enables,” Okoroafor says.

“Because PERSEUS Plus can be deployed to all devices today and provides such a significant improvement in the quality of experience, it was clear this would be an absolute game-changer for the economics of our business and something that will keep us well ahead of the competition.”

Third-party tests, as well as commercial deployments, have also demonstrated that PERSEUS Plus conserves processing resources, thereby reducing the total amount of hardware that would be required to encode at a given level of resolution without the aid of PERSEUS Plus.

For example, Meardi says in the case of encoding for UHD with AVC, the lightweight PERSEUS Plus enhancement translates to a 4x density increase compared to an unaided HEVC encode for UHD.

Notwithstanding such successes, acceptance of V-Nova as a candidate for MPEG standardization is a surprising turn of events, given the difficulties the company has had dealing with assertions from some of its competitors that claims for PERSEUS Plus were overblown and not founded in solid testing.

The blowback has been furious, thwarting the company’s efforts to crack through the network service provider and other M&E segments ever since it burst on the scene three years ago.

As reported at the time, a year after its public launch in 2015 V-Nova made known that the initial version of PERSEUS Plus had been implemented by Sky Italia on a purpose-built hardware encoder from a company that had been acquired by Harmonic, which enabled delivery of HD channels over an AVC-equipped IPTV network that had been unable to support HD using DSL technology.

The rollout was a dramatic demonstration of the fact that the technology could be integrated with proprietary hardware encoders as well as software-based platforms and that older processing-constrained set-top boxes (STBs) have no trouble accommodating the PERSEUS Plus plug-in.

Sky, now owned by Comcast, was so impressed that its investment arm took a stake in V-Nova.

But challenges to V-Nova’s credibility and the fact that it was peddling a non-standard solution kept it from getting attention from big operators in the U.S. and elsewhere.

When asked about the Sky Italia deployment during an interview last year, Thierry Fautier, vice president of video strategy at Harmonic, declined to discuss PERSEUS Plus.

Commenting on MPEG’s desire to include PERSEUS Plus in the LCEVC standard, Fautier was quoted in an IBC blog as saying V-Nova’s success had been limited in part because “this is not a standard-based solution.”

It remains to be seen what other elements will be incorporated into LCEVC.

And it’s unclear whether any of the options now competing with V-Nova for radically reducing AVC and, in some cases, HEVC bitrates are under consideration or were eliminated in favor of using PERSEUS Plus.

Certainly, MPEG has the option to utilize the enhancement extension in the HEVC standard known as Scalable HEVC to lower bitrates by 20-35 percent on that codec, but that’s no help for AVC.

As previously reported, there is a bevy of content-aware encoding solutions like Harmonic’s EyeQ and Beamr’s content-adaptive bitrate solution that deliver improvements in the 30-40 percent range.

But these don’t require a two-layer approach and, thus, would appear not to be part of the LCEVC strategy.

Meanwhile, the goal for both the other standards slated for completion next year is to define codecs that natively deliver a reduction in bitrates compared to HEVC.

In the case of EVC, also known as MPEG-5, developers are taking a two-layer approach but with a different purpose than that of LCEVC.

Here the goal is to address concerns about royalty costs and uncertainties that have plagued HEVC by leveraging royalty-free technology on which patents have expired to create a no-cost base-layer option that works on par with HEVC.

The second, royalty-laden layer, is targeted to enable a 25 percent or better improvement over HEVC.

VVC, a single-layer option with a projected gain of 40-50 percent over HEVC, is meant to outperform everything else on the immediate horizon, including AV1, albeit at cost parameters tied to a boatload of intellectual property.

Meanwhile, AV1, which Bitmovin is testing at a 30 percent improvement over HEVC, is poised for commercial introduction, says Reinhard Grandl, director of product management at Bitmovin.

“We’re just one part of the supply chain, but I’m confident [commercial deployments this year] are going to happen,” Grandl says. “We’re getting good feedback on AV1.”

But, he adds, there’s a long way to go and still a lot of uncertainty about how large a role AV1 will play.

“On the decoding side, we need hardware,” he notes. “Software-based decoding is possible, but to get to large scales we need hardware.”

So far, chipmakers aren’t revealing release dates. “We have a little bit of insight,” Grandl says. “We know they’re working on the chipsets with a high level of priority.”

But there’s broad agreement that the market is heading for a multi-codec reality. “AV1 is computationally more expensive than HEVC,” Grandl says.

“It won’t be the first step as the foremost next-gen codec for everyone. People will encode the same asset with different outputs.”

Or maybe not. If people find they are able to encode using MPEG standardized enhancements that enable 50 percent compression gains with existing devices, including STBs, the market could swing behind widescale use of LCEVC, in which case client software embedded with the LCEVC equivalent of the PERSEUS Plus player could become the norm.

Even more disruptive to the future codecs would be a situation where the base layer in EVC, delivering a royalty-free equivalent to HEVC, is used with PERSEUS Plus to deliver the 50 percent gain over HEVC envisioned for VVC.

There will be royalty costs with use of the V-Nova software, whether those charges are incurred through LCEVC or independent application of PERSEUS Plus, but probably nothing approaching the costs of encoding with VVC.

There’s nothing preventing that from happening, notes Guido Meardi. “PERSEUS Plus will always be there to increase performance no matter what codec you’re using,” he says.

Totally apart from the LVEVC initiative V-Nova has made considerable progress toward making it easier to put PERSEUS Plus in play.

For example, Meardi says, devices running on the leading OS platforms, including iOS, Android and Widows, can be enabled to decode PERSEUS Plus-enhanced encodes through access, respectively, to iOS libraries, Android Exo Player and Microsoft MFT libraries.

In addition, HTML5 browser-based decoding is available for those who want to activate PERSEUS Plus in the decoding process with any native player via triggers in HTML5-enabled browsers without reliance on a specific player.

As an Open Source platform, Meardi explains, PESEUS Plus processing can be configured through JavaScript with the help of WebGL to coordinate the hardware blocks used in decoding, leaving most of the actual processing to be performed by the device hardware.

As a result, most mobile devices are able to decode PERSEUS Plus-enhanced content distributed from HTML5-enabled websites.

Of course, it’s way too early to know how the next-gen field is going to shake out, but it’s certainly conceivable that the disruptive potential of the LCEVC initiative could cause a lot of trepidation among chipmakers, device OEMs, content producers and distributors as they weigh investments in new platforms.

And one can’t ignore the fact that those content-aware solutions are gaining traction.

As Fautier told ScreenPlays last year, eyeQ has been widely implemented among mobile operators.

But, as indicated in the aforementioned IBC blog, Fautier, along with many other industry experts, is cautiously optimistic that VVC will eventually prevail.

“VVC will wipe out all these monkey codecs, assuming it can be licensed to everyone’s satisfaction,” Fautier said. “Development has to go hand in hand with common sense.”

Whichever way the codec story plays out, it will all come down to common sense.