HEVC vs. AV1 codec competition is welcome but it’s too early to judge

NAB 2018 is the first chance for visitors to test the performance of AV1, an emerging encoding technology pitting itself against prevailing standard HEVC.

HEVC and AV1 compete as standards

Despite doing exactly what its name suggests and seen as the best solution for UHD and HDR video broadcast services, the High Efficiency Video Codec (HEVC / H.265) has faced slower than expected take up compared to previous MPEG standards.

This is put down to a reluctance among content providers, particularly online streamers, to pay what they see as exorbitant licence fees.

With three licensing pools (MPEG LA, HEVC Advance, and Velos Media) and multiple undeclared licensing entities, the codec’s fragmented licensing system is also a drawback.

What’s more there is a massive base of entrenched H.264 AVC equipment which is doing a perfectly good job facilitating HD services in large parts of the world. In addition to which, new Content Aware Coding techniques are proving to boost the picture quality, reduce the distribution cost and prolong the life of legacy H.264 kit.

In an effort to provide a truly open video codec capable of providing high quality video streaming at lower bitrates, Google founded the Alliance for Open Media (AOM) and has gained the backing of virtually all leading industry players and tech companies including ARM, Cisco, Facebook, Google, IBM, Intel, Microsoft, Mozilla, Netflix and NVIDIA and most recently, Apple.

With the code now frozen and the first test results in, AV1 is claimed to deliver a 30% bitrate saving over HEVC for the same quality. This prompted speculation that it rapidly supersede HEVC to become the new de facto standard.

Too early to speculate

Rohde & Schwarz think it too early to speculate on AV1’s viability as a competitor to other codec technologies.

Rohde & Schwarz anticipates HEVC being more slanted towards professional domains with AV1 towards consumer domains.

It uses HEVC in its encoding and multiplexing solutions for consumer delivery and HEVC in its production products also. Rohde & Schwarz also says it would use AV1 in future for professional production areas “if we thought it benefitted our customers and their workflows or demands”.

However, our reading of the situation is that for our core production workflows AV1 is not the first codec for us,” says the company. “In terms of licence costs this is of secondary importance in our professional production areas where performance is paramount. For consumer delivery systems then, of course, the license cost will affect our customers and we do need to be sensitive to that in terms of which delivery codecs we support in future.”

AV1 barely out of the lab

While HEVC is delivering today on its promise of halving bitrates over H.264 AVC, AV1 is barely out of the lab.

Then there’s the fact that creating a product with an AV1 decoder will take about 18 months and it will take longer for support to be ubiquitous. It will happen eventually, but not on the day ratification of the standard is complete.

Other variables that could impact AV1 maturation: open source software development can take unexpected twists and turns; and while royalty free, it is not ‘indemnification free’ against patent claim violations.

HEVC has broad support

While not impervious to next-generation codec advances, HEVC has a well-established base at this point with an estimated 1 billion HEVC-enabled end points in the market. HEVC also has broad support from major OTT streaming services like Amazon, Apple, and Netflix and across the encoding vendor ecosystem.

Already though AV1 has already had an impact. Bowing to pressure, HEVC Advance has decided to eliminate streaming content distribution royalty fees, on top of reducing certain royalty rates and caps.

It is conceivable though that many media companies and video-capable enterprises will take a multi-codec approach to support video infrastructures. For example, Amazon Prime Video and Netflix take a multi-codec support approach: both are AOM members; both are HEVC users; both distribute content in additional codecs like AVC depending on the device making the request; and, both are active in AV1.

Looking ahead, the industry must also develop a means to compress massive data to handle applications from multiple UHD streams to light field. MPEG, ISO and ITU is exploring ‘omni-directional’ video coding technologies and has based its work on HEVC. Expect news of its progress at NAB.

Posted by Adrian Pennington, technology journalist. March 28, 2018.