The long-heralded open source AV1 codec is now set for development of commercial product, with the code complete and ready to be frozen over the next few weeks. This has been confirmed by contributors to the standard such as Austrian transcoding software developer Bitmovin, which hopes to be among the first to bring out a product. That will happen once members of the Alliance for Open Media (AOM) that developed the codec sign off its performance.
“The biggest challenge that remains is that the encoding computational cost is quite high,” says Martin Smole, Engineering Director of Encoding at Bitmovin, which provides player and analytics solutions as well as video compression products. “So, we will be working hard to make it more efficient once the bit stream has been frozen – later this month, probably.”
The arrival of AV1 will shake up the codec industry by introducing a strongly backed royalty free open source alternative to the licence-based family of standards from ISO/IEC and MPEG. The latter’s H.264 has dominated the television landscape and it had been assumed that its successor HEVC/H.265 would do the same.
However, consensus among providers of technology to HEVC broke down, leading to fragmentation into three licensing pools, along with growing concern over the costs of royalties among device, infrastructure and content providers. Google’s royalty free VP8, followed by VP9, had gained traction partly for this reason within its own ecosystem, but AV1 – with its wide backing from nearly all major infrastructure providers as well as Amazon, Netflix and most recently Apple – is set to enjoy wider adoption.
Many broadcasters have already embarked on the HEVC route and made substantial investments in associated transcoding equipment, and they are not going to write off this cost in the near future. Also, the fact that AV1 is open source does raise questions over who will be responsible for the standard, according to Fabio Murra, SVP Product & Marketing at UK based V-Nova, architect of the independent PERSEUS codec.
“AV1’s open source model means it is not a turnkey solution for broadcasters, operators and service providers, since it introduces risks about who will be willing and able to commit to the significant development work, maintenance and testing required,” Murra says. “It will take considerable time for production workflows to be upgraded to support AV1. This means that AV1 is most likely to be adopted first in consumer-side applications such as YouTube and for video on social networks, rather than in traditional broadcast workflows.”
Even that may take some time, for while AV1 has been optimised for efficient decoding with an eye on power-constrained mobile devices, it will take around two years for chips to be developed so it can be implemented optimally in hardware. Bitmovin’s Smole admits that earlier deployments are likely to be confined to use cases like desktops where power is less of an issue and the possibility of saving CDN bandwidth is appealing.
This progressive roll-out assumes that AV1 delivers the promised improvements in compression efficiency over HEVC, which is hotly debated within the codec community and will not be clear until the first commercial products are available. What is certain is that comparative performance between AV1 and HEVC will vary with content type. Smole reckons AV1 will come out best for high motion video like sports or where there is complex texture. His company is predicting that AV1 will deliver a 30% improvement over HEVC and VP9.