It’s all very good saying “let’s implement CMAF”, but what’s implemented so far and what can you expect in the real world, away from hype and promises? RealEyes took the podium at the Video Engineering Summit to explain.
CMAF represents an evolution of the tried and tested technologies HLS and DASH. With massive scalability and built upon the well-worn tenants of HTTP, Netflix and a whole industry was born and is thriving on these still-evolving technologies. CMAF stands for the Common Media Application Format because it was created to allow both HLS and DASH to be implemented in one common standard. But the push to reduce latency further and further has resulted in CMAF being better known for it’s low-latency form which can be used to deliver streams with five to ten times lower latencies.
John Gainfort tackles explaining CMAF and highlights all the non-latency-related features before then tackling its low-latency form. We look at what it is (a manfest) and where it came from (ISO BMFF before diving in to the current possibilities and the ‘to do list’ of DRM.
Before the Q&A, John then moves on to how CMAF is implemented to deliver low-latency stream: what to expect in terms of latency and the future items which, when achieved, will deliver the full low-latency experience.
AV1 and VVC are both new codecs on the scene. Codecs touch our lives every day both at work and at home. They are the only way that anyone receives audio and video online and television. So all together they’re pretty important and finding better ones generates a lot of opinion.
So what are AV1 and VVC? VVC is one of the newest codecs on the block and is undergoing standardisation in MPEG. VVC builds on the technologies standardised by HEVC but adds many new coding tools. The standard is likely to enter draft phase before the end of 2019 resulting in it being officially standardised around a year later. For more info on VVC, check out Bitmovin’s VVC intro from Demuxed
AV1 is a new but increasingly known codec, famous for being royalty free and backed by Netflix, Apple and many other big hyper scale players. There have been reports that though there is no royalty levied on it, patent holders have still approached big manufacturers to discuss financial reimbursement so its ‘free’ status is a matter of debate. Whilst there is a patent defence programme, it is not known if it’s sufficient to insulate larger players. Much further on than VVC, AV1 has already had a code freeze and companies such as Bitmovin have been working hard to reduce the encode times – widely known to be very long – and create live services.
Here, Christian Feldmann from Bitmovin gives us the latest status on AV1 and VVC. Christian discusses AV1’s tools before discussing VVC’s tools pointing out the similarities that exist. Whilst AV1 is being supported in well known browsers, VVC is at the beginning.
There’s a look at the licensing status of each codec before a look at EVC – which stands for Essential Video Coding. This has a royalty free baseline profile so is of interest to many. Christian shares results from a Technicolor experiment.
Adaptive bitrate, ABR, is vital in effective delivery of video to the home where bandwidth varies over time. It requires creating several different renditions of your content at various bitrates, resolutions and even frame rate. These multiple encodes put a computational burden on the transcode stage.
Lowell Winger explains ways of optimising ABR encodes to reduce the computation needed to create these different versions. He explains ways to use encoding decisions from one version and use them in other encodes. This has a benefit of being able to use decisions made on high-resolution versions – which are benefiting from high definition to inform the decision in detail – on low-resolution content where the decision would otherwise be made with a lot less information.
This talk is the type of deep dive into encoding techniques that you would expect from the Video Engineering Summit which happens at Streaming Media East.
With the continual quest for lower and lower latencies in streamed video, WebRTC is an attractive technology with latencies in the milliseconds rather than seconds. Limelight’s lowest latency offerings are based on WebRTC.
Alex Gouaillard from millicast explains the brief history and current status of WebRTC including which browsers are supported. After talking about optimisations that have been made, he talks about Bandwidth Adaptive Media and other use cases to be solved.
Supported codecs and, importantly, Scalable Video Coding support is discussed along with ways of implementing WebRTC. Alex also talks about the testing that’s gone in to the standard looking at bandwidth and latencies.
Lastly, a key question around WebRTC is ‘does it scale’ which is discussed before the conclusion.