Russell Trafford-Jones, Author at The Broadcast Knowledge

Video: WebRTC: The Future Champion of Low Latency

Posted on 2nd May 2019 by Russell Trafford-Jones

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.

Watch it now!
Speaker

Alex Gouaillard
CTO,
millicast

Video: Recent Experiences with ATSC 3.0 from Seoul to Phoenix

Posted on 1st May 2019 by Russell Trafford-Jones

This talk is part of a series of talks on ATSC 3.0 we’re featuring here on The Broadcast Knowledge. ATSC 3.0 is a big change in terrestrial television transmission because even over the air, the signal is IP.

In this talk, Joe Seccia from GatesAir, a company famed for its transmission systems, talks us through where the US (and Seoul) is on its way to deploying this technology.

With major US broadcasters having pledged to be on air with ATSC 3.0 by the end of 2020, trials are turning in to deployments and this is a report back on what’s been going on.

Joe covers the history of previous tests and trials before taking us through the architecture of a typical system. After explaining the significance of the move to IP, Joe also covers other improvements such as using OFDM modulation and thus being able to use a single frequency network (SFN). This combination of technologies improves reception and coverage over the 8VSB transmissions which went before it.

We also hear about the difference between home and broadcast gateways in the system as well as the Early Alert System Augmentation features which allow a broadcaster to ‘wake up’ TVs and other devices when disasters strike or are predicted.

Watch now!

Speakers

Joe Seccia
Manager, TV Transmission Market and Product Development Strategy,
GatesAir

Video: Colour

Posted on 30th April 2019 by Russell Trafford-Jones

With the advent of digital video, the people in the middle of the broadcast chain have little do to with colour for the most part. Yet those in post production, acquisition and decoding/display are finding it life more and more difficult as we continue to expand colour gamut and deliver on new displays.

Google’s Steven Robertson takes us comprehensively though the challenges of colour from the fundamentals of sight to the intricacies of dealing with REC 601, 709, BT 2020, HDR, YUV transforms and all the mistakes people make in between.

An approachable talk which gives a great overview, raises good points and goes into detail where necessary.

An interesting point of view is that colour subsampling should die. After all, we’re now at a point where we could feed an encoded with 4:4:4 video and get it to compress the colour channels more than the luminance channel. Steven says that this would generate more accurate colour than by stripping it of a fixed amount of data like 4:2:2 subsampling does.

Given at Brightcove HQ as part of the San Francisco Video Tech meet-ups.

Watch now!

Speaker

Steven Robertson
Software Engineer,
Google

Video: Using PTP & SMPTE 2059 A Practical Experience Perspective

Posted on 29th April 2019 by Russell Trafford-Jones

NAB 2019 saw another IP Showcase with plenty of talks on the topic on many people’s minds: PTP and timing in IP systems. It seems there’s a lot which needs to be considered and, truth be told, a lot of people don’t feel they have the complete list of questions to be asking and certainly don’t know all the answers.

So, here, Greg Shay from Telos talks about the learnings from his extensive experience with timing IP signals and with PTP under SMPTE 2059. He hits the following topics;

Must you always have a GPS reference for the PTP master?
Are PTP-aware switches always necessary?
Can you safely not use PTP Peer Delay requests / responses?
What is the effect of internal oscillator tolerance and stability when designing PTP client equipment?

To my ears, these are 4 well placed questions because I’ve heard these asked; they are current in the minds of people who are grappling with current and prospective IP installations.

Greg treats gives each one of these due time and we see some interesting facts come out:
You don’t always need a time-synchronised PTP master (pretending to be in 1970 can work just fine).
Compensating for PTP Peer Delay can make things worse – which seems counter-intuitive to the point of PTP Peer Delay requests.
We also see why PTP-aware switches matter and a statistical method of managing without.

This is a talk which exemplifies IP talks which ‘go deeper’ than simply explaining the point of standards. Implementation always takes thought – not only in basic architecture but in use-cases and edge-cases. Here we learn about both.

Watch now!

Speakers