The Broadcast Knowledge

Video: Real World IP – PTP

Posted on 6th November 2019 by Russell Trafford-Jones

PTP, Precision Time Protocol, underpins the recent uncompressed video and audio over IP standards. It takes over the role of facility-wide synchronisation from black and burst signals. So it’s no surprise that The Broadcast Bridge invited Meinberg to speak at their ‘Real World IP’ event exploring all aspects of video over IP.

David Boldt, head of software engineering at Meinberg, explains how you can accurately transmit time over a network. He summarises the way that PTP accounts for the time taken for messages to move from A to B. David covers different types of clock explaining the often-heard terms ‘boundary clock’ and ‘transparent clock’ exploring their pros and cons.

Unlike black and burst which is a distributed signal, PTP is a system with bi-directional communication which makes redundancy all the more critical and, in some ways, complicated. David talks about different ways to attack the main/reserve problem.

https://www.youtube.com/watch?v=T3ekTqiyBn4

Real World IP Event – Part 3 – Daniel Boldt – Meinberg (https://www.youtube.com/watch?v=T3ekTqiyBn4)

PTP is a cross-industry standard which needs to be interpreted by devices to map the PTP time into an understanding of how the signal should look in order for everything to be in time. SMPTE 2059 does this task which David cover.

PTP-over-WAN: David looks at a case study of delivering PTP over a WAN. Commonly assumed not practical by many, David shows how this was done without using a GPS antenna at the destination. To finish off the talk, there’s a teaser of the new features coming up in the backwards-compatible PTP Version 2.1 before a Q&A.

This is part of a series of videos from The Broadcast Bridge

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Speakers

Daniel Boldt
Head of Software Engineering
Meinberg

Video: ATSC 3.0

Posted on 5th November 2019 by Russell Trafford-Jones

“OTT over the air” – ATSC 3.0 deployment has started in the US and has been deployed in Korea. Promising to bring interactivity and ‘internet-style’ services to broadcast TV, moreover allowing ‘TV’ to transition to mobile devices. To help understand what ATSC 3.0 enables, NABShow Live brings together Sinclair’s Mark Aitken, Bill Hayes from Iowa Public Television and SMPTE’s Thomas Bause Mason all of which are deeply involved in the development of ATSC 3.0.

The panelists dive in to what ATSC 1 was and how we get to 3.0, outlining the big things that have changed. One key thing is that broadcasters can now choose how robust the stream is, balanced against bandwidth. Not only that but multiple streams with different robustnesses are possible for the same channel. This allows ATSC 3.0 to be tailored to your market and support different business models.

ATSC 3.0, as Bill Hayes says was ‘built to evolve’ and to deal with new standards as they come along and was at pains to point out that all these advancements came without any extra spectrum allocations. Thomas outlined that not only is SMPTE on the board of ATSC, but the broadcast standards upstream of distribution now need to work and communicate with downstream. HDR, for instance, needs metadata and the movement of that is one of the standards SMPTE has formed. As Mark Aitken says ‘the lines are blurring’ with devices at the beginning of the end of the chain both being responsible for correct results on the TV.

The session ends by asking what the response has been from broadcasters. Are they embracing the standard? After all, they are not obliged to use ATSC 3.0.
Thomas say that interest has picked up and that large and small networks are now showing more interest with 50 broadcasters already having committed to it.

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Speakers

	Thomas Bause Mason Director Standards Development, SMPTE
	Bill Hayes Director of Engineering & Technology Iowa Public Television
	Mark Aitken SVP of Advanced Technology, Sinclair Broadcast Group
	Linda Rosner Managing Director, Artisans PR

Video: The 7th Circle of Hell; Making Facility-Wide Audio-over-IP Work

Posted on 4th November 2019 by Russell Trafford-Jones

When it comes to IP, audio has always been ahead of video. Whilst audio often makes up for it in scale, its relatively low bandwidth requirements meant computing was up to the task of audio-over-IP long before uncompressed video-over-IP. Despite the early lead, audio-over-IP isn’t necessarily trivial. However, this talk aims to give you a heads up to the main hurdles so you can address them right from the beginning.

Matt Ward, Head of Video for UK-based Jigsaw24, starts this talk revising the reasons to go audio over IP (AoIP). The benefits vary for each company. For some, reducing cabling is a benefit, many are hoping it will be cheaper, for others achievable scale is key. Matt’s quick to point out the drawbacks we should be cautious of, not least of which are complexity and skill gaps.

Matt fast-tracks us to better installations by hitting a list of easy wins some of which are basic, but a disproportionately important as the project continues i.e. naming paths and devices and having IP addresses in logical groups. Others are more nuanced like ensuring cable performance. For CAT6 cabling, it’s easy to get companies to test each of your cables to ensure the cable and all terminations are still working at peak performance.

Planning your timing system is highlighted as next on the road to success with smaller facilities more susceptible to problems if they only have one clock. But any facility has to be carefully considered and Matt points out that the Best Master Clock Algorithm (BMCA).

Network considerations are the final stop on the tour, underlining that audio doesn’t have to run in its own network as long as QoS is used to maintain performance. Matt details his reasons to keep Spanning Tree Protocol off, unless you explicitly know that you need it on. The talk finishes by discussing multicast distribution and IGMP snooping.

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Speaker

Matt Ward
Head of Audio,
Jigsaw24

Video: Mitigating Online Video Delivery Latency

Posted on 1st November 2019 by Russell Trafford-Jones

Real-world solutions to real-world streaming latency in this panel from the Content Delivery Summit at Streaming Media East. With everyone chasing reductions in latency, many with the goal of matching traditional broadcast latencies, there are a heap of tricks and techniques at each stage of the distribution chain to get things done quicker.

The panel starts by surveying the way these companies are already serving video. Comcast, for example, are reducing latency by extending their network to edge CDNs. Anevia identified encoding as latency-introducer number 1 with packaging at number 2.

Bitmovin’s Igor Oreper talks about Periscope’s work with low-latency HLS (LHLS) explaining how Bitmovin deployed their player with Twitter and worked closely with them to ensure LHLS worked seamlessly. Periscope’s LHLS is documented in this blog post.

The panel shares techniques for avoiding latency such as keeping ABR ladders small to ensure CDNs cache all the segments. Damien from Anevia points out that low latency can quickly become pointless if you end up with a low-latency stream arriving on an iPhone before Android; relative latency is really important and can be more so than absolute latency.

The importance of HTTP and the version is next up for discussion. HTTP 1.1 is still widely used but there’s increasing interest in HTTP 2 and QUIC which both handle connections better and reduce overheads thus reducing latency, though often only slightly.

The panel finishes with a Q&A after discussing how to operate in multi-CDN environments.

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Speakers

	Damien Lucas CTO & Co-Founder, Anevia
	Ryan Durfey CDN Senior Product Manager, Comcast Technology Solutions
	Igor Oreper Vice President, Solutions Bitmovin
	Eric Klein Director, Content Distribution, Disney Streaming Services (was BAMTECH Media)
	Dom Robinson Director, id3as

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