PTP

Video: Uncompressed Video over IP & PTP Timing

Posted on by Russell Trafford-Jones

PTP and uncompressed video go hand in hand so this primer on ST 2022 and ST 2110 followed by a PTP deep dive is a great way to gain your footing in the uncompressed world.

In the longest video yet on The Broadcast Knowledge, Steve Holmes on behalf of Tektronix delivers two talks and a practical demo for the SMPTE San Francisco section where he introduces the reasons for and solutions to uncompressed video and goes through the key standards and technologies from ST 2022, those being -6 video and -7 seamless switching plus the major parts of ST 2110, those being timing, video, audio and metadata.

After that, at the 47 minute mark, Steve introduces the need for PTP by reference to black and burst, and goes on to explain how SMPTE’s ST2059 brings PTP into the broadcast domain and helps us synchronise uncompressed essences. He covered how PTP actually works, boundary clocks, Grandmaster/Master/Slave clocks and everything else you need to understand the system,

This video finishes with plenty of questions plus a look at the GUI of measurement equipment showing PTP in real life.

Watch now!
Speaker

Steve Holmes Steve Holmes
Senior Applications Engineer,
Tektronix

Video: Building a Large OB Truck Using SMPTE ST 2110

Posted on by Adam K

OB vans have been notable early adopters of Video over IP, both in the form of SMPTE ST 2110 and ST 2022-6. The reasons are simple, all new vans are ‘green field’ sites, weight and space are at a premium and many need more weekly flexibility than SDI has been giving them.

In this case study, Hartmut Opfermann discusses design considerations for all IP large OB trucks dedicated for sports, music and entertainment production and explores the decisions that have been made for ORF’s new FU22 OB tuck including the drivers behind switching to IP technology and SMPTE ST 2110 for media transport.

Interesting to note is the proportion of SDI Vs IP in new IP installations. BBC Cardiff, for instance, has a minimum quota for IP-enabled endpoints but isn’t assuming it can reach 100%. There are few IP installations which are 100% IP.

In ORF’s truck we also see that, although the truck is fully based on IP technology, SDI-IP gateways have been provided to keep compatibility with existing baseband infrastructure. Keeping all internal processing in the IP domain simplifies cabling, reduces cable weight but, importantly, enables the use of flexible FPGA based processing platforms – functionality thus depends on software and can be changed on fly.

The broadcast control system provides a single point of control over complex infrastructure of the truck and provides a seamless experience for operators who used to work in the SDI domain. However, configuration and troubleshooting of IP systems requires a very different skillset, so training had to be provided to ORF engineering team.

Some other points discussed in this video are audio channel management, failover of PTP and B&B synchronisation and IP address management using the JT-NM’s TR 1001-1, which has been covered here on The Broadcast Knowledge before.

Watch now!

Speaker

Hartmut Opfermann Hartmut Opfermann
Head of Division Broadcast IT,
BFE Studio und Medien Systeme GmbH

Video: Using PTP & SMPTE 2059 A Practical Experience Perspective

Posted on 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

Greg Shay Greg Shay
CTO,
The Telos Alliance

Video: A Basic Guide For Real-Time IP Video

Posted on by Russell Trafford-Jones

There are a lot of videos looking into the details of uncompressed video over IP, but not many for those still starting out – and let’s face it, there are a lot of people who are only just embarking on this journey. Here, Andy Jones takes us through the real basics do prove very useful as a building block for understanding today’s IP technologies.

Andy Jones is well known by many broadcast engineers in the UK having spent many many years working in The BBC’s Training and Development department and subsequently running training for the IABM. The news that he passed away on Saturday is very saddening and I’m posting this video in recognition of the immense amount he has contributed to the industry through his years of tireless work. You can see from this video from NAB 2018 his passion, energy and ability to make complicated things simple.

In this talk, Andy looks at the different layers that networks operate on, including the physical layer i.e. the cables. This is because the different ways in which traffic gets from A to B in networking are interdependent and need to be considered as such. He looks at an example network which shows all the different standards in use in an IP network and talks about their relevance.

Andy briefly looks at IP addresses and the protocol that makes them work. This underpins much of what happens on most networks before looking at the Real-time Transport Protocol (RTP) which is heavily used for sending audio and video streams.

After looking at how timing is done in IP (as opposed to black and burst) he has laid enough foundations to look at SMPTE ST 2110 – the suite of standards which show how different media (essences) are sent in networks delivering uncompressed streams. AES67 for the audio is also looked at before how to control the whole kit and caboodle.

A great primer for those starting out, watch now!

Speaker

Andy Jones Andy Jones