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.
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.
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.
For many building a good network for a 2110 or other media-over-IP standards is new and a bit scary. But if there’s one person who knows how to do it, it’s Arista’s Gerard Phillips who’s here to go through the basics and build up the network needed for a large and scalable network.
Scalability is the heart of this, because life does change – your company grows, technology pushes you from SD to HD to UHD etc. So you need to build scalability in from the beginning. Getting this right comes down to choosing the right hardware and having the right architecture.
Gerard looks at switch architecture and bandwidth both in the switch and of the network cables. He then looks towards ‘hub and spoke’ Vs monolithic switch design. What are the pros and cons to each and which is right for you?
SDN – Software Defined Networking – is also a key ingredient in such a network. This is where the routing decisions of the switch infrastructure is taken out of the switches because they have automatic and blinkered algorithms and takes it to a server which has a complete overview of the whole system. For a broadcaster who deals with critical signal chains – this is usually the best approach to give determinism and safety to the network.
PTP – Precision Time Protocol – provides the foundation of the 2110 standard and is therefore very important to studio installations being used to replace black and burst. What are the best ways to distribute this and how can you deal with redundancy?
These topics and more are all covered at this IP Showcase presentation from IBC 2018.
Peter Schut is back in the sixth webinar in Axon’s Broadcast IP 101 series, this time examining timing, namely PTP, for professional essence-over-IP systems such as based on SMPTE ST 2110.
Timing needs to be rock solid in studio settings where many signals are mixed together, so your PTP system needs to be too. SMPTE 2059-2 standardises the use of PTP timecode (IEEE 1588) in broadcast. It’s important to understand how master clocks and slave clocks work, plus there is talk of ‘transparent’ and ‘boundary’ clocks in switches. Getting the architecture right is key remembering that one important different between IP timekeeping and black and burst time keeping is that the communication is two-way.
Peter gives us the benefit of his experience and insight into getting timing right in two sessions, one morning, one evening.
AES67 is a method of sending audio over IP which was standardised by the Audio Engineering Society as a way of sending uncompressed video over networks between equipment. It’s become widespread and is part of SMPTE’s professional essences-over-IP standards suite, ST 2110.
Here, Conrad Bebbington gives us an introduction to AES67 explaining why AES67 exists and what it tries to achieve. Conrad then goes on to look at interoperability with other competing standards like Dante. After going into some implementation details, importantly, the video then looks the ‘Session Description Protocol’, SDP, and ‘Session Initialisation Protocol’, SIP which are important parts of how AES67 works.
Other topics covered are:
Packetisation – how much audio is in a packet, number of channels etc.
Synchronisation – using PTP
What are SDP and SIP and how are they used
Use of IGMP multicast
Implementation availability in open source software
We’re all starting to get the hang of the basics: that PTP is the new Black and Burst, that we still need sync to make studios work and that PTP (IEEE1588) is standardised under ST 2059 for use in the broadcast industry. So given its importance, how can we make it redundant?
Thomas Kernen from Mellanox and Chair within the STMPE standards community takes about his real-lift work on implementing PTP with an eye on redundancy methods
Andy Rayner from Nevion looks at using SMPTE ST 2110 on a Wide Area Network (WAN).
While using ST 2110 is a much discussed topic in the studio or within a building, there are extra difficulties in putting it between buildings, cities and countries with some saying it shouldn’t even be done. Here, Andy examines how you can do it whilst acknowledging the industry still has some decisions to make.
John Mailhot from Imagine Communications discusses what ‘Full Stack’ means for video over IP. The SMPTE 2110 suite of standards is mainly about the transport of essences – but how to you simply plug in some equipment and get going? You need standards which discover and register the new device, you need timing to synchronise devices. It’s a whole ecosystem.
John walks us through the data flows (and workflows) necessary when you plug new 2110 kit in and we quickly discover there is more depth than we imagined.
John also discusses how DHCP can give you more than just IP addresses.
Covering IS-04, IS-05, PTP/SMPTE 2059, ST 2110 and IEE 802.1AB (LLDP). This is a very practical video. Why? Because understanding all this is key to diagnosis and troubleshooting.
Paul Briscoe explains PTP from the basics taking us through the reasons for using it and how it’s applied to the ST 2110 which to carries uncompressed video, audio and metadata.
The ST 2110 standard brings with it an entirely new way to establish system timing, through use of IEEE-1588 PTP and SMPTE ST2059. This method is native to the IP domain and to the RTP transport and media synchronization used by 2110 but also provides virtualized legacy timing capability.
• The considerations in system timing using ST2110, including those which include SDI elements.
• How PTP delivers precision time across an IP network
• How ST2059 uses PTP to virtualize any reference signal.
• The synchronization mechanisms of ST2110 including transport timestamps and media clocks
• How streams are synchronized among each other and how they interoperate with PTP
• How timing of SDI and AES3 signals is harmonized with ST2110 streams.
• Router switchpoint timing and latency considerations.
Presented By: Paul Briscoe at SMPTE Technical Conference 2017 Watch now!