Andreas Hildebrand starts by introducing 2110 and how it works in terms of sending the essences separately using multicast IP. This talk focusses on the ability of audio-only devices to subscribe to the audio streams without needing the video streams. Andreas then goes on to introduce AES67 which is a standard defining interoperability for audio defining timing, session description, encoding, QOS, transport and much more. Of all the things which are defined in AES67, discovery was deliberately not included and Andreas explains why.
Within SMPTE 2110, there are constraints added to AES67 under the sub-standard 2110-30. The different categories A, B and C (and their X counterparts) are explained in terms how how many audios are defined and the sample lengths with their implications detailed.
As for discovery and other aspects of creating a working system, Andreas looks towards AMWA’s NMOS suite summarising the specifications for Discovery & Registration, Connection Management, Network Control, Event & Tally, Audio Channel Mapping. It’s the latter which is the focus of the last part of this talk.
IS-08 defines a way of defining input and output blocks allowing a channel mapping to be defined. Using IS-05, we can determine which source stream should connect to which destination device. Then IS-08 gives the capability to determine which of the audios within this stream can be mapped to the output(s) of the receiving device and on top of this allows mapping from multiple received streams into the output(s) of one device. The talk then finishes with a deeper look at this process including where example code can be found.
AES67 is a flexible standard but with this there is complexity and nuance. Implementing it within ST 2110-30 takes some care and this talk covers lessons learnt in doing exactly that.
AES67 is a standard defined by the Audio Engineering Society to enable high-performance audio-over-IP streaming interoperability between various AoIP systems like Dante, WheatNet-IP and Livewire. It provides comprehensive interoperability recommendations in the areas of synchronization, media clock identification, network transport, encoding and streaming, session description, and connection management.
The SMPTE ST 2110 standards suite makes it possible to separately route and break away the essence streams – audio, video, and ancillary data. ST 2110-30 addresses system requirements and payload formats for uncompressed audio streams and refers to the subset of AES67 standard.
In this video Dominic Giambo from Wheatsone Corporation discusses tips for implementing AES67 and ST 2110-30 standards in a lab environment consisting of over 160 devices (consoles, sufraces, hardware and software I/O blades) and 3 different automation systems. The aim of the test was to pass audio through every single device creating a very long chain to detect any defects.
The following topics are covered:
SMPTE ST 2110-30 as a subset of AES67 (support of the PTP profile defined in SMPTE ST 2059-2, an offset value of zero between the media clock and the RTP stream clock, option to force a device to operate in PTP slave-only mode)
The importance of using IEEE-1588 PTP v2 master clock for accuracy
Packet structure (UDP and RTP header, payload type)
Network configuration considerations (mapping out IP and multicast addresses for different vendors, keeping all devices on the same subnet)
Discovery and control (SDP stream description files, configuration of signal flow from sources to destinations)
Well ahead of video, audio moved to uncompressed over IP and has been reaping the benefits ever since. With more mature workflows and, as has always been the case, a much higher quantity of feeds than video traditionally has, the solutions have a higher maturity.
Anthony from Ward-Beck Systems talks about the advantages of audio IP and the things which weren’t possible before. In a very accessible talk, you’ll hear as much about soup cans as you will about the more technical aspects, like SDP.
Whilst uncompressed audio over IP started a while ago, it doesn’t mean that it’s not still being developed – in fact it’s the interface with the video world where a lot of the focus is now with SMPTE 2110-30 and -31 determining how audio can flow alongside video and other essences. As has been seen in other talks here on The Broadcast Knowledge there’s a fair bit to know.(Here’s a full list.
To simplify this, Anthony, who is also the Vice Chair of AES Toronto, describes the work the AES is doing to certify equipment as AES 67 ‘compatible’ – and what that would actually mean.
This talk finishes with a walk-through of a real world OB deployment of AES 67 which included the simple touches as using google docs for sharing links as well as more technical techniques such as virtual sound card.
Packed full of easy-to-understand insights which are useful even to those who live for video, this IP Showcase talk is worth a look.
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.