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.
Date:Thursday, November 16, 2017 – 18:00 to 20:30 Location: Universisty of Surrey, Wates House, GU2 7XH,Guildford Map
Peter Stevens (BBC R&D) will cover AES67 and its background development within AES and how it is connected as a audio elements within SMPTE 2110. The basic operational principles of AES67 will be described in relation to its various technology components and history of audio over IP. It will conclude with a brief look at the plugfests that have taken place, along with some examples of use within broadcasting.
There is be an introduction by Tony Orme (Uni of Surrey) covering the structure of ST 2110 and its relationship with ST 2057 PTP and discovery etc. like NMOS and how it differs fundamentally from ST 2022-6 and SDI with embeded audio.
Fundamental to the new wave of IP technologies, ST 2022, ST 2110, AES67 and more is RTP, the Realtime Protocol. This 10 minute video gives an engineering fundamental look at the protocol itself and is key to practical implementation and fault finding of these technologies. Watch Now
These standards provide the interconnection framework for an all-IP infrastructure within a facility. The way in which these data packets flow across the network requires a variety of protocols to send this information bi-directionally from the source to the destination. Requiring broadcast engineers to gain an understanding of the technology and the new techniques needed to monitor these signals.
In this webcast, we will examine the basic structure of the packets for ST 2022-6 and the ST 2110 suite and how variable delay across the network introduces jitter at the receiver and how measurements can be made on the stream. Latency in the network can produce out of order packets or corruption of the data causing packets to be dropped. Therefore, it is critical to monitor the stream to ensure an eerror-free network to ensure transmission of the high bit rate media and how these errors affect the actual video and audio signal. For redundancy in the media network SMPTE ST 2022-7 can be used to provide a Path One and a Path Two stream that the downstream device can determine which path is the most appropriate to use. Measurement of the integrity of both paths is important and we will look at ways of monitoring the signal paths.