RIST solves a problem by transforming unmanaged networks into reliable paths for video contribution in an interoperable way. RIST not only improves reliability through re-requesting missing packets, but also comes with a range of features and tools, not least of which is tunnelling. Cobalt Digital’s EVP of engineering, Ciro Noronha explains how the protocol works and what’s next on the roadmap.
Ciro starts with a look at the RIST Simple Profile covering the ARQ negative acknowledgement (NACK) mechanism, link bonding and seamless switching. He then moves on to examine the missing features such as content encryption, authentication, simpler firewall configurations, in-band control, high bitrates, NULL packet extraction. These features define RIST’s Main Profile.
Tunnelling and Multiplexing is a technique to combine Simple Profile flows into a bi-directional tunnel, providing simpler network and encryption configuration. Using a GRE (RFC 8086) tunnel, RIST provides a full, protocol agnostic tunnel and a UDP-only reduced overheard mode which only requires 0.6% data overhead to implement. Ciro explains a number of setups, including one where the connection is initiated by the receiver – something that the Simple Profile doesn’t allow.
Authentication and Encryption are covered next. DTLS us the UDP implementation of TLS which is the security mechanism used on secure websites. This provides security to the tunnel so everything which travels through is covered. Ciro explains the pre-shared key (PSK) mechanism in the Main Profile.
The talk finishes by covering NULL Packet removal, also known as ‘bandwidth optimisation’, header extension which extends RTP’s sequence number to allow for more in-flight packets and questions from the audience.
JPEG XS is a new intra-frame compression standard delivering JPEG 2000 quality with 1000x lower latency – microseconds instead of milliseconds. This codec provides relatively low bandwidth (visually lossless compression at ratio of 10:1) with very-low and fixed latency, which makes it ideal for remote production of live events.
In this video Andy Rayner from Nevion shows how JPEG XS fits in all-IP broadcast technology with SMPTE ST 2110-22 standard. Then he presents the world’s first full JPEG-XS deployment for live IP production created for a large sports broadcaster. It was designed for pan-European WAN operation and based on ST 2110 standard with ST 2022-7 protection.
Andy discusses challenges of IP to IP processing (ST 2110-20 to ST 2110-22 conversion) and shows how to keep video and audio in sync through the whole processing chain.
This presentation proves that JPEG-XS is working, low latency distributed production is possible and the value of the ST2110-22 addition to the 2110 suite.
RIST is a streaming protocol which allows unreliable/lossy networks such as the internet to be used for critical streaming applications. Called Reliable Internet Stream Protocol, it uses a light-touch mechanism to request any data that’s lost by the network. As losses are often temporary and sporadic, the chances are that the data will get through the second or, perhaps, third time. For a more in-depth explanation of RIST, check out this talk from Merrick Ackermans
The panel here at the IBC 2019 IP Showcase give an brief definition of RIST and then examine how far they’ve got with the ‘Simple Profile’ of RIST calling out things that are yet to be done. Still on the to-do list are such things as ‘pull’ streams, encryption, simplifying the port structure and embedding control.
Fixed Key encryption comes under the microscope next asking whether there’s a practical threat in terms of finding the key but also in terms of whether there are any side-channel attacks in a ‘non-standard’ encryption. The fixed key encryption has been implemented in line with NIST protocols but, as Kieran highlights, getting enough eyes on the detail is difficult with the specification being created outside of an open forum.
The panels covers the recent interop testing which shows overall positive results and then discusses whether RIST is appropriate for uncompressed video. Already, Kieran points out, Amazon Direct Connect is available in 100s of Gb/s links and so it’s completely possible to do uncompressed to the cloud. RTP is over 20 years old and is being used for much more than ever imagined at the time. As technology develops, use of RIST will also develop.
What are the other uses for RIST? Videoconferencing is one possibility, creating a generally secure link to equipment and ingest into the cloud are the others offered.
The panel fishes by looking to the future. Asking how, for instance, the encoder could react to reduced quality of the link. How much of the all the technology needed should be standardised and what features could be added. Sergio Ammirata suggests opening up the protocol for the bandwidth estimation to be requested by any interested device.
This session, bringing together DVEO, OBS, Zixi and Net Insight finishes with questions from the audience.
French broadcast company M6 Group has recently moved to an all-IP workflow, employing the SMPTE ST 2110 suite of standards for professional media delivery over IP networks. The two main playout channels and MCR have been already upgraded and the next few channels will be transitioned to the new core soon.
The M6 system comprises equipment from five different vendors (Evertz, Tektronix, Harmonic, Ross and TSL), all managed and controlled using the AMWA NMOS IS-04 and IS-05 specifications. Such interoperability is an inherent feature of SMPTE ST 2110 suite of standards allowing customers to focus on the operational workflows and flexibility that IP brings them. Centralised management and configuration of the system is provided through web interfaces which also allows for easy and automated addition of a new equipment.
Thanks to Software Defined Orchestration and intuitive touch screen interfaces information such as source paths, link bandwidth / status, and device details can be quickly accessed via a web GUI. As the system is based on IP network, it is possible to come in and out of fabric numerous times without the same costs implications that you would have in the SDI world. Every point of the signal chain can be easily visualised which enables broadcast engineers to maintain and configure the system with ease.