Zixi Archives – Page 2 of 2 – The Broadcast Knowledge

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.

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Speakers

	Sergio Ammirata Deployments and Future Development, DVEO
	Kieran Kunhya Founder, Open Broadcast Systems
	Uri Avni Founder, Zixi
	Mikael Wånggren Senior Software Engineer, Net Insight
	Ciro Noronha Executive Vice President of Engineering, Cobalt Digital

An increasing amount of broadcast video is travelling over the public internet which is currently enabled by SRT, Zixi and other protocols. Here, Merrick Ackermans explains the new RIST specification which aims to allow interoperable internet-based video contribution. RIST, which stands for Reliable Internet Stream Transport, ensures reliable transmission of video and other data over lossy networks. This enables broadcast-grade contribution at a much lower cost as well as a number of other benefits.

RIST is an interesting merging of technologies from around the industry. Many people use Zixi, SRT, and VideoFlow all of which can allow safe contribution of media. Safe meaning it gets to the other end intact and un-corrupted. However, if your encoder only supports Zixi and you use it to deliver to a decoder which only supports SRT, it’s not going to work out. The industry as accepted that these formats should be reconciled into a shared standard. This is RIST.

RIST is being created by the VSF – the Video Standards Forum – who were key in introducing VS-03 and VS-04 into the AIMS group on which SMPTE ST 2022-6 was then based. So their move now into a specification for reliable transmission of media over the internet has many anticipating great things. At the point that this talk was given the simple profile has been formed. Whist Merrick gives the details, it’s worth pointing out that this doesn’t include intrinsic encryption. It can, of course, be delivered over a separately encrypted tunnel, but an intrinsic part of SRT is the security that is provided from within the protocol.

Despite Zixi, a proprietary solution, and Haivision’s open-source SRT being in competition, they are both part of the VSF working group creating RIST along with VideoFlow. This is because they see the benefit of having a widely accepted, interoperable method of exchanging media data. This can’t be achieved by any single company alone but can benefit all players in the market.

This talk remains true for the simple profile which just aims to recover packets. The main protocol, as opposed to ‘simple’, has since been released and you can hear about it in a separate video here. This protocol adds FEC, encryption and other aspects. Those who are familiar with the basics may whoosh to start there.

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