Video: 2019 What did I miss? – SRT

We’re looking at the most popular posts of 2019 now as The Broadcast Knowledge takes a break over the holiday season. Twitch’s Alex Converse had one of the most visited posts of the year in his video detailing how SRT works. It’s a great technical resource for developers and engineers wanting to understand more than just the highlights of SRT. Did it do well because it was Alex? Because the San Francisco’s Video Tech meet up is a well known part of Demuxed’s community for ‘engineers working with video’ or because its title? Any or all of these could be true and it wouldn’t invalidate it’s usefulness or its popularity. So if you haven’t already, read more about it here, or click play below.

Another SRT talk of interest this year you may want to catch up on was the IBC SRT Open Source Technical panel which looked at the general SRT features and looked at the pros and cons against SRT. The panel looked at a case study with Red Bee Media and South American broadcaster Globo and the use of RTP and SRT together. Read more detail here or click here to watch for free


Alex Converse Alex Converse
Streaming Video Software Engineer,

Video: RIST Main Profile Description

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.

Watch now!

Ciro Noronha Dr. Ciro Noronha
Executive Vice President of Engineering,
Cobalt Digital

Video: JPEG XS in Action for IP Production

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.

You can see the slides here.

Watch now!


Andy Rayner Andy Rayner
Chief Technologist
Nevion Ltd.

Video: Panel Discussion on RIST

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.

Watch now!

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