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.
In the west, RTMP is seen as a dying protocol so the hunt is on for a replacement which can be as widely adopted but keep some of it’s best parts including relatively low latency. SRT is a protocol for Secure, Reliable Transport of streams over the internet so does this have a role to play and how does it work?
Alex Converse from Twitch picks up the gauntlet to dive deep into the workings of SRT to show how it compares to RTMP and specifically how it improves upon it.
RTMP fails in many ways, two to focus on are that the spec has stopped moving forward and it doesn’t work well over problematic networks. So Alex takes a few minutes to explain where SRT has come from, the importance of t being open source and how to get hold of the code and more information.
Now, Alex starts his dive into the detail reminding us about UDP, TS Packets and Ethernet MTUs has he goes down. We look at how SRT data packets are formed which helps explain some of the features and sets us up for a more focussed look.
SRT, as with other, similar protocols which create their resilience by retransmitting missing packets, need to use buffers in order to have chance to send the missing data before it’s needed at the decoder. Alex takes us through how the sender and receiver buffers work to understand the behaviour in different situations.
Fundamental to the whole protocol is packet the packet acknowledgement and negative acknowledgements which feature heavily before we discuss handshaking as we start our ascent from the depths of the protocol. As much as acknowledgements provide the reliability, encryption provides the ‘secure’ in Secure Reliable Transport. We look at the approach taken to encryption and how it relates to current encryption for websites.
Finally Alex answers a number of questions from the audience as he concludes this talk from the San Francisco Video Tech meet up.
Real-life use cases on this innovative Open Source technology from the SRT Alliance recorded at IBC 2018.
SRT, Secure Reliable Transport, is an open source video transport protocol and technology stack that optimises streaming performance across unpredictable networks with secure streams and easy firewall traversal, bringing the best quality live video over the worst networks.
The SRT Open Source project, driven by the SRT Alliance, is a collaborative community of industry leaders and developers striving to achieve lower latency internet video transport by continuously improving open-source SRT.
At the end of the day, a technology is only as good as what it can actually do rather than what people promise and, in this talk, there are only real-world case studies from major companies. Including some brief words from Microsoft Azure’s Satish Annapureddy discussing Microsoft’s recent membership of the SRT alliance.
Glenn Goldstein, Chief Technology Convergence Officer, Viacom Marc Cymontkowski, Senior Director, Core Technology, Haivision Tony Jones, Principal Technologist, MediaKind Miljenko Logozar, Director of Technology Solutions & Integrations, Al Jazeera Chris Smith, Development Executive, News Technology, Sky News
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