• August 29, 2023
  • libRist

Talking libRIST

Talking libRIST

Sergio Ammirata, Ph.D., chief scientist, SipRadius 

Distributing video over the internet is everywhere today. But it has its technical challenges: the internet is inherently unpredictable and unreliable, and nothing we in the media industry can do is going to change that. 

So we have to find ways of making the internet less chaotic, at least for our media streams. There are a number of protocols out there which tackle this challenge. One of the most prominent is RIST: Reliable Internet Stream Transport. 

What is really important is that this is an open standard. It only has value if it is completely interoperable: you can send from any device, carry it over an unmanaged network (like the internet), and receive it on any device, completely transparently. 

It was created from an open-source forum. I took a major part in creating the specifications and delivering the code. I have a patent for a part of RIST, which I give free license to because it is important that it is available to all. 

From that work, I saw that there was a need for a practical toolkit to implement RIST, a library that can be used to add the RIST protocol to an application, easily and in complete conformance. The library became known as libRIST, and the goal was that anybody could use or implement it. 

I started the ball rolling, with my colleagues at SipRadius, under the umbrella of VideoLAN, the open-source body also responsible for the VLC player. In true open-source fashion, the code is available for anyone to contribute to refine it still further. 

But here’s the important thing. I published the original, and assigned the copyright to VideoLAN. And I made the stipulation that anyone could add to it, but they too had to give up any copyright claims so that it remains completely open. 

This is what is known as a two-clause BSD license. BSD – it originally stood for Berkeley Software Distribution – is the most common way of copyright protection for open-source materials. The two-clause version is the simplest and most permissive: anyone can use the library, providing they include the copyright statement. They do not need even need to refer to libRIST if they incorporate it into their own products. 

The result is that libRIST is, indeed, very widely used across the industry, including in products developed by some of the largest vendors. 

What’s in this for SipRadius? Like any other specialist in media distribution, a universally recognized protocol simplifies development of our own products. And, of course, we are proud to have played a major role in such a vital enabler of simple media streaming. 

Want to find out more about libRIST? Or just chat to the people behind it? Drop in for a beer and a chat at IBC2023, on stand 5.F47.