Video: RIST: Enabling Remote Work with Reliable Live Video Over Unmanaged Networks

Last week’s article on RIST, here on The Broadcast Knowledge, stirred up some interest about whether we view RIST as being against SRT & Zixi, or whether it’s an evolution thereof. Whilst the talk covered the use of RIST and the reasons one company chose to use it, this talk explains what RIST achieves in terms of features showing that it has a ‘simple’ and ‘main’ profile which bring different features to the table.

Rick Ackermans is the chair of the RIST Activity Group which is the group that develops the specifications. Rick explains some of the reasons motivating people to look at the internet and other unmanaged networks to move their video. The traditional circuit-based contribution and distribution infrastructure on which broadcasting relied has high fixed costs. Whilst this can be fully justifiable for transmitter links, though still expensive, for other ad-hoc circuits you are paying all the time for something which is only occasionally used, satellite space in the C-band is reducing squeezing people out. And, of course, remote working is much in the spotlight so technologies like RIST which don’t have a high latency (unlike HLS) are in demand.

RIST manages to solve many of the problems with using the internet such as protecting your content from theft and from packet loss. It’s a joint effort between many companies including Zixi and Haivision. The aim is to create choice in the market by removing vendor bias and control. Vendors are more likely to implement an open specification than one which has ties to another vendor so this should open up the market creating more demand for this type of solution.

In the next section, we see how RIST as a group is organised and who it fits in to the Video Services Forum, VSF. We then look at the profiles available in RIST. A full implementation aims at being a 3-layer onion with the ‘Simple Profile’ in the middle. This has basic network resilience and interoperability. On top of that, the ‘Main Profile’ is built which adds encryption, authentication and other features. The future sees an ‘Enhanced Profile’ which may bring with it channel management.

Rick then dives down into each of these profiles to uncover the details of what’s there and explain the publication status. The simple profile allows full RTP interoperability for use as a standard sender, but also adds packet recovery plus seamless switching. The Main profile introduces the use of GRE tunnels where a single connection is setup between two devices. Like a cable, multiple signals can then be sent down the cable together. From an IT perspective this makes life so much easier as the number of streams is totally transparent to the network so firewall configuration, for example, is made all the simpler. However it also means that by just running encryption on the tunnel, everything is encrypted with no further complexity. Encryption works better on higher bitrate streams so, again, running on the aggregate has a benefit than on each stream individually. Rick talks about the encryption modes with DTLS and Pre-shared Key being available as well as the all important, but often neglected, step of authenticating – ensuring you are sending to the endpoint you expected to be sending to.

The last part of the talk covers interoperability, including a comparison between RIST and SRT. Whilst there are many similarities, Rick claims RIST can cope with higher percentages of packet loss. He also says that 2022-7 doesn’t work with SRT, though The Broadcast Knowledge is aware of interoperable implementations which do allow 2022-7 to work even through SRT. The climax of this section is explaining the setup of the RIST NAB demo, a multi-vendor, international demo which proved the reliability claims. Rick finishes by examining some case studies and with a Q&A.

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Speakers

Merrick Ackermans Rick Ackermans
MVA Broadcast Consulting
RIST Activity Group Chair

Video: News in the New Norm

Whilst television marches on despite the pandemic, whilst not to overlook the decimated sports broadcasters, the mantra is ‘the show must go on’ so everyone has been trying to find ways to make TV production safe, practical yet still good! There is so many practical issues behind the camera from the typical packed OB trucks to simple bathroom sharing in the office which needs to be considered. In this video, we hear from BBC News explaining how they have managed to reshape their production to keep the news reaching the public.

“It’s hard to do your job in these circumstances.”

Morwen Williams

Morwen Williams, Head of UK News Operations at the BBC, describes the news workflows that have been created to make the news work. The term ‘Zoom workflow’ is in the fore, in the same way as a ‘Dropbox workflow’ has, perhaps forever, changed many file-based workflows, for live production a ‘Zoom workflow’ is the same. Though Morwen is quick to point out the work is as much technological as practical with the need for ‘long poles’ to ensure social distancing for sound engineers and the like. Workflows have had to remove roles, such as vision mixing, or move people to otherwise spare galleries.

Morwen explains that within the mobile journalism team, there was a pilot last year to test how well an iPhone X would be able to capture real packages which had some good results which ran on the national news. This is just one example of how the technological groundwork to enable mobile journalism during this crisis was already being laid.

Meeting virtually has its advantages, we hear, because when you have a lot of staff physical space is hard to acquire at the best of times. Since attendance can never be 100%, it’s better to have meetings more frequently to give people a better chance of attending some. Whilst this is certainly no replacement for physically meeting with people, it is likely to be retained when that is again possible.

Robin Pembrooke then takes some time to explain the shifts in production that he’s seen. All of the digital teams are now working from home. 15,000 people went from the offices to working from home which was a fraught transition but with no major outages. Radio shows are often now being presented and run by the presenter themselves from home. Talkback now takes many forms whether that be WhatsApp or other more broadcast-focused talkback-over-broadband products.

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Speakers

Morwen Williams Morwen Williams
Head of UK Operations,
BBC News
Robin Pembrooke Robin Pembrooke
Director, News Product and Systems,
BBC News

Video: RIST and Open Broadcast Systems

RIST is a streaming protocol which allows lossy networks such as the internet to be used for critical streaming applications. Called Reliable Internet Stream Transport, it uses ARQ (Adaptive Repeat reQuest) retransmission technology to request any data that is lost by the network, creating reliable paths for video contribution.

In this presentation Kieran Kunhya from Open Broadcast Systems explains why his company has chosen RIST protocol for their software-based encoders and decoders. Their initial solution for news, sports and linear channels contribution over public internet was based on FEC (Forward Error Correction), a technique used for controlling errors in transmission by sending data in a redundant way using error-correcting code. However, FEC couldn’t cope with large burst losses, there was limited interoperability and the implementation was complex. Protecting the stream by sending the same feed over multiple paths and/or sending a delayed version of the stream on the same path, had a heavy bandwidth penalty. This prompted them, instead, to implement an ARQ technique based on RFC 4585 (Extended RTP Profile for Real-time Transport Control Protocol-Based Feedback), which gave them functionality quite similar to the basic RIST functionality.

Key to the discussion, Kieran explains why they decided not to adopt the SRT protocol. As SRT is based file transfer protocol, it’s difficult or impossible to add features like bonding, multi-network and multi-point support which were available in RIST from day one. Moreover, RIST has a large IETF heritage from other industries and is vendor-independent. In Kieran’s opinion SRT will become a prosumer solution (similar to RTMP, now, for streaming) and RIST will be the professional solution (analogous to MPEG-2 Transport Streams).

Different applications for the RIST protocol are discussed, including 24/7 linear channels for satellite uplink from playout, interactive (two-way) talking heads for news, high bitrate live events and reverse vision lines for monitoring purposes. Also, there is a big potential for using RIST in cloud solutions for live broadcast production workflows. Kieran hopes that more broadcasters will start using spin-up and spin-down cloud workflows, which will help save space and money on infrastructure.

What’s interesting, Open Broadcast Solutions are not currently interested in RIST Main Profile (the main advantages of this profile are support for encryption, authentication and in-band data). Kieran explains that to control devices in remote locations you need some kind of off-the-shelf VPN anyway. These systems provide encryption and NAT port traversal, so the problem is solved at a different layer in the OSI model and this gives customers more control over the type of encryption they want.

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Speaker

Kieran Kunhya Kieran Kunhya
Founder and CEO,
Open Broadcast Systems

Video: Benefits of IP Systems for Sporting Venues

As you walk around any exhibitions there seems to be a myriad of ‘benefits’ of IP working, many of which don’t resonate for particular use cases. Only the most extraordinary businesses need all of the benefits, so in this talk, Imagine Communication’s John Mailhot discusses how IP helps sports venues.

John sets the scene by separating out the function of OB trucks and the ‘inside production’ facilities which have a whole host of non-TV production to do including driving scoreboards, displays inside the venue, replays and importantly has to deal with over 250 events a year, not all of which will have an OB truck.

We see that the scale that IP can work at is a great benefit as many signals can fit down one fibre and 2022-7 seamless switching can easily provide full redundancy for every fibre and SFP. This is a level of redundancy which is simply not seen in SDI systems. With stadia being very large, necessitating cable runs of over 500m, the fact that IP needs fewer cables overall is a great benefit.

John shows an example of an Arista switch only 7U in height which provides 144x 100G ports meaning it could support over 4000 inputs and 4000 outputs. Such density is unprecedented and for OB trucks can be a dealbreaker. For sports venues, this can also be a big motivator but also allow more flexibility in distributing the solution rather than relying on a massive central interconnect with a 1100×1100 SDI router in a central CTA.

TV is nothing without audio and the benefits to audio in 2110 are non trivial since with the audio being split off from the video, we are no longer limited to dealing with just 16 channels per video and de-embedding from a video frame any time we want to touch it.

Timing is an interesting benefit. I say this because, whilst PTP can end up being quite complex compared to black and burst, it has some big benefits. First off, it can live in the same cables as your data where as black and burst requires a whole separate cable infrastructure. PTP also allows you to timestamp all essences which helps with lip-sync throughout your workflow.

John leads us through some examples of how this works for different areas finishing by summing up the relevant benefits such as scalability, multi-format, space efficient, and timing amongst others.

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Download the slides
Speakers

John Mailhot John Mailhot
CTO, Networking & Infrastructure,
Imagine Communications