On-site trucks or REMI: What makes most sense for live production, according to Cobalt Digital

Inside EMG Italy’s gallery OB truck from stage 13 of the Giro d’Italia on 17 May 2024

By Dr Ciro Noronha, CTO at Cobalt Digital.

In the world of live production, primarily sports, crews have traditionally gone where the action is for an optimal and enticing viewer experience. The wide scope of live sports events ranges from premier events such as the Olympics, World Cup or the Super Bowl, to regional and local sports matches, and the size and complexity of the truck/van is determined by the importance of the event.

For a premier event with on-site production, there will be many cameras and audio feeds, and one or more large trucks will roll. Nowadays, such trucks are based on SMPTE ST 2110 baseband video over IP. In this environment, gateways and native ST 2110 processing elements are key to success. If the cameras are not native ST 2110, a reliable gateway can provide a high‑density conversion solution. For native ST 2110 processing for HDR, colour correction, and audio mixing, look for an option that accomplishes these and many other functions without needing to convert back to baseband video.

The adoption of HDR for live sports production will continue to happen. Going HDR gives you more bang for the buck than increasing resolution – most people would rather take a good-looking HDR 1080p signal than an SDR 4K signal. The TVs are pretty much all in place already. You will need to produce the right content and will need to get it to them. One key point here is what’s called ‘single-stream production’ – it is not practical to have parallel SDR and HDR production chains. You should be looking at workflows that are produced in HDR and provide a good-looking SDR feed at the end in parallel. HDR distribution is already happening on the streaming side, and now the ATSC 3.0 people will get it going too.

But what about smaller events and simpler OB vans? Uncompressed baseband video is nice, but the cost is still too high for these applications – for now, they need to use traditional baseband video over SDI. All the solutions described above are available for this market segment (including single-stream HDR production), with SDI baseband inputs. Moreover, for these applications there are routers and control panels to meet every need and budget, some that are available with an open architecture and API, and thus can be customised for every environment.

REMI

The primary objective of remote production is to save money: crews do not have to travel, and the same equipment can be more effectively shared between events. It is good for both capex and OPEX. However, content must be transmitted between locations without perceptible loss of quality, and with very low latency. Traditionally, these objectives have been achieved by using ST 2110 baseband video over IP, either uncompressed or lightly compressed with JPEG-XS. This requires a private network of suitable capacity; a baseband 1080p signal takes 3Gb/s, and a 4K signal takes 12Gb/s. JPEG-XS can bring down these rates by a factor of between 4 and 10, with negligible impact in latency. It is still a very high bitrate, and dedicated network links capable of such rates are costly and may negate the cost savings.

More advanced compression standards, such as HEVC, can bring down the bitrate by two to three orders of magnitude, but there is a potential latency impact. However, it turns out that it is possible to achieve sub-frame end-to-end latency with HEVC. This is what is called HEVC Ultra-Low Latency (ULL). The same 1080p signal that takes 3Gb/s uncompressed, and between 300 and 750Mb/s compressed with JPEG-XS, can now be carried at about 40Mb/s using HEVC ULL, with similar quality and latency. This mode of operation requires suitable encoders and decoders, with support for HEVC ULL.

The lower bitrate requirements also open the possibility of using the internet instead of costly dedicated network links, thus reducing opex. And when encoders and decoders support the Reliable Internet Stream Transport (RIST) suite of protocols, broadcasters can tap into numerous benefits, including:

  • Support for seamless switching, if you want to use two separate ISPs for added reliability.
  • Support for encryption and authentication (with no latency or quality penalty), to protect your content in flight.
  • Support for adapting the encoder bitrate to the instantaneous network conditions.
  • Support for multi-stream synchronisation for multiple camera use, if you are going to transport these cameras to a remote location, the playback must be synchronised, even if the latency is higher. This allows you to cut from camera to camera without any funny effects. RIST has mechanisms to synchronise an arbitrary number of cameras over the internet.

When you use the internet, there is a latency penalty to allow for packet loss recovery. More advanced protocols such as RIST allow for fine-tuning the latency to the network conditions, so contribution links can be optimised without losing the ability to operate over marginal network conditions.

You’d also be wise to look for an encoder that includes support for HDR workflows and native streaming to platforms such as YouTube and Facebook so you can stream directly there. And finally, if you are using ST 2110 uncompressed flows at the event location, find an encoder that can be configured with an option that provides a set of native ST 2110 inputs, thus removing the hassle of requiring a separate gateway to support your REMI workflow.

 

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