System Showcase: Using 5G & Starlink Contribution For ‘Mountain Attack’ Ski Mountaineering
We discuss the challenging terrain and conditions of the Mountain Attack endurance ski mountaineering event in Austria with production company Mediahaus. 5G SA & Starlink combined contribution and Blackmagic Designs URSA Broadcast G2 cameras and ATEM streaming & switching rise to the challenge.
Moving pictures long distances has traditionally been a challenge to concentrate the mind of the broadcast engineer. IP networks in general have made that easier, and radio-linked IP networks have made it much, much easier – but in the steep terrain of Austria, there’s often a large mountain in the way of the radio signals. On one recent ski event, though, an OB crew from Mediahaus in Salzburg found ways to connect mountaintop to valley without deploying any hardlines at all.
Mountain Attack is a ski competition which takes place annually in the mountains near Saalbach, Austria. Wolfgang Angermüller, Mediahaus managing director, describes an event which sounds about as intimidating for the crew as it is for the competitors. “It's a ski mountaineering race,” he begins. “The fastest on the marathon distance takes two hours twenty-five minutes to make six summits, going three thousand meters up and down the valleys. We’ve been doing Mountain Attack for ten or eleven years, and this was the twenty-sixth race.”
Angermüller’s preparation for the job involved a familiar thought process. “Every year, we think how we can create better pictures and make the setup easier. We had some analog radio communications, trying to get pictures down in valleys, and in the last few years we had modems that we installed at the cable car top stations. But it was old cables, to an encoder and then via IP to the valley.” Keen to go wireless, Angermüller looked for other options: “This year we tried out the SRT streaming on the Blackmagic URSA Broadcast G2, on four summits.”
Each of these cameras would work within a few tens of meters of a mountaintop race checkpoint, covering competitors as they passed through. Happily for Angermüller, telecommunications provider Hutchison had recently installed a 5G network in the neighboring valley in preparation for an upcoming competition – although in an area of such spectacular geography, radio performance is hard to guarantee. “In the valley next year there will be the ski world championship,” Angermüller says. “The network was usable by the end of December, and we thought we’d try it. We had another two cameras on Skidoos that followed the leaders of the race.”
In the end, Angermüller’s setup would rely heavily on Hutchison’s installation. “We were there two weeks before the race, testing the 5G coverage. It was also a test for Hutchison, for their 5G SA network which we were using on the 700 Mhz frequency band, so they provided SIM cards with dedicated bandwidth. That worked quite well. I think we had about twenty or twenty-four SIM cards in use.” These SIM cards were mainly installed in conventional Samsung Galaxy S21 cellphones, connected directly to the USB-C ports of the URSA Broadcast G2 cameras.
In extremis, terrain could get in the way, and require other solutions, as Angermüller goes on. “The antennae were in the valley, and if you’re on the back of the mountain there is no reliable 5G. In that case we used Starlink to create a WiFi access point there. In the end it worked perfectly.” With each camera using the H.265 codec, good quality pictures could be handled without demanding huge bandwidths and with minimal latency. “In the end we used twenty megabits total from the four cameras, plus the cameras on the Skidoos were five or six megabits. On bonded devices you have two or three seconds delay, so half a second is really impressive.”
At the receiving end, the SRT-over-IP streams were converted back to SDI using hardware converters. In a triumph of automation likely to bring a smile to the face of many OB camera operators, the system maintained full remote camera control and tally signalling.
“In the van we had a 300-megabit modem connection with a normal IP address. We could send the streams to that IP address, and we put in these streaming bridges that take the signal from the SRT streaming cameras and turn it into an SDI signal. We had all the RCP and CCU functions from the OB van in the valley, the color matching was done from the valley and operators could concentrate on the creative stuff.”
The other impediment to that creative stuff would be the working conditions, with the race designed to take place through the evening and into the darkness of night. “The race started at 4pm, and it was dark at about five thirty or six, so half the race took place in complete darkness. They experienced minus twelve or fifteen degrees on the summits, and some heavy snowfall, so it was hard on the hardware.”
With the trying conditions in mind, Angermüller’s operators kept things simple with the URSA cameras – with, optionally, larger-than-average sensors – in a conventional broadcast configuration. “They had all Fujinon B4 lenses on the cameras,” he reports. “We had Bebob 200 and 290 batteries, and the URSA is not taking so much power. Via the USB-C the mobile phone is powered by the camera battery. I think the whole show was three, three and a half hours, and they didn't have to change batteries.”
The whole approach economized particularly on setup. “I think we saved a whole day of setup for the whole crew,” Angermüller reflects, “getting up to the mountaintops with modems and cables. We got the camera ops up there with the cameras, put on the tethering on the mobile phone, and that was it. This is not ski downhill, this is ski mountaineering, so the budgets are a lot smaller than the big races. So, it's also a big game changer for the smaller sports, things that aren’t soccer, tennis, downhill skiing. Volleyball in Austria is covered with streaming, or just two cameras in poor quality. If you can do those things with remote production, in good quality, without big fiber connections at the venue, that's something that helps getting more sports programmes into television with lower costs.”
It would have been possible, given the larger 6K sensors of the Blackmagic URSA Broadcast G2, to use lenses with larger coverage, and achieve a big-chip look – though Angermüller prefers to maintain some separation between cinema and broadcast. “My opinion over the couple of years we've seen that is, okay, but I don't think sports has to be cinematic. For sports you have to have a crystal clear picture that's as sharp as possible. For the camera operators, they can't be so fast with cinematic lenses as they can with B4 lenses. I don't think this is a way we should go in sports production. For maybe a show production in a studio, everything’s fine, do your cinematic stuff.”
One minor practicality involved finding somewhere to put the Samsung phones: “we tried hard to mount it somewhere on the side of the camera, but there was not really an option that would work well. So, we gave them longer USB cables, and the camera operators put the phones in their pockets. Our wish for Blackmagic is that it should be possible to put a USB dongle into that port.”
Other desirable improvements might include ways to synchronize cameras around the small half-second delay. “There's a small step in getting four cameras in sync in future. I don't know how it could be done - maybe with buffering on the streaming bridges. If you have it frame-accurate synced, why couldn’t you use that on small, second or third-league soccer broadcasts? You could get there with four cameras with operators and the OB van can be here in Salzburg doing all the cutting, the graphics and the slowmo. That's the next step for the future. It's an enormous step having less cost. You don't have to send all the crew to the location. You have four or five fewer people there, you haven't got any trucks. For the CO2 footprint it's much better.”
“We did a big symphony concert last year with twelve cameras,” Angermüller says. “For the TV stations, [Austrian national broadcaster] ORF, or the German stations, they still want to have Sony PDW-700 or FS7, and we have those cameras, but if it's on our side to choose, we just use our Blackmagic tools. We're also doing it for [soccer in] Salzburg - all the test matches, all the stadium vision when they're at home. They have a whole TV show for the visitors, the VIP lounges, and the main giant screen. In that live situation, we would not change anything.”
Next January, the Mountain Attack race will run – or rather ski – again, but Angermüller is keen to find out what else 5G and SRT can achieve in the meantime. “There are marathon runs where we don't have moving cameras, but stationary cameras on the track somewhere that is too far away for normal cabling. If you have a 5G connection there, you can easily set up new camera positions with a camera and a mobile phone. Anything that's sports, that has a long track, this will be helpful.”
You might also like...
Designing IP Broadcast Systems - The Book
Designing IP Broadcast Systems is another massive body of research driven work - with over 27,000 words in 18 articles, in a free 84 page eBook. It provides extensive insight into the technology and engineering methodology required to create practical IP based broadcast…
Demands On Production With HDR & WCG
The adoption of HDR requires adjustments in workflow that place different requirements on both people and technology, especially when multiple formats are required simultaneously.
NDI For Broadcast: Part 3 – Bridging The Gap
This third and for now, final part of our mini-series exploring NDI and its place in broadcast infrastructure moves on to a trio of tools released with NDI 5.0 which are all aimed at facilitating remote and collaborative workflows; NDI Audio,…
Designing An LED Wall Display For Virtual Production - Part 2
We conclude our discussion of how the LED wall is far more than just a backdrop for the actors on a virtual production stage - it must be calibrated to work in harmony with camera, tracking and lighting systems in…
Microphones: Part 2 - Design Principles
Successful microphones have been built working on a number of different principles. Those ideas will be looked at here.