Domo delivers complete turnkey solution for World Endurance Championship

Domo Broadcast Systems has delivered a complete turnkey solution for the FIA World Endurance Championship (WEC) at this year’s 6 Hours of Imola, which took place last month.

As Max Zaja, principal design engineer at Domo, explains: “AMP Visual TV is contracted to broadcast the WEC and, after witnessing the success of our Formula E contract, got in touch two years ago asking us to develop a customised on-board transmitter to be launched on the 2023 WEC series.”

The customised device is the AOBTX2 in-car system, a H.265 encoder and COFDM transmitter. It was first used at the WEC’s Spa 2023 event and successfully completed the 100th Anniversary Le Mans racing series with 24 transmitters in the field. Twenty-four transmitters were also live during the Imola race, where the director had a total of 96 live cameras that could be switched between in order to deliver a full racing experience to viewers.

The AOBTX2 can take up to four video inputs, between which the operator can seamlessly switch. In normal operation, a single video will be transmitted back to the OB Media Centre. However, this unit can also transmit all four HD feeds in one UHD feed.

“This gives total flexibility in how the broadcaster wants to showcase the on-board cameras,” says Zaja. “The cameras are pointed in different directions around the car: mainly a forward view, driver view, rear view and/or mirror cameras. The key success of this product is that, as well as transmitting a single video and seamless switching, the transmitter records all four inputs and has the ability to playback the recording live — all controlled remotely. With previous systems, a broadcaster would have to wait for the race to be finished to collect recorded data. Now, if there is a great racing moment or incident, the operator can select playback mode and watch back the key moments on their live transmission.”

The AOBTX2 is a part of a larger system that has a fully customised user-interface to give the broadcaster full control and status information of all the transmitters running. The remote controls are sent via a secondary telemetry link back to the on-board transmitter, via remote commands such as Cyanview camera control or trigger recording playback.

In addition to the on-board units, Domo also delivered a complete turnkey solution for the WEC at Imola. In the MCR, a master hub runs the control and status user interface. The UI was designed as a one-screen solution; there are several screens to choose from, but each one gives the operator a quick picture of how the system is behaving. For example, the camera control screen enables each camera to be adjusted throughout the race, while the frequency and camera management screen enables the operator to seamlessly switch the live feed to one of the cameras, or play the unit into replay playback mode.

Around the track, several receive sites were connected through RF over fibre equipment back to the OB compound where the Domo RXD4 8-way MRC diversity receivers are located.

The transmitters transmit status information within the transport stream, which is then extrapolated by the RXD4s and sent via IP to the hub. The hub translates this status information for the operator to understand on the one-screen user interface. When the operator sends a command, the hub sends it to a telemetry transmitter that connects to the on-board units. When the on-boards receive the telemetry signal and correct ID number, they adjust the settings depending on what the operator has selected. This technique allows a full looped system to be used.

As would be expected with such a project, there were several challenges along the way. As Zaja explains: “As with any broadcast, tight timescales were critical in the development cycle and delivery period. Domo had to ensure that all the development was completed on time (within about three months from receipt of order) as there were several test events during the first season that needed a completed product. “It’s safe to say that all deadlines were met and several successful tests were completed before commissioning the system for the 100th Anniversary of Le Mans in 2023,” he says.

As with any RF system, Domo had to ensure the high-speed effects of Doppler did not affect the performance of this system. “In a traditional broadcast, when a Domo COFDM transmission is used the modulation is DVB-T,” continues Zaja. “However, due to the high carrier count and how that can negatively affect the RF receive point when there are dramatic and fast-changing signals, Domo needed to use its proprietary Ultra Mobile Video Link (UMVL) transmission system.  This modulation type has been used across several Domo transmitters, but it was not available on the WEC transmission system.

“During the manufacturing of the system, Domo software engineers tirelessly worked to port UMVL onto this platform and ensure it had the same successful performance as the other Domo products. During development Domo noted that UMVL’s performance demolished that of DVB-T. But even with perfect signal for the track, there can still be interferers, such as a gantry. This can block the RF signal for a nano second and cause an RF glitch. This is why, for the WEC 2024 season, the AOBTX2 will be using UMVL with deep-time interleaving. This was a massive software development undertaken in WEC off-season and is being deployed in future events.”

According to Pierre Chenot, RF tech manager at AMP Visual TV: “Another critical aspect to take into account is the high level of vibration inside race cars, especially in the ‘HyperCar (prototypes)’ category. After hours on the track (up to 35 hours per event, from free practice session to qualifying and end of race), any piece of equipment that is set inside a car needs to be vibration proof. A massive job has been done in collaboration between Domo and AMP Visual TV to ensure that the transmitter unit internal design, connectivity between unit and cameras, power supply, antennas … are all designed with the rule of Art.”

“Remote control from the RF-control room of any equipment set inside the car is essential during such events, more particularly the colour/painting parameters of all cameras,” says Anthony Martin, motorsport specialist at AMP Visual TV. “A race could start at daytime, then continue at night (where onboard live pictures are the main interest for the TV director), and then finish at daytime. So, camera shading is fundamental. Thanks to the experience acquired by AMP Visual TV in the world of motorsport, as well as the integration of the CyanView camera control solution embedded into Domo’s products, this aspect is fully under control.”

Zaja concludes: “The AMP Visual TV/DBS collaboration produced a far superior solution in comparison to the previous system, which only had the ability to transmit 16 on-board, using the old H264 video codec. When first deployed last year, the target was for 18 systems each race and 24 for Le Mans. This gave an even greater viewing experience for the viewers and fans. The WEC channel allowed each of the on-boards to be viewed. More cameras, more cars, more action.

“The 2024 series goes even further, with 26 cars in each race, 32 for the next 24h of Le Mans, doubling the number of on-board systems the legacy AMP Visual TV legacy technology was capable of handling. The system has the ability for even more cars to have on-board transmitters.

“Domo is always on the lookout for new challenges especially within the motorsport environment, and relishes the opportunity to collaborate with FIA suppliers, such as AMP Visual TV. The WEC still has a full season left to run, with Le Mans in June. This transmission system will be helping fans enjoy more action, more camera views and more racing fun for years to come.”


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