Australia’s NBL partnered with NEP and EVS to update its broadcast workflow, adding slow-motion clips generated by EVS’ AI-based XtraMotion to enhance replays for fans.
The Australian National Basketball League (NBL) has partnered with broadcast services provider NEP and EVS to update its broadcast workflow for the 2024/25 Hungry Jack’s NBL season, now underway. Since September when the season began in Perth, their productions have featured slow-motion clips generated by EVS’ AI-based XtraMotion service.
XtraMotion video processing can recreate a standard live video clip as a Super Slow-Motion video sequence to include with replay material. Slow-motion replays have become a regular, very popular feature of live sports broadcasts, but they have mainly relied on footage captured with high frame rate cameras or on frame duplication techniques used in post to adjust playback speeds.
Super Slow Motion without Slo-Mo Cameras
However, installing and operating high frame rate cameras at every desired camera position is complex and expensive, making it unrealistic for many producers, and traditional frame duplication often gives less-than-ideal results. Instead, the XtraMotion service uses algorithms to intelligently interpolate the additional frames between the captured frames of a video clip.
Interpolated frames, which are more like the in-betweens an animator would draw to take a character from one pose to the next in consecutive frames, allow operators to maintain clarity and fluidity in slow motion playback regardless of the original frame rate. Users initiate the process with a shortcut button. XtraMotion is able to interpolate frames within just five seconds, regardless of the clip's duration.
View From the Backboard
We had a chance to talk with Tony Skinner, Broadcast Production Director at NBL, and Paul Duncan, EVS Specialist for NEP Australia, about how XtraMotion is used during matches. “A typical NBL game deploys up to 11 cameras, four of which are manually operated. Tier-one game coverage, reserved for special games and finals, will use up to 14 cameras with six of these being manned,” said Tony.
“We have eight of the cameras connected to EVS and the XtraMotion system. These are usually NEP's specialty custom cameras. The specific camera type is not particularly important to the XtraMotion system – it has access to all venue feeds transmitted to the Andrews Hub in Melbourne, and supports content formats from HD to UHD HDR. What’s important for the live productions is that all of these cameras record varying views of the most dynamic action on the court.
“For instance, we have cameras positioned on the side of the court to follow tight shot action, including two cameras mounted on each backboard at the end of the court, both below the rim. One is shooting through the glass, and another from below the backboard, to show the action coming towards the viewer. Fans can watch as players approach for a layup or dunk, along with the tight, fast action ‘in the paint’. That’s the area on the basketball court – usually painted a different colour – located under each basket, where players can score points.”
XtraMotion at the Edge
NEP has set up XtraMotion as an on-premises edge system, integrating the EVS XtraMotion hardware into the existing IP-based EVS infrastructure at the Andrews Hub in Melbourne. In the control room, this integration gives the operators direct access to, and control of, clips existing on the EVS network, which can be sent to the XtraMotion hardware for processing.
Integration into the wider workflow is made possible through the configuration of VIA Xsquare in the backend, allowing multiple operators to send clips to XtraMotion simultaneously. Each job is processed and quickly returned to the correct operator. VIA Xsquare’s centralised database manages multiple sources – either EVS servers or files – to multiple destinations simultaneously, in this case EVS playback servers, and carries out live transcoding.
Tony said, “From the venue, signals are generated in 1080i/50 and recorded into the EVS system at 25 fps. Once ingested, we can adjust replay speeds using the regular EVS replay system, or by sending clips to XtraMotion for additional AI processing. When a clip is identified and sent to XtraMotion, it will be slowed to 33% of normal speed – from 25fps down to 75fps – which means two interpolated frames are inserted between each original frame.”
Clips are processed and returned for playout in just a few seconds – averaging around 2 to 3 seconds from the time of sending them to receiving them back for playout. “Meanwhile, NEP sets all in-venue camera shutter speeds to 1/125 sec exposure time,” said Paul. “This setting ensures that the signals are sharp and crisp, and keeps XtraMotion functioning at peak performance and delivering the clips at the appropriate speed and quality.”
Live and Archival Footage
Tony noted that, so far, NBL uses XtraMotion primarily on new, live footage. “We have done some preliminary testing on archive footage, running it through XtraMotion to gauge the quality of output, aware that this historic footage is often of a fairly low-quality or degraded,” he said. “Although the result doesn’t improve the quality of the video, it does allow for slo-motion replay of the content at a similar visual quality.”
Interpolated footage is ready for immediate use in NBL’s live broadcasts – no post-checking of any content from XtraMotion is required. The broadcasters’ promo producers and the NBL digital teams all appreciate having slo-motion footage of action plays available to add extra interest to their content creation, and they use it in different ways.
“For instance, the NBL digital team also utilises the WSC Sports platform to live clip content to send to various outlets and partners,” Tony said. “This service, also AI-driven, is focussed on personalisation and has tools that automate content analysis, creation and editing. The WSC software clips the XtraMotion content on the fly and uses it as part of the content distributed during live games.
“With the greater frames-per-second XtraMotion affords, our playback options are enhanced. XtraMotion has become a staple of the NBL broadcast product. In almost all instances of action, replays or highlights packages, we include some camera angles that have been processed through XtraMotion and slowed to accentuate the dynamic action.” www.nepgroup.com
