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It started with a simple observation: Fox plans to upscale a 1080p HDR feed to 4K for the Super Bowl LIX broadcast. The comment came from Dan Rayburn, who shared details about Fox’s planned encoding ladder, including a maximum bitrate of 15 Mbps for 4K delivery. This revelation prompted a lively LinkedIn discussion among industry experts, exploring the decision’s technical, practical, and perceptual implications.
Here’s a deeper dive into the workflow, the questions it raises, and the broader implications for live broadcasting.
Contents
Is Native 4K Necessary?
“SDI router cross points are the issue here. 3G is the best they can do for large-scale live productions. That means 1080p60 HDR.”
— Derek Prestegard, Video Engineer
Fox’s decision to upscale 1080p HDR rather than deliver native 4K content reflects current infrastructure constraints. As Derek Prestegard highlighted, large-scale productions often rely on 3G-SDI routers, which cap workflows at 1080p60. While this limitation is rooted in legacy infrastructure, Mark Kogan pointed out that IP-based workflows like SMPTE 2110 are gaining traction and could support native 4K in the future.
Still, upgrading the production chain comes with significant costs. Miguel Ángel Chacón Espín, Senior Solutions Architect at Amazon Web Services, noted that “upscaling 1080p might still be cheaper than upgrading the whole production chain to 4K,” framing the decision as a pragmatic balance between cost and capability.
“Last time I spoke to Chris at NBC about it, he said they’re trading off aperture (and depth of field) against noise performance (averaging 4 pixels in camera lowers the noise).”
— Simon Thompson, Senior R&D Engineer at the BBC
Simon Thompson’s observation adds another layer to the discussion. For live sports, where large depth of field and reduced noise are critical, compromises in camera settings can limit the benefits of native 4K production.
This raises a key question: if native 4K isn’t yet feasible, is upscaling the right alternative?
Does Upscaling to 4K Improve Quality?
“In other words: they’re doubling CDN costs to deliver the same quality as 1080p.”
— Alex Zambelli, Senior Platform Manager at Dolby Laboratories
One of the sharpest critiques came from Alex Zambelli, who questioned whether the additional expense of upscaling justified the results. From his perspective, delivering 4K adds significant cost with minimal perceptual benefit, especially if the scaling process doesn’t add meaningful detail to the picture.
Mark Kogan offered a counterpoint, suggesting that 1080p HDR upscaled with BT.2020 wide color gamut could offer a satisfactory experience for most viewers, particularly those with screens smaller than 75 inches. However, he acknowledged that native 4K has a noticeable impact on larger displays.
Subhrendu Sarkar, Engineering Leader at Warner Bros. Discovery, added that “streaming in 4K” carries significant PR value, regardless of the technical trade-offs. For Fox, the decision to label the broadcast as “4K HDR” could be as much about audience perception as technical excellence.
Adding to the complexity, Yoeri Geutskens observed that the HDR workflow itself introduces challenges:
- While production workflows often rely on BT.2020 with HLG, North American distribution primarily uses PQ (Perceptual Quantizer).
- Geutskens noted that HLG is “almost NEVER used as a distribution format in North America,” requiring conversions that could impact quality.
Mark Kogan agreed but pointed out that “fine-tuning” is often required to ensure transparency throughout the distribution chain.
Does the Bitrate Need to Be So High?
“HF is absent or fake. With HEVC, there are more effective ways to synthesize shaped HF noise than by encoding it as is.”
— Yuriy Reznik, VP Research at Brightcove
Yuriy Reznik argued that allocating a maximum bitrate of 15 Mbps for upscaled 4K may not be efficient. In his view, much of the high-frequency (HF) detail in upscaled content is synthetic and doesn’t warrant the same bitrate as native 4K. He suggested that modern codecs like HEVC offer tools to optimize such workflows, including noise filtering, adaptive quantization, and perceptual tuning.
Mark Kogan proposed an alternative: using the AV1 codec instead of HEVC. While AV1 delivers better compression efficiency, its higher computational demands make it challenging for real-time applications like live broadcasting.
Derek Smith from Disney added a lighter note:
“I guarantee this is so they can advertise, ‘In 4K!'”
This quip underscores the role marketing plays alongside technical considerations in decision-making.
The Bigger Picture
“As usual, it’s a balancing act between technical excellence and justified business objectives.”
— Andrew Krupiczka, Senior Software Engineer
Fox’s decision reflects a delicate balance between infrastructure limitations, cost considerations, and viewer expectations. While upscaling 1080p HDR to 4K may not deliver the same quality as native 4K, it allows Fox to meet PR demands and offer an enhanced viewing experience without overhauling its production chain.
As IP workflows like SMPTE 2110 and more efficient codecs like AV1 or VVC become mainstream, the future of live sports production may lean toward native 4K. For now, Fox’s approach underscores the compromises broadcasters make to navigate the intersection of technology, cost, and audience perception.
Your Turn
Do you think Fox made the right call by upscaling 1080p HDR to 4K for Super Bowl LIX? Should they have pushed for a native 4K production workflow, or is this a sensible compromise given the constraints? Share your thoughts in the comments!
