The State of 8K in 2023
Jason Durstal of Murideo, a specialist in technology to support A/V installers, interviewed Florian Friedrich, a specialist in content grading and display measurement and technology about the state of ‘8K in 2023’. The interview was published on YouTube.
Friedrich highlighted that he has already been working in 8K for some years, having started with an 8K x 2K camera seven or eight years ago, before moving to full 8K resolution with Red and other cameras. Durstal highlighted that many cinemaphotographers are now capturing in 8K, although content may have to be processed to 4K for production and distribution. Friedrich has seen this too, with 8K content often delivered eventually in 4K or even FullHD. However, his focus has been working with content that is mastered in larger color spaces such as DCI P3 and the content is often better than consumers can access.
Chroma Sub-sampling is an Issue
Even if you watch content from an UltraHD Blu-ray (the best mainstream source of good quality content), the colour content will have been significantly downgraded by chroma sub-sampling and will be delivered in a 4:2:0 format. (this is not the place for a detailed discussion of color sub-sampling, but the technique delivers colour information at a much lower resolution than the full resolution of the image. See https://en.wikipedia.org/wiki/Chroma_subsampling for a discussion of this topic)
Friedrich believes that the color data with 4:2:0 is always very compromised and believes strongly that to deliver great content quality you need ‘headroom’ – that is to say more color, dynamic range and resolution than you will end up with to allow for creative changes. He pointed out that very often in Hollywood content, the original capture might have details, such as microphones that need cropping from the edge of the image. Here, capture with 8K allows the crop still to have high quality at lower delivery resolution.
If you use sharpness enhancement at the original and delivered resolution, you also distort the image, whereas if that process happens at higher resolution, the process can run without losing detail.
Friedrich believes that ‘doing 8K well is still difficult’. He said the key advantage of the extra resolution is to eliminate the visibility of the pixels and that is what 8K is about for him. Dustal also pointed out that while up-scaling to 8K was also important, when he saw ‘true 8K HDR’ content from a hard disk at a Value Electronics shoot-out a couple of years ago, he ‘almost had his nose on the screen’, but couldn’t see the pixels. A shot from a helicopter from above really showed amazing detail.
Physical Media v Streaming
Friedrich said in response to a question, that physical disks will not appear at 8K. At the moment, the best 4K content comes on physical media when it has been well encoded. UltraHD Blu-ray can provide 70Mbps – 80Mbps and that makes a real difference compared to the 15Mbps of streams and he would love to see streams with that kind of bandwidth. However, at the moment it is not happening. He would like to see some kind of storage in sets that would allow slower download of 8K, but allow playback with ‘decent bandwidth’, even if the capacity of that storage is limited.
Durstal said that really good new masters can be made on Blu-ray, with the UltraHD Blu-ray of Jaws, as an example, being of really great quality because of the attention paid in the process. Friedrich said that there has been a lot of discussion over many years about what the real resolution of film is. That’s because film is chemistry-based and the particles (or film grain) that make up an image do not follow a grid pattern. On the other hand the kind of digital display devices that we use today are based on grid structures. That needs attention when you are transferring to a digital medium by anti-aliasing or other techniques. Some of the particles in film grain may even be smaller than an 8K pixel, depending on the film stock and chemistry.
Friedrich said that really good new masters can be made on Blu-ray, with the UltraHD Blu-ray of Jaws, as an example, being of really great quality because of the attention paid in the process. Friedrich said that there has been a lot of discussion about what the real resolution of film is. That’s because film is chemistry-based and the particles (or film grain) that make up an image do not follow a grid pattern. That needs attention when you are transferring to a digital medium by anti-aliasing or other techniques. Some of the particles in film grain may even be smaller than an 8K pixel.
Upscaling is really improving using AI and although it can introduce information that didn’t exist in the original, Friedrich said that he “wouldn’t worry about that”.
Later in the conversation, there was a lot of discussion about the differences between processing existing lower resolution content into new formats such as 8K. Although TVs can make a decision ‘on the fly’, it’s not always the best decision. It’s much better if the decision is made earlier in the content creation process and by a skilled operator.
Field of View in 8K
THX, SMPTE and other organizations suggest a 30 deg to 45 deg cone and as you move closer to a bigger screen, you need more resolution to avoid visible pixels, Durstal said. The level of processing in sets varies from OK to really great and it’s really worth paying to have better processing – a point that Friedrich agreed with.
High Dynamic Range (HDR)
Friedrich pointed out that 8K in SDR is not the same as 8K in HDR, it’s genuinely a different experience. If you don’t have very good vision, and you sit a long way from a TV, you may not need an 8K set, but the 8K sets tend to have the best processing and other features. (this is a point that the 8K Association highlights – 8K sets tend to be the premium sets in the maker’s range, with the best processors and audio as well as image quality – editor).
Apple’s latest MacBook Pro and Mac Mini can support 8K output, Friedrich pointed out and connecting to a big display can really transform images such as your own digital camera shots. This highlights that watching TV is not the only application for good 8K displays.
Dustal said that the latest great smartphones and cameras capture in very high resolution and these images can be cropped and yet still deliver high resolution.
“We have all the pixels in the world to work with – to do whatever we want”.
Friedrich pointed out that 4K resolution is just 8 megapixels and ‘nobody would buy a digital camera at such low resolution’. 8K TVs have been in the market for several years and are great for looking at detailed content such as digital photographs.
Friedrich believes that 8K is best for relatively static content such as landscapes rather than for sports with a lot of motion. When creating 8K content, you need to be able to preview it (assuming you are mastering on a 4K monitor). Resolve allows you to connect an 8K TV as a review display during the editing process to meet this requirement.
Dustal sees great opportunities and advantages in 8K for gaming, partly in allowing more detail to be seen. HDMI 2.1 also helps with some of the frame rate issues. 8K TVs with HDMI2.1 can often upscale 4K to 120Hz and that can be very impressive. Both spatial and temporal resolution are important, Durstal said. He quoted that “24fps is 100 years old”.
8K gaming is getting better and better, Friedrich said, and the rendering for games is also continually improving. 8K displays can also use a wide (32:9 or 32:10) image and either leave the rest of the display blank or have additional windows. Friedrich likes the idea of being able to send 8K by fiber (which Dustal’s company supplies) over surprisingly long cables.
“I’m a fan of better infrastructure”, he said. “Imagine being able to view 8K images from my PC on my living room 8K TV”.
There was a discussion about frame rate and 3D and Friedrich said that different content needs different treatment and that what is critical is the creative intent. It’s important to have the infrastructure that can support the creator’s decisions about how to show content with, for example, the best possible resolution (for landscapes) or highest frame rate (for sports).
Friedrich highlighted that 8K TVs are top of the line, but are now being delivered in the EU in a poor mode for viewing. It is critical that buyers set up the TV correctly for the environment. Friedrich said that his mastering monitor uses a lot of power, but he has solved this with solar panels and a battery so that his post-production is now ‘off-grid’.
Friedrich then gave an introduction to up and down scaling (you can see our articles on this here and here) and there was also a discussion about the best ways to process old content when restoring it. In both discussions, there was agreement that to do it best, it takes time and money, but AI is helping with this process.