Intel’s 8K Live Olympic Masterclass Highlights the Immersion of 8K Sports
As we recently reported, Intel has been working on 8K at the Olympics for quite some time and this year the company moved its technology on to a new level by streaming 8K at 60fps live to multiple sites around the world and to ‘thousands’ of screens through its work with Globo in Brazil. The 8K Association was among those lucky enough to see the demonstrations live from Paris shown in Hollywood (supported by the 8K Association) and in the UK.
The key point about the demonstration this time was the live nature of the content. Images were captured in 8K by NHK and Olympic Broadcast Services (OBS) in 10 bit 4:2:2 quality and output over four 12G SDI ports to Intel’s servers at 48Gbps. Intel then used its Xeon-based servers (15 of them in total to deal with all the different feeds) to encode two separate streams of video. The encoding for a single stream can be performed with a single server. On-screen graphics were added to the stream by OBS before the encoding.
The first stream was encoded in H.266 VVC format with 4:2:0 subsampling and 10 bit ST.2084 (PQ) HDR in the Rec.2020 colour space. Audio was encoded in the MPEG-H format. The encoder used was the Spin Digital software codec which exploits the Intel AMX extensions in the CPU and Intel’s DL Boost technology. In the Intel presentation, Ravi Velhal who has been leading the project explained that the AI facilities in Intel’s Xeon processors were being used to compress on a ‘Content Aware’ basis – varying the level of compression according to the scenes presented.
Bitrates
The ‘headline’ compression rate was 40-60 Mbps and in the content that we watched, much of the time the level was closer to 20Mbps, although the complexity of significant camera motio combined with a high level of detail, such as crowd scenes, pushed this higher. Velhal said that a maximum 40Mbps is really the longer term target. Despite the very heavy level of compression, the quality in the demonstrations was excellent with no obvious encoding issues (at least to this viewer!). We were watching the hammer throwing live and the sense of the speed and motion of the athletes was really impressive. In his comments, Velhal mentioned that encoding water and ensuring that it really looked like water was one of the most difficult challenges.
As an aside on frame rates, it seems that the initial viewing in the Hollywood demo seemed to be suffering from some judder – which you would not expect at 60fps, but it seems that the TV was set to refresh at 24fps for movie content. Once this was adjusted, the motion was smooth. (This highlights the need for companies to work together to ensure that viewers see the content in its optimum format). Viewers were impressed with the level of detail and immersion that is given by 8K sports.
The compression was performed in between 200 and 400ms, so very suitable for live transmission although the full stream technology took ‘a few seconds’. At the decoding end, an Intel PC with a Core i9 processor was used for decoding, using the Spin Player software decoding. As Velhal explained in response to a question, at the moment the relative lack of VVC content means that there are not so many dedicated hardware processors for the standard, but this will change over time. The content was protected as it went to the display using HDCP 2.2 content protection from an HDMI 2.1 interface on an Intel Arc graphics processor. However, the GPU was not much involved in the decoding which was being performed on the CPU.
Intel highlighted that the content could also be decoded with a Core Ultra Notebook if desired.
The content was being streamed from Paris to five locations in the US, Brazil, the UK, Germany, India and Malaysia. The transmisson was streamed over the public internet. While the rest were just single viewing locations, Globo in Brazil passed on the stream to users of 8K TVs that include the Globo player firmware.
A second version of the content was simultaneously being encoded at 300Mbps using the H.265/HEVC codec as a contribution quality resource. This stream was saved to disk in Paris and was also streamed to Globo in Brazil for contribution use. When being distributed, it was transcoded to VVC. When we arrived at the UK demonstration, this stored content was being shown after transcoding to the VVC format and we were able to enjoy watching re-runs of the closely fought 100M sprint race. You needed every pixel to see who had won!
More, Faster, Better Pixels!
Anybody that has heard Velhal speak on 8K knows his mantra of ‘More, faster, better pixels’ and that was what was on view in the demonstrations which were impressive. He also emphasized that immersive audio is important to the experience and using MPEG-H (with up to 32 channels) allows the receiving system to optimize the presentation in stereo (as it was in the UK) or in immersive 5.1 or 7.1 formats.
Although this event was a technology demonstration, Intel confirmed that the hardware and software is ready for market and the company is willing to work with broadcasters that want to have access to this next level of TV quality and immersion.
Also at Intel…
While we were at the Intel facilities, there were demonstrations of some other technologies being developed. One that caught our attention was an FPGA that had been designed to support 8K image warping. This could be used in a projection system, for example, to correct for optical distortion. Another application might be to correct for a fisheye lens used in a camera system. As well as correcting the geometry, the FPGA was performing tone mapping.
