The UHD Spain has been the one who has edited this White book, where they collect all the experiences in the tests made by the channels that are currently broadcasting or that have broadcast in UHD in Spain, like those of the UHD Spain, or some regional ones like Canal Sur. Thus, we find technical aspects such as video recording, audio and video encoding, use of HDR, etc.
The White Paper collects all the 4K experiments
Thus, this White Paper is not a technical manual, but rather a practical Guide to publicize the results of the pilot tests so that other companies do not have to fall into the same errors or problems. In turn, it also serves as a source of information for the creation of future laws or harmonization of technical aspects.
In the book, for example, it is detailed that future channels will have to issue in multiples of Full HD, either in 4K UHD (4 times more resolution than 1080p), or 8K (16 times more resolution than 1080p), all of them maintaining the aspect ratio of 16: 9. In addition, interlaced resolution (such as 1080i) will be left aside, and progressive format (such as 1080p) will be used.
The refresh rate It will still be 50 Hz, but the door is opened to reach 100 and even 120 Hz using HFR, improving the viewing experience; especially in live content. The content will have to be encoded in 10 bits, although it can also reach 12 bits. Thanks to this, a true HDR is achieved, with a more detailed color gamut, better whites and better blacks.
AC4 audio or use of future codecs
Finally, in image quality, the recommended aperture is also detailed to avoid loss of definition at the edges. As for the audio, it also talks about how to deliver it, and the use of Next Generation Audio (NGA), opening the door to 3D multichannel audio formats.
As for the use of codecs, there are several. For audio, the most serious candidate is Dolby AC-4, adopted by manufacturers such as Samsung, LG, Philips, Panasonic or Sony, and that it was also used in Euro 2020 for the emissions in UHD. Obviously, all of this will be done by DVB-T2.
As for the video, they recommend solving a serious problem: the latency, where there is even 33 seconds apart with live content. For this reason, they propose the use of LL Dash and LL HLS, which divide the content into smaller segments, allowing a latency of between 2.6 and 5 seconds.
Regarding the use of codecs, currently the most realistic options are use HEVC for 4K. For the 8K, however, they recommend using AV1 or VVC, which compress much better. They also talk about the future AV2, which is estimated to be standardized by 2024, reducing the weight of files by 50% compared to what they currently occupy with the best codecs.
Finally, currently the 50% of the population is covered with antennas and equipment capable of broadcast in 4K, and 100% through the Internet. In addition, 12 autonomous regions of the country have signed their support for UHD Spain: Andalusia, Catalonia, Madrid, Valencia, Galicia, the Basque Country, the Canary Islands, Castilla-La Mancha, Murcia, Aragon, Asturias and the Balearic Islands.