UHD Spain working groups share their latest advances at the 4K HDR Summit

Within the framework of the 4K HDR Summit, the different working groups of the association UHD Spain have shared the latest experiences they have carried out with Ultra High Definition signals in terms of production, post-production, encoding, broadcast, reception and audio.

Yeray Alfageme, at the head of the group of signal capture and production, has presented the analysis that the member companies have carried out regarding the use of cinematographic media in the production of live events, studying the depth of field and the increase in the feeling of immersion in the action. During this year, the group has also carried out the production of its own material for use by the different groups and has analyzed the challenges of multi-delivery production (UHD-HDR+HD-HDR+HD-SDR with their respective conversions) so that the viewer enjoys the best quality according to their viewing device.

The group of post-production, coordinated by Xavier Bonet, has analyzed the implication of the use of different UHD materials in the workflow. This year the group has organized several talks and has produced a clip with next-generation audio (in UHD with immersive audio sound with three languages, FX and music) and has analyzed conversion strategies in real time using LUTS, while carrying out tests with conversions between frame rates.

For the group, the IMF (Interoperable Master Format) is emerging as a highly flexible proposal although it is not a production format but is designed for finished products. Supports multiple resolutions, all color spaces and all audio formats.

As challenges for the new year, the group proposes studying Artificial Intelligence solutions for upmapping SDR-HDR conversion and SD-HD-4K upscaling. They will also analyze the real loss in technical LUTS and make comparisons regarding color management following the UHD Forum Guidelines.

Elena Burdiel, coordinator of the group of encoding, transport and headers, has outlined some of the technical tests that have been carried out in terms of multigeneration.

In these tests, the coding in the chain has been analyzed both in contribution and in emission, stopping at the stages of chained signal coding and decoding as well as in the comparison of the bit rate against the quality measures.

Xavier Redón, who is in charge of coordinating the group of emission at UHD Spain, has reviewed some of the milestones achieved throughout 2022. The companies participating in this group have developed a series of tests with experimental broadcasting of UHD content over DTT from a terrestrial network of 53 centers that cover 60% of the population.

Redón has stressed that for the development of UHD over DTT it is necessary to guarantee access to the spectrum beyond 2030. UHD Spain supports the position of “No change” before the World Radiocommunications Conference that will take place next year.

Sonia Valladares, coordinator of the group of receivers At UHD Spain, it has stopped to analyze the work developed this year such as the analysis of the Filmmaker Mode UHD Alliance, sound processing in consumer AV products.

Elena Burdiel together with Sonia Valladares, they are in charge of coordinating a new transversal group created this year with the aim of giving more importance to audio and explore Next Generation Audio. The group has organized several meetings in which they have delved into current proposals for spatial sound distribution, the use of objects, interactive audio and the foundations and standards of Audio NGA.

Technical tests

Finally, Miguel Ángel Cristobal, general director of Sapec, has detailed the conclusions of some of the technical tests that the different working groups are carrying out.

Cristóbal has highlighted that for a year and a half a UHD signal playout has been continuously maintained on 2 channels, carrying out two main tests this year: on the one hand, the analysis of the coding in the video chain; and format exchange tests on television receivers.
After these first tests, the conclusion is that MPEG algorithms are “lossy coding” although they are not appreciated by the human eye. In the “change of the video” from the source to the end user, there are usually several “encoding-decoding” steps with the consequent multigeneration.

For these tests carried out by UHD Spain live, a model was created based on 3 stages: two for contribution (HEVC with 4:2:2 and 4:2:0 profile) and one for distribution.

The test took different content from the different UHD Spain participants creating a single sequence. Subsequently, the spatial and temporal index of each sequence was calculated.
For comparisons, the Bjontengard-Delta (BD) method was used, which allows comparing two signals providing BD-Rate and BD-PSNR.