The Chair of RTVE in ETSIT-UPM took part together with other organizations in the complete live broadcast of the opera Parsifal in 4K last Thursday April 21st. This initiative was led by the Teatro Real, RTVE and Hispasat.

The 4K resolution means to have images with 3840x2160 pixels. This is from four to nine times the resolution of High Definition Television (in formats of 1080 or 720 lines). Because of this, a great level of detail is possible as people who attend the broadcast last Thursday could realise. For this reason, the Ultra High Definition TV (UHDTV) is contemplated as an ideal technology for the transmission of great cultural events such as opera. Besides the increase in resolution, the UHDTV adds other characteristics such as immersive audio, higher dynamic range, higher frame rate and wider color gamut. But these characteristics are not completely integrated yet.

Although there are very few precedents, the live broadcast was possible thanks to the collaboration of several companies and organizations. Besides the Chair and the three entities that led the initiative, other involved companies are Kinepolis, Hurí, Ovide, EVS, Dolby, Ericsson, Samsung, Abacanto Soluciones, Sapec, Hewlett Packard Enterprise, Ateme, Albalá, Grass Valley and Crosspoint.

The 4K signal with a frame rate of 50 images per second was live produced by RTVE in the Teatro Real and was broadcasted via Hispasat after encoding in real time with the new standard HEVC at 30 Mbps. The audio was encoded in Dolby Digital+. Four reception points were contemplated for this event: Kinepolis cinemas, Prado del Rey auditorium, ETSIT UPM and the Tower of Collserola in Barcelona. The Chair broadcasted on the fly the received signal with the new standard of digital terrestrial television (DVB-T2), covering a large area around Ciudad Universitaria in Madrid. The transmission frequency was 658 MHz (UHF channel 44), thanks to the temporary television broadcast license granted by the Spanish Secretary of State for Telecommunications. Cellnex Telecom did the same from the Collserola broadcasting center, assuring the coverage in Barcelona metropolitan area.

The parameters of the COFDM modulation in both DVB-T2 transmissions were: mode 32K extended, guard interval 1/128 and pilot pattern PP7. A single PLP was set (modulation 64-QAM and FEC 3/4). With this configuration, the useful maximum bit rate was 32.6 Mbps.

The amount of information in the 4K signal requires the use of the most efficient standards for the source coding(HEVC) and for the transmission (DVB-S2 in the satellite link and DVB-T2 in the DTT broadcast). Besides the known reception points, any person in the Hispasat coverage area in Europe could receive the signal from the satellite by means of an appropriate television set.

The broadcast coincided with the musical evaluation course that the professor José Ramón Tapia teaches in the ETSIT UPM. The Visual Telecommunication Application Group (G@TV) installed a 4K screen in the main lecture hall and the attendees could enjoy the transmission for the last minutes of the first act.

For José Manuel Menéndez, director of the Chair of RTVE in the ETSIT-UPM and of G@TV, "the successful experience last Thursday put in value the role that the university carries out in the knowledge generation and in the technology transfer, acting like catalyst and coordinator among the main companies in the sector".