SAPEC’s coding-level experience has allowed becoming the real heart of the RTVE Chair project, carrying out all the video processing, compression and multiplexing. With a clear commitment to innovation and technology, the development of r+d of SAPEC team has returned to contribute their know-how and experience to this project and all the activities that are underway in the field of emission of DTT of last generation, together with RTVE, the Polytechnic University (ETSIT-UPM) and Cellnex (formerly Abertis Telecom). RTVE Chair in ETSIT-UPM has activities in the field of next-generation DVB-t signal emission, via DVB-T2, UHD ultra HD signal, compression HEVC and SAPEC has been responsible for the processing, compression and multiplexing of signals before its broadcast.
Coding and signal generation
SAPEC has prepared and coded the content provided by RTVE to be able to be transmitted by DVB-T2. The demo was carried out using technologies of last generation: UHD, HEVC and DVB-T2. Three multiplexed programs were communicated through a single DVB-T2 channel that came from a single UHD signal to 12Gbps 4Kp50:
- The first programme consisted of UHD signal that was encoded in the new encoding standard HEVC with audio in Dolby Digital 5.1 generating a bit rate of 25Mbps;
- The second program consisted of an HDTV signal HEVC also encoded with Dolby Digital 2.0 audio and a rate of 3, 5Mbps.
- The third programme, was also HDTV signal which in this case is encoded in H.264/AVC and MPEG1-Layer2 audio with a bit rate of 5, 7Mbps.
All of these programs, were then multiplexed to generate a MPTS including DVB tables that were sent to a DVB-T2 modulator with 1080i transfer rate (see figure) and the PSI information. HD content was generated scaling UHD to HDTV content, and therefore it was possible to see it in different resolutions and modes of compression, with an optimal result. The transmitter was located in the ETSI de Telecomunicación and the reception was held at the Institute IORTV, where there were several televisions receiving and decoding the signal. Equipment and technologies developed by Sapec were used to perform scaling, encoding and multiplexing. In these demonstrations we could alsoverify that HEVC is not only efficient for compressing UHD signals, but it is also efficient and can be used for HD signals (even of SD), getting important savings of the bandwidth needed to transmit, the signal or improving the quality of it keeping the bandwidth.
Real time encoder HEVC
SAPEC has a HEVC (ITU H.265) coding equipment for HD/SD in real time, a standard that adds and improves tools for a more efficient video compression. This standard aims to improve efficiency while maintaining the image quality reducing to half the bit-rate, at the time that optimizes the complexity improving the parallel processing. The HEVC is a new standard of coding with a significant reduction in bit rate on the current algorithms, and allows the dissemination of the UHD by today’s infrastructures. Unlike what is often thought of in some areas, the HEVC isn’t just for video broadcasting over the Internet since it can also be used for DTT, DTH and IPTV among others. HEVC can also be used for interlaced HD and SD signals getting important compression efficiencies making it the ideal algorithm. This standard could make a better use of existing infrastructures in SD and HD, achieving a higher quality of the image to the current bit-rates.
SAPEC reaffirms again its commitment to innovation and the revitalization of the Spanish audiovisual sector, using all of those standards that allow to offer, in the near future, efficiency and quality improvements in the distribution of audiovisual content that are clearly perceived by the citizenry. Collaboration, work, effort, dedication, innovation and commitment to SAPEC technology has become to show in the RTVE-UPM Chair, where industry experts analyzed the latest generation DTT activities. SAPEC has collaborated with RTVE and the school of engineering of telecommunication of the Polytechnic University of Madrid in experiences such as the first experimental broadcasts of 4 k DTT or, earlier, in the first broadcasts in high definition and Ultra high tests definition on DTT.