Video compression, which reduces the bandwidth required to transport a digital video signal, was one of the key technologies that enabled the development of digital television (DTV). The state-of-the-art for video coding technology in the early 1990s was MPEG-2, and this became a fundamental part of the Advanced Television Systems Committee (ATSC) standard, as well as DTV standards in other parts of the world. Due to "Moore's Law," the processing speed and memory capacity of hardware devices for video encoding and decoding has advanced greatly since MPEG-2 was developed. This has enabled increasingly sophisticated compression algorithms to be developed that take advantage of the increased hardware power now available at ever-lower price points.
These new video encoding/decoding (codec) systems provide significant improvements in coding efficiency compared to MPEG- 2 and can result in equivalent or better quality at lower bit rates. However, none of the new advanced codecs are backward compatible with MPEG-2, which creates a challenge for their introduction into existing broadcast systems.
One of the new codecs that is receiving wide acceptance in deployment of new video services is Advanced Video Coding (AVC).
- In September, the ATSC published a standard to enable the use of AVC for ATSC DTV. One of the reasons for adding AVC to ATSC is that several countries that still have to decide on the DTV transmission standard to be adopted have asked for advanced codec capability, and this is needed for ATSC to be competitive with alternative systems under consideration. In the U.S., AVC is unlikely to be used in the near future for regular DTV broadcasting because the large installed base of MPEG-2 integrated receivers and set-top boxes in this country would be unable to decode such programming.
According to an ATSC press release, standards for new mobile/handheld (M/H) and non-realtime (NRT) services are now being developed in ATSC that, by their nature, would require new receiver devices. These are obvious candidates to take advantage of the improved efficiency of AVC. In fact, a high-efficiency advanced codec is virtually essential for the M/H standard in order to preserve adequate DTV channel bandwidth for existing MPEG-2 services.
In their press release on AVC, for the first time in public, the ATSC refers to "ATSC 2.0." This concept for next generation services for fixed receivers is part of the ATSC long-term strategic plan for the future of DTV. ATSC 2.0 is currently in the development stage in the ATSC Planning Committee, chaired by NAB Science & Technology staff member Graham Jones, and is a separate effort from the mobile/handheld standard now in preparation.
