NTT Develops World's First Professional 4K H.265/HEVC Real Time Encoder LSI - Suitable for High quality 4:2:2 Video Contribution -

1.Background of Development

(1)Past Development

To achieve high quality video transmission and distribution services, NTT labs have developed as below,

• the world first single-chip MPEG-2^*4 HDTV CODEC LSI "VASA" in summer 2002
  The VASA technology has been adopted in the LSIs sustaining the terrestrial digital TV broadcasting service started in December 2003 and utilized in the essential devices of various sorts of broadcasting equipment such as MPEG-2 encoders and the digital TV relaying network.
• H.264/AVC^*5 (hereinafter called H.264) CODEC LSI "SARA" in spring 2007 for professional high-quality broadcasting and distribution use

The SARA technology has also been adopted in real time transcoders that transcode MPEG-2 to H.264 for IP simulcast services of terrestrial and BS digital TV broadcasting. Both technologies are widely utilized as key components for video transmission services.

(2)Development for high quality video transmission and distribution services

Recently, ultra-high definition 4K video services with high realistic sensation have attracted attention. Enormous amount of image pixels, which is eight times larger than the standard HDTV images, is a major problem for full-scale popularization and achievement of real time encoders is craved with higher compression capability for better bandwidth efficiency and compactness for mobile and cost-efficient devices. To meet these demands, NTT labs, with technical strength cultivated by the video codec development over the years, have been involved in the research and development of HEVC-related technologies for achievement of popularization of next generation video transmission services with ultra-high definition 4K images.

2.Key Point of Development

Development of 4K HEVC real time encoder LSI for professional use (fig. 1) :
In order to achieve high quality and high compression video services to meet professionals' demands, NTT labs have developed a new HEVC real time encoder LSI (development code name: NARA [Next-generation Encoder Architecture for Real time HEVC Applications]) with 4K/4:2:2/60p video encoding capability.

(1)Unique high compression video encoding technology, enabling high-definition video services

New hardware algorithms for intra-frame and inter-frame prediction have been developed, adaptable to HEVC-specific variable block sizes, wide search range and high prediction efficiency is achieved. Multiplexing functions are also included in the LSI, leading to simplified configuration of encoding systems. (fig. 2)

fig. 2

(2)One-chip processing of 4:2:2 format images, double density chrominance data compared to 4:2:0 format (fig. 3)

4:2:2 format images for professional use has double the chrominance data density compared to the standard 4:2:0 format for video distribution, having the advantage of avoiding color signal degradation after multiple times of encoding and decoding processes. It is therefore used when multiple times of transmission and editing is anticipated, for example, live event broadcasts. Existing technologies mainly focus on the 4:2:0 format encoding, however, NTT's technology achieves both HEVC's true compression performance and 4:2:2 image encoding in real time.

fig. 3