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Development of a high-quality and low-bitrate SHVC encoding technique to enhance existing HDTV video up to 4K resolution

2014/11

Toshiba has developed a high-quality and low-bitrate video encoding technology which complies with the latest scalability extension (SHVC) to the HEVC standard to enhance existing HDTV video resolution up to 4K resolution(Note 1, 2, 3). Developed for the purpose of concurrently delivering high-quality 4K video with HDTV, this technology reduces the additional bandwidth overhead to as low as 10Mbps, which is one-third the overhead in conventional HEVC technology. This technology will be showcased at Inter BEE to be held at the Makuhari Messe starting November 19 (Wed), 2014.

Development background

Demand for 4K/8K ultra HD broadcasting and network distribution services is expected to increase as 4K TVs become more popular in the market(Note 4). Reports from the latest meeting regarding the future of 4K/8K technology held by the Ministry of Internal Affairs and Communications (MIC) identifies bandwidth assignment for 4K/8K broadcasting as an open issue since future 4K/8K services are expected to coexist with existing HDTV services in order to meet consumer requirements(Note 5). The report also states that 4K and 8K services will require as much as 30-40Mbps and 80-100Mbps, respectively, while the existing HDTV broadcasting bandwidth is only 15-20Mbps. Therefore, a technology which facilitates the concurrent transmission of video at varying resolutions within a limited bandwidth is desired.

A high-resolution SHVC encoding technique

In response to this demand, we developed an SHVC encoding technology which enhances existing HDTV to high-quality 4K video with limited bandwidth overhead. The SHVC encoding technology employs a prediction-mode decision algorithm which makes efficient decisions as to where and when different prediction methods are applied, enabling dynamic bit allocation during encoding. To reduce overall data volume, inter-layer prediction algorithms are used to extrapolate image regions with irregular movements or soft-focus backgrounds while more data bits are allocated to the encoding of relatively static, in-focus image regions and thereby improving overall subjective video quality. We achieve further bitrate compression with our novel spatiotemporal noise reduction technique. By pre-filtering spatiotemporal noise from 4K data, we succeed in limiting degradation in resolution of encoded 4K images even when the additional bitrate overhead is set to be as low as 10 Mbps.
The combination of encoding and noise reduction techniques permit the concurrent distribution of video data at varying resolutions such as HDTV and 4K/8K in limited bandwidth conditions.

Future prospects

Using this technique, we aim to develop video distribution services which offer consumers the choice of enhancing video resolution to 4K while maintaining compatibility with current HDTV video broadcasting standards, an ideal option ahead of the 2020 Tokyo Olympic and Paralympic Games.

(Note 1) 4K assuming a 60 fps video composed of 3840×2160 images

(Note 2) HEVC stands for High Efficiency Video Coding. The formal standard is ITU-T H.265 | ISO/IEC 23008-2.

(Note 3) SHVC stands for Scalable High efficiency Video Coding.

(Note 4) 8K indicates video composed of 7680×4320 images.

(Note 5) MIC "Interim Report of the Follow-up Meetings on 4K/8K Roadmap" http://www.soumu.go.jp/main_content/000312825.pdf (in Japanese)