Kawasaki, Japan, April 03, 2012
Fujitsu Laboratories today announced that it has developed the world's first technology to minimize video quality degradation during video relays. Following due-process consideration, the new technology has been adopted as a "Recommended Practice" of the Society of Motion Picture & Television Engineers (SMPTE)(1), an international professional association establishing standards in the motion imaging industries. Going forward, the adoption of video transmission systems that adhere to this Recommended Practice will make possible even higher quality video content.
Conventionally, to broadcast news reports, sports and other events, weather forecasts, and other on-site relays, video is transmitted across multiple relay points. Every time video signal passes through the video encoders installed at each of the relay points, slight degradation occurs in the color component of the image. The accumulation of this degradation has been known to lead to visible color blurring.
The new technology, which is compatible with existing equipment, minimizes the occurrence of color blurring. A paper describing the technology was awarded the SMPTE Motion Imaging Journal Certificate of Merit in 2010. Subsequently the technology was examined by SMPTE due process committees and has been published as SMPTE Recommended Practice RP 2050-1:2012.
Background
For thirty years, Fujitsu Laboratories has pursued research and development in the area of video encoding technology. The results of these R&D efforts have been adopted in international video encoding standards, including MPEG-2, MPEG-4, H.264/AVC, thereby helping to enhance performance and quality. Moreover, Fujitsu has also developed industry-leading high-definition video encoding commercialization technology that has been used to enhance the quality of a wide range of video-related products, such as peripheral devices, video encoders, and software. In particular, the IP Series of high performance media encoders, which Fujitsu has brought to market, has been recognized for its high image quality and is currently employed by broadcast networks across the world for transmitting a variety of video elements.
Adoption as a Recommended Practice by SMPTE
Established in 1916 and boasting a history of nearly one hundred years, SMPTE is recognized as the most authoritative body for developing global technology standards for motion imaging industries. A paper describing Fujitsu Laboratory's technology for minimizing video quality degradation during multiple stage video relays —a worlds' first— was awarded the SMPTE Motion Imaging Journal Certificate of Merit in 2010. Subsequently the technology was examined by SMPTE due process committees and has been published as SMPTE Recommended Practice RP 2050-1:2012.
Figure 1: Image transmitted during multi-stage relay using existing technology and Fujitsu's new technology
Technological Issues with Existing Technologies
During video relays of footage such as news reports, sporting events and other kinds of events, and weather forecasts, communications satellites and networks such as land-based wireless networks and the Internet are generally employed. Because of the high frequency in which such video relays are repeatedly reused for different programs and media, there has a need for high-quality video to be transmitted at a relatively low rate of around 10 MB/sec. On-site video transmission usually involves setting up around five different relay points, and when video is repeatedly transmitted between these relay points, the eventual occurrence of visible color degradation has become a considerable challenge (Figure 2).
Figure 2: Problem of color blurring during multi-stage video relay
In general, images can be separated into brightness components and color components. It is also widely known that the human visual system has a lower ability to discern the resolution of color components compared to brightness components. Consequently, when transmitting video at a low rate, the video transmission process usually involves using H.264/AVC(2) and other video encoding technology to shrink by half the horizontal resolution of only the video's color components with a video encoder. Technology has been widely used to then expand the resolution of the color components to their original resolution using a video decoder, and then re-render the video together with the brightness components before playing. Between the video input and output stages, however, the color components of the video after transmission become slightly degraded due to the process of shrinking and expansion. After a single video transmission, the degradation of the color components is extremely minor and has relatively no effect on video quality. But after multiple stages of video relay to multiple relay points, the color component degradation accumulates, ultimately resulting in visible color degradation (Figure 3).
Figure 3: Existing video encoders
Newly Developed Technology
Fujitsu has developed the world's first technology for minimizing color blurring that makes it possible to minimize video color degradation during multi-stage video relay.
In order to lower any potential hurdles to adoption so that the industry can quickly enjoy the benefits of the newly developed technology, it includes the following two features:
1. Design focused on inter-compatibility with existing equipment
Designing the new technology with an emphasis on compatibility with existing equipment makes it possible for companies to gradually adopt the new technology. Degradation resulting from the halving and doubling of video color components falls roughly into two categories: 1. Color blurring resulting from the degradation of color details; and 2. Color displacement resulting from the misalignment of an image's brightness and color components. Color component shrinking and expansion used in existing video encoder devices are often plagued by color blurring. Although research has been done on the "perfect reconstruction condition" in which images can be shrinked and expanded without degradation, it has been impossible to commercialize such technology because of the unavoidable color displacement that occurs when connecting it to existing video encoders.
By mathematically formulating the necessary requirements and seeking an optimal solution, however, Fujitsu Laboratories has developed the world's first technology for shrinking and expanding color components that can simultaneously minimize color degradation and color displacement. Just by using a video device that employs the new technology, it is possible to minimize color blurring, even after repeated video relays, and color displacement does not occur when connected to existing equipment (Figure 4).
Figure 4: Comparison of existing technology and new technology
Figure 1 is an example depicting an image that has undergone one round, five rounds, and ten rounds of color component shrinking and expansion using both an existing technology and Fujitsu's newly developed technology. With existing technology, color blurring occurs on the character after five and ten rounds of processing. When using Fujitsu's new technology, however, even after ten rounds of shrinking and expansion, no degradation can be seen.
2. Video encoders can be retrofitted at a low cost
The new technology can be used to inexpensively retrofit the shrinking and expansion processing components of video encoders.
Results
By equipping video encoders with the new color degradation minimizing technology, which was adopted as a SMPTE Recommended Practice RP 2050-1:2012, it is possible to inexpensively build a high-definition video transmission system that minimizes color blurring, even after repeated video relays (Figure 5). Increased adoption of the technology going forward enables general viewers to enjoy even higher quality video.
Moreover, in instances where minor color component incongruity is acceptable, such as in relay monitoring applications for checking whether video is accurately being received, it is possible to operate mixed environments combining both existing equipment with video encoders retrofitted with the new color degradationminimizing technology. This enables companies to effectively leverage existing equipment when building a multi-stage video relay system.
Figure 5: Enhanced quality of received video via RP2050-compatible video encoder
Future Plans
The color degradation minimizing technology has been incorporated into Fujitsu's IP Series of media encoders (IP-900, IP-9500, IP-9610), which are already widely used by customers. With the adoption of the technology as an SMPTE Recommended Practice, Fujitsu will strive to further expand its usage.
Figure 6: IP-9610 media encoder