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Setting the Standard for Video Coding

Radical advancements in video technologies over the past decade have us reaching for our cell phones to watch the latest viral YouTube video, or distracting ourselves from a grueling treadmill workout by watching a Hollywood blockbuster on our laptops or high-def televisions (HDTV). But with the constant consumer demand for an improved video experience, a new standard for coding—or compressing—data is needed to accommodate transmission of the massive amounts of data required to take the industry to the next level. "Free viewpoint video" (capturing an image of objects from all directions to give users a complete—360 degrees in any direction—view of objects and scenes and a realistic sense of depth) and ultra-high definition (UHD) television that will one day afford 16 times the spatial resolution of current HDTV require space- and time-saving coding techniques.

While High Efficiency Video Coding (HEVC) is the current standard established to meet demand up to UHD video, 3D-HEVC is being developed to set the standard for free viewpoint video. Recently, one video compression method developed by SCU in conjunction with global information and communications technology leader Huawei Technologies, Inc./Hisilicon, was adopted as a normative (or required) method for 3D video coding, in 3D-HEVC, targeted to be released in January 2015. In addition, another video compression method developed by the team was adopted as informative (or optional).

VideoCoding
Zhouye Gu (left) and Nam Ling
Photo: Charles Barry

When the International Standardization Organization (ISO) and International Telecommunication Union (ITU) put out a call for proposals last fall to improve the efficiency of encoding 3D video data, SCU was well positioned to accept the challenge in competition against industry titans such as Samsung, Qualcomm, BBC, Intel, Microsoft, MediaTek, NTT, and LG, as well as leading research giants like Germany's Fraunhofer Heinrich Hertz Institute (HHI). Since 2005, Nam Ling, chair and professor of computer engineering at SCU, has led a team of doctoral students and research assistants working with Huawei/Hisilicon to advance industry standards for video coding. Zhouye Gu, from Nanyang Technological University in Singapore, had recently been recruited by Ling to join SCU's team as a research scholar; his first assignment: work with the SCU-Huawei team to devise a proposed solution for this 3D competition. "Dr. Ling's group has a very good tradition of developing HEVC technology, and the lab is well equipped to run simulations with high-speed super computers," said Gu. "The eight parallel-computing work stations can each compress a 10-second video in a day and a half—a feat that would take an ordinary computer half a month to do."

Last January, Gu traveled to Geneva, Switzerland, to learn more about the expectations for the proposal. "That first meeting with worldwide leaders in video compression was kind of shocking," Gu recalled. "My previous experience was solely in an academic environment, but an industry focus is totally different. Industry cares about practicality, market viability, and giving the user a high-level experience. In industry, performance gain only is not enough, you need to work for what the market needs. I thought a proposal would have a strong chance of being adopted if it focused on simplification rather than performance gain."

Working with the team, Gu devised a simplified process in depth coding that produces a 30 percent encoding time savings without performance loss, providing the same visual quality while using the same bitrate as current methods. His solution supports multiple views for free viewpoint coding and can accommodate even greater gains in coding depth and texture data as the field advances. At a second international meeting held in Seoul, Korea, last April, Gu was one of nearly 300 attendees offering solutions, but SCU's proposal was not accepted at that time. Ling explained: "Santa Clara is known for its three Cs: competence, conscience, and compassion, but in this arena, I always say the three Cs are competence, communication, and connection. You have to connect with others in the field to gain support for your proposal in order for it to be accepted. So that was our next task."

At the third international meeting held last July in Vienna, Austria, Gu was able to gain the support of a world leading telecommunication research institution. "Our process improves upon techniques originated by them, and since they are a big player, their support holds a lot of weight," he said. In Vienna, it was announced that SCU-Huawei's proposal had been adopted as a normative method for 3D-HEVC. Between now and January 2015, SCU will continue to work with Huawei's researchers to further refine the coding process and to propose new methods for adoption.

"Getting this normative proposal adopted is significant from a university point of view, because most of our work in the past has been academically originated," said Ling. "It is important to develop methods to meet consumer needs. Also, improving accessibility of wireless video is crucial in overcoming infrastructure deficiencies in underdeveloped countries. The impact of the digital area is tremendous, and there is a lot more to be seen. As a university, it is important that SCU has a role in this. We are not just living in an ivory tower; we are changing the standards of video compression—we have our stamp on that."