Tencent Media Lab contributes to multiple standards at the 79th AVS Working Group meeting

The 79th meeting of the AVS (Audio Video coding Standard) Working Group was successfully held online via Tencent Meeting from December 6 to 10, 2021. The meeting advanced standardization work in video compression, point cloud compression, systems, quality assessment, and other areas.

Video compression

The AVS3 video coding standard began soliciting proposals in early 2018, and its baseline profile was completed in 2019. The enhanced profile was completed in the first half of 2021. Tencent Media Lab participated in standardization of the enhanced profile. Preliminary figures show that Tencent contributed more than 100 technical proposals, excluding nontechnical submissions such as bug fixes and cross-checks, with nearly half adopted by the standards organization.

Tencent ranked first among all participating organizations in both submitted and adopted proposals.

For the AVS3 enhanced profile, Tencent's multimedia standards team proposed screen content coding technologies including intra block copy (IBC), intra string copy (ISC), implicitly derived transform skip (TS), enhanced deblocking filter control, and enhanced FIMC (frequency-based most probable mode coding). These tools save more than 60% in additional bitrate over AVS3's general coding tools, substantially improving compression for screen content.

Tencent also had several technologies adopted in AVS3's general coding framework, including multiple-combination intra prediction filtering and implicitly derived inter multiple transforms, helping advance the enhanced profile.

AVS3 is benchmarked against the international VVC standard. Its key advantages include relatively accessible patent licensing and mature real-time 8K codecs and chips, making it particularly well suited to 5G+8K video. The AVS3 enhanced profile, a revision of AVS3, was recently published as an association standard, and work will continue toward national standard status.

The AVS3 deployment ecosystem, including hardware chips and live broadcasting systems, is now in place. It was successfully used for the 2021 Spring Festival Gala, the world's first live 8K ultra-high-definition television broadcast. AVS3 will also be used for the upcoming Beijing Winter Olympics 8K broadcasting project.

Point cloud compression

At this meeting, Tencent contributed five technical proposals to the AVS Point Cloud Coding Working Group; three were adopted and one was conditionally adopted.

The AVS Point Cloud Coding Working Group began soliciting input on a draft call for evidence in July 2019, receiving support from both academia and industry.

Led primarily by Peng Cheng Laboratory, Tencent, and DJI, the AVS point cloud coding effort has attracted active participation from leading universities and research institutes, including Peking University, Shanghai Jiao Tong University, Zhejiang University, and Xidian University, as well as companies such as OPPO and Xiaomi. A formal call for proposals was issued in August 2020. Experts from Tencent Media Lab serve in key roles including subgroup co-chair, standard drafter, and reference software lead.

After discussions at six meetings, the AVS point cloud coding standard has progressed toward its goal of low-complexity, high-performance coding. Tencent Media Lab submitted more than 50 technical proposals, nearly 30 of which were adopted, contributing performance improvements across all test conditions for both point cloud geometry and attributes. The Artificial Intelligence Industry Technology Innovation Strategic Alliance (AITISA) recently announced approval of the project "Information Technology — Efficient Graphics Data Coding, Part 2: Point Cloud," covering AVS point cloud coding technology.

Immersive media systems

The AVS Systems Working Group focuses on standardizing file encapsulation and delivery for immersive media, including VR360 video, free-viewpoint video, and point cloud media.

After more than two years of discussion, the standard jointly developed by Tencent, ZTE, Shanghai Jiao Tong University, Beijing University of Technology, Migu Culture Technology, ByteDance, Peng Cheng Laboratory, and others has reached the Final Committee Draft (FCD) stage. Covering VR360 video and point clouds compressed with conventional video coding, it is being prepared for national standard project approval to meet industry needs for three- and six-degrees-of-freedom immersive media. Tencent contributed more than 40 proposals during this period, with 30 adopted by the working group.

Following approval of the "Information Technology — Efficient Graphics Data Coding, Part 2: Point Cloud" standards project, the related "Part 1: Systems" standard, jointly initiated by Tencent, ZTE, and Shanghai Jiao Tong University, also entered the drafting stage.

Beyond immersive media systems, the group has worked on standardizing file formats for AVS3 video bitstreams to further promote adoption of AVS3 by Europe's DVB standards organization. Over the past year, ten Tencent technical proposals were adopted, making the company a major contributor to the file format standard.

At this meeting, Tencent submitted eight technical proposals, seven of which were adopted in standards related to immersive media and AVS3 video file formats.

Multimedia quality assessment

The complexity of point cloud rendering and the variety of application scenarios make accurate quality assessment challenging. The industry currently lacks standardized subjective and objective point cloud quality assessment methods. To address this need, the AVS Quality Assessment Group established a point cloud quality assessment subgroup at an earlier meeting and began research for standardization.

Over several rounds of meetings, the group discussed the state of research, test data, testing methods, and other aspects in detail. At this meeting, based on earlier discussions and submitted proposals, it resolved to issue a Working Draft (WD) of a subjective point cloud quality assessment standard after the meeting.

The draft is led by Dr. Xiaozhong Xu of Tencent Media Lab, co-chair of the AVS Quality Assessment Group, with contributions from Peng Cheng Laboratory, the Shenzhen Institutes of Advanced Technology of the Chinese Academy of Sciences, Shanghai Jiao Tong University, Wuhan University, and other organizations.

For different point cloud applications, the draft specifies subjective quality assessment methods based on rendered 2D video and on 6DoF VR/AR. It provides standardized testing procedures and data processing recommendations for companies and research institutions, offering methods and data support to improve point cloud user experience and advance industry technology.

This will be the first draft subjective quality assessment standard issued since the AVS Quality Assessment Group restarted in 2019, and China's first recommended approach to subjective point cloud quality assessment.

Conclusion

Corporate participation in standards development has four major benefits:

First, it helps companies enter international markets, where they need to understand and comply with relevant international standards and requirements.

Second, participation enables companies to influence standards. Specific parameters are often fiercely debated because they can determine which vendors' products qualify. Participating in international standardization gives companies a voice in shaping those standards.

Third, it strengthens brand recognition.

Fourth, alongside gaining an understanding of international rules, companies can contribute their own technology and intellectual property to standards, which often contain numerous patents in the information technology field. This can support patent cross-licensing when needed, mitigate patent risks, and save substantial costs. International standards can sometimes be expensive to use. China's AVS standard for digital audio and video coding provides a common technical foundation for the transmission, storage, and playback of digital information. Adopting AVS can avoid the high patent fees associated with international standards such as MPEG.