Standardization
In 2004, the ITU-T Video Coding Experts Group (VCEG) began significant study of technology advances that could enable creation of a new video compression standard (or substantial compression-oriented enhancements of the H.264/MPEG-4 AVC standard). In October 2004, various techniques for potential enhancement of the H.264/MPEG-4 AVC standard were surveyed. In January 2005, at the next meeting of VCEG, VCEG began designating certain topics as "Key Technical Areas" (KTA) for further investigation. A software codebase called the KTA codebase was established for evaluating such proposals. The KTA software was based on the Joint Model (JM) reference software that was developed by the MPEG & VCEG Joint Video Team for H.264/MPEG-4 AVC. Additional proposed technologies were integrated into the KTA software and tested in experiment evaluations over the next four years.
Two approaches for standardizing enhanced compression technology were considered: either creating a new standard or creating extensions of H.264/MPEG-4 AVC. The project had tentative names H.265 and H.NGVC (Next-generation Video Coding), and was a major part of the work of VCEG until its evolution into the HEVC joint project with MPEG in 2010.
The preliminary requirements for NGVC was the capability to have a bit rate reduction of 50% at the same subjective image quality compared to the H.264/MPEG-4 AVC High profile and computational complexity ranging from 1/2 to 3 times that of the High profile. NGVC would be able to provide 25% bit rate reduction along with 50% reduction in complexity at the same perceived video quality as the High profile, or to provide greater bit rate reduction with somewhat higher complexity.
The ISO/IEC Moving Picture Experts Group (MPEG) started a similar project in 2007, tentatively named High-performance Video Coding. An agreement of getting a bit rate reduction of 50% had been decided as the goal of the project by July 2007. Early evaluations were performed with modifications of the KTA reference software encoder developed by VCEG. By July 2009, experimental results showed average bit reduction of around 20% compared with AVC High Profile; these results prompted MPEG to initiate its standardization effort in collaboration with VCEG.
A formal joint Call for Proposals (CfP) on video compression technology was issued in January 2010 by VCEG and MPEG, and proposals were evaluated at the first meeting of the MPEG & VCEG Joint Collaborative Team on Video Coding (JCT-VC), which took place in April 2010. A total of 27 full proposals were submitted. Evaluations showed that some proposals could reach the same visual quality as AVC at only half the bit rate in many of the test cases, at the cost of 2×-10× increase in computational complexity; and some proposals achieved good subjective quality and bit rate results with lower computational complexity than the reference AVC High profile encodings. At that meeting, the name High Efficiency Video Coding (HEVC) was adopted for the joint project. Starting at that meeting, the JCT-VC integrated features of some of the best proposals into a single software codebase and a "Test Model under Consideration", and performed further experiments to evaluate various proposed features. The first working draft specification of HEVC was produced at the third JCT-VC meeting in October 2010. Many changes in the coding tools and configuration of HEVC were made in later JCT-VC meetings.
The Committee Draft of HEVC, based on the sixth working draft specification, was approved in February 2012.
On May 25, 2012, the JCT-VC announced that an evaluation of HEVC proposals for Scalable Video Coding (SVC) would be held in October 2012. This will eventually lead to an amendment to HEVC that will add support for SVC.
On June 26, 2012, the MPEG LA announced that they would start the process of making a joint license for HEVC patents.
The Draft International Standard of HEVC, based on the eighth working draft specification, was approved in July 2012. Per Fröjdh, Chairman of the Swedish MPEG delegation, believes that commercial products that support HEVC could be released in 2013.
On January 25, 2013, the ITU announced that HEVC had received first stage approval (consent) in the ITU-T Alternative Approval Process (AAP). The JCT-VC will continue to work on extensions for HEVC such as support for 12-bit video and 4:2:2/4:4:4 chroma subsampling. On the same day MPEG announced that HEVC had been promoted to Final Draft International Standard (FDIS) status in the MPEG standardization process.
On April 13, 2013, HEVC/H.265 was approved as an ITU-T standard. The standard was pre-published on the ITU-T website on April 18, 2013.
On June 7, 2013, the HEVC/H.265 standard was formally published on the ITU-T website as a free download.
Read more about this topic: High Efficiency Video Coding, History