August 13, 2012 - 5:04pm

The main stated goal of the HEVC development is “substantial” bitrate reduction relative to AVC High Profile. The general target of the group (although informal) is to provide about 50% compression improvements over AVC. A second goal is to serve a wide range of applications. To do this, HEVC defines support for resolutions from QVGA (320x240) to 8K (7680x4320). HEVC also targets two modes, a “low complexity” mode, which is meant to have a small decrease in complexity (especially for decoders) compared to AVC, and a “high efficiency” mode, which will contain more complex coding tools, achieve better compression, but come at higher processing costs. Finally, HEVC defines a “low delay” configuration capable of low latency operation. In general, HEVC decoders are expected to have 2-3 times the computational complexity of AVC decoders, and HEVC encoders are expected to have up to 10 times the computational complexity of AVC encoders.

The JCT-VC has published a software reference implementation of the proposed HEVC standard, called the “HEVC Test Model” or HM. The latest version is HM-7.0 (based on version 7.0 of the HEVC standard, which was proposed at the May 2012 meeting). This implementation is open-source and includes both a decoder and an encoder application. HHI hosts the subversion repository for the code and BBC hosts the issue tracker for the code. HHI also published a software reference manual and software development guidelines for the HM.
The main goal of the HM reference software is to provide a platform for testing various coding tools and technical proposals submitted to the JCT-VC. It is not necessarily an efficient implementation of any of the tools; it is merely a testbench for comparison. The JCT-VC also defines the list of common test conditions to be used for testing any new methods. This list is a matrix of 24 test streams, 8 base configurations for each stream, and 4 quantization parameter values for each of the 8 configurations.
 
The JCT-VC publishes a comparison of HEVC and H.264 coding efficiency with each release of HM. Currently, HEVC is showing an average improvement over H.264 of about 32-41% for random access streams (i.e. broadcast) and 30-44% for low delay streams (i.e. 2-way video). These objective quality measurements are done using PSNR.
Based on the current progress, the HEVC standard seems well-positioned to be the prevailing next generation video compression standard, following in the footsteps of MPEG-2 and H.264.  It appears to have wide industry and academic support. It is less than a year from official standardization. But don’t get too excited because there is still a long road ahead. Efficient hardware-based implementations of the HEVC standard are likely still several years out, and it will probably be awhile before HEVC starts to replace H.264.
 

Part Two -- The Emerging HEVC Standard - Goals and Progress