High Efficiency Video Coding

High Efficiency Video Coding
Name	High Efficiency Video Coding
Status	International standard
Organization	ITU-T, ISO, IEC
First released	2013
Predecessor	H.264/MPEG-4 AVC
Successor	Versatile Video Coding
Related to	MPEG-H

High Efficiency Video Coding. It is a video compression standard developed jointly by the Moving Picture Experts Group and the Video Coding Experts Group, formally known as ITU-T H.265 and ISO/IEC 23008-2. The standard was finalized in 2013 with the primary goal of providing substantially improved data compression compared to its predecessor, H.264/MPEG-4 AVC, enabling the delivery of higher resolution video such as 4K resolution and 8K resolution content at similar bit rates. Its development was driven by the growing demands of Ultra-high-definition television, video on demand services, and mobile broadcasting.

Overview

The creation of this standard was a major collaborative effort between the Joint Collaborative Team on Video Coding and numerous technology companies including Samsung Electronics, Qualcomm, and Broadcom Limited. It fundamentally doubles the data compression ratio compared to H.264/MPEG-4 AVC at the same level of video quality, a critical advancement for bandwidth-constrained applications like Netflix streaming and YouTube video delivery. Key application areas include broadcasting, video conferencing systems, and storage for formats like Blu-ray Disc. The standard's efficiency was a significant enabler for the commercial rollout of services like ATSC 3.0 and new offerings from Comcast.

Technical details

The architecture introduces several advanced technical features over prior standards like MPEG-2 and H.264/MPEG-4 AVC. It employs a flexible block structure called the Coding Tree Unit, which can be partitioned into larger or smaller blocks than the traditional macroblock. Enhanced prediction techniques include more sophisticated intra prediction modes and improved motion compensation with advanced motion vector prediction. The standard also uses more efficient entropy coding methods, primarily Context-adaptive binary arithmetic coding, and introduces new in-loop filters such as the Sample Adaptive Offset and a stronger deblocking filter.

Profiles, tiers, and levels

The specification defines a range of profiles, tiers, and levels to cater to diverse application requirements and hardware capabilities. The Main Profile is designed for most consumer applications and supports 8-bit color depth with 4:2:0 chroma subsampling, widely used in services from Apple Inc. and Disney+. The Main 10 Profile adds support for 10-bit color depth, crucial for High-dynamic-range video content mastered by studios like Warner Bros. The standard also defines the Main Still Picture Profile for single-image compression. Tiers, Main and High, constrain bitrates, with levels defining constraints on parameters like picture size and decoding speed.

Comparison with other standards

When benchmarked against H.264/MPEG-4 AVC, it typically achieves a 50% bit rate reduction for equivalent subjective quality, a claim validated by subjective tests conducted by organizations like the European Broadcasting Union. Compared to the earlier MPEG-4 Part 2 standard, the efficiency gains are even more substantial. Its successor, Versatile Video Coding, developed by the same Joint Video Experts Team, offers further compression improvements but at a significantly higher computational cost. The standard also competes with open royalty-free codecs like AV1, developed by the Alliance for Open Media.

Adoption and deployment

Initial adoption was led by the broadcasting industry, with early trials by NHK in Japan and deployments in South Korea for Ultra-high-definition television services. Major streaming platforms like Netflix, Amazon Prime Video, and Hulu began encoding large portions of their libraries in the format to conserve bandwidth. Hardware support accelerated with the integration of dedicated decoding blocks in system on a chip designs from Intel (Intel Quick Sync Video), AMD, and ARM, as well as in graphics processing units from Nvidia and Apple silicon. It is also a mandatory codec for 4K Blu-ray discs.

Licensing

Licensing of essential patents is administered by the MPEG LA through its patent pool, which includes contributors like Dolby Laboratories and Mitsubishi Electric. A separate licensing pool is managed by Velos Media, whose members include Ericsson and Panasonic. The complex and initially costly licensing landscape was a point of contention and influenced some developers to favor alternatives like AV1. The structure involves fees for content encoding and decoding, as well as for the sale of end-user devices, affecting manufacturers from Sony to Xiaomi.

Category:Video codecs Category:ITU-T recommendations Category:ISO standards