High Efficiency Video Coding: HEVC

Significantly better compression of next-generation video using HEVC. Learn more about our unique implementation of HEVC encoder and decoder.

Video Codec Evolution


Video compression technology has played a paramount role in the success of media applications in the last decades. In the early 90s MPEG-1 and H.261 codecs made feasible the transmission of low-resolution video using reduced bandwidth networks. Since the mid-90s MPEG-2 has been used extensively in DVD and Digital TV broadcast. H.264/AVC, standardized in 2003, has become the most widely used video codec for HD video distribution in broadcast, VoD, and Blu-ray.



To meet the demands of new applications requiring even higher quality, such as Ultra-HD TV with 4K and 8K, the High Efficiency Video Coding (HEVC) standard (also known as H.265) was developed and ratified in 2013. HEVC is capable of reducing the bitrate, at the same quality, compared to H.264/AVC by 50%.



HEVC Standard


The HEVC/H.265 standard has been developed by the ITU-T video Coding Experts Group (VCEG) and the ISO/IEC Moving Pictures Experts Group (MPEG) standardization organizations, which have joined together in a partnership known as the Joint Collaborative Team on Video Coding (JCT-VC).

HEVC provides many tools which together result in significant compression benefits. A tool is basically a video coding technique that allows the encoder to obtain video compression gains.

HEVC represents the state-of-the-art in video compression and has been widely deployed in the broadcast, VoD and other industries.

Examples of coding tools in HEVC include:


  • Larger block size extended to 64×64 instead of the 16×16 size of previous standard


  • Ability to subdivide blocks recursively into smaller blocks with a maximum depth as a parameter


  • Many more intra prediction modes: 35 modes instead of 10 in H.264


  • Advanced Motion Vector (MV) prediction technique


  • Advanced in-loop filters including deblocking filter and Sample Adaptive Offset (SAO)


  • Enhanced Context-based Adaptive Binary Arithmetic Coding (CABAC)



The HEVC standard includes additional support for HDR and WCG video quality enhancements, as well as support for temporal scalability for frame rate adaptation to heterogeneous devices (TVs, PCs, tablets, smartphones), and hierarchical Group of Pictures (GOPs) that result in higher compression gains compared to traditional coding structures.

Additionally, in order to benefit from the now widespread parallel multicore architectures, tools specially devoted for parallel processing been designed, namely: Wavefront Parallel Processing (WPP) and Tiles. Both of these tools allow subdivision of each picture into multiple partitions that can be processed in parallel.


The HEVC/H.265 standard has been enhanced with several key extensions:


  • RExt (HEVC version 2, 2014): which extends the range of color formats and bit depth to allow for very high-quality coding; including support for 4:2:2, 4:4:4, and RGB formats and bit-depths up to 12-bit


  • Scalability (HEVC version 2, 2014): which enables from a complete bitstream the extraction of one or a subset of sub-streams with lower spatio-temporal resolutions or reduced quality versions of the original video sequence


  • Multiview (HEVC version 2, 2014): which supports coding of multiple views of the scene


  • 3D video (HEVC version 3, 2015): which makes possible the efficient compression of multiple views required for glasses-free 3D


  • Screen Content Coding – SCC (HEVC version 4, 2016): which adds special tools to improve the compression of rendered video, text, and animation

As a result, HEVC allows for not only enhanced features to the traditional video applications, such as TV broadcast, VoD, and storage, but also to extend the range of applications to include VR and panoramic video, immersive projections, game streaming, remote desktop, and ultra-low-latency video conferencing.



Coding Tools and Applications for Different Codecs


The table below shows a comparison between HEVC and MPEG-2 and H.264, from different perspectives: coding tools, features, extensions, and applications.


Coding toolsLargest block size16x1616x1664x64
Smallest prediction unit16x168x8, 4x4Inter 8x4, Inter 4x8, Intra 4x4
Transform unit sizes8x88x8, 4x432x32 down to 4x4
PredictionNo Intra, half pel MV precision, maximum 2 reference frames10 Intra modes, quarter pel MV precision, up to 16 reference frames35 Intra modes, quarter pel MV precision, 8-tap filter, advanced motion vector prediction, up to 16 reference frames
In-loop filtersNoneDeblockingDeblocking improved, SAO
Entropy codingVLCCAVLC, CABACCABAC enhanced
FeaturesslicesslicesHDR, WCG, temporal scalability, hierarchical GOPs, slices, WPP, Tiles
Extensions4:2:2, 4:4:4, scalability 4:2:2, 4:4:4, up to 16 bit-depth, scalability, multiview 4:2:2, 4:4:4, up to 16 bit-depth, scalability, multiview, 3D, SCC
ApplicationsStandard TV, DVDHD TV, Blu-ray, Internet videoUHD TV, 4K Blu-ray, Internet video, VR, immersive projections, game streaming, remote desktop, low latency video conferencing



Spin Digital HEVC Codec Implementation


The HEVC standard specifies the decoding method for valid bitstreams. Different implementations can have different features and performance levels. Bitstreams decoded by different decoders should produce exactly the same video output, but different decoders can have very different performance levels. Different encoders are required to produce valid bitstreams according to the specification, but they can have a very different quality, compression, and performance level.

Spin Digital has developed a high-quality and high-performance software implementation of the HEVC codec.


High-performance HEVC Decoder


The Spin Digital HEVC software decoder has been extensively optimized in order to achieve an unparalleled level of performance, including:


  • Advanced multithreading for maximum performance and scalability on multicore architectures with tens of processor cores


  • Advanced library of SIMD optimized modules for SSE4, AVX2, and AVX-512 instruction sets


  • Extensive memory optimizations to reduce memory bandwidth using efficient pixel formats and cache-friendly data structures

Compared to other solutions available in the market Spin Digital HEVC decoder can process more than 2 times frames per second of 8K video with the same CPU, or to achieve the same real-time video quality with less CPU resources.

High-quality HEVC Encoder


The Spin Digital HEVC software encoder software delivers superior quality and compression efficiency especially for very high-quality video (4K and 8K with professional formats).


Given the same encoding speed and video quality, the Spin Digital HEVC software encoder can deliver up to 33.3% bitrate (file size) savings compared to competing HEVC solutions.





  • Sullivan G. J., Ohm J. R., Han W. J., and Wiegand T., Overview of the High Efficiency Video Coding (HEVC) Standard, IEEE Transactions on Circuits and Systems for Video Technology, vol. 22, no. 12, pp. 1649-1668, Dec. 2012.
  • Ohm J. R. et al., Comparison of the Coding Efficiency of Video Coding Standards – Including High Efficiency Video Coding (HEVC), IEEE Transactions on Circuits and Systems for Video Technology, vol. 22, no. 12, pp. 1668-1683, Dec. 2012.



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