High Efficiency Video Coding

masonchung

How Efficient is HEVC?
The new High Efficiency Video Coding (HEVC) / H.265 standard is expected to be more efficient than its predecessor, H.264 Advanced Video Coding. Just how much better it will perform is a crucial question. Will it be enough of an improvement to justify widespread industry adoption of the new standard?
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Bin Li, Gary Sullivan and Jizheng Xu published a performance comparison between H.264/AVC and Working Draft 4 of HEVC in November 2011. You can find the full document and results here:
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: I( e5 c& D5 a1 r, s3 J" cDocument JCTVC-G399

Table 4 of the document compares the compression performance of the HEVC test model ("HM") and the H.264 test model ("JM"). On average, HEVC out-performs H.264 by 39% for random access scenarios (e.g. broadcast) and by 44% for low delay scenarios (e.g. video calling).
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This means that the HEVC codec can achieve the same quality as H.264 with a bitrate saving of around 39-44%.

HEVC is still under development and we might expect to see a further increase in performance from future versions of the draft standard.
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+ J! k% e$ f8 e6 O8 M0 HHigh Efficiency Video Coding
High Efficiency Video Coding (HEVC) is a new Standard under development by the ISO and ITU-T. The Moving Picture Experts Group (MPEG) and Video Coding Experts Group (VCEG) have set up a Joint Collaborative Team on Video Coding (JCT-VC) with the aim of getting the new standard ready for publication in 2012/2013. It's likely to be published jointly as a new MPEG standard and a new ITU-T standard, possibly H.265.
( R0 @! t5 K6 H' m" ?7 f% jThe HEVC Test Model
Following the JCT-VC and MPEG meeting in October 2010, a Test Model for HEVC, HM1, was specified. The Test Model defines two broad categories of video coding tools, for (a) High Efficiency and (b) Low Complexity applications.
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6 Z8 X' U- f& uWhat's in the Test Model?
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The main components are as follows:
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% ~; n5 M( i2 L9 K" W% jCoding unit: Block sizes from 8x8 to 64x64 in tree structure
Transform: Quadtree structured block size from 4x4 to 32x32 samples
1 k$ d0 r& v& I1 B6 m! y4 x4 ?Intra prediction: Up to 34 intra prediction directions
Interpolation: 6- or 12-tap interpolation filter, down to 1/4-sample
, J, i7 |( a$ c& {4 e0 g5 lMotion prediction: Advanced motion vector prediction
Entropy coding: CABAC or Low Complexity Entropy Coding (LCEC)
Loop filter: Deblocking filter or Adaptive Loop Filter (ALF)
Precision: Extended precision options

Many coding tools have been scheduled for further investigation and may be incorporated into the Test Model if they offer suitable compression gains.

6 ^- j" o2 B! O3 f3 F- UHow will it compare to H.264/AVC?

Current indications are that the new standard could provide 2x better video compression performance (i.e. around half the bitrate for a similar quality level) at the expense of significantly higher computational complexity, compared with H.264/AVC.

$ u- k8 r& }* x6 J* t1 X4 K8 B% @When will it be finished?

4 b4 d2 g, U3 N" w; A0 D" LThe timescale for completing the HEVC standard is as follows:
6 o! d' K4 m1 ]$ t, c, kFebruary 2012: Committee Draft (complete draft of standard)
July 2012: Draft International Standard
, G2 t# W: ]+ W6 G3 R" l0 h' `January 2013: Final Draft International Standard (ready to be ratified as a Standard)
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Where can I find out more?
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  c1 `& q/ b7 aJCT-VC Meeting Documents : download JCTVC-C405 for a summary of the HEVC test model HM1.

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9 y2 L$ j) c/ x  The Joint Collaborative Team
From the ITU website:

"The Joint Collaborative Team on Video Coding is a group of video coding experts from ITU-T Study Group 16 (VCEG) and ISO/IEC JTC 1/SC 29/WG 11 (MPEG) created to develop a new generation video coding standard that will further reduce by 50% the data rate needed for high quality video coding, as compared to the current state-of-the-art AVC standard (ITU-T Rec. H.264 | ISO/IEC 14496-10). This new coding standardization initiative is being referred to as High Efficiency Video Coding (HEVC)."
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* m1 U4 \" }+ H" fTo find out more:
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Joint Collaborative Team on Video Coding