High Efficiency Video Coding

masonchung

How Efficient is HEVC?
) @+ I; Z9 D& S9 ?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?

6 t, y8 T& R6 gBin 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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* A% H9 v" [' nDocument JCTVC-G399

$ Y  ^, T6 n" b$ _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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7 k- i, Z7 M1 P9 \3 _2 [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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High Efficiency Video Coding
  t, m- p- d( [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.
The HEVC Test Model
" U: Q8 x2 s& R! JFollowing 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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What's in the Test Model?
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The main components are as follows:
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! @2 S2 @1 ~: f9 }Coding unit: Block sizes from 8x8 to 64x64 in tree structure
Transform: Quadtree structured block size from 4x4 to 32x32 samples
$ ?" w- k8 v9 D% d5 R) X  yIntra prediction: Up to 34 intra prediction directions
. E- S5 o( t( N, d' a. h0 IInterpolation: 6- or 12-tap interpolation filter, down to 1/4-sample
1 ^. y/ V# i) E  I: VMotion prediction: Advanced motion vector prediction
* _+ k3 v! ^+ T; H& m+ q1 o+ lEntropy coding: CABAC or Low Complexity Entropy Coding (LCEC)
$ p( J! V% r' F, _# hLoop filter: Deblocking filter or Adaptive Loop Filter (ALF)
Precision: Extended precision options

( R; r! F4 ?7 {+ o# l. L1 x$ R3 dMany coding tools have been scheduled for further investigation and may be incorporated into the Test Model if they offer suitable compression gains.

How 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.
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When will it be finished?
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0 o: W+ l1 l9 c& c$ F7 nThe timescale for completing the HEVC standard is as follows:
February 2012: Committee Draft (complete draft of standard)
/ ]- B6 S0 ]2 F9 Q, rJuly 2012: Draft International Standard
# \; L$ v( g0 \! s/ mJanuary 2013: Final Draft International Standard (ready to be ratified as a Standard)

Where can I find out more?
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JCT-VC Meeting Documents : download JCTVC-C405 for a summary of the HEVC test model HM1.

November 2010
  The Joint Collaborative Team
! z" R/ X5 @2 f$ @% dFrom the ITU website:
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9 t. ?6 {$ p7 i0 f" ]; d% k7 j, ?"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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To find out more:

' V/ I$ ]2 |8 G  y- P7 H% rJoint Collaborative Team on Video Coding