Optimal angular intra prediction for block-based video coding

• US 8,693,551 B2
• Filed: 11/16/2012
• Issued: 04/08/2014
• Est. Priority Date: 11/16/2011
• Status: Active Grant

• Current Assignee: Beamr Imaging Ltd.
• Original Assignee: Vanguard Software Solutions, Inc. (Dolby Laboratories Incorporated)
• Inventors: Zheludkov, Alexander, Martemyanov, Alexey, Terterov, Nickolay
• Primary Examiner(s): Lee, Young
• Application Number:
  US13/679,161
• Publication Number:
  US 20130121401A1
• Time in Patent Office: 508 Days
• Field of Search: 375/240.01, 375/240.12, 375/240.24, 375/240.26
• US Class Current: 375/240.26
• CPC Class Codes: H04N 19/11 among a plurality of spatial predictive coding modes
• CPC Class Codes: H04N 19/119 Adaptive subdivision aspects, e.g. subdivision of a picture into rectangular or non-rectangular coding blocks
• CPC Class Codes: H04N 19/137 Motion inside a coding unit, e.g. average field, frame or block difference
• CPC Class Codes: H04N 19/139 Analysis of motion vectors, e.g. their magnitude, direction, variance or reliability
• CPC Class Codes: H04N 19/14 Coding unit complexity, e.g. amount of activity or edge presence estimation H04N19/146 takes precedence
• CPC Class Codes: H04N 19/176 the region being a block, e.g. a macroblock
• CPC Class Codes: H04N 19/19 using optimisation based on Lagrange multipliers
• CPC Class Codes: H04N 19/51 Motion estimation or motion compensation
• CPC Class Codes: H04N 19/513 Processing of motion vectors
• CPC Class Codes: H04N 19/52 by predictive encoding
• CPC Class Codes: H04N 19/521 for estimating the reliability of the determined motion vectors or motion vector field, e.g. for smoothing the motion vector field or for correcting motion vectors
• CPC Class Codes: H04N 19/523 with sub-pixel accuracy
• CPC Class Codes: H04N 19/53 Multi-resolution motion estimation; Hierarchical motion estimation
• CPC Class Codes: H04N 19/533 Motion estimation using multistep search, e.g. 2D-log search or one-at-a-time search [OTS]
• CPC Class Codes: H04N 19/567 Motion estimation based on rate distortion criteria
• CPC Class Codes: H04N 19/593 involving spatial prediction techniques
• CPC Class Codes: H04N 19/65 using error resilience

Abstract

Encoding methods directed to making coding decisions and estimating coding parameters including searching for optimal angular prediction in intra-prediction mode; choosing the best intra block subdivision; and providing motion estimation for tree-structured inter coding. The methods are targeted to HEVC specifications of video compression, however, may be used with other video coding standards.

Claims

1. A method of selecting an optimal angular intra prediction mode for a block-based video coding, the method comprising:

calculating following functions for a spatial area S including a texture block beginning with coordinates (x, y);

2. The method of selecting an optimal angular intra prediction mode of claim 1, wherein the minimal activity direction for each case j= 1,4 is calculated as a vector (α

(S,W), β

(S,W));

3. The method of claim 2, wherein the four cases j= 1,4 correspond to respective intervals of the angle φ

(S,W);

[0;

π

/4], [π

/4, π

/2], [π

/2, 3π

/4] and [3π

/4, π

].

4. A method of calculating tables for minimal activity directions and corresponding angular prediction modes using signs of E and F and the value of the ratio

5. The method of claim 4, wherein integers K and L are equal to 256.