US 8,787,443 B2 · Content adaptive deblocking during video encoding and decoding

Abstract

Disclosed herein are exemplary embodiments of methods, apparatus, and systems for performing content-adaptive deblocking to improve the visual quality of video images compressed using block-based motion-predictive video coding. For instance, in certain embodiments of the disclosed technology, edge information is obtained using global orientation energy edge detection (“OEED”) techniques on an initially deblocked image. OEED detection can provide a robust partition of local directional features (“LDFs”). For a local directional feature detected in the partition, a directional deblocking filter having an orientation corresponding to the orientation of the LDF can be used. The selected filter can have a filter orientation and activation thresholds that better preserve image details while reducing blocking artifacts. In certain embodiments, for a consecutive non-LDF region, extra smoothing can be imposed to suppress the visually severe blocking artifacts.

Claims20

Dependent claims

A method for reducing block artifacts during video compression or decompression, comprising:

buffering a video frame reconstructed during block-based motion-predictive encoding or decoding;
determining edge locations and edge orientations throughout one or more blocks in the video frame;
for a selected block of the one or more blocks in the video frame, selecting a deblocking filter from two or more candidate deblocking filters based at least in part on the edge orientations in the selected block, the candidate deblocking filters including two or more directional deblocking filters adapted to reduce blockiness at a block boundary while also maintaining a real edge of a directional feature of the video frame at the block boundary, each of the directional deblocking filters being adapted for a different non-horizontal and non-vertical orientation of the directional feature of the video frame, each of the directional deblocking filters further comprising a filter bank of multiple filters in which the filters in the filter bank have the same non-horizontal and non-vertical orientation as one another;
and
applying the selected deblocking filter to the selected block and one or more blocks neighboring the selected block.

2 more elements

One or more computer memory devices or one or more computer-readable storage devices storing computer-executable instructions which when executed by a computer cause the computer to perform a video encoding or video decoding method, the method comprising:

detecting edge locations and edge orientations in a video image;
for a block of the video image having a detected edge, selecting a directional deblocking filter from among multiple directional deblocking filters, each of the directional deblocking filters being adapted for different non-horizontal and non-vertical directional feature orientations and being adapted to reduce blockiness at a boundary of the block while also maintaining an edge and orientation of a directional feature at the boundary of the block, each of the directional deblocking filters further comprising a filter bank of multiple filters in which the filters in the filter bank have the same non-horizontal and non-vertical orientation as one another;
evaluating one or more application thresholds for the selected directional deblocking filter;
if the application thresholds for the directional deblocking filter are satisfied, applying the directional deblocking filter across the boundary of the block and at least one adjacent block;
and
if the application thresholds for the directional deblocking filter are not satisfied, applying no deblocking filter to the block.

3 more elements

Dependencies are inferred from the claim text.

Content adaptive deblocking during video encoding and decoding

Life of this patent

Content adaptive deblocking during video encoding and decoding

Life of this patent

Abstract

Claims20