US 8139651

Patent Overview — US8139651B2

Title: Video deblocking filter

Patent number / application: US8139651B2; Application US12/788,210

Inventor: Cheng Huang

Original Assignee / Current Assignee (as listed): Divx LLC

Key dates (as listed): Priority date 2004-09-20; Filing date 2010-05-26; Publication of US20110069765A1 2011-03-24; Granted/Published as US8139651B2 2012-03-20; Anticipated expiration 2025-09-20; Status: Expired – Lifetime

Purpose: The invention relates to video compression, and in particular to methods of deblocking compressed video. Compression schemes that divide frames into blocks of pixels and treat adjacent blocks separately in a lossy scheme can produce artifacts at block boundaries when the frame is reconstructed. Deblocking filters are applied to pixels adjacent block boundaries to remove artifacts and improve reconstructed image quality. The disclosure notes the MPEG-4 standard (ISO/IEC 14496) contains an example deblocking filter, applied along edges of 8×8 pixel blocks to both luminance and chrominance data, operating in a "DC offset mode" (for very smooth regions) or a "default mode" (all other cases), the default mode involving complex calculations including 4-tap filtering and clipping. Smoothing a boundary lying in a high-detail region can detract from appearance.

Plain-language scope: Embodiments include deblocking filters and methods of applying them in which filter characteristics are determined based on the relative level of smoothness or detail in the region of the reconstructed frame where a block boundary is located. The level of detail is ascertained by inspecting a set of pixels including pixels from multiple rows and columns and at least one pixel not adjacent the block boundary; the set may be a block of pixels divided by the block boundary. Filter characteristics can be further determined by the level of detail (text truncated at this point).

Source: https://patents.google.com/patent/[US8139651](/patent/US8139651)/en

What the excerpt does not establish: It does not provide the full claims, the complete detailed description, or the specific filtering equations; the final sentence is truncated. It does not establish validity, enforceability, or the scope of any particular claim.