Ub Video Inc.

Other

James Au

Anthony Joch

Yu-sheng Brandon Lin

Faouzi Kossentini

Foued Ben Amara

Anthony Peter Joch

Ali Jerbi

Brandon Lin

Yu-Sheng Brandon Lin

A method of filtering to remove coding artifacts introduced at block edges in a block-based video coder, the method having the steps of: checking the content activity on every line of samples belonging to a boundary to be filtered and where content activity is based on a set of adaptively selected thresholds determined using Variable-Shift Table Indexing (VSTI); determining whether the filtering process will modify the sample values on that particular line based on said content activity; and selecting a filtering mode between at least two filtering modes to apply on a block boundary basis, implying that there would be no switching between the two primary modes on a line by line basis along a given block boundary. The two filtering modes include a default mode based on a non-recursive filter, and a strong filtering mode which features two strong filtering sub-modes and a new selection criterion that is one-sided with respect to the block boundary to determine which of the two strong filtering sub-modes to use. The two strong filtering sub-modes include a new 3-tap filter sub-mode and a 5-tap filter sub-mode that permits a more efficient implementation of the filter.

Low-complexity deblocking filter

Low complexity deblocking filter

A system and method is provided to avoid or otherwise reduce luminance and/or chrominance trailing artifacts in block-based hybrid video coders using multiple block sizes and shapes. The proposed trailing artifact avoidance approach has at its core three main components. The first component is a method to identify flat blocks in the source frame that are most susceptible to the appearance of trailing artifacts, and where flatness is determined according to several proposed criteria. The second component is a method to identify bad blocks, which refer to predicted blocks in motion estimation that correspond to flat blocks in the source frame and that contain trailing artifacts. The third component is a method to avoid trailing artifacts when they are detected within a bad block, and where the avoidance is achieved by employing one or more tools from among a proposed set of high fidelity coding tools and/or high performance motion estimation tools.

Trailing artifact avoidance system and method

A method of filtering to remove coding artifacts introduced at block edges in a block-based video coder, the method having the steps of: checking the content activity on every line of samples belonging to a boundary to be filtered and where content activity is based on a set of adaptively selected thresholds determined using Variable-Shift Table Indexing (VSTI); determining whether the filtering process will modify the sample values on that particular line based on said content activity, and selecting a filtering mode between at least two filtering modes to apply on a block boundary basis, implying that there would be no switching between the two primary modes on a line by line basis along a given block boundary. The two filtering modes include a default mode based on a non-recursive filter, and a strong filtering mode which features two strong filtering sub-modes and a new selection criterion that is one-sided with respect to the block boundary to determine which of the two strong filtering sub-modes to use. The two strong filtering sub-modes include a new 3-tap filter sub-mode and a 5-tap filter sub-mode that permits a more efficient implementation of the filter.

A pre-processing system and method is used to compensate for global brightness changes in consecutive video frames. The system and method uses a brightness change model to identify the global brightness changes and to discard the brightness in a source frame so that the brightness changes between consecutive reconstructed video frames is kept to a minimum. The Hough Transform is used as one example of the model to accumulate votes for different values of brightness change model parameters. Compensation for any detected brightness changes in the source frame is performed with filtering of the model parameters when necessary, to help avoid any artifacts in the compensated source frame. Different application sequences of the brightness change model allows for multiple levels of processing delays.

Global brightness change compensation system and method

A system and method to perform context-adaptive variable length decoding (CAVLC) of transform coefficient levels for block-based motion-compensated decoding of moving pictures, corresponding to transform coefficients. The system and method includes complexity-reduction improvements in the coefficient level decoding process, such as simplified and extended range of Lev-VLC tables. Specifically, the number of Lev-VLC tables is extended from 5 to 7 and only 1 escape code (28-bit escape code) is used for tables Lev-VLC to Lev-VLC . The system and method also includes a simplified and improved table selection process. The table selection for the first Coefficient_level after trailing ones depends on total number of non-zero coefficients and number of trailing ones which are local variables within the CAVLC module. The table selection process for subsequent Coefficient_level's has been re-designed in such a way that the same logic path can be used to select Lev-VLC table for the next coefficient regardless of block modes and quantization parameters.

Growing community of inventors

Coquitlam, Canada

James Au