New intra planar modes are introduced for predicting digital video data. As part of the new intra planar modes, various methods are offered for predicting a first sample within a prediction unit, where the first sample is needed for referencing to when processing the new intra planar modes. And once the first sample is successfully predicted, the new intra planar modes are able to predict a sample of video data within the prediction unit by processing a bi-linear interpolation of four previously reconstructed reference samples.

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.

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.

A method for adaptive loop filtering is provided that includes determining a coefficient value for each coefficient position of an adaptive loop filter, applying the adaptive loop filter to at least a portion of a reconstructed picture using the coefficient values, and entropy encoding coefficient values into a compressed bit stream using predetermined short binary codes, wherein the short binary code used depends on the coefficient position of the coefficient value.

A method for developing an enhancement model for low-quality visual data, the method comprising the steps of receiving one or more sections of higher-quality visual data; and training a hierarchical algorithm. The hierarchical algorithm is operable to increase the quality of one or more sections of lower-quality visual data so as to substantially reproduce the one or more sections of higher-quality visual data. The hierarchical algorithm is then outputted.

A method for developing an enhancement model for low-quality visual data, the method comprising the steps of receiving one or more sections of higher-quality visual data; and training a hierarchical algorithm. The hierarchical algorithm is operable to increase the quality of one or more sections of lower-quality visual data so as to substantially reproduce the one or more sections of higher-quality visual data. The hierarchical algorithm is then outputted.

An encoder: includes circuitry, and memory coupled to the circuitry; stores a first parameter into a bitstream, the first parameter indicating whether a syntax element related to a chroma tool offset is present in the bitstream; when the first parameter indicates that the syntax element is present in the bitstream, (i) stores, in the bitstream, one or more second parameters that are used in deblocking filtering for a chroma sample of a current image, in addition to the syntax element, (ii) performs the deblocking filtering using the one or more second parameters, and (iii) encodes the current image; and when the first parameter indicates that the syntax element is not present in the bitstream, encodes the current image without storing the one or more second parameters into the bitstream.

An encoder: includes circuitry, and memory coupled to the circuitry; stores a first parameter into a bitstream, the first parameter indicating whether a syntax element related to a chroma tool offset is present in the bitstream; when the first parameter indicates that the syntax element is present in the bitstream, (i) stores, in the bitstream, one or more second parameters that are used in deblocking filtering for a chroma sample of a current image, in addition to the syntax element, (ii) performs the deblocking filtering using the one or more second parameters, and (iii) encodes the current image; and when the first parameter indicates that the syntax element is not present in the bitstream, encodes the current image without storing the one or more second parameters into the bitstream.

An intra-frame prediction method and device, according to the present invention, enables deriving an intra-frame prediction mode of a current block, determining a pixel line, among a plurality of pixel lines, for the intra-frame prediction of the current block, and carrying out the intra-frame prediction of the current block on the basis of the intra-frame prediction mode and the pixel line. In addition, a first reference pixel of the determined pixel line may be selectively filtered, and a prediction pixel of the current block may be selectively corrected, and thus the accuracy of the intra-frame prediction may be improved.

A video processing apparatus may comprise one or more processors that are configured to determine an interpolation filter length for an interpolation filter associated with a coding unit (CU) based on a size of the CU. The one or more processor may be configured to determine an interpolated reference sample based on the determined interpolation filter length for the interpolation filter and a reference sample for the CU. The one or more processor may be configured to predict the CU based on the interpolated reference sample. For example, if a first CU has a size that is greater than the size of a second CU, the one or more processors may be configured to use a shorter interpolation filter for the first CU than for the second CU.