Operations of a method include obtaining a segment of image data that represents a portion of a frame of video image data to be encoded. The operations include determining, based on the segment and a target bitrate, a quantization parameter (QP) value for the segment. The operations include determining a minimum QP value and a maximum QP value that establishes a range of QP values an integrated bit rate control algorithm may use to encode the segment. The operations include encoding the segment with a first QP value that is greater than the minimum QP value and less than the maximum QP value. The operations include adjusting, by the bit rate control algorithm, the first QP value to a second QP value that is greater than the minimum QP value and less than the maximum QP value. The operations include transmitting the encoded segment to a remote device.

An image encoding/decoding method and apparatus are provided. An image decoding method according to the present disclosure may include: obtaining palette information and palette index prediction information of a current block from a bitstream; constructing a palette predictor for the current block based on the palette information and constructing a palette table for the current block based on the palette predictor; generating a palette index map for the current block based on the palette index prediction information; and decoding the current block based on the palette table and the palette index map, wherein the palette predictor may be initialized using a user defined palette entry obtained from at least one of an adaptation parameter set (APS), a picture parameter set (PPS) or a slice header.

This application is directed to decoding video data including a plurality of luma components of a plurality of pixels in a video frame. The plurality of pixels belong to a coding block, and include a boundary pixel that is inside the coding block wherein the boundary pixel is immediately adjacent to a boundary of the coding block. One or more neighboring pixels of the boundary pixel are outside of the coding block and determined as being not available. A respective luma component corresponding to the boundary pixel is assigned to a luma component corresponding to each of the one or more neighboring pixels. A boundary luma component is determined based, at least, on the luma components of the one or more neighboring pixels and the boundary pixel according to a predefined luma interpolation scheme. A boundary chroma component is converted from the boundary luma component according to a linear mapping model.

The image decoding method includes determining a context for use in a current block to be processed, from among a plurality of contexts, wherein in the determining: the context is determined under a condition that control parameters of a left block and an upper block are used, when the signal type is a first type; and the context is determined under a third condition that the control parameter of the upper block is not used and a hierarchical depth of a data unit to which the control parameter of the current block belongs is used, when the signal type is a third type, and the third type is one or more of (i) “merge_flag”, (ii) “ref_idx_I0” or “ref_idx_I1”, (iii) “inter_pred_flag”, (iv) “mvd_I0” or “mvd_I1”, (v) “intra_chroma_pred_mode”, (vi) “cbf_luma”, and (vii) “cbf_cb” or “cbf_cr”.

An image encoding device includes a first prediction parameter determination section (53) for selecting, for each of prediction units belonging to a first group, a prediction parameter from a basic set; a second prediction parameter determination section (55) for selecting, for each of prediction units belonging to a second group, a prediction parameter from a reduced set (i) including at least a part of the prediction parameter(s) selected by the first prediction parameter determination section (53) and (ii) is constituted by a prediction parameter(s), the number of which is not more than the number of prediction parameters included in the basic set; and a prediction parameter encoding section (243) for encoding (i) information indicating which one of prediction parameters is selected by the first prediction parameter determination section (53) and (ii) information indicating which one of prediction parameters is selected by the second prediction parameter determination section (55).

An image decoding method performed by a decoding apparatus according to the present disclosure comprises the steps of: obtaining a reference sample line index of a current block and most probable mode (MPM)-related information; constructing an alternative MPM list on the basis of the reference sample line index; deriving an intra prediction mode of the current block on the basis of the alternative MPM list and the MPM-related information; and generating a predicted block of the current block on the basis of the intra prediction mode, wherein the alternative MPM list is constructed on the basis of an intra prediction mode of an upper adjacent block of the current block and an intra prediction mode of a left adjacent block of the current block.

The video signal processing method according to the present invention comprises: generating a candidate mode list of a current block on the basis of an intra-prediction mode from the spatial neighboring block of the current block; modifying the candidate mode list on the basis of an intra-prediction mode from the neighboring view of the current block; inducing the intra-prediction mode of the current block on the basis of the modified candidate mode list; and predicting the current block by using the induced intra-prediction mode.

Disclosed are a method and apparatus for improving the accuracy of intra-prediction in order to improve encoding and decoding efficiency. The video decoding method may improve the prediction efficiency for the current pixel to be predicted by referring to the degree of variation in surrounding pixels, to thereby effectively decode the bit stream with improved encoding efficiency. In addition, an additional prediction candidate is used to achieve improved accuracy of intra-prediction, and the thus-improved accuracy of intra-prediction may reduce residual components and improve encoding efficiency. Further, an improved planar mode is utilized to achieve improved intra-prediction.

Embodiments in the present specification provide a video signal processing method and device. A method of processing a video signal according to an embodiment in the present specification comprises the steps of: acquiring an intra-prediction mode for a current block from the video signal; determining a modified intra-prediction mode from the intra-prediction mode for the current block on the basis of the width and height of and the intra-prediction mode for the current block; and applying a transform determined on the basis of the modified intra-prediction mode. The accuracy of prediction can be further improved by deriving a modified intra-prediction mode according to a wide-angle intra-prediction mode according to the shape of and an intra-prediction mode for a current block.

A method of palette management for palette coding in a video coding system receives input data associated with a current block in a high-level picture structure and initializes a palette predictor in the high-level picture structure before a corresponding palette of a first palette-coded block in the high-level picture structure is coded. If a palette mode is selected for the current block, the method applies the palette coding to the current block using a current palette and updates the palette predictor based on the current palette to generate an updated palette predictor for a next block coded in the palette mode.