Abstract:
Video processing methods and apparatuses receive input data associated with a current block, determine an actual intra prediction mode for the current block by performing decoder side intra mode derivation, perform intra prediction based on the actual intra prediction mode, replace the actual intra prediction mode with a pseudo mode when processing the current block by an intra mode dependent tool in syntax signaling or parsing, and encode or decode the current block. The pseudo mode referenced by the intra mode dependent tool is a predefined mode or a derived mode, which is referenced as the intra prediction mode for blocks coded using decoder side intra mode derivation, or is referenced by the intra mode dependent tool as the intra prediction mode for all intra prediction coded blocks.
Abstract:
A method and apparatus for video coding using template-based Intra prediction are disclosed. According to one method, where determining whether to apply the template-based Intra prediction or one or more parameters associated with the template-based Intra prediction depends on the current block size. According to yet another method, the quad-tree plus binary tree (QTBT) structure is used to partition an image or one or more areas of the current image into blocks. If the template-based Intra prediction is used for a current block and the current block is non-square, the width and height of the L-shaped reference pixel line are determined according to width and height of the current block. The L-shaped reference pixel line comprises a top reference pixel segment above the top template and a left reference pixel segment adjacent to a left side of the left template
Abstract:
A method and apparatus for video coding using template-based Intra prediction are disclosed. According to one method, the template-based Intra prediction searches N template matching candidates to reduce the complexity. In another method, the template-based Intra prediction assigns different weights for different pixel locations of template or uses different pixel precision for interpolation filter during cost evaluation among template matching candidates. In yet another method, truncated template size is used to reduce the complexity. In yet another method, the left and top templates may have different sizes for non-square block. In yet another method, inverse templated-based Intra prediction is used.
Abstract:
Aspects of the disclosure provide an apparatus for encoding a sequence of pictures into a coded bit stream. The apparatus can include a decoded picture buffer (DPB) configured to store reference pictures, at least one of the reference pictures being an interpolated reference picture (IRP), an interpolation circuit configured to generate the IRP based on the reference pictures stored in the DPB, an encoding circuit configured to encode a current picture in the sequence of pictures based on a value of a variable indicating whether the current picture is to be encoded using the IRP, and an encoding controller configured to determine the value of the variable according to a size of DPB and the reference pictures stored in the DPB.
Abstract:
A method and apparatus for video coding including an IntraBC (Intra-block copy) mode with flipping for prediction unit (PU) with a non-2N×2N partition size is disclosed. An IntraBC mode is selected from a mode group comprising a normal IntraBC mode and a flipping mode for a current PU with a current PU size belonging to a size group including at least one PU size selected from 2N×N, N×2N and N×N and N is a positive integer. When the IntraBC mode is used for the current PU, a flipping flag is signaled in a current PU-level syntax to indicate whether the current PU is coded using the flipping mode. Furthermore, when the current PU is coded using the flipping mode, a flip-direction flag is signaled in the current PU-level syntax to indicate a flipping direction of a corresponding flipped reference block.
Abstract:
A method and apparatus for color index coding of a block of video data using index prediction based on reconstructed neighboring pixels are disclosed. In one embodiment, color index encoding or decoding is applied to the current pixel indices by deriving index prediction from neighboring pixel indices of the reconstructed neighboring pixels. The reconstructed neighboring pixel values are first transformed into the neighboring pixel indices according to a quantization table to map between major color indices and major color values of the current block. The quantization table can be based on a major color table for the current block or can also be derived at a decoder side. The decoding process may reconstruct the current pixels by converting decoded current pixel indices to reconstructed current pixel values according to the quantization table or by directly copying the reconstructed neighboring pixel values indicated by decoded current pixel indices.
Abstract:
A method for a video encoder or decoder using an Intra Block Copy (IntraBC) mode is disclosed. If IntraBC mode is enabled and no loop filter is used for a current picture, a currently decoded reference picture for the current picture is marked as a long-term reference picture before and during decoding of the current picture. The currently decoded reference picture is assigned in reference picture list construction for IntraBC reference of the current picture and buffer fullness for the DPB is calculated before starting decoding the current picture by taking into account of only one reference picture buffer. According to another method, if the maximum DPB size is 1, a variable or a syntax element is set to a target value to impose restriction to use only one picture storage buffer in the DPB to store reference picture for encoding or decoding of a current picture.
Abstract:
A method and apparatus for chroma Intra prediction are disclosed. According to one method, a chroma Intra mode set comprising more than six chroma Intra coding modes are generated and chroma Intra-prediction encoding or decoding is applied to the current chroma block using a current chroma Intra mode selected from the chroma Intra mode set. According to another method, a chroma MPM list is determined and a current chroma Intra mode is signaled using chroma MPM process at the video encoding system or parsing the current chroma Intra mode using the chroma MPM process at the video decoding system, where the chroma MPM process comprises using a chroma MPM flag to indicate whether the current chroma Intra mode belongs to the chroma MPM list.
Abstract:
Methods and apparatus of Inter prediction including an affine Merge mode are disclosed. In one method, motion vectors associated with a set of neighbouring blocks of the current block are determined and used to generate a unified Merge candidate list. If the motion vector exists for a given neighbouring block belonging to the set of neighbouring blocks of the current block, the motion vector associated with the given neighbouring block is included in the unified Merge candidate list regardless of whether the given neighbouring block is coded using a regular mode or an affine mode. In another method, various new affine Merge candidates are disclosed, which includes a method uses temporal affine Merge candidate, a method uses previous N affine coded block and a method using global affine parameters. A Merge candidate list uses a set of decoder-side derived motion vectors is also disclosed.
Abstract:
Method and apparatus of managing a DPB (decoded picture buffer) for a video coding system are disclosed. Whether the IntraBC mode is used for a current picture is determined and a maximum allowed number of decoded pictures in the DPB is allocated based on whether the IntraBC mode is used for the current picture. The current picture is then encoded or decoded using decoded pictures stored in the DPB as reference data. In another method, a maximum number of reordered pictures in the DPB is determined. If certain conditions are true, one or more decoded pictures stored in the DPB will be emptied until none of the conditions is true. One condition corresponds to a number of decoded pictures in the DPB marked as “needed for output” being greater than the maximum number of reordered picture modified according to whether the IntraBC mode is used for the current picture.