Liwei Guo

Bio: Liwei Guo is an academic researcher from Qualcomm. The author has contributed to research in topics: Motion compensation & Encoder. The author has an hindex of 22, co-authored 98 publications receiving 1602 citations. Previous affiliations of Liwei Guo include Hong Kong University of Science and Technology & University of Hong Kong.

Palette prediction in palette-based video coding

Abstract: In palette-based coding, a video coder may form a so-called "palette" as a table of colors representing the video data of a given block. The video coder may code index values for one or more pixels values of a current block of video data, where the index values indicate entries in the palette that represent the pixel values of the current block. According to the techniques, a video coder determines one or more palette entries in a predictive palette that are copied to the current palette, and a number of new palette entries not in the predictive palette that are included in the current palette. The video coder calculates a size of the current palette equal to the sum of the number of the copied palette entries and the number of the new palette entries, and generates the current palette including the copied palette entries and the new palette entries.

Determining palette indices in palette-based video coding

Abstract: In an example, a method of coding video data includes determining a first index value associated with a first pixel in a block of video data, wherein the first index value relates a position of the first pixel to an entry of a palette of pixel values, determining, based on the first index value, one or more second index values associated with one or more second pixels in the block of video data, wherein the second index values relate the positions of the one or more second pixels to one or more entries of the palette of pixel values, and coding the first pixel and the one or more second pixels of the block of video data.

Intra prediction from a predictive block

Abstract: Techniques coding video data, including a mode for intra prediction of blocks of video data from predictive blocks of video data within the same picture, may include determining a predictive block of video data for the current block of video data, wherein the predictive block of video data is a reconstructed block of video data within the same picture as the current block of video data. A two-dimensional vector, which may be used by a video coder to identify the predictive block of video data, includes a horizontal displacement component and a vertical displacement component relative to the current block of video data. The mode for intra prediction of blocks of video data from predictive blocks of video data within the same picture may be referred to as Intra Block Copy or Intra Motion Compensation.

Adaptive overlapped block motion compensation

Abstract: In general, techniques are described for performing adaptive overlapped block motion compensation when coding video data. A video coding device configured to code video data may implement the techniques. The video coding device may comprise one or more processors configured to determine an adaptation metric from a region of support for one of a first partition and a second partition of one or more blocks of the video data separated by a partition boundary. The region of support may not be the entire one or more blocks of video data. The one or more processors may further be configured to adapt, based on the adaptation metric, application of an overlapped block motion compensation process to determine predicted pixel values near the partition boundary for a first predicted block representative of the first partition of the video block.

Non-square transform units and prediction units in video coding

Abstract: This disclosure proposes techniques for transform partitioning in an intra-prediction video coding process. In one example, for a given intra-predicted block, a reduced number of transform unit partition options is allowed, based on certain conditions. In another example, transform units are decoupled from prediction units for intra-predicted block. For a given prediction unit, transforms of different sizes and shapes from the prediction unit may be applied. In another example, a reduced number of intra-prediction modes are allowed for a prediction unit having a non-square shape.

Apparatus, a method and a computer program for video coding and decoding

Abstract: There is disclosed a method, an apparatus, a server, a client and a non-transitory computer readable medium comprising a computer program stored therein for video coding and decoding. Depth pictures from a plurality of viewing angles are projected into a single viewing angle, making it possible to have pixel-wise joint filtering to be applied to all projected depth values. This approach enables to suppress the noise in the depth map data and provides improved performance for a view synthesis.

Image processing device and method

Abstract: The present disclosure pertains to an image-processing device and method that make it possible to suppress block noise. A βLUT_input calculator and a clip processor determine βLUT_input, which is a value inputted to an existing-β generator and an expanded-β generator. When the value of βLUT_input qp from the clip processor is 51 or less, the existing-β generator determines β using a LUT conforming to the HVEC standard, and supplies same to a filter process determination unit. When the value of βLUT_input qp from the clip processor is larger than 51, the expanded-β generator determines the expanded β and supplies same to the filter process determination part. This disclosure, for example, can be applied to an image processing device.

Method and apparatus for video coding

Abstract: There is disclosed a method, apparatus and computer program product in which at least one view component of a first type and at least one view component of a second type are obtained. The order of the texture view component and the depth view component in an access unit is determined and at least one indication of the order is encoded. The coding of the view components is adapted on the basis of the order. There is also disclosed a method, apparatus and computer program product in which at least one encoded view component of a first type and at least one encoded view component of a second type are received. Also at least one encoded indication of the order of the view components is received. The at least one encoded indication is decoded and the decoding of the view component sis adapted on the basis of the order.

An apparatus, a method and a computer program for video coding and decoding

Abstract: There is disclosed a method, an apparatus, a server, a client and a non-transitory computer readable medium comprising a computer program stored therein for motion compensated video coding and decoding. Texture block motion information is used to derive disparity/depth motion information. Alternatively, disparity/depth motion information is used to derive texture block motion information.

Image coding method, image decoding method, image coding apparatus, image decoding apparatus, and image coding and decoding apparatus

Abstract: The image coding method is used to code images to generate a coded stream. The image coding method includes: writing, into a sequence parameter set in the coded stream to be generated, a first parameter representing a first bit-depth that is a bit-depth of a reconstructed sample in the images; and writing, into the sequence parameter set, a second parameter which is different from the first parameter and represents a second bit-depth that is a bit-depth of an Intra Pulse Code Modulation (IPCM) sample in the images.