For transmitting video data over a powerline communications transmission channel, a first communication device: obtains video data in the form of a succession of uncompressed images; determines the capacity of the transmission channel; performs a wavelet-decomposition of each uncompressed image, thereby obtaining data having different resolutions; compresses each wavelet-decomposed image, on the basis of the determined capacity of the powerline communications transmission channel; and performs transmission in pulse form with spreading of each compressed image to a second communication device, to introduce data redundancy, the rate of which, for each data item of said compressed image, is defined on the basis of the resolution of said video data item, the redundancy of the data having the lowest resolution being higher than the one of the data having any other resolution. The first communication device also transmits speed maps enabling the second communication device to thereby apply an image enhancement operation.

For transmitting video data over a powerline communications transmission channel, a first communication device: obtains video data in the form of a succession of uncompressed images; determines the capacity of the transmission channel; performs a wavelet-decomposition of each uncompressed image, thereby obtaining data having different resolutions; compresses each wavelet-decomposed image, on the basis of the determined capacity of the powerline communications transmission channel; and performs transmission in pulse form with spreading of each compressed image to a second communication device, to introduce data redundancy, the rate of which, for each data item of said compressed image, is defined on the basis of the resolution of said video data item, the redundancy of the data having the lowest resolution being higher than the one of the data having any other resolution. The first communication device also transmits speed maps enabling the second communication device to thereby apply an image enhancement operation.

A method for decoding an encoded code stream is provided. The method may include obtaining the encoded code stream. The method may include determining a plurality of code blocks based on the encoded code stream. The method may include determining a plurality of bit-planes for each of the plurality of code blocks, the plurality of bit-planes ranging from a most significant bit-plane to a least significant bit-plane. The method may include determining at least one query-plane for each of the plurality of bit-planes. The method may further include decoding each of the plurality of bit-planes based on the at least one query-plane.

Methods of encoding and decoding for video data are described in which multi-level significance maps are used in the encoding and decoding processes. The significant-coefficient flags that form the significance map are grouped into contiguous groups, and a significant-coefficient-group flag signifies for each group whether that group contains no non-zero significant-coefficient flags. A multi-level scan order may be used in which significant-coefficient flags are scanned group-by-group. The group scan order specifies the order in which the groups are processed, and the scan order specifies the order in which individual significant-coefficient flags within the group are processed. The bitstream may interleave the significant-coefficient-group flags and their corresponding significant-coefficient flags, if any.

Methods of encoding and decoding for video data are described in which multi-level significance maps are used in the encoding and decoding processes. The significant-coefficient flags that form the significance map are grouped into contiguous groups, and a significant-coefficient-group flag signifies for each group whether that group contains no non-zero significant-coefficient flags. A multi-level scan order may be used in which significant-coefficient flags are scanned group-by-group. The group scan order specifies the order in which the groups are processed, and the scan order specifies the order in which individual significant-coefficient flags within the group are processed. The bitstream may interleave the significant-coefficient-group flags and their corresponding significant-coefficient flags, if any.

A method for encoding a series of symbols using several models of the arithmetic or range coder type and including steps where each model is associated with a belonging criterion, the series is run through in order to determine, for each symbol, the encoding model to which each symbol belongs, according to the criteria; then a probability of occurrence of each symbol in the corresponding model is determined; then the series is run through by encoding each symbol successively; and a file is formed from the code thus obtained.

A method for encoding a series of symbols using several models of the arithmetic or range coder type and including steps where each model is associated with a belonging criterion, the series is run through in order to determine, for each symbol, the encoding model to which each symbol belongs, according to the criteria; then a probability of occurrence of each symbol in the corresponding model is determined; then the series is run through by encoding each symbol successively; and a file is formed from the code thus obtained.

Computer processor hardware receives settings information for a first image. The first image includes a set of multiple display elements. The computer processor hardware receives motion compensation information for a given display element in a second image to be created based at least in part on the first image. The motion compensation information indicates a coordinate location within a particular display element in the first image to which the given display element pertains. The computer processor hardware utilizes the coordinate location as a basis from which to select a grouping of multiple display elements in the first image. The computer processor hardware then generates a setting for the given display element in the second image based on settings of the multiple display elements in the grouping.

Computer processor hardware receives settings information for a first image. The first image includes a set of multiple display elements. The computer processor hardware receives motion compensation information for a given display element in a second image to be created based at least in part on the first image. The motion compensation information indicates a coordinate location within a particular display element in the first image to which the given display element pertains. The computer processor hardware utilizes the coordinate location as a basis from which to select a grouping of multiple display elements in the first image. The computer processor hardware then generates a setting for the given display element in the second image based on settings of the multiple display elements in the grouping.

A method for processing data for display on a screen involves encoding, using a first colour space, a first portion of image data intended to be displayed on a first area of the screen and encoding, using a second colour space, a second portion of image data intended to be displayed on a second area of the screen. The encoded first and second portions of the image data are compressed, and transmitted over a link for display on the screen. By using different colour spaces to encode image data that is displayed in different parts of a screen, differences in a users vision and/or aberrations caused by display equipment may be accounted for and so provide an improved user experience. Using different colour spaces for different screen areas may also reduce the amount of data that needs to be transmitted, for example by encoding image data more effectively and/or allowing more efficient compression of data.