An apparatus for decoding a sequence of pictures from a data stream is configured for decoding a picture of the sequence by: deriving a residual transform signal of the picture from the data stream; combining the residual transform signal with a buffered transform signal of a previous picture of the sequence so as to obtain a transform signal of the picture, the transform signal representing the picture in spectral components; and subjecting the transform signal to a spectral-to-spatial transformation, wherein the buffered transform signal comprises a selection out of spectral components representing the previous picture.

Systems and methods of encoding display data include performing a part of a first predetermined transform algorithm on at least a first part of a first frame of display data, and analyzing a light level to determine whether a different transform algorithm would be more suitable for encoding a second part of the first frame of the display data. If it is determined that a different transform algorithm would be more suitable for encoding, the second part of the first frame of the display data is encoded using the different transform algorithm to generate an encoded first frame. If it is determined that a different transform algorithm would not be more suitable for encoding, the second part of the first frame of the display data is encoded using the first predetermined transform algorithm to generate the encoded first frame.

An image decoding method and apparatus according to an embodiment may extract, from a bitstream, a quantization coefficient generated through core transformation, secondary transformation, and quantization; generate an inverse-quantization coefficient by performing inverse quantization on the quantization coefficient; generate a secondary inverse-transformation coefficient by performing secondary inverse-transformation on a low frequency component of the inverse-quantization coefficient, the secondary inverse-transformation corresponding to the secondary transformation; and perform core inverse-transformation on the secondary inverse-transformation coefficient, the core inverse-transformation corresponding to the core transformation.

An image decoding method and apparatus according to an embodiment may extract, from a bitstream, a quantization coefficient generated through core transformation, secondary transformation, and quantization; generate an inverse-quantization coefficient by performing inverse quantization on the quantization coefficient; generate a secondary inverse-transformation coefficient by performing secondary inverse-transformation on a low frequency component of the inverse-quantization coefficient, the secondary inverse-transformation corresponding to the secondary transformation; and perform core inverse-transformation on the secondary inverse-transformation coefficient, the core inverse-transformation corresponding to the core transformation.

A media encoder for encoding a stream of media data blocks has an encoder pipeline including a sequence of processing modules for processing a stream of media data blocks, and a pipeline configurator configured effect a switch in the encoder pipeline from one or more first encode parameters to one or more second encode parameters. The first processing module of the pipeline can be configured to associate a trigger value with at least a first media data block processed at the first processing module in accordance with second encode parameters, the trigger value passing to subsequent modules so as to cause those modules to adopt the second encode parameters.

An encoder that encodes a current block in a picture includes circuitry and memory. Using the memory, the circuitry: splits the current block into a first sub block, a second sub block, and a third sub block in a first direction, the second sub block being located between the first sub block and the third sub block; prohibits splitting the second sub block into two partitions in the first direction; and encodes the first sub block, the second sub block, and the third sub block.

An encoder that encodes a current block in a picture includes circuitry and memory. Using the memory, the circuitry: splits the current block into a first sub block, a second sub block, and a third sub block in a first direction, the second sub block being located between the first sub block and the third sub block; prohibits splitting the second sub block into two partitions in the first direction; and encodes the first sub block, the second sub block, and the third sub block.

A method of image compression, including, receiving at least one unprocessed image frame, transforming a domain of the at least one unprocessed image frame to output a transformed domain dataset, block processing the transformed domain dataset to yield a blocked dataset, quantizing the blocked dataset to produce a quantized dataset and entropy encoding the quantized dataset to construct at least one compressed image frame.

A method of image compression, including, receiving at least one unprocessed image frame, transforming a domain of the at least one unprocessed image frame to output a transformed domain dataset, block processing the transformed domain dataset to yield a blocked dataset, quantizing the blocked dataset to produce a quantized dataset and entropy encoding the quantized dataset to construct at least one compressed image frame.

A lossy method of compressing data, such as image data, which uses wrap-around wavelet compression is described. Each data value is divided into two parts and the first parts, which comprise the most significant bits from the data values, are compressed using wrap-around wavelet compression. Depending upon the target compression ratio and the compression ratio achieved by compressing just the first parts, none, one or more bits from the second parts, or from a data value derived from the second parts, may be appended to the compressed first parts. The method described may be lossy or may be lossless. A corresponding decompression method is also described.