Abstract: A video coding or decoding method using inter-image prediction to encode input video data in which each chrominance component has 1/Mth of the horizontal resolution of the luminance component and 1/Nth of the vertical resolution of the luminance component, where M and N are integers equal to 1 or more, comprises: storing one or more images preceding a current image; interpolating a higher resolution version of prediction units of the stored images so that the luminance component of an interpolated prediction unit has a horizontal resolution P times that of the corresponding portion of the stored image and a vertical resolution Q times that of the corresponding portion of the stored image, where P and Q are integers greater than 1; detecting inter-image motion between a current image and the one or more interpolated stored images so as to generate motion vectors between a prediction unit of the current image and areas of the one or more preceding images; and generating a motion compensated prediction of the pr

Abstract: A method encoding successive input data values includes: selecting one of plural complementary sub-ranges of a set of code values according to a current input data value, proportions of the sub-ranges relative to the set of code values defined by a context variable associated with that input data value; assigning the current input data value to a code value within the selected sub-range; modifying the set of code values based on the assigned code value and a size of the selected sub-range; detecting whether the set of code values is less than a predetermined minimum size and if so, successively increasing it until reaching the predetermined minimum size; outputting an encoded data bit in response to each size-increasing operation; modifying the context variable to increase the proportion of the set of code values in the sub-range selected; after encoding a group of input data values, terminating the output data.

Abstract: A data coding apparatus in which a set of ordered data is encoded includes: an entropy encoder encoding the ordered data, wherein each data item is split into respective data subsets that are encoded by first and second encoding systems so that for a predetermined quantity of encoded data generated in respect of a group of data items by the first encoding system, a variable quantity of zero or more data is generated in respect of that group of data by the second encoding system; and an output data stream assembler generating an output data stream from the encoded data, the output data stream including successive packets of a predetermined quantity of data generated by the first encoding system followed, in a data stream order, by the zero or more data generated by the second encoding system in respect of same data items as encoded by the first encoding system.