Method for image encoding

Encoding image data by segmenting the image into uniform sized blocks, applying a frequency-based transform to each block, defining sub-bands of coefficients of transformed image data. The coefficients of a collection (slice) 1210 of transformed blocks are converted into binary, converting zero-frequency (DC) coefficients of the collection or slice into binary using a fixed length coding scheme 1220 and converting higher frequency (AC) coefficients of the collection/slice of blocks into binary using variable length coding 1230, 1240. An error resilient coding algorithm is applied to the binarized data, the algorithm comprising: defining a number of bins of uniform size, each associated to one block of the collection. For each sub-band in turn, bits representing the current sub-band 1230 of each block in the collection are allocated to the bin corresponding to the block such that each bin starts with bits from its associated block, and any excess bits from the current sub-band in each block are allocated to a second bin in a predetermined order 1250. The error resilient algorithm is based on "Error Resilient Entropy Coding" (EREC). The key concept of this invention is applying this algorithm by sub-band, rather than by block as a whole. Equivalent decoding is also claimed.