Patent attributes
A method, computer program product and data processing apparatus for filtering data, in particular for use in deblocking filters. The method comprising applying a plurality of m filter coefficients which each have a value which is a negative power of two and which sum to one, to a plurality of m input data items to produce a filtered output data item, by performing a sequence of averaging calculations comprising averaging input data items to which a smallest filter coefficient is to be applied to produce first averaged data and averaging the first averaged data with other averaged input data or with input data items to which larger filter coefficients are to be applied the plurality of m filter coefficients being applied to the plurality of m input data items via a sequence of averaging calculations such that a data width of any calculated data does not exceed that of the input data being averaged.