The invention relates to methods, devices, systems and computer program products where input image data is received for processing in a computer system, a first transform is carried out to the input image data, the transform being done in a first direction with respect to the input image data, to obtain first transformed image data, a transposing operation is carried out to the first transformed image data to obtain first transposed image data, and a second transform in a transform is carried out to the first transposed image data, the second transform being done in a second direction with respect to the input image data, to obtain second transformed image data. The first transform and the second transform may be carried out in a processor in a parallel manner, and the transposing operation may be carried out at least partially using registers of the processor.