There is provided an apparatus, methods, to generate a set of transform coefficients for coding a block in a frame or portion thereof, comprising: a media encoder coupled to a data interface adapted to receive a frame or portion thereof, the media encoder is adapted to: select a rotational symmetry mask for the block from a plurality of rotational symmetry masks which define a plurality of different rotational symmetries in a multi-dimensional space having a size and a shape as the block; split the block to two complementary portions based on the rotational symmetry mask; generate a pair of rotational symmetry blocks each having one of the two complementary portions; and compute at least one transform coefficient for at least one member of the pair of rotational symmetry blocks.