A method and an apparatus are provided for encoding and/or decoding digital images or video streams. The encoding apparatus includes a processor configured for reading at least a portion of an image (f), determining a rotation angle (θ) on the basis of the portion of the image (f), determining rotated transform matrix (V′) which is the result of a rotation of at least one basis vector of a Discrete Cosine Transform matrix (V) by the rotation angle (θ), computing transformed coefficients (f̂) on the basis of the pixel values contained in the portion of the image (f) and the rotated transform information (V′), outputting the transformed coefficients (f̂) to the destination.