Method, device and computer program product for encoding a distorted image frame

An encoder for encoding, using a block-based video encoding algorithm, distorted image frame produced via at least one image sensor, depicting a scene, each pixel in the distorted image frame corresponding to a field of view, FOV, of the scene, the encoder being configured to:

• determine a map of maximum pixel block sizes corresponding to the distorted image frame, wherein the map of maximum pixel block sizes is determined based on a spatial resolution distribution corresponding to a distribution of extents of the corresponding FOY per pixel in the distorted image frame, such that for a first portion of the distorted image frame having a first spatial resolution, the maximum pixel block size corresponding to the first portion is set to a first value, and for a second portion for the distorted image frame having a second spatial resolution being lower than the first spatial resolution, the maximum pixel block size corresponding to the second portion is set to a second value being lower than the first value;
• and
• encode, using the block-based video encoding algorithm, the distorted image frame, wherein the map of maximum pixel block sizes is used by the block-based video encoding algorithm for defining maximum block sizes for encoding blocks of the block-based video encoding algorithm.