1. A method of determining decoding relationship for a coded multi-layer video stream defining multiple layers of pictures, said method comprises: retrieving, based on said coded multi-layer video stream, at least one direct decoding flag indicating a direct coding relationship between a layer with layer index i of said multiple layers and a layer with layer index j of said multiple layers, wherein i≠j; determining information defining any decoding relationship between said multiple layers based on said at least one direct decoding flag; and determining a type of prediction operation based on at least one scalability identifier of said layer with layer index i and at least one scalability identifier of said layer with layer index j.