A method for preparing immersive video data prior to processing into an immersive video. The method comprises receiving immersive video data containing one or more images of a scene, the scene comprising one or more image regions, and obtaining a relevance factor for at least one of the image regions, the relevance factor being indicative of the relative importance of the image region to a viewer. The immersive video data is separated into one or more sets of region data, wherein each set of region data corresponds to the data of one or more image regions and, based on the relevance factor of an image region, a bitrate is selected at which the set of region data corresponding to the image region is to be sent to an external processing unit.