1. A user terminal device comprising means for extracting artefact features from media data, means for transmitting the extracted artefact features to a server device, means for receiving quality scores for the media data from the server device, means for presenting a received quality score to a user, and means for receiving, from the user, a subjective quality score and a request for re-determining the quality score wherein the means for transmitting is adapted for communicating the request for re-determining the quality score and the subjective quality score to the server device.