A device for processing media content obtains data from a box within a file conforming to a file format for a video codec, the box comprising a syntax structure that includes the data, the file being associated with the media content and the media content being coded according to the video codec; and determines, based on the data obtained from the box, whether to accept or reject the media content associated with the file. A device for generating media content generates data in a box within a file conforming to a file format, the box comprising a syntax structure that includes the data, the file being associated with the media content, wherein the data is for use in determining whether a client is to accept or reject the media content associated with the file; and outputs the file.