Media compositor for computer-generated reality

One implementation forms a composited stream of computer-generated reality (CGR) content using multiple data streams related to a CGR experience to facilitate recording or streaming. A media compositor obtains a first data stream of rendered frames and a second data stream of additional data. The rendered frame content (e.g., 3D models) represents real and virtual content rendered during a CGR experience at a plurality of instants in time. The additional data of the second data stream relates to the CGR experience, for example, relating to audio, audio sources, metadata identifying detected attributes of the CGR experience, image data, data from other devices involved in the CGR experience, etc. The media compositor forms a composited stream that aligns the rendered frame content with the additional data for the plurality of instants in time, for example, by forming time-stamped, n-dimensional datasets (e.g., images) corresponding to individual instants in time.