Abstract: As digital media are being generated, a live preview of how that media would be presented—if encoded, stored, decoded, and presented from the decoded form—is presented to a user. The user can order changes to some or all of the encoding format or its parameters, with the effect of noting immediately what those changes would do to the nature of the output from that changed encoded form. The live preview is computed and presented by a computing device without any gaps or other jarring transitions between before and after the changes ordered by the user.