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 .