Abstract: A method or system including receiving a first single data stream representing a first multimedia file, the first single data stream including an interleaved sequence of data elements of a plurality of different types of media, and/or transmitting a second single data stream representing a second multimedia file, the second single data stream including an interleaved sequence of data elements of a plurality of different types of media, where the second multimedia file differs from said first multimedia file by at least one data element of a selected medium extracted from said first multimedia file, and/or by at least one data element of a selected medium added to the first multimedia file, and/or by at least one data element of a selected medium added to the first multimedia file being a converted version of the at least one data element of a selected medium extracted from the first multimedia file.