         By the application of alternate_group in the Track Header Box, whole audio channels in all active tracks from
            non-alternate group and/or different alternate group from each other are composited into the presentation. If
            an Opus sample consists of multiple Opus bitstreams, it can be splitted into individual Opus bitstreams and
            reconstructed into new Opus samples as long as every Opus bitstream has the same total duration in each Opus
            sample. This natur