Audio stream dependency information

There is disclosed inter alia an apparatus comprising means for receiving an audio format comprising a plurality of individual audio signal streams and metadata, wherein the metadata comprises a dependency field associated with each of the plurality of individual audio signal streams; means for determining that a dependency field associated with a first individual audio signal stream of the plurality of individual audio signal streams indicates that the first individual audio signal stream is related to a second individual audio signal stream of the plurality of individual audio signal streams; and means for encoding the first and second individual audio signal streams as a combined multichannel audio signal by an audio encoder.