The 970 will detect the incoming format and switch accordingly; this is true of any surround processor or receiver, and is necessary because trying to apply Dolby Digital to a DTS input would produce an audio mess that could damage speakers or other equipment. It will identify PCM, DTS, Dolby Digital, DTS-ES, and Dolby Digital EX and react accordingly. It will also (based on the notes about the changes to the 1070 software) remember which mode you prefer to use with Dolby 5.1 on the active input (such as Dolby Digital plus Pro Logic IIx to get surround back on a DD 5.1 track on the DVD input or straight stereo on a PCM track on the CD input) and overlay any additional processing if desired.