When building a show with a main feature containing a Dolby Surround 7.1
audio track, it is likely that some preshow content will contain 5.1 discrete
audio. In this case, users must ensure that the cinema processor is in a 5.1
discrete mode at the start of the show, and the cinema automation system must
change the cinema processor decode mode, switching to Dolby Surround 7.1 at
the appropriate point for the Dolby Surround 7.1 content. Trailers supplied with
a Dolby Surround 7.1 feature may also have 7.1 audio tracks, and this should be
considered when cues are placed to select Dolby Surround 7.1 mode.