I’ve got a question about the audio output from my Sonos Arc.  Currently, I have my Apple TV 4K connected to a HD Fury Arcana, which in turn is connected to my Sonos Arc for audio output and Vizio P75-F1 for video output.  Ever since I hooked up the Arcana back in September, I’ve been able to experience audio outputs from the Apple TV 4K ranging from Dolby Atmos to Dolby Digital 5.1 to Stereo 2.0, as confirmed in the About My System section of the Sonos app.  However, tonight I noticed in the Sonos app that Dolby Digital 5.1 is now listed as Multichannel PCM 5.1 and Stereo 2.0 is listed as Stereo PCM 2.0.  Does anyone know what might’ve changed in my A/V setup? I’m assuming one of these components had a recent software update which lead to these differences.

More importantly, can someone clarify for me if Dolby Digital 5.1 and Multichannel PCM 5.1 are the same audio output?

Sonos OS: S2 

Sonos Arc: version 12.2

Apple TV 4K: tvOS 14.2