Now a day later, I understand that the devices you mentioned -Roku, Blu Ray etc.- are sources not formats. When I push the Movie button on the AVR remote the default format is Dolby Surround, but there are several Dolby variations available and DTS, a competing format. Using the Music button, the default format is Audio Enhancer, designed to upgrade music to near HD levels. My question now is irrelevant, the AVR selects the format contained on/in the content -DVD or Blu Ray Movies or Music.
And BTW, according to my Sony manual, Dolby Surround recognizes Atmos content, making the information I was relying on from AVS Forum wrong.
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