I use Roon for two channel audio. The Oppo can't receive multi-channel audio via Roon. This is a limitation with the Oppo, not Roon. The Oppo can play .dsf and FLAC files via USB, but only FLAC is gapless hence the need for encoding the multi-channel files. It looks like any of the DSD to FLAC encoders will work, I'm just wondering if one's better than another or if there's a setting I should use for best results.
Got it, so for multichannel playback you would just connect a USB drive to the Oppo housing those multichannel files and playback that way?
Beyond the fact I don't have a multichannel system, I have also only ever made limited use of FLAC, because many years ago when I used iTunes+BitPerfect, the default had to be ALAC on macOS.
It wasn't until some years later when I migrated to JRiver that FLAC even became a possibility for me, but by that time I had ripped most all of my CDs to ALAC. So the only FLAC files I have are in the form of download purchases from HDtracks and the like, I've never actually played around with those settings and unlike with FLAC, ALAC has no similar compression settings, it's fixed (typical Apple heavy handed control).