OK, so these really need to be 2 separate questions, otherwise no one can tell exactly what you are after.
Still, on the one hand, you say "yes" you have CDs that you have ripped to FLAC, and you'd like to "convert" them to DSD.
Even that is not very clear, as "convert' literally means to take the file and convert it once and for all to DSD, the result being you no longer have a FLAC file at all, you have a DSD file. Conversion software of that type is professional level and expensive,
Weiss Saracon for example. Almost no one does that both for the cost consideration of the software, and also because the resulting file is MUCH larger to both store and stream than a Redbook CD file is, not to mention the marginal improvement in sound quality.
I think what you really mean is you have FLAC files that you'd like to upsample or transcode to DSD on-the-fly for playback purposes, meaning you aren't actually converting the file once and for all, you'd like to keep it in FLAC format for the storage savings that affords, and play it back as DSD?
That is much more easily and affordably accomplished, though I'm relatively sure no one here can tell you how to do that with Pine Player, and I'd urge you to seek out a Pine Player forum to discuss that aspect if you are married to that software.
The way most people would do that on a Mac computer is with Audirvana. No, it is not free. Yes, it is excellent player software that would allow you to transcode on-the-fly to DSD, over the previously mentioned DLNA/UPnP protocol. Audirvana would be the server, and it would stream directly to the Oppo 203 setup as a DLNA/UPnP Renderer/Endpoint/Streamer.
If you don't understand any of the above terminology, Google is your best friend, or we'd be happy to help you understand it here, but we can't easily decipher vague posts that mention two different things at once.
Lastly, I moved your original post on this topic here from the SACD ripping thread, because it has nothing to do with ripping SACD. Please try to stay on-topic in that regard. Thank you.