transcoding only for selected devices

[simoncn]

This might be possible, depending on how your control point and renderers work.

The control point issues UPnP Browse requests to the server (step 1). The results returned by the server include the audio MIME type of each track (step 2). The control point then sends the track details to the selected renderer (step 3) and the renderer requests the track from the server (step 4) and plays it.

This means the server has to commit to the MIME type (in your case, either DSF or WAV) at step 2. It can't change its mind at step 4, even if it knows that something else would be more suitable for the chosen renderer (which isn't possible using the UPnP protocol, but might be discoverable in some other way). Actually, it could change its mind and send a different MIME type, but this would be breaking the UPnP rules and might work with some renderers but not with others.

There is a UPnP tweak on this that can help in some cases, including yours. In step 2, the server can send multiple streams with different MIME types and let the control point choose which one to use for the renderer that the user has selected. For step 3, the control point can ask the renderer which MIME types it supports and can make sure it sends a stream that is OK for the renderer. Unfortunately, this part of the UPnP protocol is optional and not all renderers and control points support it.

You can try this out by setting stream.transcode to "flac:wav, dsf:-/wav24;88". With this setting, MinimServer sends the control point a DSD64 stream and a 24/88200 WAV stream in step 2 for each DSF track. The control point can ask the selected renderer whether it supports DSD64. If so, it can tell the renderer to play the DSD64 stream. If not, it can tell the renderer to play the WAV stream.

I will be interested to hear whether this works with your setup.