Avoiding internet radio transcoding to BubbleUPnP

I'm using BubbleUPnP on an old SGS1 (flashed to AOSP 4.2.2) as my renderer on an audio-only setup.

Playback of regular files is fine -- both high-bitrate AAC and lossless stuff -- but internet radio streams in various formats all seem to be transcoded down to 48kbps mp3. This is not only losing fidelity but creating some nastily audible artefacting. Is there something in the generic playback profile or how it interacts with online streams that might explain this? I tried setting it to use the most recent Samsung profile instead, but that didn't help.

Same thing seems to happen whether I select the stream from a separate control device or from the Library listing on the client.

[Illico]

Is there something in the generic playback profile or how it interacts with online streams that might explain this?

The Geneic profile (samsung too) transcode online audio to mp3 with 384kbps bitrate.
<Audio targetContainer="mp3" aBitrate="384" forceInheritance="true">

You can try to change the profiles.xml with
aBitrate="192" or aBitrate="128"
You can also try to change to
<Audio targetContainer="lpcm" forceInheritance="true">