What I did creates an ALSA loopback device that appears as a virtual sound card named "BotWave". Any audio application can output to it for immediate FM transmission. For networked setups, I built PCM streaming using HTTP octet-stream.
Some details: On install, the ALSA snd-aloop module is configured at system level, It uses pyalsaaudio for audio capture (48kHz stereo default), Async/sync generator bridging for the existing broadcast infrastructure, Tested with aplay/VLC/ffmpeg, works reliably
The feature is complete and testable on the livestream-test branch. I'm looking for feedback before merging to main, especially from anyone who's used raspotify or snapcast with ALSA devices. (I wasn't able to use raspotify since i don't have a premium Spotify account)