I've been working on BotWave, which turns a Raspberry Pi into an FM transmitter.
A user requested live streaming support so apps like Spotify (via raspotify) or
Snapcast could broadcast directly to FM instead of just playing files.
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)
If you have some spare rpis and a radio it can be pretty interesting to set it up to check on it, tho there are no "real world" utilities, since as the other comments mentions, it is illegal to use that as it is
After seeing some comments, I'd wan't to specify something that isn't really mentionned in the readme or anywhere but, this project doesn't aim to replace professional setups nor cover long ranges (that would be absolutely irresponsible to try to). I think it's mostly aimed to cover a house, garage or to be in a sort of "big faraday cage" for your own personal use, if you have some pis and radios laying around.