FMTools is a repository of apps you can use to make your FM broadcast better, pirate or not this will help you if you don't have something, maybe you want a better stereo encoder? SCA? We have what you need, for RDS just use MiniRDS

fm95

FM95 is a audio processor for FM, it does:

Pre-Emphasis
Low Pass Filter
Stereo
SSB Stereo
Polar Stereo
Polar SSB Stereo (huh)

Supports 2 inputs:

Audio (via Pulse)
MPX (via Pulse) and one output:
MPX (via Pulse or ALSA)

Note that i haven't tested it, but i will on monday (29-01-25)

SCAMod

SCAMod is a simple FM modulator which can be used to modulate a secondary audio stream, has similiar cpu usage and latency as STCode

Has a fine quality, but as it goes for 12 khz fm signals

How to compile?

To compile you need cmake and libpulse-dev, if you have those then do these commands:

mkdir build
cd build
cmake ..
make

Done!