We're happy to announce that libsigrokdecode now supports the pwm protocol decoder.
The PD was contributed by Torsten Duwe and Sebastien Bourdelin, thanks a lot!
This decoder will show the duty cycle of any signal, which in practice can mean various things. E.g. Class-D amplifiers can use PWM to encode audio data.
We have a test file in the sigrok-dumps repository containing audio data.
The decoder also supports a binary output facility which you can use to decode the audio (a direct export to WAV is planned as well, though).
$ sigrok-cli -i pwmtest.sr -P pwm:data=4 -B pwm=raw > PWM.raw $ sox -t raw -e unsigned -b 8 -r 64000 PWM.raw PWM.wav $ aplay PWM.wav