The python script can handle both encoded .wav as well as raw PCM streams. But if you’re using .wav files it can deduce the encoding from the data header which is a bit easier.
Excuses for the delay, I’ve made a PR with an implementation of the sample rate converter inside audio::TargetFile (though I’m not completely happy with it).
We can further discuss it here: https://github.com/cinder/Cinder/pull/1869