That looks like a stand-alone STK-based app.
In principle a new Bela backend could be added to
RtAudio.h, so this will help with porting this and other STK. However, there is also lots of GUI stuff in there (see
rt_lpc.cpp), that would not work on Bela, so there is stuff to be edited out there as well.
It seems that all the audio thread is doing (see
cb()) is simply copying input samples into
g_audio_buffer and then output samples from
outBuffy, while the actual LPC computation is performed in the GUI thread (
displayFunc()), where (lines 930 to 952) the calls to
lpc_synthesize() take place.
I think that you could just add the relevant files (possibly just
lpc.h to a Bela project (whatever you do, make sure you don't add a function called
main(), or it will take the place of Bela's one and nothing will work), call
setup(), lines 930to952 of
rt_lpc.cpp in an
AuxiliaryTask, and what is needed to pass data to the auxiliary task in
render(). Not straightforward, but doable.