pylibrb (py-lib-rubberband) is a simple Python extension exposing Rubber Band Library using nanobind bindings.
Since this is not a wrapper around a command-line tool (like pyrubberband), both offline and real-time modes are available.
Currently this extenstion exposes only a single class: RubberBandStretcher
, which implements all the functionalities of the underlying C++ class. The interface is nearly identical to the original library, with a few changes to make it a bit more Pythonic by:
- using
snake_case
for functions, variables and properties, andSNAKE_CASE
for constants - not using (magic) numbers to represent the state
- use
is_done()
to see if all the data has been processed and returned from the stretcher, instead ofavailable() == -1
- use
stretcher.formant_scale = pylibrb.AUTO_FORMANT_SCALE
instead ofstretcher.formant_scale = 0
- use
Throughout the library, audio is accepted and returned in the form of NumPy ndarrays.
from pylibrb import RubberBandStretcher, Option, create_audio_array
# create a stretcher
stretcher = RubberBandStretcher(sample_rate=16000,
channels=1,
options=Option.PROCESS_REALTIME | Option.ENGINE_FINER,
initial_time_ratio=0.5)
stretcher.set_max_process_size(1024)
# provide the audio to the stretcher, until some output is available
audio_in = create_audio_array(channels_num=1, samples_num=1024)
while not stretcher.available():
audio_in[:] = 0 # get the next batch of samples, here we just use silence
stretcher.process(audio_in)
# retrieve the available samples
audio_out = stretcher.retrieve_available()
For more instructions, read the docstings of the RubberBandStretcher
class and the Option
enum, or see the documentation of Rubber Band Library.