pylibrb 0.0.7

Python bindings for the RubberBand library

pylibrb

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 app (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, and SNAKE_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 of available() == -1
  • use stretcher.formant_scale = pylibrb.AUTO_FORMANT_SCALE instead of stretcher.formant_scale = 0
• not using final argument in process()
  • use flush() to finish processing and get the remaining samples

Throughout the library, audio is accepted and returned in the form of NumPy ndarrays.

Example

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(stretcher.available())

For more instructions, read the docstings of the RubberBandStretcher class and the Option enum, or see the documentation of Rubber Band Library.