sakemin / pytsmod

PyTSMod is an open-source library for Time-Scale Modification(eg. time-stretching) algorithms, by Sangeon Yong at MAC Lab, KAIST.

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PyTSMod

PyTSMod is an open-source library for Time-Scale Modification algorithms in Python 3. PyTSMod contains basic TSM algorithms such as Overlap-Add (OLA), Waveform-Similarity Overlap-Add (WSOLA), Time-Domain Pitch-Synchronous Overlap-Add (TD-PSOLA), and Phase Vocoder (PV-TSM). We are also planning to add more TSM algorithms and pitch shifting algorithms.

Time Stretching

  • With the methods OLA, WSOLA and PV-TSM, constant ratio time stretching is available with s_fixed value, and also dynamic time stretching is available with s_ap.
  • s_ap takes anchor point pair values in dict format.
  • Anchor point value is based on 0~1, 0 means the starting point of audio, and 1 means the end point of audio. (eg. 0:0, 0.5:1, 1:1.7 means first half;0~50% of the audio will be stretched 2x, and the last half;50~100% of the audio will be streched 140%.)
  • With setting absolute_second as True, anchor point value is taken with absolute second metric.

Key/Pitch Shifting

  • TD-PSOLA method offers key/pitch shifting in both constant and dynamic ways.
  • Key shifting is available with setting td_psola_pitch_shift as key.
  • td_psola_key_updown for fixed constant key shifting.
  • td_psola_dynamic_key for dynamic key shifting. Must be formatted in dict type[relative frame ratio(0.0~1.0):key_shift_amount]. (eg. [0.3:0, 0.6:1, 1:-2] means for first 0 ~ 30% part of the audio, it keeps the original key, for 30 ~ 60% key is shifted +1 and for 60 ~ 100% key is shifted -2.)
  • Pitch shifting is available with setting td_psola_pitch_shift as pitch.
  • td_psola_pitch_ratio for fixed constant pitch shifting.
  • td_psola_dynamic_pitch for dynamic pitch shifting. Must be formatted in dict type[relative frame ratio(0.0~1.0):pitch_shift_amount]. (eg. [0.5:1, 0.8:2, 1:1.3] means for first 0 ~ 50% part of the audio, it keeps the original key, for 50 ~ 80% pitch is shifted +1 octave and for 80 ~ 100% pitch is shifted 130% of original pitch value.)
  • With setting absolute_second as True, anchor point value is taken with absolute second metric.

Take a look of Examples for the use cases.

Full documentation is available on https://pytsmod.readthedocs.io