librosa.effects.time_stretch¶

librosa.effects.time_stretch(y, *, rate, **kwargs)[source]¶

Time-stretch an audio series by a fixed rate.

Parameters

ynp.ndarray [shape=(…, n)]: audio time series. Multi-channel is supported.
ratefloat > 0 [scalar]: Stretch factor. If rate > 1, then the signal is sped up. If rate < 1, then the signal is slowed down.
**kwargsadditional keyword arguments.: See librosa.decompose.stft for details.

Returns

y_stretchnp.ndarray [shape=(…, round(n/rate))]: audio time series stretched by the specified rate

See also

pitch_shift: pitch shifting
librosa.phase_vocoder: spectrogram phase vocoder
pyrubberband.pyrb.time_stretch: high-quality time stretching using RubberBand

Examples

Compress to be twice as fast

>>> y, sr = librosa.load(librosa.ex('choice'))
>>> y_fast = librosa.effects.time_stretch(y, rate=2.0)

Or half the original speed

>>> y_slow = librosa.effects.time_stretch(y, rate=0.5)