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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
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.core.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.util.example_audio_file())
>>> y_fast = librosa.effects.time_stretch(y, 2.0)

Or half the original speed

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