librosa.feature.zero_crossing_rate(y, *, frame_length=2048, hop_length=512, center=True, **kwargs)[source]

Compute the zero-crossing rate of an audio time series.

ynp.ndarray [shape=(…, n)]

Audio time series. Multi-channel is supported.

frame_lengthint > 0

Length of the frame over which to compute zero crossing rates

hop_lengthint > 0

Number of samples to advance for each frame


If True, frames are centered by padding the edges of y. This is similar to the padding in librosa.stft, but uses edge-value copies instead of zero-padding.

**kwargsadditional keyword arguments to pass to librosa.zero_crossings
thresholdfloat > 0 or None

If specified, values where -threshold <= y <= threshold are clipped to 0.

ref_magnitudefloat > 0 or callable

If numeric, the threshold is scaled relative to ref_magnitude. If callable, the threshold is scaled relative to ref_magnitude(np.abs(y)).


If True then the value 0 is interpreted as having positive sign. If False, then 0, -1, and +1 all have distinct signs.


Axis along which to compute zero-crossings. .. note:: By default, the pad parameter is set to False, which differs from the default specified by librosa.zero_crossings.

zcrnp.ndarray [shape=(…, 1, t)]

zcr[..., 0, i] is the fraction of zero crossings in frame i

See also


Compute zero-crossings in a time-series


>>> y, sr = librosa.load(librosa.ex('trumpet'))
>>> librosa.feature.zero_crossing_rate(y)
array([[0.044, 0.074, ..., 0.488, 0.355]])