librosa.util.frame

librosa.util.frame(y, frame_length=2048, hop_length=512)

Slice a time series into overlapping frames.

This implementation uses low-level stride manipulation to avoid redundant copies of the time series data.

Parameters:

y : np.ndarray [shape=(n,)]

Time series to frame. Must be one-dimensional and contiguous in memory.

frame_length : int > 0 [scalar]

Length of the frame in samples

hop_length : int > 0 [scalar]

Number of samples to hop between frames

Returns:

y_frames : np.ndarray [shape=(frame_length, N_FRAMES)]

An array of frames sampled from y: y_frames[i, j] == y[j * hop_length + i]

Raises:

ParameterError

If y is not contiguous in memory, not an np.ndarray, or not one-dimensional. See np.ascontiguous() for details.

If hop_length < 1, frames cannot advance.

If len(y) < frame_length.

Examples

Extract 2048-sample frames from y with a hop of 64 samples per frame

>>> y, sr = librosa.load(librosa.util.example_audio_file())
>>> librosa.util.frame(y, frame_length=2048, hop_length=64)
array([[ -9.216e-06,   7.710e-06, ...,  -2.117e-06,  -4.362e-07],
       [  2.518e-06,  -6.294e-06, ...,  -1.775e-05,  -6.365e-06],
       ...,
       [ -7.429e-04,   5.173e-03, ...,   1.105e-05,  -5.074e-06],
       [  2.169e-03,   4.867e-03, ...,   3.666e-06,  -5.571e-06]], dtype=float32)