librosax.feature.spectral_rolloff

spectral_rolloff(*, y: Array | None = None, sr: float = 22050, S: Array | None = None, n_fft: int = 2048, hop_length: int = 512, win_length: int | None = None, window: str = 'hann', center: bool = True, pad_mode: str = 'constant', freq: Array | None = None, roll_percent: float = 0.85) → Array[source]

Compute roll-off frequency.

The roll-off frequency is defined for each frame as the center frequency for a spectrogram bin such that at least roll_percent (0.85 by default) of the energy of the spectrum in this frame is contained in this bin and the bins below. Users should ensure S is real-valued and non-negative.

Parameters:

  • y –

    Audio time series. The last axis must be time.

    • (T,) - single waveform

    • (B, T) - batch of waveforms

  • sr – Audio sampling rate

  • S – (optional) Pre-computed spectrogram magnitude with shape (..., F, N)

  • n_fft – FFT window size

  • hop_length – Hop length for STFT

  • win_length – Window length

  • window – Window function

  • center – If True, pad the signal

  • pad_mode – Padding mode

  • freq – Center frequencies for spectrogram bins. If None, FFT bin center frequencies are used. Assumed to be sorted in increasing order.

  • roll_percent – Roll-off percentage (0 < roll_percent < 1)

Returns:

Roll-off frequency with shape (..., 1, N).

  • (T,) → (1, N)

  • (B, T) → (B, 1, N)