# spectralRolloffPoint

Spectral rolloff point for audio signals and auditory spectrograms

## Syntax

## Description

returns the spectral rolloff point of the signal, `rolloffPoint`

= spectralRolloffPoint(`x`

,`f`

)`x`

, over time. How the
function interprets `x`

depends on the shape of
`f`

.

specifies options using one or more name-value arguments.`rolloffPoint`

= spectralRolloffPoint(`x`

,`f`

,`Name=Value`

)

`spectralRolloffPoint(___)`

with no output arguments
plots the spectral rolloff point. You can specify an input combination from any of the
previous syntaxes.

If the input is in the time domain, the spectral rolloff point is plotted against time.

If the input is in the frequency domain, the spectral rolloff point is plotted against frame number.

## Examples

## Input Arguments

## Output Arguments

## Algorithms

The spectral rolloff point is calculated as described in [1]:

$$\text{rolloffPoint}=i$$

such that

$$\sum _{k={b}_{1}}^{i}{s}_{k}}=\kappa {\displaystyle \sum _{k={b}_{1}}^{{b}_{2}}{s}_{k}$$

where

*s*is the spectral value at bin_{k}*k*.*b*_{1}and*b*_{2}are the band edges, in bins, over which to calculate the spectral spread.*κ*is the percentage of total energy contained between*b*_{1}and*i*. You can set*κ*using`Threshold`

.

## References

[1] Scheirer, E., and M. Slaney,
"Construction and Evaluation of a Robust Multifeature Speech/Music Discriminator,"
*IEEE International Conference on Acoustics, Speech, and Signal
Processing*. Volume 2, 1997, pp. 1221–1224.

## Extended Capabilities

## Version History

**Introduced in R2019a**