getEnv: Get amplitude envelope

In soundgen: Sound Synthesis and Acoustic Analysis

Get amplitude envelope

Description

Returns the smoothed amplitude envelope of a waveform on the original scale. Unlike seewave::env, this function always returns an envelope of the same length as the original sound, regardless of the amount of smoothing.

Usage

getEnv(
  sound,
  windowLength_points,
  method = c("rms", "hil", "peak", "raw", "mean")[1]
)

Arguments

sound	numeric vector
windowLength_points	the length of smoothing window, in points
method	'peak' for peak amplitude per window, 'rms' for root mean square amplitude, 'mean' for mean (for DC offset removal), 'hil' for Hilbert, 'raw' for low-pass filtering the actual sound

Examples

a = rnorm(500) * seq(1, 0, length.out = 500)
windowLength_points = 50
scale = max(abs(a))
plot(a, type = 'l', ylim = c(-scale, scale))
points(soundgen:::getEnv(a, windowLength_points, 'rms'),
       type = 'l', col = 'red')
points(soundgen:::getEnv(a, windowLength_points, 'peak'),
       type = 'l', col = 'green')
points(soundgen:::getEnv(a, windowLength_points, 'hil'),
       type = 'l', col = 'blue')
points(soundgen:::getEnv(a, windowLength_points, 'mean'),
       type = 'l', lty = 3, lwd = 3)

soundgen documentation built on Sept. 29, 2023, 5:09 p.m.