Ogre Toolbox

Main Entry: ogre

Part of Speech: noun

Definition: nasty person

Synonyms: bogey, bogeyman, demon, devil, fiend, giant, monster, monstrosity, specter, spectre

Source: Roget's New Millennium Thesaurus, First Edition (v 1.2.1)

Entry: spectre

n 1: a ghostly appearing figure; "we were unprepared for the apparition that confronted us"

[syn: apparition, phantom, phantasm, phantasma, specter]

n 2: a mental representation of some haunting experience; "he looked like he had seen a ghost";

"it aroused specters from his past" [syn: ghost, shade, spook, wraith, specter]

Entry: Ogre Toolbox

Set of Matlab routines that allow manipulations sounds by rendering them into different spectral representations and later combining parts of these representations to create a new spectral form that can be eventually rendered into sound.

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Current representations (Ogre types):

Stft – Short Time Fourier Transform

LPC – Linear Prediction

Welch – Short time Welch method of power spectral estimation

Cepst – Cepstral Analysis

Ogre inversion:

Not all methods can be inverted directly into sound. Here is a list of inversion methods

IStft – Inverse Stft. Requires complex spectrum (Amplitude and Phase).

IStftw2 – Least Square Error Method of IStft. Requires complex spectrum as well.

LSEE – Least Square Estimation Error Method that can be used to invert spectral magnitudes, also called “phase-less reconstruction”.

Ogre Crossing:

New Ogres can be created by combination of Ogre parts. Known types of transformations that can be implemented using the toolbox include:

Moving Convolution

Spectral Mutations

Sound Crossing / Hybridization

Other tools:

Pvinterp – phase vocoder type of Stft interpolation. Includes both magnitude and phase interpolation. Can be used for time stretching or pitch shifting

Specinterp – interpolation of spectral magnitudes only.

(Last updated May 23, 2006):