@remotion/media-utils
Version:
Utilities for working with media files
34 lines (33 loc) • 1.31 kB
JavaScript
;
// Adapted from node-fft project by Joshua Wong and Ben Bryan
// https://github.com/vail-systems/node-fft
Object.defineProperty(exports, "__esModule", { value: true });
exports.fftAccurate = void 0;
const complex_1 = require("./complex");
const exponent_1 = require("./exponent");
const fftAccurate = function (vector) {
const X = [];
const N = vector.length;
// Base case is X = x + 0i since our input is assumed to be real only.
if (N === 1) {
if (Array.isArray(vector[0])) {
// If input vector contains complex numbers
return [[vector[0][0], vector[0][1]]];
}
return [[vector[0], 0]];
}
// Recurse: all even samples
const X_evens = (0, exports.fftAccurate)(vector.filter((_, ix) => ix % 2 === 0));
// Recurse: all odd samples
const X_odds = (0, exports.fftAccurate)(vector.filter((__, ix) => ix % 2 === 1));
// Now, perform N/2 operations!
for (let k = 0; k < N / 2; k++) {
// t is a complex number!
const t = X_evens[k];
const e = (0, complex_1.complexMultiply)((0, exponent_1.exponent)(k, N), X_odds[k]);
X[k] = (0, complex_1.complexAdd)(t, e);
X[k + N / 2] = (0, complex_1.complexSubtract)(t, e);
}
return X;
};
exports.fftAccurate = fftAccurate;