Spectrum fails with odd frame sizes, Uncaught WASM error

[jmarcosfer]

What is the issue about?

• Bug
• Feature request
• Usage question
• Documentation
• Contributing / Development

What part(s) of Essentia.js is involved?

• essentia.js-core (vanilla algorithms)
• essentia.js-model (machine learning algorithms)
• essentia.js-plot (plotting utility module)
• essentia.js-extractor (typical algorithm combinations utility)

Description

Any odd frame size for the Spectrum algorithm produces an uncaught WASM error. Neither the Essentia.js documentation nor the upstream docs mention that frame size should be even or a power of two.

Steps to reproduce / Code snippets / Screenshots

	const frames = self.essentia.FrameGenerator(msg.data.audio, frameSize, frameSize*0.5);
	for (let i = 0; i < frames.size(); i++) {
		const audioVector = frames.get(i);
		const windowedFrame = self.essentia.Windowing(audioVector, true, frameSize).frame;
		const spectrum = self.essentia.Spectrum(windowedFrame, frameSize).spectrum;
		const mfccs = self.essentia.MFCC(spectrum, 2, 11000, spectrum.size()).mfcc;
		corpusArray.push({
			id: corpusSizeCount,
			frame: self.essentia.vectorToArray(audioVector),
			analysis: self.essentia.vectorToArray(mfccs)
		});
		corpusSizeCount++;
	}

For odd frame sizes, this produces the following error on the dev console:

System info

Hardware: MacBook Pro 15 inch 2018, 16GB RAM, 2,2 GHz Intel Core i7 6 cores
OS: macOS Catalina 10.15.7
Platform: Chrome 96.0.4664.110
Library version: Essentia.js 0.1.3

[pnocera]

Did you get a workaround for this ? I'm facing the same issue.

Edit : it doesn't break with a frame of size 2048. In this case the spectrum size is 1025 and the mfcc gets calculated.