Is mel-spectrum available? about meyda

[hughrawlinson]

Yes, you can get the raw mel filter banks by calling the createMelFilterBank function from meyda/dist/esm/utilities. I made a quick demo here. Heads up: I suspect that future versions of Meyda might change how we export this, but I haven't decided yet, so keep an eye on the 6.0.0 breaking changes when that comes out.

Let me know if I can help with anything else!

[Oortone]

Ok, I see, but I need to add that in the Node client version somehow to make use of it offline? Probably easy for anyone familiar with Node, but I'm not sure how to add that into the extraction flow easily. Thanks anyway.

[hughrawlinson]

I can write you a little CLI to output the Mel Filter Bank - but I think we might be understanding the Mel Filter Bank in different ways. From my understanding of the code, the Mel Filter Bank isn't based on the signal, and therefore isn't an extracted feature - it's a list of filter coefficient sets that are used when computing the MFCCs. So in the CLI, they would just stay the same for every chunk of the audio input.

As for the MelScaled Spectrum, I would think that would mean a spectrum where the X-axis is Mels, rather than frequency. That's a different thing to the Mel filter bank. Is that what you're hoping to get?

[Oortone]

Ah, yes. Mel Scaled Spectrum is what I mean.
Isn't that generated by a matrix calculation of the amplitudeSpectrum and the mel filter bank?
Seems it might be posiible to generate using Tensorflow, there's:
tf.signal.linear_to_mel_weight_matrix

Don't know if it's in the .js version but the matrix can probably be exported.
But of course, having it as features directly is the best :-)

[hughrawlinson]

Yes, I think having it as a feature would be good! I'll convert this issue to represent a feature request.