RosaKit

RosaKit - LibRosa port to Swift for iOS and macOS platforms.

Library can generate Mel-spectrogram using Short-time Fourier transform (STFT) algorithm.

It's provide methods for calcualte Short-time Fourier transform window and Spectrogram.

Installation

Via CocoaPods:

pod 'RosaKit'

Goals

• Generate Spectrogram for visualisations

• Preprocessing steps for most Machine Learning models in Sound Recognition Sphere

Original Project:

https://librosa.github.io

melspectrogram:

https://librosa.github.io/librosa/generated/librosa.feature.melspectrogram.html

Usage in swift

You can use such code:

let rawAudioData = Data(...)

let chunkSize = 66000
let chunkOfSamples = Array(rawAudioData[0..<chunkSize])    

let powerSpectrogram = samples.melspectrogram(nFFT: 1024, hopLength: 512, sampleRate: Int(sampleRate), melsCount: 128)

Results of processing:

Please look in Examples

Used in Applications:

Decibel Meter:

https://apps.apple.com/app/decibel-meter/id1361845683?mt=12