DechorderAutomatic Recognition of Chords in Music

Yuriy Guts

ProblemFor amateur musicians, ear training is hard

Requires Years of Practice

I’ve heard this so many times.It’s a II – V – I blues progression

starting with a B flat minor

Umm… it sounds minor-ish...Or is it a minor 7th?

How do I know for sure?

Maybe a Machine Can HelpAnalyze any piece of music through frequency decomposition

Detect the chords it’s built on

Provide insights into the structure of the song

System Scope

• Recording / importing audio• Submitting audio to the server• Playback and visualization

• Audio feature extraction• Learning and prediction model• Web API services

Client Side Server Side

Recognition: Step 1

Convert time domain to frequency domain(Fast Fourier Transform)

Produce chromagrams

Recognition: Step 2

Classify chromagrams with a Feed-Forward Neural Network

chord probabilities

chromastrengths

Client: iOS App

Audio Recording Data Persistence Audio Playback

Waveform VisualizationAsync Networking

Technology: Client

• Programming Language: Swift 2.1• Audio operations: AVFoundation, EZAudio• Persistence: CoreData (SQLite)• Network: Alamofire, SwiftyJSON

Technology: Server

• Programming language: Python 2• Preprocessing and feature extraction: scipy.signal• Machine Learning: scikit-learn, ffnet• API services: Flask-RESTful

Coming Soon to App Store :)

Dechorder