CS 525 Semester Project Audio Signal MIDI Transcription Music Transcription Extraction of onset duration and pitch information from digital audio signals Twophased approach Extract Temporal Information Onset amp Duration ID: 342259
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Devon BryantCS 525 Semester Project
Audio Signal MIDI TranscriptionSlide2
Music Transcription
Extraction of “onset”, “duration”, and “pitch” information from digital audio signals
Two-phased approach
Extract Temporal Information (Onset & Duration)
Extract Frequency Information (Pitch)
Many applications
MIDI representation for low bandwidth
Sheet music score generation
Comparison against DB for copyright or searchSlide3
Extraction of Temporal EventsSlide4
Extraction of Temporal Events
Spectral Flux – change in magnitude spectrum between consecutive frames
“Onsets” = window start, “Offsets” = window stop
Audio File
Frames
FFT
MagSlide5
Extraction of Pitch InformationSlide6
Extraction of Pitch Information
Process event frames through Fast Fourier Transform (FFT) to bin frequencies
Use a-priori instrument knowledge to find fundamental
f
0
frequencies in spectrum
Event Window Frames
FFT
f
0
Estimation
MIDI FileSlide7
Issues Encountered
Noise artifacts or fluctuations can trigger false onsets
Frequency resolution on shorter events/notes is poorSlide8
Results
Single Note Scale
Original audio
Transcribed MIDI
Chords
Original audio
Transcribed MIDI
Short Song
Original audioTranscribed MIDISlide9
Questions?