You too can be a synesthete! With this python script You can create simple melodies, or cacophonies, from images. Yes, it means You can actualy hear the images.
- PIL
- pygame - only for playing final midi song
- midiUtil: https://code.google.com/p/midiutil/
- Clone or download
- In cmd type:
python img2midi.py input.jpg song.midi --play - Enjoy
input and output are required to run script, play flag is optional. Script will create midi file. Please note: The larger the input image file the longer final song will be.
Converter uses naive way of converting pixel colors to midi notes. Each pixel's color consists of RGB components and each of those components has a value in range [0; 255]. Midi notes can take any value from 21 - A0 note(low A, 0th octave), to 108 - C8 (high C, 8th octave) note, therefore conversion between those ranges must be made. For simplicity I arbitrarily decided that, final song's tempo will be 240 BPM.
Color to pitch conversion is made using following algorithm for every pixel:
- Take average of RGB color components of a pixel. This will be value in range (0; 255)
- Divide it by 2, this value was arbitrarily decided, so that final notes will be less spread out on a scale
- Normalize it by dividing by 255
- Using linear interpolation convert normalized pixel value to note.
- This is a final midi note value in range [21; 108]
Base note duration was chosen to be 1 beat. However if the same value is repeated in the final song data 1 beat is added for each repetition.
Example:
[50, 50, 50, 80, 40, 40, 50, 50] will result in 4 notes:
- D3(50) with duration of 3 beats
- G#5(80) with duration of 1 beat
- E2(40) with duration of 2 beats
- D3(50) with duration of 2 beats