Data-Driven DJ Track 2: Rhapsody In Grey
You can listen to this track and read the full description here.
All software required for making this song from scratch is free and open-source
- ChucK - a programming language for real-time sound synthesis and music creation
- Python - I am running version 2.7.3
- Processing - optional, for supporting visualization
Select And Process Data
- Download an .edf file from PhysioNet. In my piece, I selected chb01_15.edf, which is the fifteenth hour of the first patient's session. Files that contain seizures are marked with .seizures. You can also look at a patient's summary file for more details about when the seizures occur.
- Open the file preprocess_data.py and update the config at the top:
- INPUT_FILE: the file that you downloaded from the previous step
- SEIZURE_START/SEIZURE_END: when the seizure starts/ends in seconds (found in the patient's summary file)
- SONG_START/SONG_END: when the song starts/ends; the song should start before the seizure start and end after the seizure end
python preprocess_data.pyfrom the command line in this directory
- This generates
data/eeg.csvwhich will be used to generate your song later steps
Prepare Sound And Configure Files
- Create a tab-delimited instruments.csv file based on instruments.csv.sample file and place in folder
- Channel is the electrode associated with this instrument. A value of "all" will be applied to all channels
- Amp Min and Amp Max are the amplitude range the instrument is allowed to play in. This value is normalized between 0 and 1.
- Freq Min and Freq Max are the frequency range the instrument is allowed to play in. This value is normalized between 0 and 1.
- Sync Min and Sync Max are the syncrony range the instrument is allowed to play in. This value is normalized between 0 and 1.
- File is the filename of the instruments sound file
- From Gain and To Gain is the volume range this instrument can oscillate between. A value of 0 is silent.
- Tempo is the relative tempo of the instrument. A value of 1 is standard BPM, 2 is twice as fast, 0.5 is twice as slow.
- Tempo Offset is the offset as a percentage of the instruments tempo. For example if an instrument's tempo is 1 and the tempo offset is 0.5, the instrument will on the half beat.
- Interval Phase, Interval, Interval Offset control at what intervals the instruments can play. For example, if interval phase is 16, interval is 2, and interval offset is 1, every 16 beats, the instrument can play on the 2nd half of the beats (8-16).
- Active essentially activates or deactivates an instrument
- Prepare all your sound files and place in folder
/instruments. All files should be in .wav format. For best results, I'd recommend using very short clips (< 500ms).
Configure The Scripts
- Python script: brain.py
- BPM is the song's beats per minute. I'd recommend using 60, 75, 100, 120, or 150. You will otherwise run the risk of having rounding errors caused by flaws in this script--sorry!
- DIVISIONS_PER_BEAT is how the beats are divided. For example, a value of 4 would create quarter-notes as the smallest unit, 8 would create eighth-notes, etc.
- ChucK script: brain.ck
- padding is the amount of milliseconds before and after the song.
- instrument_buffers is the number of buffers each instrument has. If you hear clipping in your song, you will want to increase this number.
- start is which millisecond you would like the song to start on. Useful for debugging a particular part of the song.
Generating The Song
python brain.pyin the project's directory. This will generate two files that ChucK will use:
data/ck_instruments.csv: A manifest of instrument files
data/ck_sequence.csv: A sequence of instruments
- Open up brain.ck in ChucK. You can either export the song to .ogg/.wav or start your VM and add a new shred
Generating The Visualization
- Open visualization/visualization.pde in Processing. This script generates a scrolling EEG brain wave visualization.
- this script uses data (eeg.json) generated from previous python script
boolean captureFrames = true;to output frames to output folder
- run script, this will generate frames at the framerate (
fps) in the configuration.