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Running on Zero
| #!/usr/bin/env python3 | |
| """Trap Style MIDI Transformer""" | |
| import pretty_midi as pm | |
| import numpy as np | |
| import random | |
| from pathlib import Path | |
| class TrapTransformer: | |
| def __init__(self, bpm=140): | |
| self.bpm = bpm | |
| self.beat_duration = 60.0 / bpm | |
| def extract_bass_notes(self, midi_data): | |
| """Pull low notes that can become 808s""" | |
| bass_notes = [] | |
| for track in midi_data.instruments: | |
| if track.is_drum: | |
| continue | |
| for note in track.notes: | |
| if note.pitch < 48: # Below C3 | |
| bass_notes.append(note) | |
| return bass_notes | |
| def create_808_bass(self, bass_notes, duration_seconds): | |
| """Longer sustain + louder = 808 feel""" | |
| enhanced = [] | |
| for note in bass_notes: | |
| new_note = pm.Note( | |
| velocity=min(note.velocity + 20, 127), | |
| pitch=note.pitch, | |
| start=note.start, | |
| end=min(note.end + 0.3, duration_seconds), | |
| ) | |
| enhanced.append(new_note) | |
| return enhanced | |
| def add_hi_hats(self, duration_seconds): | |
| """Fast hi-hat rolls (trap signature)""" | |
| hat_track = pm.Instrument(program=0, is_drum=True, name="HiHats") | |
| t = 0.0 | |
| while t < duration_seconds: | |
| step = self.beat_duration / 4 # 1/16 notes | |
| if random.random() < 0.3: # 30% chance → roll | |
| rolls = random.choice([4, 8]) | |
| for i in range(rolls): | |
| hat_track.notes.append( | |
| pm.Note( | |
| velocity=random.randint(80, 120), | |
| pitch=42, | |
| start=t + (i * step / rolls), | |
| end=t + ((i + 1) * step / rolls), | |
| ) | |
| ) | |
| else: | |
| hat_track.notes.append( | |
| pm.Note( | |
| velocity=random.randint(90, 115), | |
| pitch=42, | |
| start=t, | |
| end=t + step * 0.5, | |
| ) | |
| ) | |
| t += step | |
| return hat_track | |
| def add_trap_drums(self, duration_seconds): | |
| """Half-time kicks + snares""" | |
| drum_track = pm.Instrument(program=0, is_drum=True, name="TrapDrums") | |
| bar = self.beat_duration * 2 # Half-time bar | |
| num_bars = int(duration_seconds / bar) | |
| for b in range(num_bars): | |
| kick_t = b * bar | |
| snare_t = b * bar + self.beat_duration # Snare on beat 3 (half-time) | |
| drum_track.notes.append( | |
| pm.Note(velocity=120, pitch=36, start=kick_t, end=kick_t + 0.1) | |
| ) | |
| drum_track.notes.append( | |
| pm.Note(velocity=110, pitch=38, start=snare_t, end=snare_t + 0.08) | |
| ) | |
| return drum_track | |
| def apply_sidechain(self, midi_data, kick_times): | |
| """Simulate sidechain pump — duck melody before kicks""" | |
| for instrument in midi_data.instruments: | |
| if instrument.is_drum: | |
| continue | |
| for note in instrument.notes: | |
| for kt in kick_times: | |
| if note.start <= kt <= note.end: | |
| note.velocity = max(1, note.velocity - 10) | |
| return midi_data | |
| def transform_to_trap(self, input_midi_path, output_midi_path=None): | |
| """Main: transform any MIDI → Trap""" | |
| midi_data = pm.PrettyMIDI(str(input_midi_path)) | |
| duration = midi_data.get_end_time() | |
| # Enhance existing bass | |
| bass_notes = self.extract_bass_notes(midi_data) | |
| enhanced_bass = self.create_808_bass(bass_notes, duration) | |
| # Add new drum + hat tracks | |
| hat_track = self.add_hi_hats(duration) | |
| drum_track = self.add_trap_drums(duration) | |
| # Sidechain | |
| kick_times = [n.start for n in drum_track.notes if n.pitch == 36] | |
| midi_data = self.apply_sidechain(midi_data, kick_times) | |
| # Append trap layers | |
| midi_data.instruments.append(hat_track) | |
| midi_data.instruments.append(drum_track) | |
| # Set tempo | |
| try: | |
| for tempo_change in midi_data._tempo_changes: | |
| tempo_change.tempo = self.bpm | |
| except Exception: | |
| pass | |
| if output_midi_path: | |
| midi_data.write(str(output_midi_path)) | |
| return midi_data |