midi_tools.py•11.3 kB
import reapy
from reapy import reascript_api as RPR
class MidiTools:
"""Tools for MIDI composition and editing in REAPER."""
def __init__(self, config):
"""
Initialize MidiTools with configuration.
Args:
config (dict): Configuration dictionary
"""
self.config = config
# Define standard MIDI note mappings for drum patterns
self.drum_mappings = {
"kick": 36, # C1
"snare": 38, # D1
"hihat_closed": 42, # F#1
"hihat_open": 46, # A#1
"tom_low": 41, # F1
"tom_mid": 45, # A1
"tom_high": 48, # C2
"crash": 49, # C#2
"ride": 51 # D#2
}
# Define chord mappings
self.chord_types = {
"maj": [0, 4, 7],
"min": [0, 3, 7],
"dim": [0, 3, 6],
"aug": [0, 4, 8],
"maj7": [0, 4, 7, 11],
"min7": [0, 3, 7, 10],
"dom7": [0, 4, 7, 10],
"dim7": [0, 3, 6, 9],
"hdim7": [0, 3, 6, 10],
"sus2": [0, 2, 7],
"sus4": [0, 5, 7]
}
# Note name to MIDI note number mapping
self.note_to_number = {
"C": 0, "C#": 1, "Db": 1, "D": 2, "D#": 3, "Eb": 3,
"E": 4, "F": 5, "F#": 6, "Gb": 6, "G": 7, "G#": 8,
"Ab": 8, "A": 9, "A#": 10, "Bb": 10, "B": 11
}
def create_midi_item(self, track_id, start_position, length):
"""
Create a new MIDI item on the specified track.
Args:
track_id (int): Track ID
start_position (float): Start position in seconds
length (float): Length in seconds
Returns:
dict: MIDI item information
"""
try:
# Get track by ID
track = reapy.Track.from_id(track_id)
# Create new MIDI item
item = track.add_midi_item(start_position, start_position + length)
# Get the MIDI take
take = item.active_take
return {
"success": True,
"item_id": item.id,
"take_id": take.id,
"position": item.position,
"length": item.length,
"track_id": track_id
}
except Exception as e:
return {
"success": False,
"error": str(e)
}
def add_midi_note(self, item_id, pitch, start, length, velocity=100):
"""
Add a MIDI note to the specified MIDI item.
Args:
item_id (int): MIDI item ID
pitch (int): MIDI note number (0-127)
start (float): Start position in seconds relative to item start
length (float): Note length in seconds
velocity (int): Note velocity (1-127)
Returns:
dict: Result of the operation
"""
try:
# Get item by ID
item = reapy.Item.from_id(item_id)
# Get the active take
take = item.active_take
# Ensure take is MIDI
if not take.is_midi:
return {
"success": False,
"error": "Take is not MIDI"
}
# Add MIDI note
# Note: start is relative to item start
take.add_note(
start=start,
end=start + length,
pitch=pitch,
velocity=velocity,
channel=0 # Default MIDI channel
)
return {
"success": True,
"item_id": item_id,
"pitch": pitch,
"start": start,
"length": length,
"velocity": velocity
}
except Exception as e:
return {
"success": False,
"error": str(e)
}
def _parse_chord(self, chord_str):
"""
Parse a chord string into MIDI note numbers.
Args:
chord_str (str): Chord string (e.g., "C", "Dm", "G7")
Returns:
list: List of MIDI note numbers relative to root
"""
# Extract root note and chord type
if len(chord_str) == 1:
root = chord_str
chord_type = "maj"
elif len(chord_str) >= 2:
if chord_str[1] in ["#", "b"]:
root = chord_str[0:2]
chord_type = chord_str[2:] or "maj"
else:
root = chord_str[0]
chord_type = chord_str[1:] or "maj"
# Map chord type to intervals
if chord_type == "m":
chord_type = "min"
elif chord_type == "7":
chord_type = "dom7"
# Get intervals for chord type
intervals = self.chord_types.get(chord_type, self.chord_types["maj"])
# Get root note number
root_num = self.note_to_number.get(root, 0)
# Return intervals (will be transposed in the calling function)
return intervals, root_num
def create_chord_progression(self, track_id, chords, start_position, beats_per_chord=4):
"""
Create a chord progression on the specified track.
Args:
track_id (int): Track ID
chords (str): Comma-separated list of chords (e.g., "C,G,Am,F")
start_position (float): Start position in seconds
beats_per_chord (int): Number of beats per chord
Returns:
dict: Result of the operation
"""
try:
# Get project and track
project = reapy.Project()
track = reapy.Track.from_id(track_id)
# Parse chord list
chord_list = [c.strip() for c in chords.split(",")]
# Calculate seconds per beat
seconds_per_beat = 60.0 / project.bpm
chord_length = seconds_per_beat * beats_per_chord
# Create MIDI item for the entire progression
total_length = chord_length * len(chord_list)
item = track.add_midi_item(start_position, start_position + total_length)
take = item.active_take
# Add chords
added_chords = []
for i, chord_str in enumerate(chord_list):
try:
# Parse chord
intervals, root_num = self._parse_chord(chord_str)
# Calculate position within item
chord_start = i * chord_length
# Add chord notes (in middle C octave)
for interval in intervals:
note_num = 60 + root_num + interval # Middle C (60) + root + interval
take.add_note(
start=chord_start,
end=chord_start + chord_length * 0.95, # Slightly shorter than full length
pitch=note_num,
velocity=80,
channel=0
)
added_chords.append({
"chord": chord_str,
"position": chord_start,
"length": chord_length
})
except Exception as e:
# Continue with next chord if one fails
print(f"Error adding chord {chord_str}: {e}")
return {
"success": True,
"item_id": item.id,
"chords": added_chords,
"start_position": start_position,
"total_length": total_length
}
except Exception as e:
return {
"success": False,
"error": str(e)
}
def create_drum_pattern(self, track_id, pattern, start_position, beats=4, repeats=1):
"""
Create a drum pattern on the specified track.
Args:
track_id (int): Track ID
pattern (str): Drum pattern string (e.g., "k...k...s...k.s.")
k=kick, s=snare, h=hihat_closed, o=hihat_open,
t=tom_low, m=tom_mid, f=tom_high, c=crash, r=ride
start_position (float): Start position in seconds
beats (int): Number of beats in the pattern
repeats (int): Number of times to repeat the pattern
Returns:
dict: Result of the operation
"""
try:
# Get project and track
project = reapy.Project()
track = reapy.Track.from_id(track_id)
# Calculate timing
seconds_per_beat = 60.0 / project.bpm
pattern_length = seconds_per_beat * beats
total_length = pattern_length * repeats
# Create MIDI item
item = track.add_midi_item(start_position, start_position + total_length)
take = item.active_take
# Map pattern characters to drum notes
char_to_drum = {
"k": "kick",
"s": "snare",
"h": "hihat_closed",
"o": "hihat_open",
"t": "tom_low",
"m": "tom_mid",
"f": "tom_high",
"c": "crash",
"r": "ride"
}
# Calculate time per character
time_per_char = pattern_length / len(pattern)
# Add notes for each repeat
for repeat in range(repeats):
offset = repeat * pattern_length
for i, char in enumerate(pattern):
if char in char_to_drum:
drum_name = char_to_drum[char]
note_num = self.drum_mappings[drum_name]
# Position within the pattern
note_start = offset + (i * time_per_char)
# Add note (short duration for drums)
take.add_note(
start=note_start,
end=note_start + (time_per_char * 0.5),
pitch=note_num,
velocity=100,
channel=9 # Standard MIDI drum channel
)
return {
"success": True,
"item_id": item.id,
"pattern": pattern,
"repeats": repeats,
"start_position": start_position,
"total_length": total_length
}
except Exception as e:
return {
"success": False,
"error": str(e)
}