Content #!/usr/bin/env python3 # # You can find a description of RTTTL here: https://en.wikipedia.org/wiki/Ring_Tone_Transfer_Language NOTE = [ 440.0, # A 493.9, # B or H 261.6, # C 293.7, # D 329.6, # E 349.2, # F 392.0, # G 0.0, # pad 466.2, # A# 0.0, 277.2, # C# 311.1, # D# 0.0, 370.0, # F# 415.3, # G# 0.0, ] class RTTTL: def __init__(self, tune): tune_pieces = tune.split(':') if len(tune_pieces) != 3: raise ValueError('tune should contain exactly 2 colons') self.tune = tune_pieces[2] self.tune_idx = 0 self.parse_defaults(tune_pieces[1]) def parse_defaults(self, defaults): # Example: d=4,o=5,b=140 val = 0 id = ' ' for char in defaults: char = char.lower() if char.isdigit(): val *= 10 val += ord(char) - ord('0') if id == 'o': self.default_octave = val elif id == 'd': self.default_duration = val elif id == 'b': self.bpm = val elif char.isalpha(): id = char val = 0 # 240000 = 60 sec/min * 4 beats/whole-note * 1000 msec/sec self.msec_per_whole_note = 240000.0 / self.bpm def next_char(self): if self.tune_idx < len(self.tune): char = self.tune[self.tune_idx] self.tune_idx += 1 if char == ',': char = ' ' return char return '|' def notes(self): """Generator which generates notes. Each note is a tuple where the first element is the frequency (in Hz) and the second element is the duration (in milliseconds). """ while True: # Skip blank characters and commas char = self.next_char() while char == ' ': char = self.next_char() # Parse duration, if present. A duration of 1 means a whole note. # A duration of 8 means 1/8 note. duration = 0 while char.isdigit(): duration *= 10 duration += ord(char) - ord('0') char = self.next_char() if duration == 0: duration = self.default_duration if char == '|': # marker for end of tune return note = char.lower() if note >= 'a' and note <= 'g': note_idx = ord(note) - ord('a') elif note == 'h': note_idx = 1 # H is equivalent to B else: note_idx = 7 # pause char = self.next_char() # Check for sharp note if char == '#': note_idx += 8 char = self.next_char() # Check for duration modifier before octave # The spec has the dot after the octave, but some places do it # the other way around. duration_multiplier = 1.0 if char == '.': duration_multiplier = 1.5 char = self.next_char() # Check for octave if char >= '4' and char <= '7': octave = ord(char) - ord('0') char = self.next_char() else: octave = self.default_octave # Check for duration modifier after octave if char == '.': duration_multiplier = 1.5 char = self.next_char() freq = NOTE[note_idx] * (1 << (octave - 4)) msec = (self.msec_per_whole_note / duration) * duration_multiplier #print('note ', note, 'duration', duration, 'octave', octave, 'freq', freq, 'msec', msec) yield freq, msec