+import sounddevice as sd
+import audioop
+import time
+
+frame_rate = 44100
+channels = 2
+sample_width = 2
+
+class Mixer:
+ def __init__(self):
+ self.stream = sd.RawOutputStream(samplerate=frame_rate,
+ channels=channels,
+ dtype='int' + str(8*sample_width), # FIXME: ?
+ latency="high",
+ blocksize=5000,
+ callback=self.play_callback,
+ )
+ self.open_files = []
+
+ def add_file(self, music_file):
+ if music_file not in self.open_files:
+ self.open_files.append(music_file)
+ self.start()
+
+ def remove_file(self, music_file):
+ self.open_files.remove(music_file)
+ if len(self.open_files) == 0:
+ self.stop()
+
+ def stop(self):
+ self.stream.stop()
+
+ def start(self):
+ self.stream.start()
+
+ def play_callback(self, out_data, frame_count, time_info, status_flags):
+ out_data_length = len(out_data)
+ empty_data = b"\0" * out_data_length
+ data = b"\0" * out_data_length
+
+ for open_file in self.open_files:
+ file_data = open_file.play_callback(out_data_length, frame_count)
+
+ if data == empty_data:
+ data = file_data
+ elif file_data != empty_data:
+ data = audioop.add(data, file_data, sample_width)
+
+ out_data[:] = data
+