audiomixer – Support for audio mixing

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class audiomixer.Mixer(voice_count: int = 2, buffer_size: int = 1024, channel_count: int = 2, bits_per_sample: int = 16, samples_signed: bool = True, sample_rate: int = 8000)

Mixes one or more audio samples together into one sample.

Create a Mixer object that can mix multiple channels with the same sample rate. Samples are accessed and controlled with the mixer’s audiomixer.MixerVoice objects.

Parameters
  • voice_count (int) – The maximum number of voices to mix

  • buffer_size (int) – The total size in bytes of the buffers to mix into

  • channel_count (int) – The number of channels the source samples contain. 1 = mono; 2 = stereo.

  • bits_per_sample (int) – The bits per sample of the samples being played

  • samples_signed (bool) – Samples are signed (True) or unsigned (False)

  • sample_rate (int) – The sample rate to be used for all samples

Playing a wave file from flash:

import board
import audioio
import audiocore
import audiomixer
import digitalio

a = audioio.AudioOut(board.A0)
music = audiocore.WaveFile(open("cplay-5.1-16bit-16khz.wav", "rb"))
drum = audiocore.WaveFile(open("drum.wav", "rb"))
mixer = audiomixer.Mixer(voice_count=2, sample_rate=16000, channel_count=1,
                         bits_per_sample=16, samples_signed=True)

print("playing")
# Have AudioOut play our Mixer source
a.play(mixer)
# Play the first sample voice
mixer.voice[0].play(music)
while mixer.playing:
  # Play the second sample voice
  mixer.voice[1].play(drum)
  time.sleep(1)
print("stopped")
playing :bool

True when any voice is being output. (read-only)

sample_rate :int

32 bit value that dictates how quickly samples are played in Hertz (cycles per second).

voice :Tuple[MixerVoice, Ellipsis]

A tuple of the mixer’s audiomixer.MixerVoice object(s).

>>> mixer.voice
(<MixerVoice>,)
deinit() None

Deinitialises the Mixer and releases any hardware resources for reuse.

__enter__() Mixer

No-op used by Context Managers.

__exit__() None

Automatically deinitializes the hardware when exiting a context. See Lifetime and ContextManagers for more info.

play(sample: circuitpython_typing.AudioSample, *, voice: int = 0, loop: bool = False) None

Plays the sample once when loop=False and continuously when loop=True. Does not block. Use playing to block.

Sample must be an audiocore.WaveFile, audiocore.RawSample, audiomixer.Mixer or audiomp3.MP3Decoder.

The sample must match the Mixer’s encoding settings given in the constructor.

stop_voice(voice: int = 0) None

Stops playback of the sample on the given voice.

class audiomixer.MixerVoice

Voice objects used with Mixer

Used to access and control samples with audiomixer.Mixer.

MixerVoice instance object(s) created by audiomixer.Mixer.

level :float

The volume level of a voice, as a floating point number between 0 and 1.

playing :bool

True when this voice is being output. (read-only)

play(sample: circuitpython_typing.AudioSample, *, loop: bool = False) None

Plays the sample once when loop=False, and continuously when loop=True. Does not block. Use playing to block.

Sample must be an audiocore.WaveFile, audiocore.RawSample, audiomixer.Mixer or audiomp3.MP3Decoder.

The sample must match the audiomixer.Mixer’s encoding settings given in the constructor.

stop() None

Stops playback of the sample on this voice.