audiomp3 – Support for MP3-compressed audio files

class audiomp3.MP3Decoder(file: BinaryIO, buffer: _typing.WriteableBuffer)

Load a mp3 file for audio playback

Load a .mp3 file for playback with audioio.AudioOut or audiobusio.I2SOut.

  • file (typing.BinaryIO) – Already opened mp3 file

  • buffer (WriteableBuffer) – Optional pre-allocated buffer, that will be split in half and used for double-buffering of the data. If not provided, two buffers are allocated internally. The specific buffer size required depends on the mp3 file.

Playing a mp3 file from flash:

import board
import audiomp3
import audioio
import digitalio

# Required for CircuitPlayground Express
speaker_enable = digitalio.DigitalInOut(board.SPEAKER_ENABLE)

data = open("cplay-16bit-16khz-64kbps.mp3", "rb")
mp3 = audiomp3.MP3Decoder(data)
a = audioio.AudioOut(board.A0)

while a.playing:
file :BinaryIO

File to play back.

sample_rate :int

32 bit value that dictates how quickly samples are loaded into the DAC in Hertz (cycles per second). When the sample is looped, this can change the pitch output without changing the underlying sample.

bits_per_sample :int

Bits per sample. (read only)

channel_count :int

Number of audio channels. (read only)

rms_level :float

The RMS audio level of a recently played moment of audio. (read only)


Deinitialises the MP3 and releases all memory resources for reuse.


No-op used by Context Managers.


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