The audio API allows you to easily play audio files or stream URLs (.mp3, .wav, and modtracker .mod, .s3m, .xm). It is a wrapper around sndmixer, which can do much more but is a bit more verbose.
Reference
| Function | Parameters | Returns | Description |
|---|---|---|---|
| play | filename_or_url, [volume], [loop], [sync_beat], [start_at_next], [on_finished] | Channel ID (int) | Play a file (e.g. ‘/apps/myapp/sound.mp3’) or stream from a url (e.g. ‘http://my.stream/song.mp3’). Filename or url needs to end with the filetype (.mp3, .wav, .mod, .s3m, .xm). Use volume (0-255) to set the volume for this channel (defaults to system volume). Use loop=True to repeat after playback is done. Use sync_beat=(BPM of the music, e.g. 120) and start_at_next (1-32) to start playback at the next x-th 8th note (example: 1 starts at next 8th, 2 at next 4th (namely 2x an 8th), 4 at half note, 8 at whole note, 32 at whole bar). If on_finished is a function, it is called when the playback ends. Resources are automatically freed after playback finishes. |
| stop_looping | channel_id | - | Cancel the looping status of a channel. This will end playback after the sound is finished with its current playback. |
| stop_channel | channel_id | - | Cancel the playback of a channel immediately, and free its resources. |
Example
Playing an MP3 file at a given volume
import audio
channel_id = audio.play('/apps/myapp/doom.mp3', volume=150)
Known problems
- Playing audio from an HTTP stream can be laggy at the moment on the Pixel. Local playback is smooth.
- Due to a bug in (presumably) our MicroPython version, stopping audio playback from a streaming URL causes a freeze in the MicroPython task. Therefore, you have to reboot your badge before you can play a different URL.
- The current implementation can play around 4 wav files or 2 mp3 files at the same time without glitches or slowdowns. Any more can cause noticable artifacts.