audiomp3 only accepts io.FileIO objects, documentation suggests it could take io.BytesIO object as well

[studiostephe]

CircuitPython version

CircuitPython 7.3.3; Adafruit KB2040 with rp2040

Code/REPL

mp3 = io.BytesIO(my_mp3_as_bytes)
decoder = MP3Decoder(mp3)

Behavior

TypeError: file must be a file opened in byte mode

Description

I read a small (32kb) mp3 file into memory as bytes, from serial. Currently I must write those bytes to a file on the filesystem and then reopen it, because MP3Decoder only accepts FileIO objects. It would be useful to be able to give a BytesIO object to MP3Decoder, especially since the objects are functionally very similar.

Additional information

The source line in question: https://github.com/adafruit/circuitpython/blob/main/shared-bindings/audiomp3/MP3Decoder.c#L96

[jepler]

The C implementation works only if the MP3 resides on a FAT filesystem such as CIRCUITPY or an SD card, because it makes calls like f_read to read data and f_lseek to seek.

It would be great if a community member could change the implementation so that it is in fact compatible with an in-memory file. At the same time, maybe it would be possible to implement streaming of mp3s over wifi.

Failing that, a doc fix for the type signature would also be good.