How to decode Ogg Opus in django?

Question

JavaScript

Good day, the following base64 encoded blob is sent to the server:

var blob = new Blob(chunks, {"type" : "audio/ogg; codecs=opus"});
blob = get_base64(blob);

On the server (django) there is a task to get the duration of this file using mutagen, that is:

import base64
from mutagen.oggopus import OggOpus
blob = request.get("blob").split(";base64")[1]
blob = OggOpus(base64.b64decode(blob))

The following error appears, here is part of it:
blob = OggOpus(base64.b64decode(blob))
File "/usr/lib/python3.10/site-packages/mutagen/_file.py", line 48, in __init__
self. load(*args, **kwargs)
File "/usr/lib/python3.10/site-packages/mutagen/_util.py", line 154, in wrapper
with _openfile(self, filething, filename, fileobj,
File "/ usr/lib/python3.10/contextlib.py", line 135, in __enter__
return next(self.gen)
File "/usr/lib/python3.10/site-packages/mutagen/_util.py", line 251, in _openfile
fileobj = open(filename, "rb+" if writable else "rb")
ValueError: embedded null byte

Please tell mewhy is OggOpus not accepting the file and how to do it right?