Raise FileTypeError for WAVE_FORMAT_MPEGLAYER3 WAV files

docs/changelog.rst

@@ -3,6 +3,10 @@ Changelog
 
 Upcoming
 --------
+- Raise ``FileTypeError`` for WAV files containing non-PCM audio streams
+  that mutagen cannot tag correctly, including ``WAVE_FORMAT_MPEGLAYER3``
+  (0x0055), ``WAVE_FORMAT_ADPCM`` (0x0002), ``WAVE_FORMAT_ALAW`` (0x0006),
+  and ``WAVE_FORMAT_MULAW`` (0x0007).
 
 v0.16.0
 -------

mediafile/__init__.py

@@ -187,6 +187,17 @@ def __init__(self, filething, id3v23=False):
         elif type(self.mgfile).__name__ == "DSF":
             self.type = "dsf"
         elif type(self.mgfile).__name__ == "WAVE":
+            # WAV files can contain non-PCM audio streams that mutagen
+            # cannot tag correctly. Rejects them with a clear error.
+            _unsupported_wav_formats = {
+                0x0002: "WAVE_FORMAT_ADPCM",
+                0x0006: "WAVE_FORMAT_ALAW",
+                0x0007: "WAVE_FORMAT_MULAW",
+                0x0055: "WAVE_FORMAT_MPEGLAYER3",
+            }
+            audio_fmt = getattr(self.mgfile.info, "audio_format", 0x0001)
+            if audio_fmt in _unsupported_wav_formats:
+                raise FileTypeError(self.filename, _unsupported_wav_formats[audio_fmt])
             self.type = "wav"
         else:
             raise FileTypeError(self.filename, type(self.mgfile).__name__)

test/test_mediafile_edge.py

@@ -173,6 +173,12 @@ def test_broken_symlink(self):
         finally:
             os.unlink(fn)
 
+    def test_mpeglayer3_wav_raises_filetypeerror(self):
+        # WAV files with WAVE_FORMAT_MPEGLAYER3 (OxOO55) contain a MP3 stream
+        # and cannot be tagged correctly
+        fn = os.path.join(_common.RSRC, b"mpeglayer3.wav")
+        self.assertRaises(mediafile.FileTypeError, mediafile.MediaFile, fn)
+
 
 class SideEffectsTest(unittest.TestCase):
     def setUp(self):