Opening a wave file in Python: unknown format: 49. What's going wrong?

Question

I try to open a wave file with the wave module, but I keep getting the same error whatever I try. The line with the error is the following:

wav = wave.open(f)

This is the error message:

Traceback (most recent call last):
  File "annotate.py", line 47, in <module>
    play(file)
  File "annotate.py", line 33, in play
    wav = wave.open(f)
  File "C:\Program Files (x86)\Python\lib\wave.py", line 498, in open
    return Wave_read(f)
  File "C:\Program Files (x86)\Python\lib\wave.py", line 163, in __init__
    self.initfp(f)
  File "C:\Program Files (x86)\Python\lib\wave.py", line 143, in initfp
    self._read_fmt_chunk(chunk)
  File "C:\Program Files (x86)\Python\lib\wave.py", line 269, in _read_fmt_chunk
    raise Error('unknown format: %r' % (wFormatTag,))
wave.Error: unknown format: 49

String f is a path to a .WAV file and it works when played in any of my media players.

I have of course imported the wave module. I tried f both as a relative and an absolute path. I tried replacing "WAV" by "wav".

What is the error caused by?

Looks like `wave` module returns that error when you try to read a 32-bit .wav files. — Ashwini Chaudhary, Jun 25 '13 at 12:25
@ChrisProsser In order to get data. I know that the `wave` module can't play a file. — Lewistrick, Jun 25 '13 at 12:29
Found two related posts: http://forums.devshed.com/python-programming-11/open-wav-with-wave-module-732901.html and http://bugs.python.org/issue1144504. Seems like your `.wav` file is a IEEE float wave file, which is not supported yet. — Ashwini Chaudhary, Jun 25 '13 at 12:35

score 12 · Accepted Answer · answered Nov 24 '14 at 09:47

12

Python's wave module works with a specific type of WAV: PCM (WAVE_FORMAT_PCM: 0x0001).

In your case, you're using a WAV of type WAVE_FORMAT_GSM610 [0x0031 = hex(49)].

You can use a program like Audacity or some lib for converting codecs to change the type of the WAV file.

You can see a list of WAV types here: https://www.videolan.org/developers/vlc/doc/doxygen/html/vlc__codecs_8h.html

Python's wave module source code: https://github.com/python/cpython/blob/master/Lib/wave.py

answered Nov 24 '14 at 09:47

Leonardo Andrade

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This is exactly what I did to solve it. I used ffmpeg to convert the files, and `subprocess` to call it. – Lewistrick Nov 24 '14 at 12:40
@Lewistrick : Can you post what command you are using to convert the files? I have also tried converting them but it isn't working. – pankaj Oct 04 '18 at 13:09
@Leonardo Andrade the WAVE_FORMAT_PCM = 0x0001 is hard coded in wave.py If we change this to WAVE_FORMAT_GSM610 [0x0031 = hex(49)] will this work ? – DSBLR Oct 31 '19 at 01:17
I don't know, @DSBLR. I'm not a specialist on WAVE formats. You can try but note that this will change the behaviour of a python's standard lib. Maybe not a good strategy to solve your problem. – Leonardo Andrade Nov 01 '19 at 02:50

score 2 · Answer 2 · answered Jun 25 '13 at 14:06

2

The file is compressed and the wave module does not support this type of compression.

answered Jun 25 '13 at 14:06

Lewistrick

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Opening a wave file in Python: unknown format: 49. What's going wrong?

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