unable to read the .WAV file using python - python-3.x

Question

I am trying to read a FM signal which is recorded as WAV file using GNU radio Companion, using python. I am attaching the .grc file used.
I can clearly hear the recorded signal but reading the data gives a null ([] ) value.
The python code
import soundfile as sf
data, fs = sf.read('/home/fm_record_RSM_10_01_2019_dat.wav')
for i in data:
print(i)
this gives
data
array([], dtype=float64)
fs
96000
When the following code is used,
import wave
input_wave_file= wave.open('/home/fm_record_RSM_10_01_2019_dat.wav', 'r')
nc,sw,fr,nf,ct,cn = input_wave_file.getparams()
another error is raised as given below
Error Traceback (most recent call last)
<ipython-input-3-5009fe3506e7> in <module>()
1 import wave
2
----> 3 input_wave_file= wave.open('/home/fm_record_RSM_10_01_2019_dat.wav', 'r')
4 nc,sw,fr,nf,ct,cn = input_wave_file.getparams()
5 frame_data = input_wave_file.readframes(5)
~/anaconda3/lib/python3.7/wave.py in open(f, mode)
508 mode = 'rb'
509 if mode in ('r', 'rb'):
--> 510 return Wave_read(f)
511 elif mode in ('w', 'wb'):
512 return Wave_write(f)
~/anaconda3/lib/python3.7/wave.py in __init__(self, f)
162 # else, assume it is an open file object already
163 try:
--> 164 self.initfp(f)
165 except:
166 if self._i_opened_the_file:
~/anaconda3/lib/python3.7/wave.py in initfp(self, file)
131 raise Error('file does not start with RIFF id')
132 if self._file.read(4) != b'WAVE':
--> 133 raise Error('not a WAVE file')
134 self._fmt_chunk_read = 0
135 self._data_chunk = None
Error: not a WAVE file
Could someone help me to find what the problem could be? Is it because of any mistake in the setting of record wav block in .grc file or any mistake in python file? Kindly help
Thanks a lot
Msr

Answer 1

#! /usr/bin/env python3
import soundfile as sf
import wave
import sys
if len(sys.argv) < 2:
print("Expected filename.wav on cmdline")
quit(1)
data, fs = sf.read(sys.argv[1])
for i in range(10):
print(i)
print('...')
input_wave_file= wave.open(sys.argv[1], 'r')
nc,sw,fr,nf,ct,cn = input_wave_file.getparams()
print('nc', nc)
print('sw', sw)
print('fr', fr)
print('nf', nf)
print('ct', ct)
print('cn', cn)
chunk = 1024
data = input_wave_file.readframes(chunk)
print('data[0:10] =', data[0:10])
print('data[0:10] =', end='')
for i in range(10):
print(data[i],' ',end='')
print('')
In a linux environment, I put the above into a file named playsound.py .
Then I executed (at the cmdline prompt)
$ chmod +x playsound.py
$ ./playsound.py file.wav
[ 0.06454468 0.05557251]
[ 0.06884766 0.05664062]
[ 0.0552063 0.06777954]
[ 0.04733276 0.0708313 ]
[ 0.05505371 0.065979 ]
[ 0.05358887 0.06677246]
[ 0.05621338 0.06045532]
[ 0.04891968 0.06298828]
[ 0.04986572 0.06817627]
[ 0.05410767 0.06661987]
...
nc 2
sw 2
fr 44100
nf 32768
ct NONE
cn not compressed
data[0:10] = b'C\x08\x1d\x07\xd0\x08#\x07\x11\x07'
data[0:10] =67 8 29 7 208 8 64 7 17 7
file.wav was some existing .wav file I had handy.
I previously tried
for i in data:
print(i)
as you had done, that worked also, but the output was too much.
I think you should check that the filename you are supplying points to a valid WAV file.
For instance, the path you list is "/home/filename.wav" .
Usually it will be at least "/home/username/filename.wav"