1

I am trying to generate a wav file with G. 711 alaw companding from a mp3 file using Pydub library. The wav file is getting generated but it is not resampled to frequency 8 kHz. I have tried following code:

from_path = '/home/nikhil/Music/m1.mp3' #this is a mp3 file
to_path = '/home/nikhil/Music/m1.wav' #resulted file
from_format = 'mp3'
to_format = 'wav'
params = ["-acodec", "pcm_alaw", "-ar", "8000"]
AudioSegment.from_file(from_path, from_format).export(to_path, format=to_format, parameters=params)

Can someone help me?

Nikhil N
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2 Answers2

2

I was looking over the code in the export method and I realized that ffmpeg is not used when the output format is "wav".

Since wav is used internally it just writes the in-memory version of the audio directly to disk (this was done to make ffmpeg an optional dependency, if you only need wav support you don't need to install it).

I have 2 ideas that may allow you to get around this issue:

  1. Use a different format kwarg, like "pcm". I'm not sure if this will work, and I don't have ffmpeg on my current machine to test, but definitely worth a try.

    from_path = '/home/nikhil/Music/m1.mp3' #this is a mp3 file
to_path = '/home/nikhil/Music/m1.wav' #resulted file
from_format = 'mp3'
to_format = 'pcm'
params = ["-acodec", "pcm_alaw", "-ar", "8000"]
AudioSegment.from_file(from_path, from_format).export(to_path, format=to_format, parameters=params)

  2. Use pydub's internal mechanism for resampling to 8kHz: Again, I can't test this right at the moment...

    from_path = '/home/nikhil/Music/m1.mp3' #this is a mp3 file
to_path = '/home/nikhil/Music/m1.wav' #resulted file

seg = AudioSegment.from_mp3(from_path)
seg = seg.set_frame_rate(8000)
seg.export(to_path, format="wav")
Jiaaro
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  • Second one is working fine..bt for first one when I am trying to open converted file in audacity it says its invalid file. – Nikhil N Dec 03 '13 at 05:51
0

Changing

to_format = 'pcm'

to

to_format = 'wav'

resolves the problem in the replay

Eric Aya
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user3073001
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