Change the volume of a wav file in python
audio, python, volume, wav, wave
Solution
As you can see in the comments of the question, there are several solutions, some more efficient.
The problem was immediately detected by Jan Dvorak ("the * 5 part is clipping and overflowing") and the straightforward solution was:
s = numpy.fromstring(s, numpy.int16) / 10 * 5
In this case, this solution was perfect for me, just good enough.
Thank you all folks!
Problem
I have a 2 seconds 16bit single channel 8khz wav file and I need to change its volume. It should be quite straightforward, because changing the volume is the same as changing the amplitude of the signal, and I just need to attenuate it, that is to multiply it for a number between 0 and 1. But it doesn't work: the new sound is lower but VERY full of noise. What am I doing wrong? Here is my code: ``` import wave, numpy, struct # Open w = wave.open("input.wav","rb") p = w.getparams() f = p[3] # number of frames s = w.readframes(f) w.close() # Edit s = numpy.fromstring(s, numpy.int16) * 5 / 10 # half amplitude s = struct.pack('h'*len(s), *s) # Save w = wave.open("output.wav","wb") w.setparams(p) w.writeframes(s) w.close() ``` Thank you guys!