The standard scipy.signal.resample is used to resample the signals, can anybody tell me how we can change the sampling frequency of speech signal from 44100 Hz to 8000 Hz using scipy.signal.resample function??
Well, presumably if you have some signal loaded into Python as an array x, then you can just run
resampled_signal = scipy.signal.resample( x, 8000 )
This is what the documentation suggests. Is there some reason this isn't working for you?
Hi,
Here is a suggestion, but not using scipy.
You can do a lot of things using "sox" like getting information about your audio recording, subsampling, trimming ..
Once installed using :
>> sudo apt-get install sox
This will install many binaries like :
- soxi : used to get information about a recording
- sox : used to process a recording
- play : used to play a recording
Here is an example :
You can get information about a sphere audio file "file.sph" by typing :
>> soxi file.sph
-------
Input File : 'file.sph'
Channels : 1
Sample Rate : 8000
Precision : 14-bit
Duration : 00:05:09.95 = 2479616 samples ~ 23246.4 CDDA sectors
File Size : 2.48M
Bit Rate : 64.0k
Sample Encoding: 8-bit u-law
------
Here, the sampling frequency is 8000Hz. To do a subsampling (8000Hz --> 7000Hz for example), you can do something like :
>> sox file.sph -r 7000 file2.sph
then you can check the produced file using soxi :
>> soxi file.sph
------
Input File : 'file2.sph'
Channels : 1
Sample Rate : 7000
Precision : 14-bit
Duration : 00:05:09.95 = 2169664 samples ~ 23246.4 CDDA sectors
File Size : 2.17M
Bit Rate : 56.0k
Sample Encoding: 8-bit u-law
------
You can do the same on your files. sox supports a lot of file formats : WAV, SPHERE, RAW, amongst others.
@Stephen Politzer-Ahles: scipy.signal.resample does not working as you suggest....
Can you explain what is "not working" about it? Typically when reporting a coding problem, you will want to report, at the least, what code you entered and what error message or other problem you experienced.
Hi again,
There is an examples for signal downsampling using scipy here :
http://stackoverflow.com/questions/30619740/python-downsampling-wav-audio-file
You might want to check the type of your input (string/unsigned int) before applying scipy.signal.resample.
@Stephen for resampling it should work something like this
fs,s (44100, and input signal(int16))
to use the scipy.signal.resample, we need a ratio of 44100/8000, which is 5.5125 and should be used with
s = resample(s,s.size()/5.5125), and here the problem is float number of s.size()/5.5125?
but with s = resample(s,8000), I don't think it works.
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