[Freeswitch-users] .wav vs .gsm file sizes for recording calls.

Wes wes-fs at 499x.com
Sat Jun 25 01:26:06 MSD 2011

In my tests, if I record a call in .wav format, a 10 second file is 
about 177,000 bytes, while a 10 second .gsm file is 17,000 bytes.

I  then used sox to convert the .gsm file to a .wav file, and it stayed 
at around 17,000 bytes.  So, is the default recording format for .wav 
using a higher sample rate? vs the default conversion format for the sox 

checking the file type using "file" I see that the larger one is:
RIFF (little-endian) data, WAVE audio, Microsoft PCM, 16 bit, mono 8000 Hz

and the wav created by sox via the default conversion from .gsm is:
RIFF (little-endian) data, WAVE audio, GSM 6.10, mono 8000 Hz

So apparently the larger wav file is 16 bit... how are these recording 
parameters controlled?  Can I set it to record directly into the smaller 
wav format? Or will I have to run sox on every file...

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