Re: [SoX-users] First time use of SoX : converting wav to mono 8000Hz

[Jan S. <ha...@st...>]

> [root@asterisk testing]# file testExtended.wav
> testExtended.wav: RIFF (little-endian) data, WAVE audio, Microsoft PCM,  
> 16 bit, stereo 44100 Hz

What does soxi(1) say about the file?

> [root@asterisk testing]# file testLong.wav
> testLong.wav: RIFF (little-endian) data, WAVE audio, 20294 channels  
> 1414676809 Hz

I very much doubt that you have a 202294-chanel file with a samplerate
of 1414676809 Hz. The wav header of this file is probably broken. What
does soxi say about the file. Is play(1) able to play it?

> to mono :
> sox testExtended.wav -r 8000 -c1  testExtended2.wav resample -ql
> sox sox: effect `resample' is deprecated; see sox(1) for an alternative

Why are you using deprecated effects??

sox -V testExtended.wav testExtended2.wav remix - rate 8000
sox -V testExtended.wav -c 1 -r 8000 testExtended2.wav

> [root@asterisk testing]# sox testLong.wav -r 8000 -c1 testLong2.wav  
> resample -ql
> sox sox: effect `resample' is deprecated; see sox(1) for an alternative
> sox effects: resample clipped 2 samples; decrease volume?

Again, why are you using 'resample'? That's a deprecated alias for 'rate',
which you already specified with the '-r 8000'.

> afterwards :
> [root@asterisk testing]# file testLong2.wav
> testLong2.wav: RIFF (little-endian) data, WAVE audio, Microsoft PCM, 16  
> bit, mono 8000 Hz

Looks good; what does soxi(1) say about the file?
Can you play the resulting mono/8000 file?

> [root@asterisk testing]# file testExtended2.wav
> testExtended2.wav: RIFF (little-endian) data, WAVE audio, Microsoft PCM,  
> 16 bit, mono 8000 Hz

It seems that sox somehow converted the original file (which most likely
is _not_ a 20294c/1414676809Hz file) into a mono/8000.  It would be useful
to know the output of 'sox -V' wehn running this.  Are you able to play
the file?


> But my Asterisk-server can not open them :
> [root@asterisk testing]# asterisk -rx "file convert testExtended2.wav  
> testExtended2.alaw"
> Unable to open input file: testExtended2.wav
> [root@asterisk testing]# asterisk -rx "file convert testLong2.wav  
> testLong2.alaw"
> Unable to open input file: testLong2.wav


That has nothing to do with sox, right?
Ask on the asterisk mailing list.


> The file has decreased in file size :
> -rw-r--r-- 1 root root 885K 2010-08-17 08:59 testExtended2.wav
> -rw-r--r-- 1 root root 9.6M 2010-08-17 08:57 testExtended.wav

Of course. Both the number of channels and the sample rate have been
reduced, so the file size got reduced, too. (Are you sure you know what
a 'sample rate' is?)

The numbers seem right: the new file's size is about
a ((1*8000)/(2*44100))-th of the old one.

> I can play the original and the resampled file perfectly in Gnome  
> Mplayer, but my Asterisk-server can not read the file to convert it to  
> alaw. Could there be something wrong with the wav-file ?!

9.6M and 885K is small enough to put the files
somewehere on the web so we can look at them.