asterisk users - Jun 2005 - GSM -> ULAW sound conversion

Hello,

I have figured out that my audio problem was just how I was converting
the sound files.  I am trying to convert the Asterisk gsm files to
ULAW.

I just did a: sox file.gsm file.ul, open it in Audacity.  I used:
Project, Import Raw, U-law, No endian, 1 channel, start offest 1 byte,
sample rate 8000hz.  The file sounds fine in Audacity.

Now, if I do a record on Asterisk, using pcm, au, or ul, I get pops in
the audio.  What am I doing wrong?

Also, what types of wav (not WAV) files does Asterisk generate?  I have
a couple wav files to convert too.  I believe if I do a sox file.wav -r
8000 -c 1 fle.wav file.gsm, I have the same type of problem.


Thanks,

Kevin Bockman

> Now, if I do a record on Asterisk, using pcm, au, or ul, I get pops in
> the audio.  What am I doing wrong?
> 
> Also, what types of wav (not WAV) files does Asterisk generate?  I have
> a couple wav files to convert too.  I believe if I do a sox file.wav -r
> 8000 -c 1 fle.wav file.gsm, I have the same type of problem.
> 
> Kevin Bockman
If I store the file as gsm and record it as gsm, open it was gsm 6.10
with Audacity, it is fine.  I know I am doing something wrong with the
u-law conversion.

On a similar note, I have seen in the archives where people have an
output of the file type, showing Hz, bits, etc.. what are they using
for that? 

Thanks,

Kevin Bockman

Hi Michiel,
> As I said in my last mail, 'file' should do it.
> I checked it with a recorded voicemail:
> sin# file msg0000.WAV
> msg0000.WAV: Microsoft RIFF, WAVE audio data, mono 8000 Hz
> -- 
> Michiel van Baak
That is what I figured.  Mine does not give that information:

output of file tt-weasels.gsm:
tt-weasels.gsm: data

output of file -v:
file-4.12
magic file from /usr/share/misc/file/magic

Maybe I have a different version of file.  I have Gentoo.  I will see if
I can find a different version.

Did you see my origional post?  I had to add on to it.  My real problem
is trying to convert gsm and wav files to ulaw.  That is my real goal.


Thanks,

Kevin Bockman

> I have figured out that my audio problem was just how I was converting
> the sound files.  I am trying to convert the Asterisk gsm files to
> ULAW.
> 
> Kevin Bockman
I have the files in Signed 16bit PCM, little endian, 1 channel, start
offset 1 byte, sample rate 8000hZ.  Is this correct so it will not have
to transcode for u-law?


Thanks,

Kevin Bockman