[Asterisk-Users] VoiceMailBox wav file format in EMAIL.

[Anon]

On Tuesday 13 April 2004 12:12 am, James Gardiner wrote:
> Hi all,
> I am not sure if tis is a bug but..
> Was learning about VM etc to see how it all worked, and I noticed the
> following..
>
> In the default install, the VM system leaves 3 different copies of the
> Voice message.
> Size	filename
> 13kb	Msg0000.gsm
> 13kb	Msg0000.wav
> 122kb	Msg0000.WAV  <- under UNIX we have case sensitive file names of
> course.
>
> I wanted to have a look at these files so loaded them into SOUND FORGE 6.
> This first thing I noticed was that the LARGER file is of much HIGHER
> volume. Like it had been normalised to 100%
> The smaller was file, when loaded into sound forge, did not load properly,
> only the first 2 seconds loads.
>
> Can anyone explain these issues and why they exist?
>
> All in all, I was wondering what would be the best format for best quality
> but with still great compression.
>
> I want to archive all calls for a period of time with self expire. (For
> example dedicate 5 gig disk space to the last number of calls that can fit
> in the 5gig.) I want to store the best quality possible but also make best
> use of disk space, so I can store for even longer periods.  I was
> considering ogg but then is occurred to me that GSM or other codecs
> designed for audio with this frequency response may be better. (But the GSM
> file above is not as clear as the WAV ones produced.)
>
> I was also wondering if the VM system when emailing the audio can be setup
> to use something like ogg or MP3?
>
> Comments appreciated,
> James Gardiner
That is a very interesting observation I had not seen yet.

There are certainly a few ways to do this.  Here is an idea: run a cron job that
downsamples the WAV file using sox, then compresses it, and deletes the redundant
files.  Make sure to have the cron job run during the least-busy part of the day.

Yes, it is a crude solution.  ;)  Yet it may get you by until you get a better solution.

Anon