[asterisk-bugs] [Asterisk 0012093]: Listening to Allison voicemail prompt on SIP phone causes [pop] sounds

[noreply at bugs.digium.com]

A NOTE has been added to this issue. 
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http://bugs.digium.com/view.php?id=12093 
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Reported By:                mustardman
Assigned To:                
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Project:                    Asterisk
Issue ID:                   12093
Category:                   Sounds
Reproducibility:            always
Severity:                   minor
Priority:                   normal
Status:                     new
Asterisk Version:           1.4.18 
SVN Branch (only for SVN checkouts, not tarball releases): N/A 
SVN Revision (number only!):  
Disclaimer on File?:        N/A 
Request Review:              
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Date Submitted:             02-27-2008 17:57 CST
Last Modified:              03-18-2008 13:17 CDT
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Summary:                    Listening to Allison voicemail prompt on SIP phone
causes [pop] sounds
Description: 
This is something that has been bugging me for awhile.  I have noticed it
on multiple systems with different hardware, different brands and models of
hardphones, with and without zaptel cards, and various versions of Asterisk
in the 1.2 and 1.4 branches.

A bit hard to describe.  Using a SIP hardphone I log into my voicemail at
which point Allison says "you have x messages.....".  There are various
other prompts that exhibit the same problem that are not necessarily part
of voicemail but that is one easy to explain and reproduce one. The problem
is there is a slight 'pop' sound usually during the first syllable of each
word.  So the prompt sounds like "y[pop]ou h[pop]ave t[pop]wo
me[pop]ssages".  If I dial *43 to do an echo test and Allison says "you are
about to enter an echo test....." it's not there so it's only in certain
modes this happens.

It's relatively minor and not something people generally complain about
but it's definitely there and (at least to me) kinda makes the system seem
to be a bit less polished sounding.  I thought it had something to do with
the prompts I am using but when I play back the actual files in a sound
player I don't hear those pops.  I tried using various format prompts
including gsm, ulaw etc. but it doesn't change anything.

This problem has always been there for as long as I can remember.  Doesn't
matter what version Asterisk/Zaptel/Sounds I am using.


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---------------------------------------------------------------------- 
 qwell - 03-18-08 13:17  
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I listened to the file that you've supplied, and it just sounds like it was
transcoded multiple times.  I also listened to the stock gsm prompts, and
they do have some slight issues like this..  I'm fairly certain that this
is just a result of over-transcoding, and not something Asterisk is
specifically doing.

I'm going to leave this open for a short while, but I feel that there is
nothing we can really do to resolve this, except for you to use better
quality sounds (not gsm), and don't transcode unless needed.

You should run `make menuselect` and install the ulaw prompts.  You'll
also need to verify that you aren't transcoding back and forth.  That
should help a little bit, at least. 

Issue History 
Date Modified   Username       Field                    Change               
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03-18-08 13:17  qwell          Note Added: 0084154                          
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