[asterisk-dev] dvossel: trunk r239712 - in /trunk: ./ apps/ main/

[John Todd]

On Jan 18, 2010, at 9:17 AM, Russell Bryant wrote:

> ----- "John Todd" <jtodd at digium.com> wrote:
>
>> Might there be a better way to do this?  If the user tries to send
>> silence for G.729, as an example, and has no G.729 licenses  
>> installed,
>> then this will fail, correct?  Same with any other codec that is  
>> being
>> handled through but does not exist on that system.
>
> Correct.
>
>> Would it not be useful to just (repeatedly) send one of the pre-
>> recorded "sounds/silence" files in the appropriate pre-generated  
>> codec
>> form?  This would eliminate any transcoding issues.  Those files are
>> part of the standard sounds distribution, and we might even consider
>> adding them into the baseline distro since they are not language
>> specific.
>
> This would certainly be a better way.  It's just a bit more  
> complicated to implement.  I will get this written down as an  
> enhancement to work on at some point.



I'd say that it is almost a block on this patch, actually, since the  
other way to do it seems to be significantly better.  Correct me if  
I'm wrong: by putting this patch in place, we will cause channels to  
be hung up ("No available codec") when previously they were merely  
unavailable in ChanSpy and a few other places.

The good news is that this now has a flag to turn this SLIN transcode  
silence transmission on or off, so it is possible to avoid that  
problem with addition of more complexity in configuration.  But if we  
implement this patch now, and we do the patch later where we just send  
pre-transcoded silence from a file (or even from a binary blob  
embedded in a library, which seems like a better solution the more I  
think about it - no filesystem access, and only a millisecond of  
silence needs to be sampled) then we're setting ourselves up for  
having to remove that option from the config files since it becomes un- 
necessary.

JT

---
John Todd                       email:jtodd at digium.com
Digium, Inc. | Asterisk Open Source Community Director
445 Jan Davis Drive NW -  Huntsville AL 35806  -   USA
direct: +1-256-428-6083         http://www.digium.com/