[Linphone-users]Re: TrueSpeech codec

[Robert W. Brewer]

Simon Morlat wrote:

> This is a very nice solution. I think the Yahoo messenger should then
> initiate a SIP call to linphone and put in the SDP message the correct
> settings (port, codec). Then the user would ring and the user would have
> to accept the call as normally. The Yahoo messenger would receive the
> 200 Ok from linphone and then do the necessary signaling to the remote
> Yahoo messenger. Doing as this, linphone does not need any modifications
> in its interfaces.
>  
Ahh, that does sound like a nice way to do it.  I didn't realize SIP/SDP 
could specify ports anywhere they wanted, but I guess that makes sense 
for things like call transfer.  I'm actually not totally sure what the 
use case would be like, there are at least two different ones on 
Yahoo...  point-to-point voice chat with one other person and voice chat 
in a conference room.  The conference room uses Yahoo's server as a 
reflector, I think point-to-point can go direct to the other IP or 
through the server.  It probably doesn't matter much to Linphone as long 
as it's told where to go.  If we get to this scheme it might be useful 
to have a way of doing auto-answer in Linphone (maybe configurable by 
the user from only trusted sources?).  This would allow the user to 
approve the call in the messenger and not be bothered pressing another 
button in Linphone to get it going.  But something like that is still a 
ways off...  :)

> I would be very interested in having this dll support in linphone.
> That's why I suggest the following:
> First step:
> * you add support for TrueSpeech codec in linphone, I can take in charge
> the signaling side for this codec (all code that is not in
> mediastreamer/), if you wish
> * you take the linphone code into your messenger to test all that.
>
> Second step:
> * you implement the Yahoo-to-SIP call forwarding. If you need help, I'm
> there.
>
> What do you think of that ?
> I can provide you rw access to linphone's cvs, to avoid wasting time in
> merging patches.
> Note that linphone-0.11.0 is already deprecated compared to the cvs
> code... No changes in mediastreamer, but some important changes in the
> way linphone understands codecs.
> I'm waiting for your comments.
>  
Ok, I think that's a good way forward.  We've got encoding and decoding 
of TrueSpeech files under Linux today, so putting a TrueSpeech codec in 
Linphone is the next step.  Once it's in it shouldn't be too hard for 
those interested to add other codecs supported by Microsoft's ACM (Audio 
Compression Manager).  The main thing needed is to create some test .wav 
files under Windows to find out the correct headers to configure the 
.dll.  Mplayer's codecs.conf is helpful for finding the right .dll to 
load.  :)  I'll include a note about this with the code.

I pulled down the CVS.  I intend to add msTrueSpeechencoder.*, 
msTrueSpeechdecoder.*, test_truespeech.c, and a separate directory for 
all the .dll loading infrastructure.  I haven't yet located how to 
register a new codec with the rest of the code, is that the signalling 
you're describing?  It may be a couple weeks before I can get this 
added.  My savannah account is rbrewer if you'd like to add me.  Thanks.

-Rob