[App_rpt-users] ilbc codec source code ?

[David McGough]

Hi,

I don't have a cookbook solution for installing G.729 (or CODEC2), they
are more complex to install than iLBC, which was originally part of the
Asterisk distribution.

When considering real bandwidth, remember all the IAX2 protocol overhead
on top of the actual CODEC requirements. Here is a previous message, which 
has more details and actual measurements:

http://lists.hamvoip.org/pipermail/arm-allstar/2017-July/005624.html

I don't recall for certain the bandwidth needed for G.729. I think it was
similar to GSM. I'll measure the bandwidth and document it when I get a
chance.


73, David KB4FXC





On Fri, 25 Aug 2017, Toussaint OTTAVI wrote:

> 
Le 25/08/2017 à 21:47, David McGough a écrit :
> I think Zoiper 3 and later has different CODECS (iLBC20 and iLBC30)

Thank you. I have iLBC30 installed, but I didn't see there was an iLBC20 
:-) Good news :-)

> I have tested G.729, but found it to have lower audio quality than iLBC,
> to my ear, at least, with about the same bandwidth use. The patents which
> did encumber most G.729 implementations are now expired.

Did you remember how you installed the codec on Asterisk side ?

AFAIK specs say iLBC is 15 kbps and g729 is 8 kbps, so it should be half 
bandwidth ?

> I have also experimentally added CODEC2 / 3200bps. Other than being CPU
> heavy (as expected), it works fine, but sounds closer to DMR-quality audio
> than is typically desirable for most AllStar use...But, this CODEC is by
> far the low-bandwidth leader of the free CODECs I've tested.

I'd like to test, too. To see if there is an interest to use it with 
poor mobile networks (but if a mobile network can't carry 8 kbps, it may 
not be able to carry 4 kbps much better...)

Of course, I won't use it for my Asterisk backbone :-) But as far as we 
plan to integrate gateways with d-star and DMR, there won't be much 
difference if there are also IAX2 users @3kbps... Moreover, the quality 
of a 3kbps codec transcoded to another 3kbps codec is something I'm 
fearing a bit HI ;-)

Do you know any mobile software that can support codec2 ?

73 de TK1BI
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