[asterisk-users] G723 problems with TC400B

[Andres]

Jovanny Saravia wrote:

> Hello asteriskers, I hope someone could help me ... !!
>
> I bought a TC400B, and I am testing doing calls with G729 and G723.
>
> When I used G729 it works fine, but when I try to use G723 the RTP has 
> very low quality and is not possible to hear to the other person in 
> the phone.
>
> I try to find out the problem but the only weird that I saw in the 
> debug info is this line (using asterisk 1.2.17):
>
> asterisk*CLI> Apr 15 19:42:44 WARNING[17321] chan_zap.c: Frame too large
> Apr 15 19:42:48 WARNING[17321]: chan_zap.c:4931 zt_write: Frame too large
>
Looks like you are going to have to modify the frame size for G723 on 
the phones.  Not sure what frame size asterisk is expecting but I would 
guess 20ms or 30ms.

> This is my scenario:
>
> - 1 Intel(R) Core(TM)2 CPU (Core 2 Duo with 2.13GHz)
> - 1 Gigabit Memory
> - kernel  2.6.18-1.2798.fc6 x86_64
> - OS: Fedora Core 6
>
> I tried first with asterisk 1.4.1 and its dependencies but the problem 
> is there, too much noise when someone speeaks (poor voice quality).
>
> In asterisk 1.2.17 and its dependencies (libpri, zaptel and addons) is 
> a little better but the voice quality is not good anyway. In this 
> scenario appears the Warning : Frame too large.
>
> The show transcoders and show translations looks fine in asterisk CLI:
> asterisk*CLI> show transcoder
> 0/0 encoders/decoders of 92 channels (G.729a / G.723.1 5.3 kbps) are 
> in use.
>
> asterisk*CLI> show translation
>          Translation times between formats (in milliseconds)
>           Source Format (Rows) Destination Format(Columns)
>
>          g723   gsm  ulaw  alaw  g726 adpcm  slin lpc10  g729 speex  ilbc
>    g723     -     4     1     1     3     3     2     5     2     -    14
>     gsm     3     -     2     2     2     2     1     4     3     -    13
>    ulaw     1     3     -     1     2     2     1     4     1     -    13
>    alaw     1     3     1     -     2     2     1     4     1     -    13
>    g726     3     3     2     2     -     2     1     4     3     -    13
>   adpcm     3     3     2     2     2     -     1     4     3     -    13
>    slin     2     2     1     1     1     1     -     3     2     -    12
>   lpc10     4     4     3     3     3     3     2     -     4     -    14
>    g729     2     4     1     1     3     3     2     5     -     -    14
>   speex     -     -     -     -     -     -     -     -     -     -     -
>    ilbc     4     4     3     3     3     3     2     5     4     -     -
> asterisk*CLI>
>
> After of this I upgrade the kernel to 2.6.20-1.2944.fc6 x86_64, and 
> the problem remains.
>
> Any help will be so much appreciated.
>
> -- 
> Jovanny Saravia
> Solutions Manager
> e-solutions Ltda
> jovanny.saravia at gmail.com <mailto:jovanny.saravia at gmail.com>
> +57-310-7676163
>
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-- 
Andres
Technical Support
http://www.telesip.net