[pjsip] G.729 Annex B support using APS/VAS Direct

Nanang Izzuddin nanang at pjsip.org
Sat Sep 4 00:36:08 CDT 2010

Hi Vikram,

Just recalled that we also have problems with APS/VAS G729, e.g:
ticket #735 (http://trac.pjsip.org/repos/ticket/735). So the APS/VAS
G729 behaviour will be:
- G.729 encoder always disables VAD, so no SID/DTX frames will be generated.
- G.729 decoder will be able to handle SID/DTX frames (when VAD is enabled).

Also see inline comments.

On Sat, Sep 4, 2010 at 2:40 AM, Vikram Ragukumar
<vragukumar at signalogic.com> wrote:
> Nanang,
>> Yes, it is supported, please check doxygen doc in
>> pjmedia/include/pjmedia-codec/passthrough.h for more info (the online
>> doc hasn't been updated yet).
> Thank you for your response.
> Support for G.729B when accessed through APS/VAS Direct assumes that the
> firmware running on the phone includes this codec... correct ?

APS/VAS can enumerate supported codecs in runtime, and yes, annex B is
always assumed to be there when G729 is supported.

> So, is it possible that there are Nokia phones running a version of firmware
> that does not include G729.B? Are there any messages generated in pjsip's
> log under such a circumstance ?

Don't know. Will be no explicit log message.

> Where can I find a list of firmware level Nokia E-series supported features?

Don't know.

> With some searching on google i found
> - Several posts on Nokia's forum where people are complaining about VAD not
> working when using APS/VAS

As mentioned before, we experienced it too (in encoding side).

> - Nokia's datasheets do not indicate explicitly that G729B is supported when
> using APS/VAS

I think I read it somewhere, couldn't remember.

> Does PJSIP/PJMEDIA implement a VAD/DTX scheme in front of the G729 codec ?

Not for APS/VAS direct.


> Thanks and Regards,
> Vikram.

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