Speex dev - Dec 2006 - get the mode from a incoming speex stream

In a "normal" frame that doesn't have in-band signalling (which
nobody
seems to use anyway), the frame starts with the narrowband information.
If the frame is in wideband, then this will be followed by a bit of
wideband information that starts with a bit set to 1 (narrowband starts
with a bit set to 0). Have a look at what the Speex decoder does. You
may actually want to have similar code in a "null decoder".

	Jean-Marc

Aymeric Moizard a ?crit :
> 
> Hi speexers,
> 
> I want to be able to automatically detect the mode (narrowband/wb..)
> of the RTP stream I'm receiving.
> 
> I guess this information is included in frames? Isn'it?
> How can I read it?
> 
> tks,
> Aymeric MOIZARD / ANTISIP
> amsip - http://www.antisip.com
> osip2 - http://www.osip.org
> eXosip2 - http://savannah.nongnu.org/projects/exosip/
> 
> _______________________________________________
> Speex-dev mailing list
> Speex-dev@xiph.org
> http://lists.xiph.org/mailman/listinfo/speex-dev
> 
>

Hi Jean-Marc,

I remember you said that the SDP tells the mode information.
Is SDP what you called in-band signalling?

Lianghu

On 12/6/06, Jean-Marc Valin <jean-marc.valin@usherbrooke.ca>
wrote:
>
> In a "normal" frame that doesn't have in-band signalling
(which nobody
> seems to use anyway), the frame starts with the narrowband information.
> If the frame is in wideband, then this will be followed by a bit of
> wideband information that starts with a bit set to 1 (narrowband starts
> with a bit set to 0). Have a look at what the Speex decoder does. You
> may actually want to have similar code in a "null decoder".
>
>         Jean-Marc
>
> Aymeric Moizard a ?crit :
> >
> > Hi speexers,
> >
> > I want to be able to automatically detect the mode (narrowband/wb..)
> > of the RTP stream I'm receiving.
> >
> > I guess this information is included in frames? Isn'it?
> > How can I read it?
> >
> > tks,
> > Aymeric MOIZARD / ANTISIP
> > amsip - http://www.antisip.com
> > osip2 - http://www.osip.org
> > eXosip2 - http://savannah.nongnu.org/projects/exosip/
> >
> > _______________________________________________
> > Speex-dev mailing list
> > Speex-dev@xiph.org
> > http://lists.xiph.org/mailman/listinfo/speex-dev
> >
> >
> _______________________________________________
> Speex-dev mailing list
> Speex-dev@xiph.org
> http://lists.xiph.org/mailman/listinfo/speex-dev
>
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On Wed, 6 Dec 2006, lianghu xu wrote:
> Hi Jean-Marc,
>
> I remember you said that the SDP tells the mode information.
Right.

But a decoder like speex can always be configured from information 
contained in the incoming stream.

That makes your application more interroperable.

Aymeric MOIZARD / ANTISIP
amsip - http://www.antisip.com
osip2 - http://www.osip.org
eXosip2 - http://savannah.nongnu.org/projects/exosip/
> Is SDP what you called in-band signalling?
> Lianghu
>
> On 12/6/06, Jean-Marc Valin <jean-marc.valin@usherbrooke.ca> wrote:
>> 
>> In a "normal" frame that doesn't have in-band signalling
(which nobody
>> seems to use anyway), the frame starts with the narrowband information.
>> If the frame is in wideband, then this will be followed by a bit of
>> wideband information that starts with a bit set to 1 (narrowband starts
>> with a bit set to 0). Have a look at what the Speex decoder does. You
>> may actually want to have similar code in a "null decoder".
>>
>>         Jean-Marc
>> 
>> Aymeric Moizard a ?crit :
>> >
>> > Hi speexers,
>> >
>> > I want to be able to automatically detect the mode
(narrowband/wb..)
>> > of the RTP stream I'm receiving.
>> >
>> > I guess this information is included in frames? Isn'it?
>> > How can I read it?
>> >
>> > tks,
>> > Aymeric MOIZARD / ANTISIP
>> > amsip - http://www.antisip.com
>> > osip2 - http://www.osip.org
>> > eXosip2 - http://savannah.nongnu.org/projects/exosip/
>> >
>> > _______________________________________________
>> > Speex-dev mailing list
>> > Speex-dev@xiph.org
>> > http://lists.xiph.org/mailman/listinfo/speex-dev
>> >
>> >
>> _______________________________________________
>> Speex-dev mailing list
>> Speex-dev@xiph.org
>> http://lists.xiph.org/mailman/listinfo/speex-dev
>> 
>