[Speex-dev] get the mode from a incoming speex stream

[lianghu xu]

Hi,

How can you be able to automatically detect the mode (narrowband/wb..) of
the RTP stream?

I have looked through the decoder source and find it is difficult to do so.
Although the mode information NB/WB/UWB is identified by 0x/10/11 somewhere,
but it's hard
to know it before you do decoder intial.

Any ideas?

Lianghu

On 12/6/06, Aymeric Moizard <jack at atosc.org> wrote:
>
>
>
> 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 at 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 écrit :
> >> >
> >> > 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 at xiph.org
> >> > http://lists.xiph.org/mailman/listinfo/speex-dev
> >> >
> >> >
> >> _______________________________________________
> >> Speex-dev mailing list
> >> Speex-dev at xiph.org
> >> http://lists.xiph.org/mailman/listinfo/speex-dev
> >>
> >
>
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