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

Aymeric Moizard jack at atosc.org
Wed Dec 6 03:13:00 PST 2006



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
>> 
>


More information about the Speex-dev mailing list