Re: [Linphone-developers] Using oRTP to send supplemental data besides the audio

[Steve Strobel]

> > Vadim Lebedev <address@hidden> wrote:
>
> I mean encode nibble data.

Yuck.  Like you said, usable for at most a few bytes of data.

> > If I used just the one RTP session and sent some packets with the 
> > G. 711u payload type and other packets as a different (maybe non-audio)
> > type, would a standard RTP endpoint ignore the non-audio packets and
> > continue to process the G.711u packets, or would it puke on the 
> > non- audio packets?
>
> There is no such thing as standard RTP endpoint.
> There are RTP stacks which will ignore unknown payloads,
> but there are others which will die horrible death on unknown payload.

OK, scratch that idea.

> > I understand that RTP packets sent via UDP will not be resent if
> > lost.  I can live with that.  Are you suggesting, though, that
> > sending the data as DTMF would be any different?
>
> well oRTP at least retransmit  DTMF signals several times so that the
> chances of loss are minimized.

I didn't know that.  Good info.

> Btw, if you setup a sparet oRtp session for your data using PCM as
> payload you should be ewavre that first dozen of packet risk to not to
> be delivered.
> Rtp need some initial amount of packets to be sure that  incoming data
> constitute a valid RTP stream

Yuck again.

Any idea if the method used to send RTCP packets could be used to 
send extra data without confusing things?

I don't understand FMTP at all.  Any idea if it might be useful?

> Thanks
> Vadim

Thanks for your help,
Steve



---
Steve Strobel
Link Communications, Inc.
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