Subject: Re: [Fwd: RTP Packetization]

From: [email-masked]
Date: Mon, 15 Nov 1999 15:25:06 -0600

If the subject is about how to pack and unpack one or more frames of
encoded media in a single RTP payload, then I think that the RTP audio
profile addressed this already.  The method varies across vocoders; for
G.723.1 there is a dibit in the first byte of each encoded frame which
indicates the frame's length.  G729A is different; the profile specifies
the constraint that G729A payloads must consist of one or more active
frames followed by zero or one SIDs, which also permits a unique parsing of
the payload.  These may be the in-band codings to which H225 refers.  Seems
to me, however, that they are more out-of-band -- in-band instead to the
audio profile.  It is hard to imagine how this would break any robust RTP
implementations.

Vince Virgilio

Jonathan Rosenberg <[email-masked]> on 11/13/99 12:38:13 PM

To:   [email-masked]
cc:    (bcc: Vincent Virgilio)
Subject:  [Fwd: RTP Packetization]

this question is best addressed by avt..

-Jonathan R.
--
Jonathan D. Rosenberg                       200 Executive Drive
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[email-masked]                     FAX:   (732) 741-4778
http://www.cs.columbia.edu/~jdrosen         PHONE: (732) 741-7244
http://www.dynamicsoft.com

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Date: Sat, 13 Nov 1999 09:39:16
To: [email-masked]
From: Ramana Yarlagadda <[email-masked]>
Subject: RTP Packetization
Sender: [email-masked]

Hi all,

In section 6.2.1/H225v2 it is mentioned as :
For audio algorithms such as G.723 which use more than one size of audio

frame, audio frame boundaries within each packet shall be signalled
in-band to the audio channel.

If we consider it from RTP point of view, then in a RTP packet
there can be various combinations of the silence and voice frames.
Let's consider one RTP packet like this:
<voice><voice><SID><voice><SID>.
so, audio frame boundaries can be
1. between two voice frames or
2. between voice frame and a non-voice frame.
3. or both 1 and 2.
My question is exactely which of the above mentioned audio boundaries,
according to the section 6.2.1/h225v2 needs to be signalled in the RTP
packet?

And, the boubndaries are to be signalled in-band, it means we have to
add the boundary signalling in the RTP payload itself.
am I correct?

If we are going to put the boundary signalling inside the RTP payload,
and this sort of signalling is H323 specific thing. then I think it will
create some interoperability problems with RTP implementations other
than
H323.

-Thanks in advance.
-ramana

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