Subject: Re: [AVT] RTP/RTCP Timestamp and transmission time

From: Lorenzo Polidori <[email-masked]>
Date: Fri, 19 Sep 2003 09:36:21 +0200 (added by [email-masked])

At 12.56 18/09/2003 +0100, Colin Perkins wrote:

>You need to schedule the transmission time of the RTP packets according 
>to their RTP timestamp. Since the packets are timed, there is a 
>correlation with the wall-clock.

Ok, now it's clear, thanks all. But I have an other question. I must
schedule  the transmission time of the RTP packets and the packets
containing the same MPEG2 picture have the same RTP TS, since the time
reference of the slides belonging to the same picture does not change. Am I
obliged to send a burst of RTP data packets every MPEG2 scheduled picture,
containing all the relative slides?

Wall clock:       0------------10----------20-----------30
Send time:       |           |        |            |        |
                        PB       PB    PB       PB    PB  .......

PB=Burst of RTP Packets containing all the slides of an MPEG picture, with
the same RTP packets, according to RFC 2250, section 3.3.

Best Regards
Lorenzo

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_______________________________________________
Audio/Video Transport Working Group
[email-masked]
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From: Colin Perkins <[email-masked]>
Date: Sat, 20 Sep 2003 00:30:58 +0100

> containing all the relative slides?

You are not obliged to send them in a burst, however RTP provides no 
way for the receiver to distinguish sender-induced delay from 
network-induced delay.

-- 
Colin Perkins
http://csperkins.org/

---

From: "Alan Clark" <[email-masked]>
Date: Mon, 22 Sep 2003 08:04:12 -0400

Colin

Does the RTCP PPDV/jitter calculation accomodate this situation where a
burst of RTP packets with the same TS are sent (or RTP frames are not
transmitted with uniform spacing)?

Alan Clark
Telchemy

-----Original Message-----
From: [email-masked] [mailto:[email-masked]]On Behalf Of Colin
Perkins
Sent: Friday, September 19, 2003 7:31 PM
To: Lorenzo Polidori
Cc: [email-masked]
Subject: Re: [AVT] RTP/RTCP Timestamp and transmission time

--
Colin Perkins
http://csperkins.org/

---

From: Colin Perkins <[email-masked]>
Date: Mon, 22 Sep 2003 16:38:01 +0100

> transmitted with uniform spacing)?

Not really. This is a known limitation of the jitter calculation.

-- 
Colin Perkins
http://csperkins.org/