Subject: [AVT] RFC 3611 - what is packet duration?

From: "Jorge Canas" <[email-masked]>
Date: Thu, 15 Mar 2007 13:02:38 -0500

I have a question regarding the following two excerpts from RFC 3611:  What 
does "packet duration mean"?  I did not think packets had a duration...

   burst duration: 16 bits
         The mean duration, expressed in milliseconds, of the burst
         periods that have occurred since the beginning of reception.
         The duration of each period is calculated based upon the
         packets that mark the beginning and end of that period.  It is
         equal to the timestamp of the end packet, plus the duration of
         the end packet, minus the timestamp of the beginning packet.
         If the actual values are not available, estimated values MUST
         be used.  If there have been no burst periods, the burst
         duration value MUST be zero.

   gap duration: 16 bits
         The mean duration, expressed in milliseconds, of the gap
         periods that have occurred since the beginning of reception.
         The duration of each period is calculated based upon the packet
         that marks the end of the prior burst and the packet that marks
         the beginning of the subsequent burst.  It is equal to the
         timestamp of the subsequent burst packet, minus the timestamp
         of the prior burst packet, plus the duration of the prior burst
         packet.  If the actual values are not available, estimated
         values MUST be used.  In the case of a gap that occurs at the
         beginning of reception, the sum of the timestamp of the prior
         burst packet and the duration of the prior burst packet are
         replaced by the reception start time.  In the case of a gap
         that occurs at the end of reception, the timestamp of the
         subsequent burst packet is replaced by the reception end time.
         If there have been no gap periods, the gap duration value MUST
         be zero.

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From: "Alan Clark" <[email-masked]>
Date: Thu, 15 Mar 2007 17:29:27 -0500

Jorge

In this case, duration means the duration of time corresponding to the
packet.  If the RTP packet represents 20ms of encoded speech then the
"duration" would be 20ms

Regards

Alan

-----Original Message-----
From: Jorge Canas [mailto:[email-masked]] 
Sent: Thursday, March 15, 2007 1:03 PM
To: [email-masked]
Subject: [AVT] RFC 3611 - what is packet duration?

   burst duration: 16 bits

   gap duration: 16 bits