[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [AVT] RFC2833 (and draft) question regarding packet format
Wong, David wrote:
I wanted to make sure that my understanding of the packet formats for
named events is correct.
In section 3.6 of RFC2833 (and the draft), there is the statement "If
there has been no new event in the last interval, the event SHOULD be
retransmitted three times or until the next event is recognized." Say an
event for the digit "9" is detected and is to be transmitted. Does this
mean that the packet containing the event for digit 9 should be sent out
3 times, without incrementing the RTP timestamp or changing the RTP
header, but perhaps only changing the identifier in the IP header? How
strictly should this be interpreted (ie. would this be interpreted as a
"must" in this case).
In the same paragraph: "In both cases, the RTP sequence number is
incremented by one in each RTP packet."
In section 3.7, there is the statement "During an event, the RTP event
payload format provides incremental updates on the event." Sections 3.8
and 3.9 contain an example of the digits "911" being dialed. Should the
format of the packet described in Figure 2 be taken as a "must" for the
format? Ie. as long as the time offset can fit into 14 bits, that
information should be included in the packet?
Yes, although I don't understand your question. What would you like to
change?
I also have a question for transmitting both in-band and out-of-band
information. Take the example of "911" in the RFC/draft with the pauses
in between the digits. If audio clips for the digits are to be
transmitted in addition to named events, then the audio clips would be
the primary encoding and the named events the redundant info?
Yes.
Would it
be correct to send out a silence audio clip between the digit audio clips?
Not sure what you mean by a "silence audio clip". You could certainly
send samples representing silence, if that's what you mean. Not
particularly helpful and wasteful of bandwidth, but possible.
*David Wong*
Software Engineer*
*Communications Infrastructure Test Group
*****p|* 978.661.1241* f|* 978.988.0148
*email |* dwong@empirix.com
205 Lowell Street | Wilmington, MA***** |* 01887
*****E M P I R I X
__*___http://www.empirix.com _
_______________________________________________
Audio/Video Transport Working Group
avt@ietf.org
https://www1.ietf.org/mailman/listinfo/avt