If using approach (1) below, How do you distinguish between two same Events
like digit '1' in '911' with no (noticeable) gaps between the events ? If
bis-01 went with approach (1), implementations would(should ?) recognize
'91'.
-----Original Message-----
From: Henning Schulzrinne [mailto:hgs@cs.columbia.edu]
Sent: Monday, October 21, 2002 1:11 PM
To: Paul Smith; avt@ietf.org
Subject: [AVT] Re: RFC 2833: Is there a way to handle tones with a
duration over 8 a pproximately seconds?
(Cc'ing AVT, for general input)
There are, I believe, two approaches:
(1) have two or more contiguous tones of 8 seconds each. You will be
able able tell from the timestamps that there was no gap, i.e., that
this is one tone instead of two;
(2) define a different, lower sampling rate for the event 'codec' if it
is anticipated that tones could last longer than 8 seconds.
I'm adding wording on (1) to bis-01.
How common is this, btw?
Paul Smith wrote:
Mr. Schulzrinne,
Since a DTMF tone can last longer than 8 seconds: How should this be
handled?
From RFC 2833:
3.5 Payload Format
duration: Duration of this digit, in timestamp units. Thus, the event
began
at the instant identified by the RTP timestamp and has so far lasted
as long
as indicated by this parameter. The event may or may not have ended. For a
sampling rate of 8000 Hz, this field is sufficient to express event
durations of up to approximately 8 seconds.
E: If set to a value of one, the "end" bit indicates that this packet
contains the end of the event. Thus, the duration parameter above measures
the complete duration of the event.
Thank you for your time,
Paul Smith
_______________________________________________
Audio/Video Transport Working Group
avt@ietf.org
https://www1.ietf.org/mailman/listinfo/avt
_______________________________________________
Audio/Video Transport Working Group
avt@ietf.org
https://www1.ietf.org/mailman/listinfo/avt