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From: | Nicola Baldo |
Subject: | Re: [Linphone-developers] help in unit of RTT in RTCP parse |
Date: | Tue, 28 Jun 2005 21:12:08 +0200 |
User-agent: | Debian Thunderbird 1.0.2 (X11/20050331) |
julien thai wrote:
I read rtcpparse, in function report_block_parse,you found that you calcule RTT ( actually, i spent one day to understand your algorithm, it's great )
The algorithm is actually defined within RFC 1889, it's a part of the RTP standard. If you look on the above mentioned RFC, on page 28, there's a pretty straightforward explanation on how it works.
I think unit of RTT you calculed is microsecond. Can you confirme it?
Well, referring to the file rtcpparse.c, the 'delay_snc_last_sr' and 'lsr' values are in units of 1/65536 seconds (that's the specification in the RFC for the LSR and DLSR fields), the 'rcv_time' variable is also calculated in the same units. So the value of the 'rtt' variable, after the division by 65536, is in seconds.
Regards, Nicola
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