Re: [Linphone-developers] help in unit of RTT in RTCP parse

[Nicola Baldo]

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