[Live-devel] RTP Timestamp to UTC time

[Ross Finlayson]

>We are developing a client application using Live555.

Do "we" not have a domain name?  (If you use a "@gmail.com" email 
address, then you are assumed to be a casual hobbiest (whose posts 
are moderated and given a very low-priority), not a "we".)


>  Our application have some specific requirement of converting the 
>rtp timestamp of each video frame to utc time. So I have following 
>query regarding this:
>
>1.The MediaSink class of Live555 gets the presentation time as a 
>parameter in aftergettingframe function.This presentation time can 
>be converted to RTP timestamp using convertToRTPTimestamp function 
>in RTPSink class.I just want to know how this rtp timestamp can be 
>converted to UTC time.

You don't need to know or care about RTP timestamps.  Our software 
automatically converts from presentation time to RTP timestamp (at 
the server end), and then back from RTP timestamp to presentation 
time (at the client end).  This is assuming, of course, that you use 
RTCP (which is a required part of the RTP/RTCP standard).

So, just make sure that you give your streams proper presentation 
times at the server end - and you will get them automatically at the 
client end.  These presentation times must be aligned with 'wall 
clock' time - i.e., the time that you would get by calling 
"gettimeofday()".  (If "gettimeofday()" does not return UTC time, 
then you will need to apply the appropriate conversion at the client 
end.
-- 

Ross Finlayson
Live Networks, Inc.
http://www.live555.com/