[Live-devel] Clock drift compensation

[Gilles Chanteperdrix]

Hi,

when using live555 as a server, and vlc as a client (so using live555 as
well) over long periods of time, with a server which is not running ntp,
I observed the following phenomenon: depending on which clock (the
server's or the client's) is running faster, either vlc stops or it
plays images with a big latencies, like 10 seconds.

>From what I understand of live555 code, the presentation time output by
live555 on the client side, is essentially a server clock timestamp, and
I believe the phenomenon observed with vlc is due to the drift between
the server clock and the client clock.

>From what I understand of RTP/RTCP, I believe this drift could be
compensated by comparing the NTP timestamp in RTCP sender reports, with
the actual client time when the RTCP sender report is received,
potentially averaging over a few reports to mitigate network jitter.

Now, the question is: what is the best place to implement this? In the
application? Or in live555 server or client code?

Thanks in advance.
Regards.

-- 
                                                                Gilles.