[FFmpeg-user] getting wall clock time from rtsp stream

Moritz Barsnick barsnick at gmx.net
Fri Mar 18 10:15:50 CET 2016

On Fri, Mar 18, 2016 at 09:38:05 +0100, Daniel Oberhoff wrote:
> that or a logging option would be cool. The ntp is really important
> for synchronization, and it would be cool if we would not have to
> patch our own ffmpeg. I would like to propose a patch to devel for
> this. I guess the av_log option would be the least intrusive for now.

I was thinking (and googling) a bit more about my thoughts... I'm not
sure the PTS is a good place to store a "real" time, but I couldn't
find much info on that. MPEG(-TS) also supports a PCR field, a "clock
reference" which is supposed to hold a wallclock time - that which is
the reference for the timestamps. (IIUC.) ffprobe should be able to
query that as well. Yet ffmpeg would need to gain a capability to
forward the value and to write this, I think.

You could also consider an option to add the wallclock to stream
metadata automatically - this wouldn't get lost along the way, and
could automatically land in the output stream.

But go ahead, do suggest something to devel, and let's see what they
think is sane.


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