[Bug 762910] onvifparse: extract and apply onvif timestamp

GStreamer (GNOME Bugzilla) bugzilla at gnome.org
Sat Mar 5 18:50:29 UTC 2016


https://bugzilla.gnome.org/show_bug.cgi?id=762910

--- Comment #4 from Nicola <lists at svrinformatica.it> ---
(In reply to Sebastian Dröge (slomo) from comment #3)
> Do we have any information from which clock those timestamps are actually
> generated? A property seems acceptable, but just a GstMeta might be better
> as we have no way to do anything meaningful with those timestamps out of the
> box.

from onvif streaming spec, 

http://www.onvif.org/specs/stream/ONVIF-Streaming-Spec-v230.pdf

6.2.1

"""
The NTP timestamps in the RTP extension header shall increase monotonically
over successive packets within a single RTP stream. They should correspond to
wallclock time as measured at the original transmitter of the stream, adjusted
if necessary to preserve monotonicity
"""

please note that onvif replay is broken anyway using gstreamer, there is a
single rtsp url that serve non contigous recording, for example on my test
camera I have a recording on february 17 and another one on march 3, both are
accessible using this url

rtsp://192.168.10.144:554/ProfileG/Recording-1/recording/play.smp 

a pipeline like rtspsrc ! fakesink will error out at the end of the first
recording, with these logs (there is a huge timestamp gap)

0:04:35.046476045  1878 0x7fdc98030370 WARN                 rtspsrc
gstrtspsrc.c:3140:on_timeout:<rtspsrc0> source 77e5a2cc, stream 77e5a2cc in
session 1 timed out
0:04:35.271076208  1878 0x7fdc98030400 WARN                 rtspsrc
gstrtspsrc.c:3140:on_timeout:<rtspsrc0> source 9b0c26e8, stream 9b0c26e8 in
session 0 timed out
/GstPipeline:pipeline0/GstFakeSink:fakesink0: last-message = event   *******
(fakesink0:sink) E (type: eos (28174), ) 0x7fdc80001920
0:04:35.271238280  1878 0x7fdc98030630 INFO                    task
gsttask.c:315:gst_task_func:<rtpjitterbuffer0:src> Task going to paused


using the patch here at least the stream play until the end with no error,

the point is that onvifparse is a specialized element and it is not
autoplugged, if you put it in your pipeline is beacuse you are dealing with an
onvif camera and so you are interested to onvif timestamps 

For info, I provided another patch that allow to send the custom headers needed
for onvif playback using rtspsrc here:

https://bugzilla.gnome.org/show_bug.cgi?id=762884

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