[gst-devel] How do I get gst-inspect properties for v4l2src device other than /dev/video0?

Kulecz, Walter (JSC-SK)[WYLE INTEG. SCI. & ENG.] walter.kulecz-1 at nasa.gov
Fri Apr 16 21:53:56 CEST 2010

> Camera sources are live-sources. That means GST_BUFFER_TIMESTAMP(buf) is
> a clock sample of the time when the frame was captured
> (clocktime-basetime). Thats why it is a good idea to use operating
> system mechanisms to run those capture threads at higher priority or
> even under realtime scheduling (avoiding jitter in the timestamps).
> Stefan

Thanks for the reply.  This sounds like what I wanted to hear!
My version one code runs on the RT kernal from Ubuntu Studio.

Any clues about how to read the buffer time stamps after I've pulled 
them in with appsink would be greatly appreciated.   Its not clear to me 
what the nested macro definition does:

#define GST_BUFFER_TIMESTAMP(buf) (GST_BUFFER_CAST(buf)->timestamp)

If buf is a pointer to a GstBuffer does this turn into the value of the buffer's timestamp,
or a pointer to it?

I haven't stumbled on the definition of  the GST_BUFFER_CAST macro yet :(

Also, what is the use/purpose of the duration value stored in the buffer struct definition?


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