time of day timestamps handling in gstreamer (v4l2 source)

[Philippe De Muyter]

On Wed, Aug 27, 2014 at 12:19:16PM -0400, Nicolas Dufresne wrote:
> Le mercredi 27 août 2014 à 16:58 +0200, Philippe De Muyter a écrit :
> > How can a source having known timeofday timestamps (perhaps even old timestamps
> > as with dv1394 or matroska files) ensure that they are preserved and made
> > available for the sink ?
> 
> Would it possible to clarify this question ? Initially you mention
> v4l2src, other sources behave differently. User can't really assume what
> is the meaning of a timestamp, but can transform it in one of the known
> form using the segment. Known forms are stream time, running time, clock
> time.

I have two use cases :

- the first one is real-time acquisition with a v4l2 driver producing
timeofday timestamps.  In addition to my own processing where I must get access
to the timeofday timestamps, I would like to use standard gstreamer plugins
to produce video files containing those timestamps.

- I must be able to replay those video files to feed them again to my own
processing and here also I need to get the original timeofday timestamps.

Thus, of course, I need a container format able to save those timestamps.

Philippe