[gst-devel] v4l2src fails to change video norm from PAL to NTSC

[Tim-Philipp Müller]

On Tue, 2010-12-07 at 15:39 -0800, wally_bkg wrote:

> Looks like another undocumented or unintentional change to gstreamer, need to
> set pipeline to READY instead of PAUSED now before using the interface.
> 
> Change:
> 
>  gst_element_set_state (pipeline, GST_STATE_PAUSED); 
> 
> To:
> 
> gst_element_set_state (pipeline, GST_STATE_READY); 
> 
> And the PAL to NTSC switch happens correctly now.

I believe this change (open device when going to READY, not PAUSED) was
intentional, to align v4l2src with other elements (opening the device in
the NULL->READY state change), but by itself shouldn't break anything.
It shouldn't make a difference at the v4l2src level, since the device
will go to READY state before going to PAUSED state.

The reason this breaks for you between 0.10.7 and is probably that
you're dealing with the pipeline as a whole, and latency handling was
introduced around 0.10.12-0.10.14, which introduced behavioural
incompatibilities for some cases which were thought not to work properly
before anyway (there was a transition period with warnings for a few
releases, but that doesn't help if you upgrade from an ancient release
to a very new one of course).

 Cheers
  -Tim