how can i know the result of "cap negotiation"

[Stas Sergeev]

04.09.2011 13:36, 宋喜佳 wrote:
> Hi friends,
> Maybe it is really a simple question, but I am afraid that i do not
> now the answer. that is how can i know the final result of cap
> negotiation. the caps of a pad tell us all of possible formats it can
> support, but at actual running time, how can i know the format it is
> using?
> for example, we know the ffmpegcolorspace plugin support  many formats
> at its srcpad, but at running time ,when linked to a sink element
> ,which supports many formats too, how can i know the final format they
> use after cap negotiation ? ( I program with  C language)
Use gst_pad_set_setcaps_function() to register your
own handler for the caps negotiation on pad.
But if you use the ghostpad (you probably do not),
you are out of luck, but the patch here may help:
https://bugzilla.gnome.org/show_bug.cgi?id=658076