Simplify sub-instanciation by defining an absract type and using subtype
class and instance init callback. This also fixes a bug where the template
pads get initialized too late.
https://bugzilla.gnome.org/show_bug.cgi?id=727925
For each videoCdevice probe it input/output capabilities
if it match with video decoder requirement register a new element.
Signed-off-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
https://bugzilla.gnome.org/show_bug.cgi?id=722128
