In addition to the setup virtual function, you should also override the GstBaseTransform::transform and/or GstBaseTransform::transform_ip virtual function.
setup
Convenience function to add pad templates to this element class, with This function is usually used from within a GObject base_init function.
what formats the filter can handle, as #GstCaps
In addition to the
setupvirtual function, you should also override the GstBaseTransform::transform and/or GstBaseTransform::transform_ip virtual function.