Finds the features in this that has the index
index, and returns it.
WARNING: This function takes a const GstCaps *, but returns a non-const GstCapsFeatures *. This is for programming convenience -- the caller
should be aware that structures inside a constant Caps should not be modified. However,
if you know the caps are writable, either because you have just copied them or made them writable with
may modify the features returned in the usual way, e.g. with functions like
You do not need to free or unref the structure returned, it belongs to the Caps.
the index of the structure
a pointer to the CapsFeatures corresponding to