Modifies a pointer to a GstContext to point to a different GstContext. The
modification is done atomically (so this is useful for ensuring thread safety
in some cases), and the reference counts are updated appropriately (the old
context is unreffed, the new one is reffed).
Either new_context or the GstContext pointed to by old_context may be NULL.
Modifies a pointer to a GstContext to point to a different GstContext. The modification is done atomically (so this is useful for ensuring thread safety in some cases), and the reference counts are updated appropriately (the old context is unreffed, the new one is reffed). Either new_context or the GstContext pointed to by old_context may be NULL.