A reliable method for preparation of buckled self-supported films of BaTiO₃ and SrTiO₃ is described.  The method is based on crystallization of self-supported amorphous films.The structural evolution of the amorphous phase upon heating has been investigated in detail. Amorphous BaTiO₃ undergoes a large (up to 10%) pre-nucleation expansion, which is related to the fact that this phase is a network of randomly connected TiO₆ octahedra. The pre-nucleation expansion results in the formation of a low-density amorphous phase in which nucleation can occur. The degree of pre-nucleation expansion and the symmetry of the crystallization product (hexagonal or perovskite phase of BaTiO₃) can be modified by the presence of a thin (20 nm) buffer layer of MgO. Crystallization in a traveling temperature gradient promotes growth of crystallites in the direction perpendicular to the plane of the film. Therefore, one can prepare crystalline films with a film-window misfit strain within the range of 0-10% by varying the peak temperature and the heater traveling rate. Large positive misfit strain gives films exceptional mechanical stability and makes them very attractive for a wide range of applications. The substrate-free crystallization technique has proven to be very efficient (yield > 99%) for preparation of self-supported films of perovskite BaTiO₃ with a grain size of 20-100 nm and lateral dimensions up to 1000 µm.