mlt_frame_set_image( frame, *buffer, size, mlt_pool_release );
mlt_frame_set_alpha( frame, alpha, alpha_size, mlt_pool_release );
mlt_properties_set_double( properties, "aspect_ratio", mlt_properties_get_double( producer_props, "aspect_ratio" ) );
mlt_frame_set_image( frame, *buffer, size, mlt_pool_release );
mlt_frame_set_alpha( frame, alpha, alpha_size, mlt_pool_release );
mlt_properties_set_double( properties, "aspect_ratio", mlt_properties_get_double( producer_props, "aspect_ratio" ) );