ition_y (when present) specifies the y component of the (x, y) coordinate pair for constituent frame 0. framel_grid_position_x (when present) specifies the X component of the (x, y) coordinate pair for constituent frame 1. framel_grid_position_y (when present) specifies the y component of the (x, y) coordinate pair for constituent frame 1. When quincunx_sampling_flag is equal to 0 and frame_packing_arrangement_type is not equal to 5 the (x, y) coordinate pair for each constituent frame is interpreted as follows: If the (x, y) coordinate pair for a constituent frame is equal to (0, 0), this indicates a default sampling grid alignment specified as follows: If rame_packing_arrangement_type is equal to 1 or 3, the indicated position is the same as for the (x, y) coordinate pair value (4,8), as illustrated in Figure D-2 and Figure D-6. Otherwise (frame_packing_arrangement_type is equal to 2 or 4), the indicated position is the same as for the (x, y) coordinate pair value (8, 4), as illustrated in Figure D-4 and Figure D-8. Otherwise, if the (x, coordinate pair for a constituent frame is equal to (15, 15), this indicates that the sampling grid alignment is unknown or unspecified or specified by other means not specified in this Recommendation International Standard. Otherwise, the X and y elements of the (x, y) coordinate pair specify the indicated horizontal and vertical sampling grid alignment positioning to the right of and below the upper left corner of the rectangular area represented by the corresponding constituent frame, respectively, in units of one sixteenth of the luma sample grid spacing between the samples of the columns and rows of the constituent frame that are present in the decoded frame (prior to any upsampling for display or other purposes). NOTE 10 - The spatial location reference information frame0_grid_position_x,frame0_grid_position framel_grid_position_x and framel_grid_position_y is not provided when quincunx_sampling_flag is equal to 1 because the spatial alignment in this case is assumed to b