From 7.4.3.3.1:

num_tile_columns_minus1 shall be in the range of 0 to PicWidthInCtbsY - 1, inclusive.
num_tile_rows_minus1 shall be in the range of 0 to PicHeightInCtbsY - 1, inclusive.
Reviewed-by: Michael Niedermayer <michael@niedermayer.cc>
Signed-off-by: James Almer <jamrial@gmail.com>