vdec_vp9_slice_tile_offset
start = vdec_vp9_slice_tile_offset(i, mi_rows, rows_log2);
end = vdec_vp9_slice_tile_offset(i + 1, mi_rows, rows_log2);
start = vdec_vp9_slice_tile_offset(i, mi_cols, cols_log2);
end = vdec_vp9_slice_tile_offset(i + 1, mi_cols, cols_log2);