diff -r 000000000000 -r 6474c204b198 media/libvpx/vp9/common/vp9_tile_common.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/media/libvpx/vp9/common/vp9_tile_common.c	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,51 @@
+/*
+ *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "vp9/common/vp9_tile_common.h"
+
+#include "vp9/common/vp9_onyxc_int.h"
+
+#define MIN_TILE_WIDTH_B64 4
+#define MAX_TILE_WIDTH_B64 64
+
+static int get_tile_offset(int idx, int mis, int log2) {
+  const int sb_cols = mi_cols_aligned_to_sb(mis) >> MI_BLOCK_SIZE_LOG2;
+  const int offset = ((idx * sb_cols) >> log2) << MI_BLOCK_SIZE_LOG2;
+  return MIN(offset, mis);
+}
+
+void vp9_tile_init(TileInfo *tile, const VP9_COMMON *cm, int row, int col) {
+  tile->mi_row_start = get_tile_offset(row, cm->mi_rows, cm->log2_tile_rows);
+  tile->mi_row_end = get_tile_offset(row + 1, cm->mi_rows, cm->log2_tile_rows);
+  tile->mi_col_start = get_tile_offset(col, cm->mi_cols, cm->log2_tile_cols);
+  tile->mi_col_end = get_tile_offset(col + 1, cm->mi_cols, cm->log2_tile_cols);
+}
+
+void vp9_get_tile_n_bits(int mi_cols,
+                         int *min_log2_tile_cols, int *max_log2_tile_cols) {
+  const int sb_cols = mi_cols_aligned_to_sb(mi_cols) >> MI_BLOCK_SIZE_LOG2;
+  int min_log2 = 0, max_log2 = 0;
+
+  // max
+  while ((sb_cols >> max_log2) >= MIN_TILE_WIDTH_B64)
+    ++max_log2;
+  --max_log2;
+  if (max_log2 < 0)
+    max_log2 = 0;
+
+  // min
+  while ((MAX_TILE_WIDTH_B64 << min_log2) < sb_cols)
+    ++min_log2;
+
+  assert(min_log2 <= max_log2);
+
+  *min_log2_tile_cols = min_log2;
+  *max_log2_tile_cols = max_log2;
+}