Cherry pick buffer re-allocation fix

source/libvpx/vp9/common/vp9_alloccommon.c

 /*
  *  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.
  */
 
@@ skipping 38 matching lines @@
 }
 
 static int alloc_seg_map(VP9_COMMON *cm, int seg_map_size) {
   int i;
 
   for (i = 0; i < NUM_PING_PONG_BUFFERS; ++i) {
     cm->seg_map_array[i] = (uint8_t *)vpx_calloc(seg_map_size, 1);
     if (cm->seg_map_array[i] == NULL)
       return 1;
   }
+  cm->seg_map_alloc_size = seg_map_size;
 
   // Init the index.
   cm->seg_map_idx = 0;
   cm->prev_seg_map_idx = 1;
 
   cm->current_frame_seg_map = cm->seg_map_array[cm->seg_map_idx];
   if (!cm->frame_parallel_decode)
     cm->last_frame_seg_map = cm->seg_map_array[cm->prev_seg_map_idx];
 
   return 0;
@@ skipping 41 matching lines @@
 void vp9_free_context_buffers(VP9_COMMON *cm) {
   cm->free_mi(cm);
   free_seg_map(cm);
   vpx_free(cm->above_context);
   cm->above_context = NULL;
   vpx_free(cm->above_seg_context);
   cm->above_seg_context = NULL;
 }
 
 int vp9_alloc_context_buffers(VP9_COMMON *cm, int width, int height) {
-  vp9_free_context_buffers(cm);
+  int new_mi_size;
 
   vp9_set_mb_mi(cm, width, height);
-  if (cm->alloc_mi(cm, cm->mi_stride * calc_mi_size(cm->mi_rows)))
-    goto fail;
+  new_mi_size = cm->mi_stride * calc_mi_size(cm->mi_rows);
+  if (cm->mi_alloc_size < new_mi_size) {
+    cm->free_mi(cm);
+    if (cm->alloc_mi(cm, new_mi_size))
+      goto fail;
+  }
 
-  // Create the segmentation map structure and set to 0.
-  free_seg_map(cm);
-  if (alloc_seg_map(cm, cm->mi_rows * cm->mi_cols))
-    goto fail;
+  if (cm->seg_map_alloc_size < cm->mi_rows * cm->mi_cols) {
+    // Create the segmentation map structure and set to 0.
+    free_seg_map(cm);
+    if (alloc_seg_map(cm, cm->mi_rows * cm->mi_cols))
+      goto fail;
+  }
 
-  cm->above_context = (ENTROPY_CONTEXT *)vpx_calloc(
-      2 * mi_cols_aligned_to_sb(cm->mi_cols) * MAX_MB_PLANE,
-      sizeof(*cm->above_context));
-  if (!cm->above_context) goto fail;
+  if (cm->above_context_alloc_cols < cm->mi_cols) {
+    vpx_free(cm->above_context);
+    cm->above_context = (ENTROPY_CONTEXT *)vpx_calloc(
+        2 * mi_cols_aligned_to_sb(cm->mi_cols) * MAX_MB_PLANE,
+        sizeof(*cm->above_context));
+    if (!cm->above_context) goto fail;
 
-  cm->above_seg_context = (PARTITION_CONTEXT *)vpx_calloc(
-      mi_cols_aligned_to_sb(cm->mi_cols), sizeof(*cm->above_seg_context));
-  if (!cm->above_seg_context) goto fail;
+    vpx_free(cm->above_seg_context);
+    cm->above_seg_context = (PARTITION_CONTEXT *)vpx_calloc(
+        mi_cols_aligned_to_sb(cm->mi_cols), sizeof(*cm->above_seg_context));
+    if (!cm->above_seg_context) goto fail;
+    cm->above_context_alloc_cols = cm->mi_cols;
+  }
 
   return 0;
 
  fail:
   vp9_free_context_buffers(cm);
   return 1;
 }
 
 void vp9_remove_common(VP9_COMMON *cm) {
   vp9_free_context_buffers(cm);
@@ skipping 12 matching lines @@
 
 void vp9_swap_current_and_last_seg_map(VP9_COMMON *cm) {
   // Swap indices.
   const int tmp = cm->seg_map_idx;
   cm->seg_map_idx = cm->prev_seg_map_idx;
   cm->prev_seg_map_idx = tmp;
 
   cm->current_frame_seg_map = cm->seg_map_array[cm->seg_map_idx];
   cm->last_frame_seg_map = cm->seg_map_array[cm->prev_seg_map_idx];
 }