Replace heap with stack memory allocation

Replaced the dynamic memory allocation of the
second_pred buffer with an allocation on the stack.

Change-Id: I2716c46b71e8587714ca5733a99eca2c68419b23

vp9/encoder/vp9_rdopt.c

@@ -1549,13 +1549,6 @@ static void joint_motion_search(VP9_COMP *cpi, MACROBLOCK *x,
                        mbmi->ref_frame[1] < 0 ? 0 : mbmi->ref_frame[1]};
   int_mv ref_mv[2];
   int ite, ref;
-  // Prediction buffer from second frame.
-#if CONFIG_VP9_HIGHBITDEPTH
-  uint8_t *second_pred;
-  uint8_t *second_pred_alloc;
-#else
-  uint8_t *second_pred = vpx_memalign(16, pw * ph * sizeof(uint8_t));
-#endif  // CONFIG_VP9_HIGHBITDEPTH
   const InterpKernel *kernel = vp9_get_interp_kernel(mbmi->interp_filter);
   struct scale_factors sf;
 
@@ -1566,14 +1559,13 @@ static void joint_motion_search(VP9_COMP *cpi, MACROBLOCK *x,
     vp9_get_scaled_ref_frame(cpi, mbmi->ref_frame[0]),
     vp9_get_scaled_ref_frame(cpi, mbmi->ref_frame[1])
   };
+
+  // Prediction buffer from second frame.
 #if CONFIG_VP9_HIGHBITDEPTH
-  if (xd->cur_buf->flags & YV12_FLAG_HIGHBITDEPTH) {
-    second_pred_alloc = vpx_memalign(16, pw * ph * sizeof(uint16_t));
-    second_pred = CONVERT_TO_BYTEPTR(second_pred_alloc);
-  } else {
-    second_pred_alloc = vpx_memalign(16, pw * ph * sizeof(uint8_t));
-    second_pred = second_pred_alloc;
-  }
+  DECLARE_ALIGNED_ARRAY(16, uint16_t, second_pred_alloc_16, 64 * 64);
+  uint8_t *second_pred;
+#else
+  DECLARE_ALIGNED_ARRAY(16, uint8_t, second_pred, 64 * 64);
 #endif  // CONFIG_VP9_HIGHBITDEPTH
 
   for (ref = 0; ref < 2; ++ref) {
@@ -1628,6 +1620,7 @@ static void joint_motion_search(VP9_COMP *cpi, MACROBLOCK *x,
     // Get the prediction block from the 'other' reference frame.
 #if CONFIG_VP9_HIGHBITDEPTH
     if (xd->cur_buf->flags & YV12_FLAG_HIGHBITDEPTH) {
+      second_pred = CONVERT_TO_BYTEPTR(second_pred_alloc_16);
       vp9_highbd_build_inter_predictor(ref_yv12[!id].buf,
                                        ref_yv12[!id].stride,
                                        second_pred, pw,
@@ -1637,6 +1630,7 @@ static void joint_motion_search(VP9_COMP *cpi, MACROBLOCK *x,
                                        mi_col * MI_SIZE, mi_row * MI_SIZE,
                                        xd->bd);
     } else {
+      second_pred = (uint8_t *)second_pred_alloc_16;
       vp9_build_inter_predictor(ref_yv12[!id].buf,
                                 ref_yv12[!id].stride,
                                 second_pred, pw,
@@ -1722,12 +1716,6 @@ static void joint_motion_search(VP9_COMP *cpi, MACROBLOCK *x,
                                 &mbmi->ref_mvs[refs[ref]][0].as_mv,
                                 x->nmvjointcost, x->mvcost, MV_COST_WEIGHT);
   }
-
-#if CONFIG_VP9_HIGHBITDEPTH
-  vpx_free(second_pred_alloc);
-#else
-  vpx_free(second_pred);
-#endif  // CONFIG_VP9_HIGHBITDEPTH
 }
 
 static int64_t rd_pick_best_sub8x8_mode(VP9_COMP *cpi, MACROBLOCK *x,