diff --git a/src/encoderstate.c b/src/encoderstate.c
index 71a068b0..da37cd20 100644
--- a/src/encoderstate.c
+++ b/src/encoderstate.c
@@ -795,9 +795,10 @@ static void encoder_state_encode_leaf(encoder_state_t * const state)
 #endif
       kvz_threadqueue_free_job(&state->tile->wf_jobs[lcu->id]);
       state->tile->wf_jobs[lcu->id] = kvz_threadqueue_submit(state->encoder_control->threadqueue, encoder_state_worker_encode_lcu, (void*)lcu, 1, job_description);
-      
+      threadqueue_job_t **job = &state->tile->wf_jobs[lcu->id];
+
       // If job object was returned, add dependancies and allow it to run.
-      if (state->tile->wf_jobs[lcu->id]) {
+      if (job[0]) {
         // Add inter frame dependancies when ecoding more than one frame at
         // once. The added dependancy is for the first LCU of each wavefront
         // row to depend on the reconstruction status of the row below in the
@@ -806,26 +807,33 @@ static void encoder_state_encode_leaf(encoder_state_t * const state)
             state->previous_encoder_state->tqj_recon_done &&
             state->frame->slicetype != KVZ_SLICE_I)
         {
-          if (!lcu->left) {
-            const lcu_order_element_t * const ref_lcu = &ref_state->lcu_order[i];
-            if (lcu->below) {
-              kvz_threadqueue_job_dep_add(state->tile->wf_jobs[lcu->id], ref_lcu->below->encoder_state->tqj_recon_done);
+          // We need to wait until the CTUs whose pixels we refer to are
+          // done before we can start this CTU.
+          if (lcu->below) {
+            if (lcu->below->right) {
+              kvz_threadqueue_job_dep_add(job[0], ref_state->tile->wf_jobs[lcu->below->right->id]);
             } else {
-              kvz_threadqueue_job_dep_add(state->tile->wf_jobs[lcu->id], ref_lcu->encoder_state->tqj_recon_done);
+              kvz_threadqueue_job_dep_add(job[0], ref_state->tile->wf_jobs[lcu->below->id]);
+            }
+          } else {
+            if (lcu->right) {
+              kvz_threadqueue_job_dep_add(job[0], ref_state->tile->wf_jobs[lcu->right->id]);
+            } else {
+              kvz_threadqueue_job_dep_add(job[0], ref_state->tile->wf_jobs[lcu->id]);
             }
           }
         }
 
         // Add local WPP dependancy to the LCU on the left.
         if (lcu->left) {
-          kvz_threadqueue_job_dep_add(state->tile->wf_jobs[lcu->id], state->tile->wf_jobs[lcu->id - 1]);
+          kvz_threadqueue_job_dep_add(job[0], job[-1]);
         }
         // Add local WPP dependancy to the LCU on the top right.
         if (lcu->above) {
           if (lcu->above->right) {
-            kvz_threadqueue_job_dep_add(state->tile->wf_jobs[lcu->id], state->tile->wf_jobs[lcu->id - state->tile->frame->width_in_lcu + 1]);
+            kvz_threadqueue_job_dep_add(job[0], job[-state->tile->frame->width_in_lcu + 1]);
           } else {
-            kvz_threadqueue_job_dep_add(state->tile->wf_jobs[lcu->id], state->tile->wf_jobs[lcu->id - state->tile->frame->width_in_lcu]);
+            kvz_threadqueue_job_dep_add(job[0], job[-state->tile->frame->width_in_lcu]);
           }
         }
 
diff --git a/src/inter.c b/src/inter.c
index d0c90a88..adc16507 100644
--- a/src/inter.c
+++ b/src/inter.c
@@ -1005,6 +1005,7 @@ static INLINE bool add_mvp_candidate(const encoder_state_t *state,
 {
   if (!cand) return false;
 
+  assert(cand->inter.mv_dir != 0);
   const int cand_list = cand->inter.mv_dir & (1 << reflist) ? reflist : !reflist;
 
   if (scaling) {
diff --git a/src/search_inter.c b/src/search_inter.c
index 78e39978..4ff55c2c 100644
--- a/src/search_inter.c
+++ b/src/search_inter.c
@@ -40,9 +40,50 @@
  */
 static INLINE bool fracmv_within_tile(const encoder_state_t *state, const vector2d_t* orig, int x, int y, int width, int height, int wpp_limit)
 {
+  const encoder_control_t *ctrl = state->encoder_control;
+
+  if (ctrl->cfg.owf && ctrl->cfg.wpp) {
+    // Check that the block does not reference pixels that are not final.
+
+    // Fractional motion estimation and odd chroma interpolation need
+    // 4 pixels below the bottom edge of the block.
+    int margin = 4;
+    if (ctrl->cfg.sao_enable) {
+      // Make sure we don't refer to pixels for which SAO reconstruction
+      // has not been done.
+      margin += SAO_DELAY_PX;
+    } else if (ctrl->cfg.deblock_enable) {
+      // Make sure we don't refer to pixels that have not been deblocked.
+      margin += DEBLOCK_DELAY_PX;
+    }
+
+    // Coordinates of the top-left corner of the containing LCU.
+    const vector2d_t orig_lcu = {
+      .x = orig->x / LCU_WIDTH,
+      .y = orig->y / LCU_WIDTH,
+    };
+    // Difference between the coordinates of the LCU containing the
+    // bottom-left corner of the referenced block and the LCU containing
+    // this block.
+    const vector2d_t mv_lcu = {
+      .x = (((orig->x + width  + margin) << 2) + x) / (LCU_WIDTH << 2) - orig_lcu.x,
+      .y = (((orig->y + height + margin) << 2) + y) / (LCU_WIDTH << 2) - orig_lcu.y,
+    };
+
+    // TODO: Remove hard coded constants.
+    if (mv_lcu.y > 1) {
+      return false;
+    }
+
+    // TODO: Remove hard coded constants.
+    if (mv_lcu.x + mv_lcu.y > 2) {
+      return false;
+    }
+  }
+
   if (state->encoder_control->cfg.mv_constraint == KVZ_MV_CONSTRAIN_NONE) {
-    return (wpp_limit == -1 || y + (height << 2) <= (wpp_limit << 2));
-  };
+    return true;
+  }
 
   int margin = 0;
   if (state->encoder_control->cfg.mv_constraint == KVZ_MV_CONSTRAIN_FRAME_AND_TILE_MARGIN) {
@@ -1711,6 +1752,13 @@ void kvz_search_cu_smp(encoder_state_t * const state,
 
     search_pu_inter(state, x, y, depth, part_mode, i, lcu, &cost, &bitcost);
 
+    if (cost >= MAX_INT) {
+      // Could not find any motion vector.
+      *inter_cost    = MAX_INT;
+      *inter_bitcost = MAX_INT;
+      return;
+    }
+
     *inter_cost    += cost;
     *inter_bitcost += bitcost;