General code cleanup.

Removing redundant code, lower case variable names, better indentation,
better parameter names, adding const to readonly parameters.

Change-Id: Ibfdee00f60316fdc5b3f024028c7aaa76a627483

vp9/common/vp9_entropymv.c

@@ -116,11 +116,8 @@ MV_CLASS_TYPE vp9_get_mv_class(int z, int *offset) {
 }
 
 int vp9_use_nmv_hp(const MV *ref) {
-  if ((abs(ref->row) >> 3) < COMPANDED_MVREF_THRESH &&
-      (abs(ref->col) >> 3) < COMPANDED_MVREF_THRESH)
-    return 1;
-  else
-    return 0;
+  return (abs(ref->row) >> 3) < COMPANDED_MVREF_THRESH &&
+         (abs(ref->col) >> 3) < COMPANDED_MVREF_THRESH;
 }
 
 int vp9_get_mv_mag(MV_CLASS_TYPE c, int offset) {
@@ -231,13 +228,13 @@ static void adapt_prob(vp9_prob *dest, vp9_prob prep,
   }
 }
 
-void vp9_counts_process(nmv_context_counts *NMVcount, int usehp) {
-  counts_to_context(&NMVcount->comps[0], usehp);
-  counts_to_context(&NMVcount->comps[1], usehp);
+void vp9_counts_process(nmv_context_counts *nmv_count, int usehp) {
+  counts_to_context(&nmv_count->comps[0], usehp);
+  counts_to_context(&nmv_count->comps[1], usehp);
 }
 
 void vp9_counts_to_nmv_context(
-    nmv_context_counts *NMVcount,
+    nmv_context_counts *nmv_count,
     nmv_context *prob,
     int usehp,
     unsigned int (*branch_ct_joint)[2],
@@ -250,29 +247,29 @@ void vp9_counts_to_nmv_context(
     unsigned int (*branch_ct_class0_hp)[2],
     unsigned int (*branch_ct_hp)[2]) {
   int i, j, k;
-  vp9_counts_process(NMVcount, usehp);
+  vp9_counts_process(nmv_count, usehp);
   vp9_tree_probs_from_distribution(vp9_mv_joint_tree,
                                    prob->joints,
                                    branch_ct_joint,
-                                   NMVcount->joints, 0);
+                                   nmv_count->joints, 0);
   for (i = 0; i < 2; ++i) {
-    prob->comps[i].sign = get_binary_prob(NMVcount->comps[i].sign[0],
-                                          NMVcount->comps[i].sign[1]);
-    branch_ct_sign[i][0] = NMVcount->comps[i].sign[0];
-    branch_ct_sign[i][1] = NMVcount->comps[i].sign[1];
+    prob->comps[i].sign = get_binary_prob(nmv_count->comps[i].sign[0],
+                                          nmv_count->comps[i].sign[1]);
+    branch_ct_sign[i][0] = nmv_count->comps[i].sign[0];
+    branch_ct_sign[i][1] = nmv_count->comps[i].sign[1];
     vp9_tree_probs_from_distribution(vp9_mv_class_tree,
                                      prob->comps[i].classes,
                                      branch_ct_classes[i],
-                                     NMVcount->comps[i].classes, 0);
+                                     nmv_count->comps[i].classes, 0);
     vp9_tree_probs_from_distribution(vp9_mv_class0_tree,
                                      prob->comps[i].class0,
                                      branch_ct_class0[i],
-                                     NMVcount->comps[i].class0, 0);
+                                     nmv_count->comps[i].class0, 0);
     for (j = 0; j < MV_OFFSET_BITS; ++j) {
-      prob->comps[i].bits[j] = get_binary_prob(NMVcount->comps[i].bits[j][0],
-                                               NMVcount->comps[i].bits[j][1]);
-      branch_ct_bits[i][j][0] = NMVcount->comps[i].bits[j][0];
-      branch_ct_bits[i][j][1] = NMVcount->comps[i].bits[j][1];
+      prob->comps[i].bits[j] = get_binary_prob(nmv_count->comps[i].bits[j][0],
+                                               nmv_count->comps[i].bits[j][1]);
+      branch_ct_bits[i][j][0] = nmv_count->comps[i].bits[j][0];
+      branch_ct_bits[i][j][1] = nmv_count->comps[i].bits[j][1];
     }
   }
   for (i = 0; i < 2; ++i) {
@@ -280,25 +277,25 @@ void vp9_counts_to_nmv_context(
       vp9_tree_probs_from_distribution(vp9_mv_fp_tree,
                                        prob->comps[i].class0_fp[k],
                                        branch_ct_class0_fp[i][k],
-                                       NMVcount->comps[i].class0_fp[k], 0);
+                                       nmv_count->comps[i].class0_fp[k], 0);
     }
     vp9_tree_probs_from_distribution(vp9_mv_fp_tree,
                                      prob->comps[i].fp,
                                      branch_ct_fp[i],
-                                     NMVcount->comps[i].fp, 0);
+                                     nmv_count->comps[i].fp, 0);
   }
   if (usehp) {
     for (i = 0; i < 2; ++i) {
       prob->comps[i].class0_hp =
-          get_binary_prob(NMVcount->comps[i].class0_hp[0],
-                          NMVcount->comps[i].class0_hp[1]);
-      branch_ct_class0_hp[i][0] = NMVcount->comps[i].class0_hp[0];
-      branch_ct_class0_hp[i][1] = NMVcount->comps[i].class0_hp[1];
-
-      prob->comps[i].hp = get_binary_prob(NMVcount->comps[i].hp[0],
-                                          NMVcount->comps[i].hp[1]);
-      branch_ct_hp[i][0] = NMVcount->comps[i].hp[0];
-      branch_ct_hp[i][1] = NMVcount->comps[i].hp[1];
+          get_binary_prob(nmv_count->comps[i].class0_hp[0],
+                          nmv_count->comps[i].class0_hp[1]);
+      branch_ct_class0_hp[i][0] = nmv_count->comps[i].class0_hp[0];
+      branch_ct_class0_hp[i][1] = nmv_count->comps[i].class0_hp[1];
+
+      prob->comps[i].hp = get_binary_prob(nmv_count->comps[i].hp[0],
+                                          nmv_count->comps[i].hp[1]);
+      branch_ct_hp[i][0] = nmv_count->comps[i].hp[0];
+      branch_ct_hp[i][1] = nmv_count->comps[i].hp[1];
     }
   }
 }
@@ -308,32 +305,26 @@ static unsigned int adapt_probs(unsigned int i,
                                 vp9_prob this_probs[],
                                 const vp9_prob last_probs[],
                                 const unsigned int num_events[]) {
-  unsigned int left, right, weight;
   vp9_prob this_prob;
 
-  if (tree[i] <= 0) {
-    left = num_events[-tree[i]];
-  } else {
-    left = adapt_probs(tree[i], tree, this_probs, last_probs,
-                       num_events);
-  }
-  if (tree[i + 1] <= 0) {
-    right = num_events[-tree[i + 1]];
-  } else {
-    right = adapt_probs(tree[i + 1], tree, this_probs, last_probs,
-                        num_events);
-  }
+  const uint32_t left = tree[i] <= 0
+          ? num_events[-tree[i]]
+          : adapt_probs(tree[i], tree, this_probs, last_probs, num_events);
+
+  const uint32_t right = tree[i + 1] <= 0
+          ? num_events[-tree[i + 1]]
+          : adapt_probs(tree[i + 1], tree, this_probs, last_probs, num_events);
 
-  weight = left + right;
+  uint32_t weight = left + right;
   if (weight) {
     this_prob = get_binary_prob(left, right);
     weight = weight > MV_COUNT_SAT ? MV_COUNT_SAT : weight;
-    this_prob = weighted_prob(last_probs[i>>1], this_prob,
+    this_prob = weighted_prob(last_probs[i >> 1], this_prob,
                               MV_MAX_UPDATE_FACTOR * weight / MV_COUNT_SAT);
   } else {
     this_prob = last_probs[i >> 1];
   }
-  this_probs[i>>1] = this_prob;
+  this_probs[i >> 1] = this_prob;
   return left + right;
 }
 

vp9/common/vp9_extend.c

@@ -11,159 +11,137 @@
 #include "vp9/common/vp9_extend.h"
 #include "vpx_mem/vpx_mem.h"
 
-static void copy_and_extend_plane(uint8_t *s,       /* source */
-                                  int sp,           /* source pitch */
-                                  uint8_t *d,       /* destination */
-                                  int dp,           /* destination pitch */
-                                  int h,            /* height */
-                                  int w,            /* width */
-                                  int et,           /* extend top border */
-                                  int el,           /* extend left border */
-                                  int eb,           /* extend bottom border */
-                                  int er) {         /* extend right border */
-  int i;
-  uint8_t *src_ptr1, *src_ptr2;
-  uint8_t *dest_ptr1, *dest_ptr2;
-  int linesize;
-
-  /* copy the left and right most columns out */
-  src_ptr1 = s;
-  src_ptr2 = s + w - 1;
-  dest_ptr1 = d - el;
-  dest_ptr2 = d + w;
+static void copy_and_extend_plane(const uint8_t *src, int src_pitch,
+                                  uint8_t *dst, int dst_pitch,
+                                  int w, int h,
+                                  int extend_top, int extend_left,
+                                  int extend_bottom, int extend_right) {
+  int i, linesize;
+
+  // copy the left and right most columns out
+  const uint8_t *src_ptr1 = src;
+  const uint8_t *src_ptr2 = src + w - 1;
+  uint8_t *dst_ptr1 = dst - extend_left;
+  uint8_t *dst_ptr2 = dst + w;
 
   for (i = 0; i < h; i++) {
-    vpx_memset(dest_ptr1, src_ptr1[0], el);
-    vpx_memcpy(dest_ptr1 + el, src_ptr1, w);
-    vpx_memset(dest_ptr2, src_ptr2[0], er);
-    src_ptr1  += sp;
-    src_ptr2  += sp;
-    dest_ptr1 += dp;
-    dest_ptr2 += dp;
+    vpx_memset(dst_ptr1, src_ptr1[0], extend_left);
+    vpx_memcpy(dst_ptr1 + extend_left, src_ptr1, w);
+    vpx_memset(dst_ptr2, src_ptr2[0], extend_right);
+    src_ptr1 += src_pitch;
+    src_ptr2 += src_pitch;
+    dst_ptr1 += dst_pitch;
+    dst_ptr2 += dst_pitch;
   }
 
-  /* Now copy the top and bottom lines into each line of the respective
-   * borders
-   */
-  src_ptr1 = d - el;
-  src_ptr2 = d + dp * (h - 1) - el;
-  dest_ptr1 = d + dp * (-et) - el;
-  dest_ptr2 = d + dp * (h) - el;
-  linesize = el + er + w;
-
-  for (i = 0; i < et; i++) {
-    vpx_memcpy(dest_ptr1, src_ptr1, linesize);
-    dest_ptr1 += dp;
+  // Now copy the top and bottom lines into each line of the respective
+  // borders
+  src_ptr1 = dst - extend_left;
+  src_ptr2 = dst + dst_pitch * (h - 1) - extend_left;
+  dst_ptr1 = dst + dst_pitch * (-extend_top) - extend_left;
+  dst_ptr2 = dst + dst_pitch * (h) - extend_left;
+  linesize = extend_left + extend_right + w;
+
+  for (i = 0; i < extend_top; i++) {
+    vpx_memcpy(dst_ptr1, src_ptr1, linesize);
+    dst_ptr1 += dst_pitch;
   }
 
-  for (i = 0; i < eb; i++) {
-    vpx_memcpy(dest_ptr2, src_ptr2, linesize);
-    dest_ptr2 += dp;
+  for (i = 0; i < extend_bottom; i++) {
+    vpx_memcpy(dst_ptr2, src_ptr2, linesize);
+    dst_ptr2 += dst_pitch;
   }
 }
 
-void vp9_copy_and_extend_frame(YV12_BUFFER_CONFIG *src,
+void vp9_copy_and_extend_frame(const YV12_BUFFER_CONFIG *src,
                                YV12_BUFFER_CONFIG *dst) {
-  int et = dst->border;
-  int el = dst->border;
-  int eb = dst->border + dst->y_height - src->y_height;
-  int er = dst->border + dst->y_width - src->y_width;
+  const int et_y = dst->border;
+  const int el_y = dst->border;
+  const int eb_y = dst->border + dst->y_height - src->y_height;
+  const int er_y = dst->border + dst->y_width - src->y_width;
+
+  const int et_uv = dst->border >> 1;
+  const int el_uv = dst->border >> 1;
+  const int eb_uv = (dst->border >> 1) + dst->uv_height - src->uv_height;
+  const int er_uv = (dst->border >> 1) + dst->uv_width - src->uv_width;
 
   copy_and_extend_plane(src->y_buffer, src->y_stride,
                         dst->y_buffer, dst->y_stride,
-                        src->y_height, src->y_width,
-                        et, el, eb, er);
-
-  et = dst->border >> 1;
-  el = dst->border >> 1;
-  eb = (dst->border >> 1) + dst->uv_height - src->uv_height;
-  er = (dst->border >> 1) + dst->uv_width - src->uv_width;
+                        src->y_width, src->y_height,
+                        et_y, el_y, eb_y, er_y);
 
   copy_and_extend_plane(src->u_buffer, src->uv_stride,
                         dst->u_buffer, dst->uv_stride,
-                        src->uv_height, src->uv_width,
-                        et, el, eb, er);
+                        src->uv_width, src->uv_height,
+                        et_uv, el_uv, eb_uv, er_uv);
 
   copy_and_extend_plane(src->v_buffer, src->uv_stride,
                         dst->v_buffer, dst->uv_stride,
-                        src->uv_height, src->uv_width,
-                        et, el, eb, er);
+                        src->uv_width, src->uv_height,
+                        et_y, el_y, eb_uv, er_uv);
 }
 
-void vp9_copy_and_extend_frame_with_rect(YV12_BUFFER_CONFIG *src,
+void vp9_copy_and_extend_frame_with_rect(const YV12_BUFFER_CONFIG *src,
                                          YV12_BUFFER_CONFIG *dst,
                                          int srcy, int srcx,
                                          int srch, int srcw) {
-  int et = dst->border;
-  int el = dst->border;
-  int eb = dst->border + dst->y_height - src->y_height;
-  int er = dst->border + dst->y_width - src->y_width;
-  int src_y_offset = srcy * src->y_stride + srcx;
-  int dst_y_offset = srcy * dst->y_stride + srcx;
-  int src_uv_offset = ((srcy * src->uv_stride) >> 1) + (srcx >> 1);
-  int dst_uv_offset = ((srcy * dst->uv_stride) >> 1) + (srcx >> 1);
-
   // If the side is not touching the bounder then don't extend.
-  if (srcy)
-    et = 0;
-  if (srcx)
-    el = 0;
-  if (srcy + srch != src->y_height)
-    eb = 0;
-  if (srcx + srcw != src->y_width)
-    er = 0;
-
-  copy_and_extend_plane(src->y_buffer + src_y_offset,
-                        src->y_stride,
-                        dst->y_buffer + dst_y_offset,
-                        dst->y_stride,
-                        srch, srcw,
-                        et, el, eb, er);
-
-  et = (et + 1) >> 1;
-  el = (el + 1) >> 1;
-  eb = (eb + 1) >> 1;
-  er = (er + 1) >> 1;
-  srch = (srch + 1) >> 1;
-  srcw = (srcw + 1) >> 1;
-
-  copy_and_extend_plane(src->u_buffer + src_uv_offset,
-                        src->uv_stride,
-                        dst->u_buffer + dst_uv_offset,
-                        dst->uv_stride,
-                        srch, srcw,
-                        et, el, eb, er);
-
-  copy_and_extend_plane(src->v_buffer + src_uv_offset,
-                        src->uv_stride,
-                        dst->v_buffer + dst_uv_offset,
-                        dst->uv_stride,
-                        srch, srcw,
-                        et, el, eb, er);
+  const int et_y = srcy ? 0 : dst->border;
+  const int el_y = srcx ? 0 : dst->border;
+  const int eb_y = srcy + srch != src->y_height ? 0 :
+                      dst->border + dst->y_height - src->y_height;
+  const int er_y = srcx + srcw != src->y_width ? 0 :
+                      dst->border + dst->y_width - src->y_width;
+  const int src_y_offset = srcy * src->y_stride + srcx;
+  const int dst_y_offset = srcy * dst->y_stride + srcx;
+
+  const int et_uv = (et_y + 1) >> 1;
+  const int el_uv = (el_y + 1) >> 1;
+  const int eb_uv = (eb_y + 1) >> 1;
+  const int er_uv = (er_y + 1) >> 1;
+  const int src_uv_offset = ((srcy * src->uv_stride) >> 1) + (srcx >> 1);
+  const int dst_uv_offset = ((srcy * dst->uv_stride) >> 1) + (srcx >> 1);
+  const int srch_uv = (srch + 1) >> 1;
+  const int srcw_uv = (srcw + 1) >> 1;
+
+  copy_and_extend_plane(src->y_buffer + src_y_offset, src->y_stride,
+                        dst->y_buffer + dst_y_offset, dst->y_stride,
+                        srcw, srch,
+                        et_y, el_y, eb_y, er_y);
+
+  copy_and_extend_plane(src->u_buffer + src_uv_offset, src->uv_stride,
+                        dst->u_buffer + dst_uv_offset, dst->uv_stride,
+                        srcw_uv, srch_uv,
+                        et_uv, el_uv, eb_uv, er_uv);
+
+  copy_and_extend_plane(src->v_buffer + src_uv_offset, src->uv_stride,
+                        dst->v_buffer + dst_uv_offset, dst->uv_stride,
+                        srcw_uv, srch_uv,
+                        et_uv, el_uv, eb_uv, er_uv);
 }
 
-/* note the extension is only for the last row, for intra prediction purpose */
-void vp9_extend_mb_row(YV12_BUFFER_CONFIG *ybf, uint8_t *YPtr,
-                       uint8_t *UPtr, uint8_t *VPtr) {
+// note the extension is only for the last row, for intra prediction purpose
+void vp9_extend_mb_row(YV12_BUFFER_CONFIG *buf,
+                       uint8_t *y, uint8_t *u, uint8_t *v) {
   int i;
 
-  YPtr += ybf->y_stride * 14;
-  UPtr += ybf->uv_stride * 6;
-  VPtr += ybf->uv_stride * 6;
+  y += buf->y_stride * 14;
+  u += buf->uv_stride * 6;
+  v += buf->uv_stride * 6;
 
   for (i = 0; i < 4; i++) {
-    YPtr[i] = YPtr[-1];
-    UPtr[i] = UPtr[-1];
-    VPtr[i] = VPtr[-1];
+    y[i] = y[-1];
+    u[i] = u[-1];
+    v[i] = v[-1];
   }
 
-  YPtr += ybf->y_stride;
-  UPtr += ybf->uv_stride;
-  VPtr += ybf->uv_stride;
+  y += buf->y_stride;
+  u += buf->uv_stride;
+  v += buf->uv_stride;
 
   for (i = 0; i < 4; i++) {
-    YPtr[i] = YPtr[-1];
-    UPtr[i] = UPtr[-1];
-    VPtr[i] = VPtr[-1];
+    y[i] = y[-1];
+    u[i] = u[-1];
+    v[i] = v[-1];
   }
 }

vp9/common/vp9_extend.h

@@ -14,15 +14,17 @@
 #include "vpx_scale/yv12config.h"
 #include "vpx/vpx_integer.h"
 
-void vp9_extend_mb_row(YV12_BUFFER_CONFIG *ybf, uint8_t *YPtr,
-                       uint8_t *UPtr, uint8_t *VPtr);
 
-void vp9_copy_and_extend_frame(YV12_BUFFER_CONFIG *src,
+void vp9_copy_and_extend_frame(const YV12_BUFFER_CONFIG *src,
                                YV12_BUFFER_CONFIG *dst);
 
-void vp9_copy_and_extend_frame_with_rect(YV12_BUFFER_CONFIG *src,
+void vp9_copy_and_extend_frame_with_rect(const YV12_BUFFER_CONFIG *src,
                                          YV12_BUFFER_CONFIG *dst,
                                          int srcy, int srcx,
                                          int srch, int srcw);
 
+void vp9_extend_mb_row(YV12_BUFFER_CONFIG *buf,
+                       uint8_t *y, uint8_t *u, uint8_t *v);
+
+
 #endif  // VP9_COMMON_VP9_EXTEND_H_

vp9/common/vp9_postproc.c

@@ -336,11 +336,8 @@ void vp9_deblock(YV12_BUFFER_CONFIG         *source,
                                 source->uv_height, source->uv_width, ppl);
 }
 
-void vp9_de_noise(YV12_BUFFER_CONFIG         *src,
-                  YV12_BUFFER_CONFIG         *post,
-                  int                         q,
-                  int                         low_var_thresh,
-                  int                         flag) {
+void vp9_denoise(YV12_BUFFER_CONFIG *src, YV12_BUFFER_CONFIG *post,
+                 int q, int low_var_thresh, int flag) {
   double level = 6.0e-05 * q * q * q - .0067 * q * q + .306 * q + .0065;
   int ppl = (int)(level + .5);
   (void) post;

vp9/common/vp9_postproc.h

@@ -29,8 +29,8 @@ struct postproc_state {
 int vp9_post_proc_frame(struct VP9Common *oci, YV12_BUFFER_CONFIG *dest,
                         vp9_ppflags_t *flags);
 
-void vp9_de_noise(YV12_BUFFER_CONFIG *source, YV12_BUFFER_CONFIG *post,
-                  int q, int low_var_thresh, int flag);
+void vp9_denoise(YV12_BUFFER_CONFIG *source, YV12_BUFFER_CONFIG *post,
+                 int q, int low_var_thresh, int flag);
 
 void vp9_deblock(YV12_BUFFER_CONFIG *source, YV12_BUFFER_CONFIG *post,
                  int q, int low_var_thresh, int flag);

vp9/decoder/vp9_dboolhuff.h

@@ -88,34 +88,28 @@ static int decode_value(BOOL_DECODER *br, int bits) {
   int bit;
 
   for (bit = bits - 1; bit >= 0; bit--) {
-    z |= (decode_bool(br, 0x80) << bit);
+    z |= decode_bool(br, 0x80) << bit;
   }
 
   return z;
 }
 
 static int bool_error(BOOL_DECODER *br) {
-  /* Check if we have reached the end of the buffer.
-   *
-   * Variable 'count' stores the number of bits in the 'value' buffer, minus
-   * 8. The top byte is part of the algorithm, and the remainder is buffered
-   * to be shifted into it. So if count == 8, the top 16 bits of 'value' are
-   * occupied, 8 for the algorithm and 8 in the buffer.
-   *
-   * When reading a byte from the user's buffer, count is filled with 8 and
-   * one byte is filled into the value buffer. When we reach the end of the
-   * data, count is additionally filled with VP9_LOTS_OF_BITS. So when
-   * count == VP9_LOTS_OF_BITS - 1, the user's data has been exhausted.
-   */
-  if ((br->count > VP9_BD_VALUE_SIZE) && (br->count < VP9_LOTS_OF_BITS)) {
-    /* We have tried to decode bits after the end of
-     * stream was encountered.
-     */
-    return 1;
-  }
-
-  /* No error. */
-  return 0;
+  // Check if we have reached the end of the buffer.
+  //
+  // Variable 'count' stores the number of bits in the 'value' buffer, minus
+  // 8. The top byte is part of the algorithm, and the remainder is buffered
+  // to be shifted into it. So if count == 8, the top 16 bits of 'value' are
+  // occupied, 8 for the algorithm and 8 in the buffer.
+  //
+  // When reading a byte from the user's buffer, count is filled with 8 and
+  // one byte is filled into the value buffer. When we reach the end of the
+  // data, count is additionally filled with VP9_LOTS_OF_BITS. So when
+  // count == VP9_LOTS_OF_BITS - 1, the user's data has been exhausted.
+  //
+  // 1 if we have tried to decode bits after the end of stream was encountered.
+  // 0 No error.
+  return br->count > VP9_BD_VALUE_SIZE && br->count < VP9_LOTS_OF_BITS;
 }
 
 int vp9_decode_unsigned_max(BOOL_DECODER *br, int max);

vp9/decoder/vp9_onyxd_if.c

@@ -154,8 +154,8 @@ void vp9_remove_decompressor(VP9D_PTR ptr) {
   if (!pbi)
     return;
 
-  // Delete sementation map
-  if (pbi->common.last_frame_seg_map != 0)
+  // Delete segmentation map
+  if (pbi->common.last_frame_seg_map)
     vpx_free(pbi->common.last_frame_seg_map);
 
   vp9_remove_common(&pbi->common);
@@ -163,6 +163,10 @@ void vp9_remove_decompressor(VP9D_PTR ptr) {
   vpx_free(pbi);
 }
 
+static int equal_dimensions(YV12_BUFFER_CONFIG *a, YV12_BUFFER_CONFIG *b) {
+    return a->y_height == b->y_height && a->y_width == b->y_width &&
+           a->uv_height == b->uv_height && a->uv_width == b->uv_width;
+}
 
 vpx_codec_err_t vp9_copy_reference_dec(VP9D_PTR ptr,
                                        VP9_REFFRAME ref_frame_flag,
@@ -176,22 +180,20 @@ vpx_codec_err_t vp9_copy_reference_dec(VP9D_PTR ptr,
    * vpxenc --test-decode functionality working, and will be replaced in a
    * later commit that adds VP9-specific controls for this functionality.
    */
-  if (ref_frame_flag == VP9_LAST_FLAG)
+  if (ref_frame_flag == VP9_LAST_FLAG) {
     ref_fb_idx = pbi->common.ref_frame_map[0];
-  else {
+  } else {
     vpx_internal_error(&pbi->common.error, VPX_CODEC_ERROR,
                        "Invalid reference frame");
     return pbi->common.error.error_code;
   }
 
-  if (cm->yv12_fb[ref_fb_idx].y_height != sd->y_height ||
-      cm->yv12_fb[ref_fb_idx].y_width != sd->y_width ||
-      cm->yv12_fb[ref_fb_idx].uv_height != sd->uv_height ||
-      cm->yv12_fb[ref_fb_idx].uv_width != sd->uv_width) {
+  if (!equal_dimensions(&cm->yv12_fb[ref_fb_idx], sd)) {
     vpx_internal_error(&pbi->common.error, VPX_CODEC_ERROR,
                        "Incorrect buffer dimensions");
-  } else
+  } else {
     vp8_yv12_copy_frame(&cm->yv12_fb[ref_fb_idx], sd);
+  }
 
   return pbi->common.error.error_code;
 }
@@ -202,7 +204,6 @@ vpx_codec_err_t vp9_set_reference_dec(VP9D_PTR ptr, VP9_REFFRAME ref_frame_flag,
   VP9D_COMP *pbi = (VP9D_COMP *) ptr;
   VP9_COMMON *cm = &pbi->common;
   int *ref_fb_ptr = NULL;
-  int free_fb;
 
   /* TODO(jkoleszar): The decoder doesn't have any real knowledge of what the
    * encoder is using the frame buffers for. This is just a stub to keep the
@@ -221,20 +222,17 @@ vpx_codec_err_t vp9_set_reference_dec(VP9D_PTR ptr, VP9_REFFRAME ref_frame_flag,
     return pbi->common.error.error_code;
   }
 
-  if (cm->yv12_fb[*ref_fb_ptr].y_height != sd->y_height ||
-      cm->yv12_fb[*ref_fb_ptr].y_width != sd->y_width ||
-      cm->yv12_fb[*ref_fb_ptr].uv_height != sd->uv_height ||
-      cm->yv12_fb[*ref_fb_ptr].uv_width != sd->uv_width) {
+  if (!equal_dimensions(&cm->yv12_fb[*ref_fb_ptr], sd)) {
     vpx_internal_error(&pbi->common.error, VPX_CODEC_ERROR,
                        "Incorrect buffer dimensions");
   } else {
-    /* Find an empty frame buffer. */
-    free_fb = get_free_fb(cm);
-    /* Decrease fb_idx_ref_cnt since it will be increased again in
-     * ref_cnt_fb() below. */
+    // Find an empty frame buffer.
+    const int free_fb = get_free_fb(cm);
+    // Decrease fb_idx_ref_cnt since it will be increased again in
+    // ref_cnt_fb() below.
     cm->fb_idx_ref_cnt[free_fb]--;