diff --git a/aom_dsp/psnrhvs.c b/aom_dsp/psnrhvs.c
index 69a1d99..25f075a 100644
--- a/aom_dsp/psnrhvs.c
+++ b/aom_dsp/psnrhvs.c
@@ -34,6 +34,7 @@
       *(y + ystride * i + j) = (*(y + ystride * i + j) + 4) >> 3;
 }
 
+#if CONFIG_AV1_HIGHBITDEPTH
 static void hbd_od_bin_fdct8x8(tran_low_t *y, int ystride, const int16_t *x,
                                int xstride) {
   int i, j;
@@ -43,6 +44,7 @@
     for (j = 0; j < 8; j++)
       *(y + ystride * i + j) = (*(y + ystride * i + j) + 4) >> 3;
 }
+#endif  // CONFIG_AV1_HIGHBITDEPTH
 
 /* Normalized inverse quantization matrix for 8x8 DCT at the point of
  * transparency. This is not the JPEG based matrix from the paper,
@@ -210,6 +212,7 @@
         }
       }
       s_gvar = 1.f / (36 - n + 1) * s_gmean / 36.f;
+#if CONFIG_AV1_HIGHBITDEPTH
       if (!buf_is_hbd) {
         od_bin_fdct8x8(dct_s_coef, 8, dct_s, 8);
         od_bin_fdct8x8(dct_d_coef, 8, dct_d, 8);
@@ -217,6 +220,10 @@
         hbd_od_bin_fdct8x8(dct_s_coef, 8, dct_s, 8);
         hbd_od_bin_fdct8x8(dct_d_coef, 8, dct_d, 8);
       }
+#else
+      od_bin_fdct8x8(dct_s_coef, 8, dct_s, 8);
+      od_bin_fdct8x8(dct_d_coef, 8, dct_d, 8);
+#endif  // CONFIG_AV1_HIGHBITDEPTH
       for (i = 0; i < 8; i++)
         for (j = (i == 0); j < 8; j++)
           s_mask += dct_s_coef[i * 8 + j] * dct_s_coef[i * 8 + j] * mask[i][j];
diff --git a/aom_dsp/ssim.c b/aom_dsp/ssim.c
index 357da99..d85b995 100644
--- a/aom_dsp/ssim.c
+++ b/aom_dsp/ssim.c
@@ -49,24 +49,6 @@
   }
 }
 
-#if CONFIG_AV1_HIGHBITDEPTH
-void aom_highbd_ssim_parms_8x8_c(const uint16_t *s, int sp, const uint16_t *r,
-                                 int rp, uint32_t *sum_s, uint32_t *sum_r,
-                                 uint32_t *sum_sq_s, uint32_t *sum_sq_r,
-                                 uint32_t *sum_sxr) {
-  int i, j;
-  for (i = 0; i < 8; i++, s += sp, r += rp) {
-    for (j = 0; j < 8; j++) {
-      *sum_s += s[j];
-      *sum_r += r[j];
-      *sum_sq_s += s[j] * s[j];
-      *sum_sq_r += r[j] * r[j];
-      *sum_sxr += s[j] * r[j];
-    }
-  }
-}
-#endif
-
 static const int64_t cc1 = 26634;        // (64^2*(.01*255)^2
 static const int64_t cc2 = 239708;       // (64^2*(.03*255)^2
 static const int64_t cc1_10 = 428658;    // (64^2*(.01*1023)^2
@@ -111,15 +93,6 @@
   return similarity(sum_s, sum_r, sum_sq_s, sum_sq_r, sum_sxr, 64, 8);
 }
 
-static double highbd_ssim_8x8(const uint16_t *s, int sp, const uint16_t *r,
-                              int rp, uint32_t bd, uint32_t shift) {
-  uint32_t sum_s = 0, sum_r = 0, sum_sq_s = 0, sum_sq_r = 0, sum_sxr = 0;
-  aom_highbd_ssim_parms_8x8(s, sp, r, rp, &sum_s, &sum_r, &sum_sq_s, &sum_sq_r,
-                            &sum_sxr);
-  return similarity(sum_s >> shift, sum_r >> shift, sum_sq_s >> (2 * shift),
-                    sum_sq_r >> (2 * shift), sum_sxr >> (2 * shift), 64, bd);
-}
-
 // We are using a 8x8 moving window with starting location of each 8x8 window
 // on the 4x4 pixel grid. Such arrangement allows the windows to overlap
 // block boundaries to penalize blocking artifacts.
@@ -143,31 +116,9 @@
   return ssim_total;
 }
 
-static double aom_highbd_ssim2(const uint8_t *img1, const uint8_t *img2,
-                               int stride_img1, int stride_img2, int width,
-                               int height, uint32_t bd, uint32_t shift) {
-  int i, j;
-  int samples = 0;
-  double ssim_total = 0;
-
-  // sample point start with each 4x4 location
-  for (i = 0; i <= height - 8;
-       i += 4, img1 += stride_img1 * 4, img2 += stride_img2 * 4) {
-    for (j = 0; j <= width - 8; j += 4) {
-      double v = highbd_ssim_8x8(CONVERT_TO_SHORTPTR(img1 + j), stride_img1,
-                                 CONVERT_TO_SHORTPTR(img2 + j), stride_img2, bd,
-                                 shift);
-      ssim_total += v;
-      samples++;
-    }
-  }
-  ssim_total /= samples;
-  return ssim_total;
-}
-
-void aom_calc_ssim(const YV12_BUFFER_CONFIG *source,
-                   const YV12_BUFFER_CONFIG *dest, double *weight,
-                   double *fast_ssim) {
+void aom_lowbd_calc_ssim(const YV12_BUFFER_CONFIG *source,
+                         const YV12_BUFFER_CONFIG *dest, double *weight,
+                         double *fast_ssim) {
   double abc[3];
   for (int i = 0; i < 3; ++i) {
     const int is_uv = i > 0;
@@ -422,6 +373,54 @@
   return inconsistency_total;
 }
 
+#if CONFIG_AV1_HIGHBITDEPTH
+void aom_highbd_ssim_parms_8x8_c(const uint16_t *s, int sp, const uint16_t *r,
+                                 int rp, uint32_t *sum_s, uint32_t *sum_r,
+                                 uint32_t *sum_sq_s, uint32_t *sum_sq_r,
+                                 uint32_t *sum_sxr) {
+  int i, j;
+  for (i = 0; i < 8; i++, s += sp, r += rp) {
+    for (j = 0; j < 8; j++) {
+      *sum_s += s[j];
+      *sum_r += r[j];
+      *sum_sq_s += s[j] * s[j];
+      *sum_sq_r += r[j] * r[j];
+      *sum_sxr += s[j] * r[j];
+    }
+  }
+}
+
+static double highbd_ssim_8x8(const uint16_t *s, int sp, const uint16_t *r,
+                              int rp, uint32_t bd, uint32_t shift) {
+  uint32_t sum_s = 0, sum_r = 0, sum_sq_s = 0, sum_sq_r = 0, sum_sxr = 0;
+  aom_highbd_ssim_parms_8x8(s, sp, r, rp, &sum_s, &sum_r, &sum_sq_s, &sum_sq_r,
+                            &sum_sxr);
+  return similarity(sum_s >> shift, sum_r >> shift, sum_sq_s >> (2 * shift),
+                    sum_sq_r >> (2 * shift), sum_sxr >> (2 * shift), 64, bd);
+}
+
+static double aom_highbd_ssim2(const uint8_t *img1, const uint8_t *img2,
+                               int stride_img1, int stride_img2, int width,
+                               int height, uint32_t bd, uint32_t shift) {
+  int i, j;
+  int samples = 0;
+  double ssim_total = 0;
+
+  // sample point start with each 4x4 location
+  for (i = 0; i <= height - 8;
+       i += 4, img1 += stride_img1 * 4, img2 += stride_img2 * 4) {
+    for (j = 0; j <= width - 8; j += 4) {
+      double v = highbd_ssim_8x8(CONVERT_TO_SHORTPTR(img1 + j), stride_img1,
+                                 CONVERT_TO_SHORTPTR(img2 + j), stride_img2, bd,
+                                 shift);
+      ssim_total += v;
+      samples++;
+    }
+  }
+  ssim_total /= samples;
+  return ssim_total;
+}
+
 void aom_highbd_calc_ssim(const YV12_BUFFER_CONFIG *source,
                           const YV12_BUFFER_CONFIG *dest, double *weight,
                           uint32_t bd, uint32_t in_bd, double *fast_ssim) {
@@ -455,3 +454,22 @@
     fast_ssim[1] = abc[0] * .8 + .1 * (abc[1] + abc[2]);
   }
 }
+#endif  // CONFIG_AV1_HIGHBITDEPTH
+
+void aom_calc_ssim(const YV12_BUFFER_CONFIG *orig,
+                   const YV12_BUFFER_CONFIG *recon, const uint32_t bit_depth,
+                   const uint32_t in_bit_depth, int is_hbd, double *weight,
+                   double *frame_ssim2) {
+#if CONFIG_AV1_HIGHBITDEPTH
+  if (is_hbd) {
+    aom_highbd_calc_ssim(orig, recon, weight, bit_depth, in_bit_depth,
+                         frame_ssim2);
+    return;
+  }
+#else
+  (void)bit_depth;
+  (void)in_bit_depth;
+  (void)is_hbd;
+#endif  // CONFIG_AV1_HIGHBITDEPTH
+  aom_lowbd_calc_ssim(orig, recon, weight, frame_ssim2);
+}
diff --git a/aom_dsp/ssim.h b/aom_dsp/ssim.h
index d635ef5..b481ae9 100644
--- a/aom_dsp/ssim.h
+++ b/aom_dsp/ssim.h
@@ -68,18 +68,25 @@
                             int img2_pitch, int width, int height, Ssimv *sv2,
                             Metrics *m, int do_inconsistency);
 
-void aom_calc_ssim(const YV12_BUFFER_CONFIG *source,
-                   const YV12_BUFFER_CONFIG *dest, double *weight,
-                   double *fast_ssim);
+void aom_lowbd_calc_ssim(const YV12_BUFFER_CONFIG *source,
+                         const YV12_BUFFER_CONFIG *dest, double *weight,
+                         double *fast_ssim);
 
 double aom_calc_fastssim(const YV12_BUFFER_CONFIG *source,
                          const YV12_BUFFER_CONFIG *dest, double *ssim_y,
                          double *ssim_u, double *ssim_v, uint32_t bd,
                          uint32_t in_bd);
 
+#if CONFIG_AV1_HIGHBITDEPTH
 void aom_highbd_calc_ssim(const YV12_BUFFER_CONFIG *source,
                           const YV12_BUFFER_CONFIG *dest, double *weight,
                           uint32_t bd, uint32_t in_bd, double *fast_ssim);
+#endif  // CONFIG_AV1_HIGHBITDEPTH
+
+void aom_calc_ssim(const YV12_BUFFER_CONFIG *orig,
+                   const YV12_BUFFER_CONFIG *recon, const uint32_t bit_depth,
+                   const uint32_t in_bit_depth, int is_hbd, double *weight,
+                   double *frame_ssim2);
 
 #ifdef __cplusplus
 }  // extern "C"
diff --git a/av1/encoder/encoder.c b/av1/encoder/encoder.c
index e1b1c4c..76ab19c 100644
--- a/av1/encoder/encoder.c
+++ b/av1/encoder/encoder.c
@@ -3585,12 +3585,8 @@
       ppi->total_samples[0] += psnr.samples[0];
       samples = psnr.samples[0];
 
-      // TODO(yaowu): unify these two versions into one.
-      if (cm->seq_params->use_highbitdepth)
-        aom_highbd_calc_ssim(orig, recon, weight, bit_depth, in_bit_depth,
-                             frame_ssim2);
-      else
-        aom_calc_ssim(orig, recon, &weight[0], &frame_ssim2[0]);
+      aom_calc_ssim(orig, recon, bit_depth, in_bit_depth,
+                    cm->seq_params->use_highbitdepth, weight, frame_ssim2);
 
       ppi->worst_ssim = AOMMIN(ppi->worst_ssim, frame_ssim2[0]);
       ppi->summed_quality += frame_ssim2[0] * weight[0];
diff --git a/test/hbd_metrics_test.cc b/test/hbd_metrics_test.cc
index 8044b51..39c2b4c 100644
--- a/test/hbd_metrics_test.cc
+++ b/test/hbd_metrics_test.cc
@@ -88,7 +88,7 @@
 double compute_aomssim(const YV12_BUFFER_CONFIG *source,
                        const YV12_BUFFER_CONFIG *dest) {
   double ssim, weight;
-  aom_calc_ssim(source, dest, &weight, &ssim);
+  aom_lowbd_calc_ssim(source, dest, &weight, &ssim);
   return 100 * pow(ssim / weight, 8.0);
 }
 
diff --git a/test/test.cmake b/test/test.cmake
index d5ee7b9..7c58ac7 100644
--- a/test/test.cmake
+++ b/test/test.cmake
@@ -49,7 +49,7 @@
               "${AOM_ROOT}/test/decode_test_driver.h")
 endif()
 
-if(CONFIG_INTERNAL_STATS)
+if(CONFIG_INTERNAL_STATS AND CONFIG_AV1_HIGHBITDEPTH)
   list(APPEND AOM_UNIT_TEST_COMMON_SOURCES
               "${AOM_ROOT}/test/hbd_metrics_test.cc")
 endif()