diff --git a/vp9/encoder/vp9_encoder.c b/vp9/encoder/vp9_encoder.c
index ac66627..6da237d 100644
--- a/vp9/encoder/vp9_encoder.c
+++ b/vp9/encoder/vp9_encoder.c
@@ -1649,7 +1649,7 @@
     cpi->total_ssimg_v = 0;
     cpi->total_ssimg_all = 0;
   }
-
+  cpi->total_fastssim_all = 0;
 #endif
 
   cpi->first_time_stamp_ever = INT64_MAX;
@@ -1883,14 +1883,18 @@
         const double totalp_ssim = 100 * pow(cpi->summedp_quality /
                                                 cpi->summedp_weights, 8.0);
 
+
         fprintf(f, "Bitrate\tAVGPsnr\tGLBPsnr\tAVPsnrP\tGLPsnrP\t"
-                "VPXSSIM\tVPSSIMP\t  Time(ms)\n");
-        fprintf(f, "%7.2f\t%7.3f\t%7.3f\t%7.3f\t%7.3f\t%7.3f\t%7.3f\t%8.0f\n",
+                "VPXSSIM\tVPSSIMP\tFASTSSIM  Time(ms)\n");
+        fprintf(f, "%7.2f\t%7.3f\t%7.3f\t%7.3f\t%7.3f\t%7.3f\t"
+                "%7.3f\t%7.3f\t%8.0f\n",
                 dr, cpi->total / cpi->count, total_psnr,
                 cpi->totalp / cpi->count, totalp_psnr, total_ssim, totalp_ssim,
+                cpi->total_fastssim_all / cpi->count,
                 total_encode_time);
       }
 
+
       if (cpi->b_calculate_ssimg) {
         fprintf(f, "BitRate\tSSIM_Y\tSSIM_U\tSSIM_V\tSSIM_A\t  Time(ms)\n");
         fprintf(f, "%7.2f\t%6.4f\t%6.4f\t%6.4f\t%6.4f\t%8.0f\n", dr,
@@ -4176,6 +4180,17 @@
         cpi->total_ssimg_v += v;
         cpi->total_ssimg_all += frame_all;
       }
+      {
+        double y, u, v, frame_all;
+        frame_all = vp9_calc_fastssim(cpi->Source, cm->frame_to_show, &y, &u,
+                                      &v);
+
+        cpi->total_fastssim_y += y;
+        cpi->total_fastssim_u += u;
+        cpi->total_fastssim_v += v;
+        cpi->total_fastssim_all += frame_all;
+        /* TODO(JBB): add 10/12 bit support */
+      }
     }
   }
 
diff --git a/vp9/encoder/vp9_encoder.h b/vp9/encoder/vp9_encoder.h
index 42305a9..e0ed608 100644
--- a/vp9/encoder/vp9_encoder.h
+++ b/vp9/encoder/vp9_encoder.h
@@ -415,6 +415,11 @@
   double total_ssimg_v;
   double total_ssimg_all;
 
+  double total_fastssim_y;
+  double total_fastssim_u;
+  double total_fastssim_v;
+  double total_fastssim_all;
+
   int b_calculate_ssimg;
 #endif
   int b_calculate_psnr;
diff --git a/vp9/encoder/vp9_fastssim.c b/vp9/encoder/vp9_fastssim.c
new file mode 100644
index 0000000..f1d408c
--- /dev/null
+++ b/vp9/encoder/vp9_fastssim.c
@@ -0,0 +1,465 @@
+/*
+ *  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.
+ *
+ *  This code was originally written by: Nathan E. Egge, at the Daala
+ *  project.
+ */
+#include <math.h>
+#include <string.h>
+#include "./vpx_config.h"
+#include "./vp9_rtcd.h"
+#include "vp9/encoder/vp9_ssim.h"
+/* TODO(jbb): High bit depth version of this code needed */
+typedef struct fs_level fs_level;
+typedef struct fs_ctx fs_ctx;
+
+#define SSIM_C1 (255 * 255 * 0.01 * 0.01)
+#define SSIM_C2 (255 * 255 * 0.03 * 0.03)
+
+#define FS_MINI(_a, _b) ((_a) < (_b) ? (_a) : (_b))
+#define FS_MAXI(_a, _b) ((_a) > (_b) ? (_a) : (_b))
+
+struct fs_level {
+  uint16_t *im1;
+  uint16_t *im2;
+  double *ssim;
+  int w;
+  int h;
+};
+
+struct fs_ctx {
+  fs_level *level;
+  int nlevels;
+  unsigned *col_buf;
+};
+
+static void fs_ctx_init(fs_ctx *_ctx, int _w, int _h, int _nlevels) {
+  unsigned char *data;
+  size_t data_size;
+  int lw;
+  int lh;
+  int l;
+  lw = (_w + 1) >> 1;
+  lh = (_h + 1) >> 1;
+  data_size = _nlevels * sizeof(fs_level)
+      + 2 * (lw + 8) * 8 * sizeof(*_ctx->col_buf);
+  for (l = 0; l < _nlevels; l++) {
+    size_t im_size;
+    size_t level_size;
+    im_size = lw * (size_t) lh;
+    level_size = 2 * im_size * sizeof(*_ctx->level[l].im1);
+    level_size += sizeof(*_ctx->level[l].ssim) - 1;
+    level_size /= sizeof(*_ctx->level[l].ssim);
+    level_size += im_size;
+    level_size *= sizeof(*_ctx->level[l].ssim);
+    data_size += level_size;
+    lw = (lw + 1) >> 1;
+    lh = (lh + 1) >> 1;
+  }
+  data = (unsigned char *) malloc(data_size);
+  _ctx->level = (fs_level *) data;
+  _ctx->nlevels = _nlevels;
+  data += _nlevels * sizeof(*_ctx->level);
+  lw = (_w + 1) >> 1;
+  lh = (_h + 1) >> 1;
+  for (l = 0; l < _nlevels; l++) {
+    size_t im_size;
+    size_t level_size;
+    _ctx->level[l].w = lw;
+    _ctx->level[l].h = lh;
+    im_size = lw * (size_t) lh;
+    level_size = 2 * im_size * sizeof(*_ctx->level[l].im1);
+    level_size += sizeof(*_ctx->level[l].ssim) - 1;
+    level_size /= sizeof(*_ctx->level[l].ssim);
+    level_size *= sizeof(*_ctx->level[l].ssim);
+    _ctx->level[l].im1 = (uint16_t *) data;
+    _ctx->level[l].im2 = _ctx->level[l].im1 + im_size;
+    data += level_size;
+    _ctx->level[l].ssim = (double *) data;
+    data += im_size * sizeof(*_ctx->level[l].ssim);
+    lw = (lw + 1) >> 1;
+    lh = (lh + 1) >> 1;
+  }
+  _ctx->col_buf = (unsigned *) data;
+}
+
+static void fs_ctx_clear(fs_ctx *_ctx) {
+  free(_ctx->level);
+}
+
+static void fs_downsample_level(fs_ctx *_ctx, int _l) {
+  const uint16_t *src1;
+  const uint16_t *src2;
+  uint16_t *dst1;
+  uint16_t *dst2;
+  int w2;
+  int h2;
+  int w;
+  int h;
+  int i;
+  int j;
+  w = _ctx->level[_l].w;
+  h = _ctx->level[_l].h;
+  dst1 = _ctx->level[_l].im1;
+  dst2 = _ctx->level[_l].im2;
+  w2 = _ctx->level[_l - 1].w;
+  h2 = _ctx->level[_l - 1].h;
+  src1 = _ctx->level[_l - 1].im1;
+  src2 = _ctx->level[_l - 1].im2;
+  for (j = 0; j < h; j++) {
+    int j0offs;
+    int j1offs;
+    j0offs = 2 * j * w2;
+    j1offs = FS_MINI(2 * j + 1, h2) * w2;
+    for (i = 0; i < w; i++) {
+      int i0;
+      int i1;
+      i0 = 2 * i;
+      i1 = FS_MINI(i0 + 1, w2);
+      dst1[j * w + i] = src1[j0offs + i0] + src1[j0offs + i1]
+          + src1[j1offs + i0] + src1[j1offs + i1];
+      dst2[j * w + i] = src2[j0offs + i0] + src2[j0offs + i1]
+          + src2[j1offs + i0] + src2[j1offs + i1];
+    }
+  }
+}
+
+static void fs_downsample_level0(fs_ctx *_ctx, const unsigned char *_src1,
+                                 int _s1ystride, const unsigned char *_src2,
+                                 int _s2ystride, int _w, int _h) {
+  uint16_t *dst1;
+  uint16_t *dst2;
+  int w;
+  int h;
+  int i;
+  int j;
+  w = _ctx->level[0].w;
+  h = _ctx->level[0].h;
+  dst1 = _ctx->level[0].im1;
+  dst2 = _ctx->level[0].im2;
+  for (j = 0; j < h; j++) {
+    int j0;
+    int j1;
+    j0 = 2 * j;
+    j1 = FS_MINI(j0 + 1, _h);
+    for (i = 0; i < w; i++) {
+      int i0;
+      int i1;
+      i0 = 2 * i;
+      i1 = FS_MINI(i0 + 1, _w);
+      dst1[j * w + i] = _src1[j0 * _s1ystride + i0]
+          + _src1[j0 * _s1ystride + i1] + _src1[j1 * _s1ystride + i0]
+          + _src1[j1 * _s1ystride + i1];
+      dst2[j * w + i] = _src2[j0 * _s2ystride + i0]
+          + _src2[j0 * _s2ystride + i1] + _src2[j1 * _s2ystride + i0]
+          + _src2[j1 * _s2ystride + i1];
+    }
+  }
+}
+
+static void fs_apply_luminance(fs_ctx *_ctx, int _l) {
+  unsigned *col_sums_x;
+  unsigned *col_sums_y;
+  uint16_t *im1;
+  uint16_t *im2;
+  double *ssim;
+  double c1;
+  int w;
+  int h;
+  int j0offs;
+  int j1offs;
+  int i;
+  int j;
+  w = _ctx->level[_l].w;
+  h = _ctx->level[_l].h;
+  col_sums_x = _ctx->col_buf;
+  col_sums_y = col_sums_x + w;
+  im1 = _ctx->level[_l].im1;
+  im2 = _ctx->level[_l].im2;
+  for (i = 0; i < w; i++)
+    col_sums_x[i] = 5 * im1[i];
+  for (i = 0; i < w; i++)
+    col_sums_y[i] = 5 * im2[i];
+  for (j = 1; j < 4; j++) {
+    j1offs = FS_MINI(j, h - 1) * w;
+    for (i = 0; i < w; i++)
+      col_sums_x[i] += im1[j1offs + i];
+    for (i = 0; i < w; i++)
+      col_sums_y[i] += im2[j1offs + i];
+  }
+  ssim = _ctx->level[_l].ssim;
+  c1 = (double) (SSIM_C1 * 4096 * (1 << 4 * _l));
+  for (j = 0; j < h; j++) {
+    unsigned mux;
+    unsigned muy;
+    int i0;
+    int i1;
+    mux = 5 * col_sums_x[0];
+    muy = 5 * col_sums_y[0];
+    for (i = 1; i < 4; i++) {
+      i1 = FS_MINI(i, w - 1);
+      mux += col_sums_x[i1];
+      muy += col_sums_y[i1];
+    }
+    for (i = 0; i < w; i++) {
+      ssim[j * w + i] *= (2 * mux * (double) muy + c1)
+          / (mux * (double) mux + muy * (double) muy + c1);
+      if (i + 1 < w) {
+        i0 = FS_MAXI(0, i - 4);
+        i1 = FS_MINI(i + 4, w - 1);
+        mux += col_sums_x[i1] - col_sums_x[i0];
+        muy += col_sums_x[i1] - col_sums_x[i0];
+      }
+    }
+    if (j + 1 < h) {
+      j0offs = FS_MAXI(0, j - 4) * w;
+      for (i = 0; i < w; i++)
+        col_sums_x[i] -= im1[j0offs + i];
+      for (i = 0; i < w; i++)
+        col_sums_y[i] -= im2[j0offs + i];
+      j1offs = FS_MINI(j + 4, h - 1) * w;
+      for (i = 0; i < w; i++)
+        col_sums_x[i] += im1[j1offs + i];
+      for (i = 0; i < w; i++)
+        col_sums_y[i] += im2[j1offs + i];
+    }
+  }
+}
+
+#define FS_COL_SET(_col, _joffs, _ioffs) \
+  do { \
+    unsigned gx; \
+    unsigned gy; \
+    gx = gx_buf[((j + (_joffs)) & 7) * stride + i + (_ioffs)]; \
+    gy = gy_buf[((j + (_joffs)) & 7) * stride + i + (_ioffs)]; \
+    col_sums_gx2[(_col)] = gx * (double)gx; \
+    col_sums_gy2[(_col)] = gy * (double)gy; \
+    col_sums_gxgy[(_col)] = gx * (double)gy; \
+  } \
+  while (0)
+
+#define FS_COL_ADD(_col, _joffs, _ioffs) \
+  do { \
+    unsigned gx; \
+    unsigned gy; \
+    gx = gx_buf[((j + (_joffs)) & 7) * stride + i + (_ioffs)]; \
+    gy = gy_buf[((j + (_joffs)) & 7) * stride + i + (_ioffs)]; \
+    col_sums_gx2[(_col)] += gx * (double)gx; \
+    col_sums_gy2[(_col)] += gy * (double)gy; \
+    col_sums_gxgy[(_col)] += gx * (double)gy; \
+  } \
+  while (0)
+
+#define FS_COL_SUB(_col, _joffs, _ioffs) \
+  do { \
+    unsigned gx; \
+    unsigned gy; \
+    gx = gx_buf[((j + (_joffs)) & 7) * stride + i + (_ioffs)]; \
+    gy = gy_buf[((j + (_joffs)) & 7) * stride + i + (_ioffs)]; \
+    col_sums_gx2[(_col)] -= gx * (double)gx; \
+    col_sums_gy2[(_col)] -= gy * (double)gy; \
+    col_sums_gxgy[(_col)] -= gx * (double)gy; \
+  } \
+  while (0)
+
+#define FS_COL_COPY(_col1, _col2) \
+  do { \
+    col_sums_gx2[(_col1)] = col_sums_gx2[(_col2)]; \
+    col_sums_gy2[(_col1)] = col_sums_gy2[(_col2)]; \
+    col_sums_gxgy[(_col1)] = col_sums_gxgy[(_col2)]; \
+  } \
+  while (0)
+
+#define FS_COL_HALVE(_col1, _col2) \
+  do { \
+    col_sums_gx2[(_col1)] = col_sums_gx2[(_col2)] * 0.5; \
+    col_sums_gy2[(_col1)] = col_sums_gy2[(_col2)] * 0.5; \
+    col_sums_gxgy[(_col1)] = col_sums_gxgy[(_col2)] * 0.5; \
+  } \
+  while (0)
+
+#define FS_COL_DOUBLE(_col1, _col2) \
+  do { \
+    col_sums_gx2[(_col1)] = col_sums_gx2[(_col2)] * 2; \
+    col_sums_gy2[(_col1)] = col_sums_gy2[(_col2)] * 2; \
+    col_sums_gxgy[(_col1)] = col_sums_gxgy[(_col2)] * 2; \
+  } \
+  while (0)
+
+static void fs_calc_structure(fs_ctx *_ctx, int _l) {
+  uint16_t *im1;
+  uint16_t *im2;
+  unsigned *gx_buf;
+  unsigned *gy_buf;
+  double *ssim;
+  double col_sums_gx2[8];
+  double col_sums_gy2[8];
+  double col_sums_gxgy[8];
+  double c2;
+  int stride;
+  int w;
+  int h;
+  int i;
+  int j;
+  w = _ctx->level[_l].w;
+  h = _ctx->level[_l].h;
+  im1 = _ctx->level[_l].im1;
+  im2 = _ctx->level[_l].im2;
+  ssim = _ctx->level[_l].ssim;
+  gx_buf = _ctx->col_buf;
+  stride = w + 8;
+  gy_buf = gx_buf + 8 * stride;
+  memset(gx_buf, 0, 2 * 8 * stride * sizeof(*gx_buf));
+  c2 = SSIM_C2 * (1 << 4 * _l) * 16 * 104;
+  for (j = 0; j < h + 4; j++) {
+    if (j < h - 1) {
+      for (i = 0; i < w - 1; i++) {
+        unsigned g1;
+        unsigned g2;
+        unsigned gx;
+        unsigned gy;
+        g1 = abs(im1[(j + 1) * w + i + 1] - im1[j * w + i]);
+        g2 = abs(im1[(j + 1) * w + i] - im1[j * w + i + 1]);
+        gx = 4 * FS_MAXI(g1, g2) + FS_MINI(g1, g2);
+        g1 = abs(im2[(j + 1) * w + i + 1] - im2[j * w + i]);
+        g2 = abs(im2[(j + 1) * w + i] - im2[j * w + i + 1]);
+        gy = 4 * FS_MAXI(g1, g2) + FS_MINI(g1, g2);
+        gx_buf[(j & 7) * stride + i + 4] = gx;
+        gy_buf[(j & 7) * stride + i + 4] = gy;
+      }
+    } else {
+      memset(gx_buf + (j & 7) * stride, 0, stride * sizeof(*gx_buf));
+      memset(gy_buf + (j & 7) * stride, 0, stride * sizeof(*gy_buf));
+    }
+    if (j >= 4) {
+      int k;
+      col_sums_gx2[3] = col_sums_gx2[2] = col_sums_gx2[1] = col_sums_gx2[0] = 0;
+      col_sums_gy2[3] = col_sums_gy2[2] = col_sums_gy2[1] = col_sums_gy2[0] = 0;
+      col_sums_gxgy[3] = col_sums_gxgy[2] = col_sums_gxgy[1] =
+          col_sums_gxgy[0] = 0;
+      for (i = 4; i < 8; i++) {
+        FS_COL_SET(i, -1, 0);
+        FS_COL_ADD(i, 0, 0);
+        for (k = 1; k < 8 - i; k++) {
+          FS_COL_DOUBLE(i, i);
+          FS_COL_ADD(i, -k - 1, 0);
+          FS_COL_ADD(i, k, 0);
+        }
+      }
+      for (i = 0; i < w; i++) {
+        double mugx2;
+        double mugy2;
+        double mugxgy;
+        mugx2 = col_sums_gx2[0];
+        for (k = 1; k < 8; k++)
+          mugx2 += col_sums_gx2[k];
+        mugy2 = col_sums_gy2[0];
+        for (k = 1; k < 8; k++)
+          mugy2 += col_sums_gy2[k];
+        mugxgy = col_sums_gxgy[0];
+        for (k = 1; k < 8; k++)
+          mugxgy += col_sums_gxgy[k];
+        ssim[(j - 4) * w + i] = (2 * mugxgy + c2) / (mugx2 + mugy2 + c2);
+        if (i + 1 < w) {
+          FS_COL_SET(0, -1, 1);
+          FS_COL_ADD(0, 0, 1);
+          FS_COL_SUB(2, -3, 2);
+          FS_COL_SUB(2, 2, 2);
+          FS_COL_HALVE(1, 2);
+          FS_COL_SUB(3, -4, 3);
+          FS_COL_SUB(3, 3, 3);
+          FS_COL_HALVE(2, 3);
+          FS_COL_COPY(3, 4);
+          FS_COL_DOUBLE(4, 5);
+          FS_COL_ADD(4, -4, 5);
+          FS_COL_ADD(4, 3, 5);
+          FS_COL_DOUBLE(5, 6);
+          FS_COL_ADD(5, -3, 6);
+          FS_COL_ADD(5, 2, 6);
+          FS_COL_DOUBLE(6, 7);
+          FS_COL_ADD(6, -2, 7);
+          FS_COL_ADD(6, 1, 7);
+          FS_COL_SET(7, -1, 8);
+          FS_COL_ADD(7, 0, 8);
+        }
+      }
+    }
+  }
+}
+
+#define FS_NLEVELS (4)
+
+/*These weights were derived from the default weights found in Wang's original
+ Matlab implementation: {0.0448, 0.2856, 0.2363, 0.1333}.
+ We drop the finest scale and renormalize the rest to sum to 1.*/
+
+static const double FS_WEIGHTS[FS_NLEVELS] = {0.2989654541015625,
+    0.3141326904296875, 0.2473602294921875, 0.1395416259765625};
+
+static double fs_average(fs_ctx *_ctx, int _l) {
+  double *ssim;
+  double ret;
+  int w;
+  int h;
+  int i;
+  int j;
+  w = _ctx->level[_l].w;
+  h = _ctx->level[_l].h;
+  ssim = _ctx->level[_l].ssim;
+  ret = 0;
+  for (j = 0; j < h; j++)
+    for (i = 0; i < w; i++)
+      ret += ssim[j * w + i];
+  return pow(ret / (w * h), FS_WEIGHTS[_l]);
+}
+
+static double calc_ssim(const unsigned char *_src, int _systride,
+                 const unsigned char *_dst, int _dystride, int _w, int _h) {
+  fs_ctx ctx;
+  double ret;
+  int l;
+  ret = 1;
+  fs_ctx_init(&ctx, _w, _h, FS_NLEVELS);
+  fs_downsample_level0(&ctx, _src, _systride, _dst, _dystride, _w, _h);
+  for (l = 0; l < FS_NLEVELS - 1; l++) {
+    fs_calc_structure(&ctx, l);
+    ret *= fs_average(&ctx, l);
+    fs_downsample_level(&ctx, l + 1);
+  }
+  fs_calc_structure(&ctx, l);
+  fs_apply_luminance(&ctx, l);
+  ret *= fs_average(&ctx, l);
+  fs_ctx_clear(&ctx);
+  return ret;
+}
+
+static double convert_ssim_db(double _ssim, double _weight) {
+  return 10 * (log10(_weight) - log10(_weight - _ssim));
+}
+
+double vp9_calc_fastssim(YV12_BUFFER_CONFIG *source, YV12_BUFFER_CONFIG *dest,
+                         double *ssim_y, double *ssim_u, double *ssim_v) {
+  double ssimv;
+  vp9_clear_system_state();
+
+  *ssim_y = calc_ssim(source->y_buffer, source->y_stride, dest->y_buffer,
+                      dest->y_stride, source->y_crop_width,
+                      source->y_crop_height);
+
+  *ssim_u = calc_ssim(source->u_buffer, source->uv_stride, dest->u_buffer,
+                      dest->uv_stride, source->uv_crop_width,
+                      source->uv_crop_height);
+
+  *ssim_v = calc_ssim(source->v_buffer, source->uv_stride, dest->v_buffer,
+                      dest->uv_stride, source->uv_crop_width,
+                      source->uv_crop_height);
+  ssimv = (*ssim_y) * .8 + .1 * ((*ssim_u) + (*ssim_v));
+
+  return convert_ssim_db(ssimv, 1.0);
+}
diff --git a/vp9/encoder/vp9_ssim.h b/vp9/encoder/vp9_ssim.h
index e75623b..b197f41 100644
--- a/vp9/encoder/vp9_ssim.h
+++ b/vp9/encoder/vp9_ssim.h
@@ -23,6 +23,9 @@
 double vp9_calc_ssimg(YV12_BUFFER_CONFIG *source, YV12_BUFFER_CONFIG *dest,
                       double *ssim_y, double *ssim_u, double *ssim_v);
 
+double vp9_calc_fastssim(YV12_BUFFER_CONFIG *source, YV12_BUFFER_CONFIG *dest,
+                         double *ssim_y, double *ssim_u, double *ssim_v);
+
 #if CONFIG_VP9_HIGHBITDEPTH
 double vp9_highbd_calc_ssim(YV12_BUFFER_CONFIG *source,
                             YV12_BUFFER_CONFIG *dest,
diff --git a/vp9/vp9cx.mk b/vp9/vp9cx.mk
index f8da734..e886dbd 100644
--- a/vp9/vp9cx.mk
+++ b/vp9/vp9cx.mk
@@ -34,6 +34,7 @@
 VP9_CX_SRCS-yes += encoder/vp9_ethread.h
 VP9_CX_SRCS-yes += encoder/vp9_ethread.c
 VP9_CX_SRCS-yes += encoder/vp9_extend.c
+VP9_CX_SRCS-$(CONFIG_INTERNAL_STATS) += encoder/vp9_fastssim.c
 VP9_CX_SRCS-yes += encoder/vp9_firstpass.c
 VP9_CX_SRCS-yes += encoder/vp9_block.h
 VP9_CX_SRCS-yes += encoder/vp9_writer.h