diff --git a/vpx_dsp/ssim.h b/vpx_dsp/ssim.h
new file mode 100644
index 0000000..b1579f7
--- /dev/null
+++ b/vpx_dsp/ssim.h
@@ -0,0 +1,105 @@
+/*
+ *  Copyright (c) 2014 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.
+ */
+
+#ifndef VPX_ENCODER_VP9_SSIM_H_
+#define VPX_ENCODER_VP9_SSIM_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "./vpx_config.h"
+#include "vpx_scale/yv12config.h"
+
+// TODO(aconverse): Unify vp8/vp9_clear_system_state
+#if ARCH_X86 || ARCH_X86_64
+void vpx_reset_mmx_state(void);
+#define vpx_clear_system_state() vpx_reset_mmx_state()
+#else
+#define vpx_clear_system_state()
+#endif
+
+// metrics used for calculating ssim, ssim2, dssim, and ssimc
+typedef struct {
+  // source sum ( over 8x8 region )
+  uint64_t sum_s;
+
+  // reference sum (over 8x8 region )
+  uint64_t sum_r;
+
+  // source sum squared ( over 8x8 region )
+  uint64_t sum_sq_s;
+
+  // reference sum squared (over 8x8 region )
+  uint64_t sum_sq_r;
+
+  // sum of source times reference (over 8x8 region)
+  uint64_t sum_sxr;
+
+  // calculated ssim score between source and reference
+  double ssim;
+} Ssimv;
+
+// metrics collected on a frame basis
+typedef struct {
+  // ssim consistency error metric ( see code for explanation )
+  double ssimc;
+
+  // standard ssim
+  double ssim;
+
+  // revised ssim ( see code for explanation)
+  double ssim2;
+
+  // ssim restated as an error metric like sse
+  double dssim;
+
+  // dssim converted to decibels
+  double dssimd;
+
+  // ssimc converted to decibels
+  double ssimcd;
+} Metrics;
+
+double vpx_get_ssim_metrics(uint8_t *img1, int img1_pitch, uint8_t *img2,
+                      int img2_pitch, int width, int height, Ssimv *sv2,
+                      Metrics *m, int do_inconsistency);
+
+double vpx_calc_ssim(YV12_BUFFER_CONFIG *source, YV12_BUFFER_CONFIG *dest,
+                     double *weight);
+
+double vpx_calc_ssimg(YV12_BUFFER_CONFIG *source, YV12_BUFFER_CONFIG *dest,
+                      double *ssim_y, double *ssim_u, double *ssim_v);
+
+double vpx_calc_fastssim(YV12_BUFFER_CONFIG *source, YV12_BUFFER_CONFIG *dest,
+                         double *ssim_y, double *ssim_u, double *ssim_v);
+
+double vpx_psnrhvs(YV12_BUFFER_CONFIG *source, YV12_BUFFER_CONFIG *dest,
+                   double *ssim_y, double *ssim_u, double *ssim_v);
+
+#if CONFIG_VP9_HIGHBITDEPTH
+double vpx_highbd_calc_ssim(YV12_BUFFER_CONFIG *source,
+                            YV12_BUFFER_CONFIG *dest,
+                            double *weight,
+                            unsigned int bd);
+
+double vpx_highbd_calc_ssimg(YV12_BUFFER_CONFIG *source,
+                             YV12_BUFFER_CONFIG *dest,
+                             double *ssim_y,
+                             double *ssim_u,
+                             double *ssim_v,
+                             unsigned int bd);
+#endif  // CONFIG_VP9_HIGHBITDEPTH
+
+#ifdef __cplusplus
+}  // extern "C"
+#endif
+
+#endif  // VPX_ENCODER_VP9_SSIM_H_