Update libvpx snapshot to v0.9.7-p1 (Cayuga).

source/libvpx/vp8/encoder/ssim.c

Index: source/libvpx/vp8/encoder/ssim.c
===================================================================
--- source/libvpx/vp8/encoder/ssim.c	(revision 96967)
+++ source/libvpx/vp8/encoder/ssim.c	(working copy)
@@ -18,225 +18,8 @@
 #else
 #define IF_RTCD(x)  NULL
 #endif
-// Google version of SSIM
-// SSIM
-#define KERNEL 3
-#define KERNEL_SIZE  (2 * KERNEL + 1)
 
-typedef unsigned char uint8;
-typedef unsigned int uint32;
 
-static const int K[KERNEL_SIZE] =
-{
-    1, 4, 11, 16, 11, 4, 1    // 16 * exp(-0.3 * i * i)
-};
-static const double ki_w = 1. / 2304.;  // 1 / sum(i:0..6, j..6) K[i]*K[j]
-double get_ssimg(const uint8 *org, const uint8 *rec,
-                 int xo, int yo, int W, int H,
-                 const int stride1, const int stride2
-                )
-{
-    // TODO(skal): use summed tables
-    int y, x;
-
-    const int ymin = (yo - KERNEL < 0) ? 0 : yo - KERNEL;
-    const int ymax = (yo + KERNEL > H - 1) ? H - 1 : yo + KERNEL;
-    const int xmin = (xo - KERNEL < 0) ? 0 : xo - KERNEL;
-    const int xmax = (xo + KERNEL > W - 1) ? W - 1 : xo + KERNEL;
-    // worst case of accumulation is a weight of 48 = 16 + 2 * (11 + 4 + 1)
-    // with a diff of 255, squares. That would a max error of 0x8ee0900,
-    // which fits into 32 bits integers.
-    uint32 w = 0, xm = 0, ym = 0, xxm = 0, xym = 0, yym = 0;
-    org += ymin * stride1;
-    rec += ymin * stride2;
-
-    for (y = ymin; y <= ymax; ++y, org += stride1, rec += stride2)
-    {
-        const int Wy = K[KERNEL + y - yo];
-
-        for (x = xmin; x <= xmax; ++x)
-        {
-            const  int Wxy = Wy * K[KERNEL + x - xo];
-            // TODO(skal): inlined assembly
-            w   += Wxy;
-            xm  += Wxy * org[x];
-            ym  += Wxy * rec[x];
-            xxm += Wxy * org[x] * org[x];
-            xym += Wxy * org[x] * rec[x];
-            yym += Wxy * rec[x] * rec[x];
-        }
-    }
-
-    {
-        const double iw = 1. / w;
-        const double iwx = xm * iw;
-        const double iwy = ym * iw;
-        double sxx = xxm * iw - iwx * iwx;
-        double syy = yym * iw - iwy * iwy;
-
-        // small errors are possible, due to rounding. Clamp to zero.
-        if (sxx < 0.) sxx = 0.;
-
-        if (syy < 0.) syy = 0.;
-
-        {
-            const double sxsy = sqrt(sxx * syy);
-            const double sxy = xym * iw - iwx * iwy;
-            static const double C11 = (0.01 * 0.01) * (255 * 255);
-            static const double C22 = (0.03 * 0.03) * (255 * 255);
-            static const double C33 = (0.015 * 0.015) * (255 * 255);
-            const double l = (2. * iwx * iwy + C11) / (iwx * iwx + iwy * iwy + C11);
-            const double c = (2. * sxsy      + C22) / (sxx + syy + C22);
-
-            const double s = (sxy + C33) / (sxsy + C33);
-            return l * c * s;
-
-        }
-    }
-
-}
-
-double get_ssimfull_kernelg(const uint8 *org, const uint8 *rec,
-                            int xo, int yo, int W, int H,
-                            const int stride1, const int stride2)
-{
-    // TODO(skal): use summed tables
-    // worst case of accumulation is a weight of 48 = 16 + 2 * (11 + 4 + 1)
-    // with a diff of 255, squares. That would a max error of 0x8ee0900,
-    // which fits into 32 bits integers.
-    int y_, x_;
-    uint32 xm = 0, ym = 0, xxm = 0, xym = 0, yym = 0;
-    org += (yo - KERNEL) * stride1;
-    org += (xo - KERNEL);
-    rec += (yo - KERNEL) * stride2;
-    rec += (xo - KERNEL);
-
-    for (y_ = 0; y_ < KERNEL_SIZE; ++y_, org += stride1, rec += stride2)
-    {
-        const int Wy = K[y_];
-
-        for (x_ = 0; x_ < KERNEL_SIZE; ++x_)
-        {
-            const int Wxy = Wy * K[x_];
-            // TODO(skal): inlined assembly
-            const int org_x = org[x_];
-            const int rec_x = rec[x_];
-            xm  += Wxy * org_x;
-            ym  += Wxy * rec_x;
-            xxm += Wxy * org_x * org_x;
-            xym += Wxy * org_x * rec_x;
-            yym += Wxy * rec_x * rec_x;
-        }
-    }
-
-    {
-        const double iw = ki_w;
-        const double iwx = xm * iw;
-        const double iwy = ym * iw;
-        double sxx = xxm * iw - iwx * iwx;
-        double syy = yym * iw - iwy * iwy;
-
-        // small errors are possible, due to rounding. Clamp to zero.
-        if (sxx < 0.) sxx = 0.;
-
-        if (syy < 0.) syy = 0.;
-
-        {
-            const double sxsy = sqrt(sxx * syy);
-            const double sxy = xym * iw - iwx * iwy;
-            static const double C11 = (0.01 * 0.01) * (255 * 255);
-            static const double C22 = (0.03 * 0.03) * (255 * 255);
-            static const double C33 = (0.015 * 0.015) * (255 * 255);
-            const double l = (2. * iwx * iwy + C11) / (iwx * iwx + iwy * iwy + C11);
-            const double c = (2. * sxsy      + C22) / (sxx + syy + C22);
-            const double s = (sxy + C33) / (sxsy + C33);
-            return l * c * s;
-        }
-    }
-}
-
-double calc_ssimg(const uint8 *org, const uint8 *rec,
-                  const int image_width, const int image_height,
-                  const int stride1, const int stride2
-                 )
-{
-    int j, i;
-    double SSIM = 0.;
-
-    for (j = 0; j < KERNEL; ++j)
-    {
-        for (i = 0; i < image_width; ++i)
-        {
-            SSIM += get_ssimg(org, rec, i, j, image_width, image_height, stride1, stride2);
-        }
-    }
-
-    for (j = KERNEL; j < image_height - KERNEL; ++j)
-    {
-        for (i = 0; i < KERNEL; ++i)
-        {
-            SSIM += get_ssimg(org, rec, i, j, image_width, image_height, stride1, stride2);
-        }
-
-        for (i = KERNEL; i < image_width - KERNEL; ++i)
-        {
-            SSIM += get_ssimfull_kernelg(org, rec, i, j,
-                                         image_width, image_height, stride1, stride2);
-        }
-
-        for (i = image_width - KERNEL; i < image_width; ++i)
-        {
-            SSIM += get_ssimg(org, rec, i, j, image_width, image_height, stride1, stride2);
-        }
-    }
-
-    for (j = image_height - KERNEL; j < image_height; ++j)
-    {
-        for (i = 0; i < image_width; ++i)
-        {
-            SSIM += get_ssimg(org, rec, i, j, image_width, image_height, stride1, stride2);
-        }
-    }
-
-    return SSIM;
-}
-
-
-double vp8_calc_ssimg
-(
-    YV12_BUFFER_CONFIG *source,
-    YV12_BUFFER_CONFIG *dest,
-    double *ssim_y,
-    double *ssim_u,
-    double *ssim_v
-)
-{
-    double ssim_all = 0;
-    int ysize  = source->y_width * source->y_height;
-    int uvsize = ysize / 4;
-
-    *ssim_y = calc_ssimg(source->y_buffer, dest->y_buffer,
-                         source->y_width, source->y_height,
-                         source->y_stride, dest->y_stride);
-
-
-    *ssim_u = calc_ssimg(source->u_buffer, dest->u_buffer,
-                         source->uv_width, source->uv_height,
-                         source->uv_stride, dest->uv_stride);
-
-
-    *ssim_v = calc_ssimg(source->v_buffer, dest->v_buffer,
-                         source->uv_width, source->uv_height,
-                         source->uv_stride, dest->uv_stride);
-
-    ssim_all = (*ssim_y + *ssim_u + *ssim_v) / (ysize + uvsize + uvsize);
-    *ssim_y /= ysize;
-    *ssim_u /= uvsize;
-    *ssim_v /= uvsize;
-    return ssim_all;
-}
-
-
 void ssim_parms_c
 (
     unsigned char *s,
@@ -290,8 +73,8 @@
      }
 }
 
-const static long long c1 =  426148; // (256^2*(.01*255)^2
-const static long long c2 = 3835331; //(256^2*(.03*255)^2
+const static int64_t cc1 =  26634; // (64^2*(.01*255)^2
+const static int64_t cc2 = 239708; // (64^2*(.03*255)^2
 
 static double similarity
 (
@@ -303,11 +86,20 @@
     int count
 )
 {
-    long long ssim_n = (2*sum_s*sum_r+ c1)*(2*count*sum_sxr-2*sum_s*sum_r+c2);
+    int64_t ssim_n, ssim_d;
+    int64_t c1, c2;
 
-    long long ssim_d = (sum_s*sum_s +sum_r*sum_r+c1)*
-            (count*sum_sq_s-sum_s*sum_s + count*sum_sq_r-sum_r*sum_r +c2) ;
+    //scale the constants by number of pixels
+    c1 = (cc1*count*count)>>12;
+    c2 = (cc2*count*count)>>12;
 
+    ssim_n = (2*sum_s*sum_r+ c1)*((int64_t) 2*count*sum_sxr-
+          (int64_t) 2*sum_s*sum_r+c2);
+
+    ssim_d = (sum_s*sum_s +sum_r*sum_r+c1)*
+        ((int64_t)count*sum_sq_s-(int64_t)sum_s*sum_s +
+        (int64_t)count*sum_sq_r-(int64_t) sum_r*sum_r +c2) ;
+
     return ssim_n * 1.0 / ssim_d;
 }
 
@@ -332,23 +124,38 @@
            const vp8_variance_rtcd_vtable_t *rtcd)
 {
     unsigned long sum_s=0,sum_r=0,sum_sq_s=0,sum_sq_r=0,sum_sxr=0;
-    double ssim3;
-    long long ssim_n;
-    long long ssim_d;
+    int64_t ssim3;
+    int64_t ssim_n1,ssim_n2;
+    int64_t ssim_d1,ssim_d2;
+    int64_t ssim_t1,ssim_t2;
+    int64_t c1, c2;
 
+    // normalize by 256/64
+    c1 = cc1*16;
+    c2 = cc2*16;
+
     rtcd->ssimpf(s, sp, r, rp, &sum_s, &sum_r, &sum_sq_s, &sum_sq_r, &sum_sxr);
-    ssim_n = (2*sum_s*sum_r+ c1)*(2*256*sum_sxr-2*sum_s*sum_r+c2);
+    ssim_n1 = (2*sum_s*sum_r+ c1);
 
-    ssim_d = (sum_s*sum_s +sum_r*sum_r+c1)*
-            (256*sum_sq_s-sum_s*sum_s + 256*sum_sq_r-sum_r*sum_r +c2) ;
+    ssim_n2 =((int64_t) 2*256*sum_sxr-(int64_t) 2*sum_s*sum_r+c2);
 
-    ssim3 = 256 * (ssim_d-ssim_n) / ssim_d;
-    return (long)( 256*ssim3 * ssim3 );
+    ssim_d1 =((int64_t)sum_s*sum_s +(int64_t)sum_r*sum_r+c1);
+
+    ssim_d2 = (256 * (int64_t) sum_sq_s-(int64_t) sum_s*sum_s +
+                    (int64_t) 256*sum_sq_r-(int64_t) sum_r*sum_r +c2) ;
+
+    ssim_t1 = 256 - 256 * ssim_n1 / ssim_d1;
+    ssim_t2 = 256 - 256 * ssim_n2 / ssim_d2;
+
+    ssim3 = 256 *ssim_t1 * ssim_t2;
+    if(ssim3 <0 )
+        ssim3=0;
+    return (long)( ssim3  );
 }
-// TODO: (jbb) this 8x8 window might be too big + we may want to pick pixels
-// such that the window regions overlap block boundaries to penalize blocking
-// artifacts.
 
+// 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.
 double vp8_ssim2
 (
     unsigned char *img1,
@@ -361,20 +168,21 @@
 )
 {
     int i,j;
-
+    int samples =0;
     double ssim_total=0;
 
-    // we can sample points as frequently as we like start with 1 per 8x8
-    for(i=0; i < height; i+=8, img1 += stride_img1*8, img2 += stride_img2*8)
+    // 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; j+=8 )
+        for(j=0; j < width-8; j+=4 )
         {
-            ssim_total += ssim_8x8(img1, stride_img1, img2, stride_img2, rtcd);
+            double v = ssim_8x8(img1+j, stride_img1, img2+j, stride_img2, rtcd);
+            ssim_total += v;
+            samples++;
         }
     }
-    ssim_total /= (width/8 * height /8);
+    ssim_total /= samples;
     return ssim_total;
-
 }
 double vp8_calc_ssim
 (
@@ -406,3 +214,35 @@
 
     return ssimv;
 }
+
+double vp8_calc_ssimg
+(
+    YV12_BUFFER_CONFIG *source,
+    YV12_BUFFER_CONFIG *dest,
+    double *ssim_y,
+    double *ssim_u,
+    double *ssim_v,
+    const vp8_variance_rtcd_vtable_t *rtcd
+)
+{
+    double ssim_all = 0;
+    double a, b, c;
+
+    a = vp8_ssim2(source->y_buffer, dest->y_buffer,
+                 source->y_stride, dest->y_stride, source->y_width,
+                 source->y_height, rtcd);
+
+    b = vp8_ssim2(source->u_buffer, dest->u_buffer,
+                 source->uv_stride, dest->uv_stride, source->uv_width,
+                 source->uv_height, rtcd);
+
+    c = vp8_ssim2(source->v_buffer, dest->v_buffer,
+                 source->uv_stride, dest->uv_stride, source->uv_width,
+                 source->uv_height, rtcd);
+    *ssim_y = a;
+    *ssim_u = b;
+    *ssim_v = c;
+    ssim_all = (a * 4 + b + c) /6;
+
+    return ssim_all;
+}