ref: 6c565fada0820c9c2be6e931237b858cf8bbb5d1
parent: aeca599087409c83cf4e24a59b5830a380e22327
author: Yaowu Xu <yaowu@google.com>
date: Mon May 2 11:27:14 EDT 2011
change to use fast ssim code for internal ssim calculations The commit also removed the slow ssim calculation that uses a 7x7 kernel, and revised the comments to better describe how sample ssim values are computed and averaged Change-Id: I1d874073cddca00f3c997f4b9a9a3db0aa212276
--- a/vp8/encoder/onyx_if.c
+++ b/vp8/encoder/onyx_if.c
@@ -96,7 +96,8 @@
YV12_BUFFER_CONFIG *dest,
double *ssim_y,
double *ssim_u,
- double *ssim_v
+ double *ssim_v,
+ const vp8_variance_rtcd_vtable_t *rtcd
);
@@ -4984,7 +4985,8 @@
if (cpi->b_calculate_ssimg)
{double y, u, v, frame_all;
- frame_all = vp8_calc_ssimg(cpi->Source, cm->frame_to_show, &y, &u, &v);
+ frame_all = vp8_calc_ssimg(cpi->Source, cm->frame_to_show,
+ &y, &u, &v, IF_RTCD(&cpi->rtcd.variance));
cpi->total_ssimg_y += y;
cpi->total_ssimg_u += u;
cpi->total_ssimg_v += v;
--- a/vp8/encoder/ssim.c
+++ b/vp8/encoder/ssim.c
@@ -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,
@@ -369,10 +152,10 @@
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,
@@ -388,7 +171,7 @@
int samples =0;
double ssim_total=0;
- // we can sample points as frequently as we like start with 1 per 4x4
+ // 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 )
@@ -400,7 +183,6 @@
}
ssim_total /= samples;
return ssim_total;
-
}
double vp8_calc_ssim
(
@@ -431,4 +213,36 @@
*weight = 1;
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;
}
\ No newline at end of file