From: sdeng <sdeng@google.com>
Date: Fri, 14 Dec 2018 00:47:10 +0000 (-0800)
Subject: No need to shift in SSIM calculations
X-Git-Tag: v1.8.0~56
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=d931eb556b414e6c4176cb5b94cc5c31519d7360;p=libvpx

No need to shift in SSIM calculations

We only need to shift in the encoder when the input bit depth
does not equal to the encoder internal bit depth.

Change-Id: If9af62382ac6824f33dc7dcdd3d3ff7802b92e9a
---

diff --git a/tools/tiny_ssim.c b/tools/tiny_ssim.c
index 6be190393..be52e4445 100644
--- a/tools/tiny_ssim.c
+++ b/tools/tiny_ssim.c
@@ -272,12 +272,11 @@ static double ssim_8x8(const uint8_t *s, int sp, const uint8_t *r, int rp) {
 
 #if CONFIG_VP9_HIGHBITDEPTH
 static double highbd_ssim_8x8(const uint16_t *s, int sp, const uint16_t *r,
-                              int rp, uint32_t bd, uint32_t shift) {
+                              int rp, uint32_t bd) {
   uint32_t sum_s = 0, sum_r = 0, sum_sq_s = 0, sum_sq_r = 0, sum_sxr = 0;
   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);
+  return similarity(sum_s, sum_r, sum_sq_s, sum_sq_r, sum_sxr, 64, bd);
 }
 #endif  // CONFIG_VP9_HIGHBITDEPTH
 
@@ -306,7 +305,7 @@ static double ssim2(const uint8_t *img1, const uint8_t *img2, int stride_img1,
 #if CONFIG_VP9_HIGHBITDEPTH
 static double 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 height, uint32_t bd) {
   int i, j;
   int samples = 0;
   double ssim_total = 0;
@@ -315,9 +314,9 @@ static double highbd_ssim2(const uint8_t *img1, const uint8_t *img2,
   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);
+      double v =
+          highbd_ssim_8x8(CONVERT_TO_SHORTPTR(img1 + j), stride_img1,
+                          CONVERT_TO_SHORTPTR(img2 + j), stride_img2, bd);
       ssim_total += v;
       samples++;
     }
@@ -688,7 +687,7 @@ int main(int argc, char *argv[]) {
     psnr = calc_plane_error(buf0, w, buf1, w, w, h);                           \
   } else {                                                                     \
     ssim = highbd_ssim2(CONVERT_TO_BYTEPTR(buf0), CONVERT_TO_BYTEPTR(buf1), w, \
-                        w, w, h, bit_depth, bit_depth - 8);                    \
+                        w, w, h, bit_depth);                                   \
     psnr = calc_plane_error16(CAST_TO_SHORTPTR(buf0), w,                       \
                               CAST_TO_SHORTPTR(buf1), w, w, h);                \
   }