shithub: libvpx

Download patch

ref: 6dc612758cac7d4f07e58c020ee2a1422b49a26d
parent: 5fbc7a286b4d72883392fdbb10ec52bace662f66
author: sdeng <sdeng@google.com>
date: Tue Dec 4 11:35:34 EST 2018 

Fix overflow in calculating highbd SSIM

Example internal stats
Before the fix:
Bitrate	AVGPsnr	GLBPsnr	AVPsnrP	GLPsnrP	VPXSSIM	VPSSIMP	FASTSIM	PSNRHVS	WstPsnr	WstSsim	WstFast	WstHVS	AVPsnrY	APsnrCb	APsnrCr	  Block	WstBlck	Consist	WstCons	    Time	RcErr	AbsErr
 153.39	 37.131	 36.420	 37.151	 36.437	716.077	817.445	 10.422	 34.347	 32.980	  0.916	  9.281	 30.208	 36.024	 41.830	 40.581	  0.000	  0.000	100.000	100.000	   55006	   2.26	   2.26
No mismatch detected in recon buffers

After the fix:
Bitrate	AVGPsnr	GLBPsnr	AVPsnrP	GLPsnrP	VPXSSIM	VPSSIMP	FASTSIM	PSNRHVS	WstPsnr	WstSsim	WstFast	WstHVS	AVPsnrY	APsnrCb	APsnrCr	  Block	WstBlck	Consist	WstCons	    Time	RcErr	AbsErr
 153.39	 37.131	 36.420	 37.151	 36.437	 69.808	 70.023	 10.422	 34.347	 32.980	  0.910	  9.281	 30.208	 36.024	 41.830	 40.581	  0.000	  0.000	100.000	100.000	   55067	   2.26	   2.26
No mismatch detected in recon buffers

Change-Id: I820abc498c1543548f193874046582b50afd0238


--- a/tools/tiny_ssim.c
+++ b/tools/tiny_ssim.c
@@ -237,7 +237,7 @@
 static double similarity(uint32_t sum_s, uint32_t sum_r, uint32_t sum_sq_s,
                          uint32_t sum_sq_r, uint32_t sum_sxr, int count,
                          uint32_t bd) {
-  int64_t ssim_n, ssim_d;
+  double ssim_n, ssim_d;
   int64_t c1 = 0, c2 = 0;
   if (bd == 8) {
     // scale the constants by number of pixels
@@ -253,14 +253,14 @@
     assert(0);
   }
 
-  ssim_n = (2 * sum_s * sum_r + c1) *
-           ((int64_t)2 * count * sum_sxr - (int64_t)2 * sum_s * sum_r + c2);
+  ssim_n = (2.0 * sum_s * sum_r + c1) *
+           (2.0 * count * sum_sxr - 2.0 * 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);
+  ssim_d = ((double)sum_s * sum_s + (double)sum_r * sum_r + c1) *
+           ((double)count * sum_sq_s - (double)sum_s * sum_s +
+            (double)count * sum_sq_r - (double)sum_r * sum_r + c2);
 
-  return ssim_n * 1.0 / ssim_d;
+  return ssim_n / ssim_d;
 }
 
 static double ssim_8x8(const uint8_t *s, int sp, const uint8_t *r, int rp) {
--- a/vpx_dsp/ssim.c
+++ b/vpx_dsp/ssim.c
@@ -73,7 +73,7 @@
 static double similarity(uint32_t sum_s, uint32_t sum_r, uint32_t sum_sq_s,
                          uint32_t sum_sq_r, uint32_t sum_sxr, int count,
                          uint32_t bd) {
-  int64_t ssim_n, ssim_d;
+  double ssim_n, ssim_d;
   int64_t c1, c2;
   if (bd == 8) {
     // scale the constants by number of pixels
@@ -90,14 +90,14 @@
     assert(0);
   }
 
-  ssim_n = (2 * sum_s * sum_r + c1) *
-           ((int64_t)2 * count * sum_sxr - (int64_t)2 * sum_s * sum_r + c2);
+  ssim_n = (2.0 * sum_s * sum_r + c1) *
+           (2.0 * count * sum_sxr - 2.0 * 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);
+  ssim_d = ((double)sum_s * sum_s + (double)sum_r * sum_r + c1) *
+           ((double)count * sum_sq_s - (double)sum_s * sum_s +
+            (double)count * sum_sq_r - (double)sum_r * sum_r + c2);
 
-  return ssim_n * 1.0 / ssim_d;
+  return ssim_n / ssim_d;
 }
 
 static double ssim_8x8(const uint8_t *s, int sp, const uint8_t *r, int rp) {