[VCQ-169] Fix signed integer overflow UB leading to negative PSNR

libvmaf/src/feature/integer_psnr.c

@@ -20,6 +20,7 @@
 #include <float.h>
 #include <math.h>
 #include <stddef.h>
+#include <stdlib.h>
 #include <string.h>
 
 #include "feature_collector.h"
@@ -172,8 +173,8 @@ static int psnr_hbd(VmafPicture *ref_pic, VmafPicture *dist_pic,
         uint64_t sse = 0;
         for (unsigned i = 0; i < ref_pic->h[p]; i++) {
             for (unsigned j = 0; j < ref_pic->w[p]; j++) {
-                const int32_t e = ref[j] - dis[j];
-                sse += (uint32_t)(e * e);
+                const uint32_t e = abs(ref[j] - dis[j]);
+                sse += e * e;
             }
             ref += ref_pic->stride[p] / 2;
             dis += dist_pic->stride[p] / 2;