Index: trunk/ippTools/src/difftool.c
===================================================================
--- trunk/ippTools/src/difftool.c	(revision 12262)
+++ trunk/ippTools/src/difftool.c	(revision 13691)
@@ -498,4 +498,14 @@
     }
 
+    psString path_base = psMetadataLookupStr(&status, config->args, "-path_base");
+    if (!status) {
+        psError(PS_ERR_UNKNOWN, false, "failed to lookup value for -path_base");
+        return false;
+    }
+    if (!path_base) {
+        psError(PS_ERR_UNKNOWN, true, "-path_base is required");
+        return false;
+    }
+
     // optional
     psF64 bg = psMetadataLookupF64(&status, config->args, "-bg");
@@ -519,4 +529,5 @@
             (psS64)atoll(diff_id),
             uri,
+            path_base,
             bg,
             bg_stdev