Fix check for maximum subpic id len

source/Lib/EncoderLib/SEIEncoder.cpp

@@ -444,7 +444,7 @@ void SEIEncoder::initSEIScalableNesting(SEIScalableNesting *scalableNestingSEI,
     scalableNestingSEI->m_snNumSubpics = (uint32_t) subpictureIDs.size();
     scalableNestingSEI->m_snSubpicId   = subpictureIDs;
     scalableNestingSEI->m_snSubpicIdLen = max(1, ceilLog2(maxSubpicIdInPic + 1));
-    CHECK ( scalableNestingSEI->m_snSubpicIdLen > 15, "Subpicture ID too large. Length must be <= 15 bits");
+    CHECK ( scalableNestingSEI->m_snSubpicIdLen > 16, "Subpicture ID too large. Length must be <= 16 bits");
   }
   scalableNestingSEI->m_nestedSEIs.clear();
   for (SEIMessages::iterator it = nestedSEIs.begin(); it != nestedSEIs.end(); it++)