diff --git a/codec/decoder/core/src/decode_slice.cpp b/codec/decoder/core/src/decode_slice.cpp
index 6c728a57..bd09f195 100644
--- a/codec/decoder/core/src/decode_slice.cpp
+++ b/codec/decoder/core/src/decode_slice.cpp
@@ -79,8 +79,8 @@ int32_t WelsTargetSliceConstruction (PWelsDecoderContext pCtx) {
   pCurLayer->iMbXyIndex = iNextMbXyIndex;
 
   if (0 == iNextMbXyIndex) {
-    pCurLayer->pDec->iSpsId = pSliceHeader->iSpsId;
-    pCurLayer->pDec->iPpsId = pSliceHeader->iPpsId;
+    pCurLayer->pDec->iSpsId = pCtx->pSps->iSpsId;
+    pCurLayer->pDec->iPpsId = pCtx->pPps->iPpsId;
 
     pCurLayer->pDec->uiQualityId = pCurLayer->sLayerInfo.sNalHeaderExt.uiQualityId;
   }
@@ -744,6 +744,9 @@ int32_t WelsDecodeMbCabacPSliceBaseMode0 (PWelsDecoderContext pCtx, PWelsNeighAv
     int32_t iQpDelta, iId8x8, iId4x4;
 
     WELS_READ_VERIFY (ParseDeltaQpCabac (pCtx, iQpDelta));
+    if (iQpDelta > 25 || iQpDelta < -26) { //out of iQpDelta range
+      return ERR_INFO_INVALID_QP;
+    }
     pCurLayer->pLumaQp[iMbXy] = (pSlice->iLastMbQp + iQpDelta + 52) % 52; //update last_mb_qp
     pSlice->iLastMbQp = pCurLayer->pLumaQp[iMbXy];
     pCurLayer->pChromaQp[iMbXy] = g_kuiChromaQpTable[WELS_CLIP3 (pSlice->iLastMbQp +
diff --git a/codec/decoder/core/src/manage_dec_ref.cpp b/codec/decoder/core/src/manage_dec_ref.cpp
index 34d9ab72..285bf0b7 100644
--- a/codec/decoder/core/src/manage_dec_ref.cpp
+++ b/codec/decoder/core/src/manage_dec_ref.cpp
@@ -119,6 +119,8 @@ int32_t WelsInitRefList (PWelsDecoderContext pCtx, int32_t iPoc) {
       if (pRef != NULL) {
         // IDR lost, set new
         pRef->bIsComplete = false; // Set complete flag to false for lost IDR ref picture
+        pRef->iSpsId = pCtx->pSps->iSpsId;
+        pRef->iPpsId = pCtx->pPps->iPpsId;
         pCtx->iErrorCode |= dsDataErrorConcealed;
         bool bCopyPrevious = ((ERROR_CON_FRAME_COPY_CROSS_IDR == pCtx->eErrorConMethod)
                               || (ERROR_CON_SLICE_COPY_CROSS_IDR == pCtx->eErrorConMethod)
@@ -260,8 +262,8 @@ int32_t WelsMarkAsRef (PWelsDecoderContext pCtx) {
 
   pCtx->pDec->uiQualityId = pCtx->pCurDqLayer->sLayerInfo.sNalHeaderExt.uiQualityId;
   pCtx->pDec->uiTemporalId = pCtx->pCurDqLayer->sLayerInfo.sNalHeaderExt.uiTemporalId;
-  pCtx->pDec->iSpsId = pCtx->pCurDqLayer->sLayerInfo.sSliceInLayer.sSliceHeaderExt.sSliceHeader.iSpsId;
-  pCtx->pDec->iPpsId = pCtx->pCurDqLayer->sLayerInfo.sSliceInLayer.sSliceHeaderExt.sSliceHeader.iPpsId;
+  pCtx->pDec->iSpsId = pCtx->pSps->iSpsId;
+  pCtx->pDec->iPpsId = pCtx->pPps->iPpsId;
 
   for (j = pCurAU->uiStartPos; j <= pCurAU->uiEndPos; j++) {
     if (pCurAU->pNalUnitsList[j]->sNalHeaderExt.sNalUnitHeader.eNalUnitType == NAL_UNIT_CODED_SLICE_IDR