diff --git a/codec/api/svc/codec_app_def.h b/codec/api/svc/codec_app_def.h
index e4f074d8..129a05d5 100644
--- a/codec/api/svc/codec_app_def.h
+++ b/codec/api/svc/codec_app_def.h
@@ -275,6 +275,7 @@ typedef struct TagEncParamExt
   int     iMaxBitrate;        // max bitrate desired
   int     iMaxQp;
   int     iMinQp;
+  unsigned int uiMaxNalSize;
 
   /*LTR settings*/
   bool     bEnableLongTermReference; // 0: on, 1: off
diff --git a/codec/encoder/core/inc/param_svc.h b/codec/encoder/core/inc/param_svc.h
index 0ff439b3..66146726 100644
--- a/codec/encoder/core/inc/param_svc.h
+++ b/codec/encoder/core/inc/param_svc.h
@@ -188,6 +188,7 @@ static void FillDefault (SEncParamExt& param, const bool kbEnableRc) {
   param.iMaxQp = 51;
   param.iMinQp = 0;
   param.iUsageType = CAMERA_VIDEO_REAL_TIME;
+  param.uiMaxNalSize = 0;
 
   for(int32_t iLayer = 0;iLayer< MAX_SPATIAL_LAYER_NUM;iLayer++){
     param.sSpatialLayers[iLayer].uiProfileIdc = PRO_BASELINE;
@@ -333,6 +334,7 @@ int32_t ParamTranscode (const SEncParamExt& pCodingParam) {
   iTargetBitrate		= pCodingParam.iTargetBitrate;	// target bitrate
   iMaxBitrate           = pCodingParam.iMaxBitrate;
 
+  uiMaxNalSize          = pCodingParam.uiMaxNalSize;
   /* Denoise Control */
   bEnableDenoise = pCodingParam.bEnableDenoise ? true : false;    // Denoise Control  // only support 0 or 1 now
 
diff --git a/codec/encoder/core/inc/wels_const.h b/codec/encoder/core/inc/wels_const.h
index 3e9c4437..fca7c065 100644
--- a/codec/encoder/core/inc/wels_const.h
+++ b/codec/encoder/core/inc/wels_const.h
@@ -167,6 +167,8 @@
 #define UNAVAILABLE_DQ_ID		((uint8_t)(-1))
 #define LAYER_NUM_EXCHANGEABLE	2
 
+#define NAL_HEADER_ADD_0X30BYTES 50
+
 #define MAX_NAL_UNIT_NUM_IN_AU	256	// predefined maximal number of NAL Units in an access unit
 #define MAX_ACCESS_UINT_CAPACITY	(1<<20)	// Maximal AU capacity in bytes: 1024 KB predefined
 #define MAX_ACCESS_UNIT_CACHE_NUM	2	// Maximal Access Unit(AU) cache number to be processed, denote current AU and the next coming AU.
diff --git a/codec/encoder/core/src/encoder_ext.cpp b/codec/encoder/core/src/encoder_ext.cpp
index 815a0cd5..c3f9132b 100644
--- a/codec/encoder/core/src/encoder_ext.cpp
+++ b/codec/encoder/core/src/encoder_ext.cpp
@@ -196,7 +196,10 @@ int32_t ParamValidationExt (sWelsEncCtx*pCtx,SWelsSvcCodingParam* pCodingParam)
       WelsLog (pCtx, WELS_LOG_ERROR, "ParamValidationExt(), invalid uiSliceMode (%d) settings!\n", fDlp->sSliceCfg.uiSliceMode);
       return ENC_RETURN_UNSUPPORTED_PARA;
     }
-
+    if((pCodingParam->uiMaxNalSize != 0) && (fDlp->sSliceCfg.uiSliceMode != SM_DYN_SLICE)){
+      WelsLog (pCtx, WELS_LOG_ERROR,"ParamValidationExt(), invalid uiSliceMode (%d) settings!,MaxNalSize = %d\n", fDlp->sSliceCfg.uiSliceMode,pCodingParam->uiMaxNalSize);
+      return ENC_RETURN_UNSUPPORTED_PARA;
+    }
     //check pSlice settings under multi-pSlice
     if (kiPicWidth <= 16 && kiPicHeight <= 16) {
       //only have one MB, set to single_slice
@@ -328,6 +331,19 @@ int32_t ParamValidationExt (sWelsEncCtx*pCtx,SWelsSvcCodingParam* pCodingParam)
                  fDlp->sSliceCfg.sSliceArgument.uiSliceSizeConstraint);
         return ENC_RETURN_UNSUPPORTED_PARA;
       }
+
+     if( pCodingParam->uiMaxNalSize <= NAL_HEADER_ADD_0X30BYTES) {
+       WelsLog (pCtx, WELS_LOG_ERROR, "ParamValidationExt(), invalid uiMaxNalSize (%d) settings!\n",
+                pCodingParam->uiMaxNalSize);
+       return ENC_RETURN_UNSUPPORTED_PARA;
+      }
+
+      if( fDlp->sSliceCfg.sSliceArgument.uiSliceSizeConstraint > (pCodingParam->uiMaxNalSize - NAL_HEADER_ADD_0X30BYTES)){
+        WelsLog (pCtx, WELS_LOG_WARNING, "ParamValidationExt(), slice mode = SM_DYN_SLICE, uiSliceSizeConstraint = %d ,uiMaxNalsize = %d!\n",
+                 fDlp->sSliceCfg.sSliceArgument.uiSliceSizeConstraint,pCodingParam->uiMaxNalSize);
+        fDlp->sSliceCfg.sSliceArgument.uiSliceSizeConstraint =  pCodingParam->uiMaxNalSize - NAL_HEADER_ADD_0X30BYTES;
+      }
+
       // considering the coding efficient and performance, iCountMbNum constraint by MIN_NUM_MB_PER_SLICE condition of multi-pSlice mode settting
       if (iMbWidth * iMbHeight <= MIN_NUM_MB_PER_SLICE) {
         fDlp->sSliceCfg.uiSliceMode	= SM_SINGLE_SLICE;