diff --git a/codec/common/inc/macros.h b/codec/common/inc/macros.h
index 56778779..ed3f3d64 100644
--- a/codec/common/inc/macros.h
+++ b/codec/common/inc/macros.h
@@ -116,6 +116,10 @@
 #define WELS_ROUND(x)	((int32_t)(0.5+(x)))
 #endif//WELS_ROUND
 
+#ifndef WELS_ROUND64
+#define WELS_ROUND64(x)	((int64_t)(0.5+(x)))
+#endif//WELS_ROUND
+
 #ifndef WELS_DIV_ROUND
 #define WELS_DIV_ROUND(x,y)	((int32_t)((y)==0?((x)/((y)+1)):(((y)/2+(x))/(y))))
 #endif//WELS_DIV_ROUND
diff --git a/codec/encoder/core/inc/rc.h b/codec/encoder/core/inc/rc.h
index 2dcd6b8d..1dd35fa8 100644
--- a/codec/encoder/core/inc/rc.h
+++ b/codec/encoder/core/inc/rc.h
@@ -159,7 +159,7 @@ int32_t   iBitRate;
 int32_t   iPreviousBitrate;
 int32_t   iPreviousGopSize;
 double    fFrameRate;
-int32_t   iBitsPerFrame; // *INT_MULTIPLY
+int64_t   iBitsPerFrame; // *INT_MULTIPLY
 double    dPreviousFps;
 
 // bits allocation and status
diff --git a/codec/encoder/core/src/ratectl.cpp b/codec/encoder/core/src/ratectl.cpp
index 6d8e7314..ebc95ea6 100644
--- a/codec/encoder/core/src/ratectl.cpp
+++ b/codec/encoder/core/src/ratectl.cpp
@@ -230,7 +230,7 @@ void RcUpdateBitrateFps (sWelsEncCtx* pEncCtx) {
   SSpatialLayerInternal* pDLayerParamInternal     = &pEncCtx->pSvcParam->sDependencyLayers[pEncCtx->uiDependencyId];
   const int32_t kiGopSize	= (1 << pDLayerParamInternal->iDecompositionStages);
   const int32_t kiHighestTid = pDLayerParamInternal->iHighestTemporalId;
-  int32_t input_iBitsPerFrame = WELS_ROUND (pDLayerParam->iSpatialBitrate * INT_MULTIPLY /
+  int64_t input_iBitsPerFrame = WELS_ROUND64 (((int64_t)pDLayerParam->iSpatialBitrate) * INT_MULTIPLY /
                                 pDLayerParamInternal->fInputFrameRate);
   const int32_t kiGopBits	= WELS_DIV_ROUND (input_iBitsPerFrame * kiGopSize, INT_MULTIPLY);
   int32_t i;
@@ -255,7 +255,7 @@ void RcUpdateBitrateFps (sWelsEncCtx* pEncCtx) {
 
   //change remaining bits
   if (pWelsSvcRc->iBitsPerFrame > REMAIN_BITS_TH)
-    pWelsSvcRc->iRemainingBits = pWelsSvcRc->iRemainingBits * input_iBitsPerFrame / pWelsSvcRc->iBitsPerFrame;
+    pWelsSvcRc->iRemainingBits = (int32_t) (pWelsSvcRc->iRemainingBits * input_iBitsPerFrame / pWelsSvcRc->iBitsPerFrame);
   pWelsSvcRc->iBitsPerFrame = input_iBitsPerFrame;
 }