diff --git a/codec/encoder/core/inc/wels_preprocess.h b/codec/encoder/core/inc/wels_preprocess.h
index 21db359f..4a271fc1 100644
--- a/codec/encoder/core/inc/wels_preprocess.h
+++ b/codec/encoder/core/inc/wels_preprocess.h
@@ -108,8 +108,8 @@ class CWelsPreProcess {
 
  public:
   int32_t WelsPreprocessReset (sWelsEncCtx* pEncCtx);
-  int32_t WelsPreprocessStep1 (sWelsEncCtx* pEncCtx, const SSourcePicture** kppSrcPicList, const int32_t kiConfiguredLayerNum);
-  int32_t WelsPreprocessStep3 (sWelsEncCtx* pEncCtx, const int32_t kiDIdx);
+  int32_t BuildSpatialPicList (sWelsEncCtx* pEncCtx, const SSourcePicture** kppSrcPicList, const int32_t kiConfiguredLayerNum);
+  int32_t AnalyzeSpatialPic (sWelsEncCtx* pEncCtx, const int32_t kiDIdx);
 
  private:
   int32_t WelsPreprocessCreate();
diff --git a/codec/encoder/core/src/encoder_ext.cpp b/codec/encoder/core/src/encoder_ext.cpp
index 72bc5487..5c4e1f31 100644
--- a/codec/encoder/core/src/encoder_ext.cpp
+++ b/codec/encoder/core/src/encoder_ext.cpp
@@ -3136,7 +3136,7 @@ int32_t WelsEncoderEncodeExt (sWelsEncCtx* pCtx, void* pDst, const SSourcePictur
   pFbi->iLayerNum	= 0;	// for initialization
 
   // perform csc/denoise/downsample/padding, generate spatial layers
-  iSpatialNum = pCtx->pVpp->WelsPreprocessStep1 (pCtx, ppSrcList, iConfiguredLayerNum);
+  iSpatialNum = pCtx->pVpp->BuildSpatialPicList (pCtx, ppSrcList, iConfiguredLayerNum);
   if (iSpatialNum < 1) {	// skip due to temporal layer settings (different frame rate)
     ++ pCtx->iCodingIndex;
     return WELS_FRAME_TYPE_SKIP;
@@ -3184,7 +3184,7 @@ int32_t WelsEncoderEncodeExt (sWelsEncCtx* pCtx, void* pDst, const SSourcePictur
     SDLayerParam* param_d		= &pSvcParam->sDependencyLayers[d_idx];
 
     pCtx->uiDependencyId	= iCurDid = (int8_t)d_idx;
-    pCtx->pVpp->WelsPreprocessStep3 (pCtx, d_idx);
+    pCtx->pVpp->AnalyzeSpatialPic (pCtx, d_idx);
 
     pCtx->pEncPic	 = pEncPic = (pSpatialIndexMap + iSpatialIdx)->pSrc;
     pCtx->pEncPic->iPictureType	= pCtx->eSliceType;
diff --git a/codec/encoder/core/src/wels_preprocess.cpp b/codec/encoder/core/src/wels_preprocess.cpp
index 4933fd8b..e337dd83 100644
--- a/codec/encoder/core/src/wels_preprocess.cpp
+++ b/codec/encoder/core/src/wels_preprocess.cpp
@@ -260,7 +260,7 @@ int32_t CWelsPreProcess::WelsPreprocessReset (sWelsEncCtx* pCtx) {
   return iRet;
 }
 
-int32_t CWelsPreProcess::WelsPreprocessStep1 (sWelsEncCtx* pCtx, const SSourcePicture** kppSrcPicList,
+int32_t CWelsPreProcess::BuildSpatialPicList (sWelsEncCtx* pCtx, const SSourcePicture** kppSrcPicList,
     const int32_t kiConfiguredLayerNum) {
   SWelsSvcCodingParam* pSvcParam = pCtx->pSvcParam;
   int32_t	iNumDependencyLayer = (int32_t)pSvcParam->iNumDependencyLayer;
@@ -309,7 +309,7 @@ int32_t CWelsPreProcess::WelsPreprocessStep1 (sWelsEncCtx* pCtx, const SSourcePi
   return iSpatialNum;
 }
 
-int32_t CWelsPreProcess::WelsPreprocessStep3 (sWelsEncCtx* pCtx, const int32_t kiDidx) {
+int32_t CWelsPreProcess::AnalyzeSpatialPic (sWelsEncCtx* pCtx, const int32_t kiDidx) {
   SWelsSvcCodingParam* pSvcParam = pCtx->pSvcParam;
   bool bNeededMbAq = (pSvcParam->bEnableAdaptiveQuant && (pCtx->eSliceType == P_SLICE));
   bool bCalculateBGD = (pCtx->eSliceType == P_SLICE && pSvcParam->bEnableBackgroundDetection);