diff --git a/Source/Lib/Codec/EbDefinitions.h b/Source/Lib/Codec/EbDefinitions.h
index a1700a758..ae7d712fd 100644
--- a/Source/Lib/Codec/EbDefinitions.h
+++ b/Source/Lib/Codec/EbDefinitions.h
@@ -54,8 +54,8 @@ extern "C" {
     typedef int errno_t;
 #endif  /* _ERRNO_T_DEFINED */
 
-
-
+// To sharpen frame background.
+#define USE_SOURCE_REFERENCE 0
 
 //Maximum 8192x4320
 #define EB_TILE_COLUMN_MAX_COUNT                    20u
diff --git a/Source/Lib/Codec/EbPictureDecisionProcess.c b/Source/Lib/Codec/EbPictureDecisionProcess.c
index 6b9863408..717ed2725 100644
--- a/Source/Lib/Codec/EbPictureDecisionProcess.c
+++ b/Source/Lib/Codec/EbPictureDecisionProcess.c
@@ -1020,9 +1020,15 @@ void* PictureDecisionKernel(void *inputPtr)
 
                         pictureControlSetPtr->disableTmvpFlag = sequenceControlSetPtr->staticConfig.unrestrictedMotionVector == 0 ? EB_TRUE : EB_FALSE;
 
+                        // FIXME: work around the increased BDBR regression issue induced by the
+                        // tile group implementation (PR #348), when ImproveSharpness is used.
+#if USE_SOURCE_REFERENCE
                         pictureControlSetPtr->useSrcRef = (sequenceControlSetPtr->staticConfig.improveSharpness && pictureControlSetPtr->temporalLayerIndex > 0) ?
                             EB_TRUE :
                             EB_FALSE;
+#else
+                        pictureControlSetPtr->useSrcRef = EB_FALSE;
+#endif
 
                         SignalDerivationMultiProcessesOq(
                                 sequenceControlSetPtr,