Worked around the increased BDBR regression issue.

The regression was caused by the tile group implementation (PR #348),
when ImproveSharpness is used, as it would impact the QP values of
each CU and latter mode decision process.

So temporarily work around the issue and need to fix it in the future.

Signed-off-by: Austin Hu <austin.hu@intel.com>

Author: Austin-Hu

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

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,