M0854

source/Lib/CommonLib/TypeDef.h

@@ -127,6 +127,7 @@
 #define JVET_M0464_UNI_MTS                                1
 #define JVET_M0068_M0171_MMVD_CLEANUP                     1 // MMVD cleanup with 1) flip removal, 2) L1 zero vector fix, 3) bi-pred restriction after merge/MMVD
 #define JVET_M0255_FRACMMVD_SWITCH                        1 // disable fractional MVD in MMVD adaptively
+#define JVET_M0854_FRACMMVD_SWITCH_FOR_UHD                1 // disable fractional MVD for UHD pictures
 #define JVET_M0823_MMVD_ENCOPT                            1 // encoder optimization for MMVD
 
 #define JVET_M0147_DMVR                                   1 //Decoder side Motion Vector Refinement

source/Lib/EncoderLib/EncSlice.cpp

@@ -1431,6 +1431,12 @@ void EncSlice::checkDisFracMmvd( Picture* pcPic, uint32_t startCtuTsAddr, uint32
   {
     pcSlice->setDisFracMMVD( true );
   }
+#if JVET_M0854_FRACMMVD_SWITCH_FOR_UHD
+  if (!pcSlice->getDisFracMMVD()) {
+    bool useIntegerMVD = (pcPic->lwidth()*pcPic->lheight() > 1920 * 1080);
+    pcSlice->setDisFracMMVD( useIntegerMVD );
+  }
+#endif
 }
 #endif