Encoder crash under particular condition in predInterSearch func

[YuchengSun]

In predInterSearch func line 2776-2783, REF_PIC_LIST_0 and REF_PIC_LIST_1 should be used instead of eRefPicList. Following code may lead to encoder crash when using the same reference list index "eRefPicList":

xCopyAMVPInfo(&aacAMVPInfo[0][iRefIdxBi[0]], &amvp[REF_PIC_LIST_0]);
xCheckBestMVP( REF_PIC_LIST_0, cMvBi[0], cMvPredBi[0][iRefIdxBi[0]], aaiMvpIdxBi[0][iRefIdxBi[0]], amvp[eRefPicList], uiBits[2], uiCostBi, pu.cu->imv);
if(!cs.slice->getMvdL1ZeroFlag())
{
   xCopyAMVPInfo(&aacAMVPInfo[1][iRefIdxBi[1]], &amvp[REF_PIC_LIST_1]);
   xCheckBestMVP( REF_PIC_LIST_1, cMvBi[1], cMvPredBi[1][iRefIdxBi[1]], aaiMvpIdxBi[1][iRefIdxBi[1]], amvp[eRefPicList], uiBits[2], uiCostBi, pu.cu->imv);
}

[XiangLi]

Thanks for the report. Could you provide detailed encoder settings so that we may duplicate the crash you mentioned? Could you also share the results of the fix?

[YuchengSun]

Dear coordinators, in current platform this code will be invoked when meet the follwing coditions：
1、the value of beChanged(InterSearch.cpp line 2716) is false;
2、the value of enforcedGBiPred(InterSearch.cpp line 2674) is true;
3、MvdL1Zero algorithm is enabled;
Because the MvdL1Zero algorithm can't be disabled by cfg in current platform, we can't provide the cfg that lead to the crash without changing the source code. However, I think it's a consensus that the AMVP list for List0 can't be used to check the best MVP for list 1, it maybe better to fix it even this problems won't happen in current CTC.

[XiangLi]

Fixed in ​https://vcgit.hhi.fraunhofer.de/jvet/VVCSoftware_VTM/merge_requests/537. No impact on CTC.