Encoder crashes in all intra configuration due to wrong slice type while encoding enhancement layers when inter-layer prediction is disabled.

SHM2.0 was able to code all intra but the problem occurs in SHM3.0.1 and SHM4.0.

Below piece of code in initEncSlice function, TEncSlice.cpp line 431, sets the slice type of enhancement layers to B_SLICE.

#if SVC_EXTENSION

if(m_pcCfg->getLayerId() > 0) {

eSliceType=B_SLICE;

}

#endif

In SHM2.0, some later process was correcting the slice type, however in the later versions of the software, slice type is not set correctly. The issue is resolved by changing the code as:

if(m_pcCfg->getLayerId() > 0 && m_pcCfg->getNumActiveRefLayers()>0) {

eSliceType=B_SLICE;

}

But I am not sure whether it should be corrected at this stage or at a later process as in SHM2.0.

In a 4 layered scenario where layer 1 depends on layer 0, layer 2 is independent and layer 3 depends on layer 2 so that a decoder can skip layers 0 and 1 and start decoding from layer 3, encoder does not work properly. When I checked the code, I realized that layer 3 does not refer to layer 2 in mode decision due to a bug in the predInterSearchILRUni function. The bugfix may be to change the line number 6013 in TEncSearch.cpp in SHM-6.0 as follows:

if( pcCU->getSlice()->getRefPic(eRefPicList, refIdx)->isILR(pcCU->getLayerId())) && pcCU->getSlice()->getRefPic(eRefPicList, refIdx)->getLayerId() == refLayerId )

I removed the last part where the reference layer Id is compared to refLayerId variable which is obtained from pcSlice->getInterLayerPredLayerIdc(refLayer). (reference layer Id is 2 but the InterLayerPredLayerIdc is 0)

I attached a configuration file where you can duplicate the problem and two encoder log files for SHM-6.0 and bugfix.

I observed random decoder crashes using SHM6.0 (CGS=0). I ran an automatic leak detector with the attached bitstream and found various memory leaks. I’d like to raise this issue to the software coordinator's attention.