VTM does not correctly apply the C5.2.2 process

[marie-pierre.gallasso]

As said in specification, before decoding the current picture, the C5.2.2 "Output and removal of pictures from DPB" process is invoked and the first point is:
The decoding process for RPL construction as specified in subclause 8.3.2 and decoding process for reference picture marking as specified in subclause 8.3.3 are invoked.

In source/Lib/DecoderLib/DecLib.cpp (in function xActivateParameterSets()), the VTM tries to get an empty pic storage buffer before applying the decoder process for RPL construction and the decoder process for reference pic marking (function applyReferencePictureListBasedMarking()) which may update the flags "neededForOutput" or "referenced".

If all pic storage buffers are full, a new pic storage buffer cannot be found to add the current picture even if there is a pic storage buffer containing a picture that is "not needed for output" and "not used as reference".

[ksuehring]

fixed in ​https://vcgit.hhi.fraunhofer.de/jvet/VVCSoftware_VTM/-/merge_requests/1970