id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc
891	Incorrect temporal sublayer decoding	ksuehring		"The VTM decoder crashes, when decoding only TL=0 pictures, trying to re-create a missing reference picture.

Steps to reproduce:

1) Create a RA-GOP bistream with at least 33 pictures:

{{{
EncoderApp  -c ../cfg/encoder_randomaccess_vtm.cfg  -c ../cfg/per-sequence/RaceHorses.cfg -q 32 -f 33 --SEIDecodedPictureHash=1
}}}

2) Decode only layer sub-layer 0

{{{
DecoderApp -b str.bin -o dec.yuv --MaxTemporalLayer=0
}}}

3) The decoder crashes trying to re-create a picture with POC=8 (which has TL=1)

{{{
VVCSoftware: VTM Decoder Version 8.0rc1 [Mac OS X][clang 11.0.0][64 bit] [SIMD=AVX2] [ENABLE_TRACING] 

Tracing is enabled: DecTrace.txt : D_HEADER:final==1
POC    0 LId:  0 TId: 0 ( I-SLICE, QP 29 ) [DT  0.235] [L0] [L1] [MD5:6bb0209cfe465d93ebffd8b621ea31e5,92d430f1c3319c95d252834ad7790718,67972cf6ab1cf72988f4811e361db8c8,(OK)] 
POC   16 LId:  0 TId: 0 ( B-SLICE, QP 33 ) [DT  0.178] [L0 0] [L1 0c] [MD5:9f1617fa5db97aa1d4755225506bb58e,84d84250b2f80a14e26bb913404ac43d,9aaff168a37d6e64644efb2a14135784,(OK)] 

Current picture: 32 Short-term reference picture with POC =   8 seems to have been removed or not correctly decoded.Segmentation fault: 11
}}}

The crash happens when the decoder is trying to call xCreateLostPicture()

As far as I could debug, the check does not seem to care whether the picture in the reference picture is actually used as reference."	defect	closed	minor	VTM-8.1	VTM	VTM-7.3	fixed		ksuehring XiangLi fbossen jvet@…