Opened 12 months ago

Last modified 12 months ago

#1511 new defect

decoder failed when two PPSs are coded and IBC is disabled in one PPS and enabled in another one

Reported by: Weijia Owned by:
Priority: minor Milestone:
Component: HM SCC Version: SCC-7.0 (HM16.8)
Keywords: Cc: jct-vc@…

Description

The decoder has mismatches for the following case: two PPSs are signalled in the bitstream, pps_curr_pic_ref_enabled_flag are set to false and true in the first and second PPS, respectively, and the first few frames are coded referring to the first PPS and remaining frames are coded referring to the second PPS. In the current SCM, when a frame referring to the second PPS starts to be decoded(the variable m_pcTwoVersionsOfCurrDecPicFlag is set from false to true), the reconstructed frame before loop filtering(e.g. deblocking/SAO) should be removed after decoding the current frame. However, in the current SCM, a frame is removed when the m_bCurPic flag and the m_bIsLongTerm flag are true and false respectively. When the decoder performs the removal, the first frame in the current picture list, a frame decoded referring to the first SPS, will be undesirably removed instead of the current picture before being filtered, which results in errors on constructing the reference frame list when decoding of the successive frames. And, the encoder works well.

Change History (2)

comment:1 follow-up: Changed 12 months ago by axink

@Weijia,

Does a later version of SCM, say SCM-8.6 behave the same?
I remember the DPB feature of IBC was integrated in a later stage but not sure the exact version.

Best,
Xiaozhong

comment:2 in reply to: ↑ 1 Changed 12 months ago by Weijia

Yes, the latest version of SCM has the same bug.

Best
Weijia

Replying to axink:

@Weijia,

Does a later version of SCM, say SCM-8.6 behave the same?
I remember the DPB feature of IBC was integrated in a later stage but not sure the exact version.

Best,
Xiaozhong

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