Opened 4 years ago

Last modified 4 years ago

#1461 assigned defect

Decoder need to check if the DPB is overflowed

Reported by: xiaozhongxu0000 Owned by: yaohualibin@…
Priority: major Milestone:
Component: HM SCC Version: SCC-7.0 (HM16.8)
Keywords: SCM DPB TwoVersionsCurrDecPicFlag Cc: jct-vc@…

Description

In HEVC SCC, in case that the DPB size is N and two versions of current pictures are different, there should be at most N-2 temporal reference pictures. When two versions of current pictures are the same (loop filters are off), there should be at most N-1 temporal reference pictures.

In SCM software, the removal of unnecessary pictures in the DPB is done after current picture is decoded and after the extra version of current picture (as reference picture) is removed. If the encoder has assigned N-1 temporal reference pictures to current picture, while two versions of current pictures are different, the decoder can still decode such an illegal bitstream.

In the provided patch, an assertion is made such that after removing unnecessary pictures from the DPB for current picture (and after decoding current picture), the DPB fullness including the current decoded picture itself should be at most N - TwoVersionsCurrDecPicFlag.

Attachments (1)

SCC_DPB.patch (1.3 KB) - added by xiaozhongxu0000 4 years ago.

Download all attachments as: .zip

Change History (5)

Changed 4 years ago by xiaozhongxu0000

comment:1 Changed 4 years ago by xiaozhongxu0000

  • Owner set to yaohualibin@…
  • Status changed from new to assigned

comment:2 Changed 4 years ago by ksuehring

This may be related to HM issue #1304, which reports that the DPB bumping process is not implemented exactly following the order in the text and may thus require one more DPB entry than specified.

Unfortunately we never received the patch mentioned in the discussion.

comment:3 Changed 4 years ago by xiaozhongxu0000

Dear Karsten,

Did you mean you cannot find the attachment (patch) in my original ticket?
I can see that from my side. Please help to clarify, thanks!

comment:4 Changed 4 years ago by ksuehring

I was referring to the patch mentioned in the discussion of #1304.

As far as I understand the description this is only for SCC, not the base spec, right?

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