#623 closed defect (fixed)

Typos and undefined variables in ACT related text

Reported by: vdrugeon Owned by:
Priority: blocker Milestone: VVC D10
Component: spec Version: VVC D9 vB
Keywords: Cc: ksuehring, bbross, XiangLi, fbossen, jvet@…

Description

  1. Typo in semantics of sps_act_enabled_flag: "sps_act_enabled_flag specifies that whether adaptive colour transform is enabled. "
  1. Typo in semantics of cu_act_enabled_flag: "cu_act_enabled_flag is equal to 0 specifies that the residuals of the current coding unit are coded in original colour space"
  1. In 8.4.5.1 General decoding process for intra blocks, the last step (step 4) in the process uses the variable resSample as input: "the picture reconstruction process for a colour component as specified in clause 8.7.5 is invoked with the transform block location ( xTbComp, yTbComp ) set equal to ( xTb0 + nW * xPartIdx, yTb0 + nH * yPartIdx ), the transform block width nTbW, the transform block height nTbH set equal to nW and nH, the variable cIdx, the (nW)x(nH) array predSamples[ x ][ y ] with x = xPartPbIdx * nW..( xPartPbIdx +1 ) * nW − 1, y = 0..nH − 1, and the (nW)x(nH) array resSamples as inputs,". However, when controlPara is equal to 2, resSamples is not derived in this process anymore, so that this variable is undefined when it is used. At first sight, it seems that resSamples should be one of the inputs of this process when controlPara is equal to 2. However, I think that it would probably be editorially cleaner to remove the picture reconstruction process step for this process and apply it one level higher in the specification (i.e. in 8.4.1 General decoding process for coding units coded in intra prediction mode). It would remove the need to have a process that has inputs and outputs that depends on the value of cu_act_enabled_flag.

Attachments (1)

ACT text bugfix.docx (22.0 KB) - added by xyxiu 11 months ago.
ACT text bugfix

Download all attachments as: .zip

Change history (10)

comment:1 Changed 19 months ago by yk

I fixed the first two aspects (semantics of sps_act_enabled_flag and sps_act_enabled_flag) in JVET-P2001-vC/v12, but did not check item 3.

comment:2 Changed 18 months ago by bbross

  • Version set to VVC D7 vC

comment:3 Changed 18 months ago by bbross

  • Version changed from VVC D7 vC to VVC D7 vD

comment:4 Changed 18 months ago by bbross

  • Version changed from VVC D7 vD to VVC D7 vE

comment:5 Changed 16 months ago by bbross

  • Version changed from VVC D7 vE to VVC D8 vB

comment:6 Changed 11 months ago by bbross

  • Milestone set to VVC D10
  • Version changed from VVC D8 vB to VVC D9 vB

comment:7 Changed 11 months ago by bbross

  • Priority changed from minor to blocker

Changed 11 months ago by xyxiu

ACT text bugfix

comment:8 Changed 11 months ago by xyxiu

It is confirmed that in section 8.4.5.1, when controlPara is equal to 2, the (nW)x(nH) residual array resSamples are undefined. But, it seems the solution of moving the whole reconstruction process (step 4 in section 8.4.5.1) needs more text changes to the current specification. Instead, it is suggested to add resSamples as one input of section 8.4.5.1 when controlPara is equal to 2. This also complies with the way of how ACT text is written in the HEVC.

The corresponding text changes are attached.

comment:9 Changed 11 months ago by bbross

  • Resolution set to fixed
  • Status changed from new to closed

Thanks for providing the spec text and this is fixed in JVET-S2001-v9.

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