Opened 6 years ago

Closed 6 years ago

#67 closed defect (fixed)

Implicit vertical BT split at picture boundary issue

Reported by: bbross Owned by:
Priority: minor Milestone: VVC D2 v2
Component: spec Version: VVC D2 v1
Keywords: Cc: ksuehring, bbross, XiangLi, fbossen, jvet@…


Consider the following case:

If a CU:

  • crosses the right boundary of the picture and
  • has cbSize size is greater than MinQtSizeY and smaller than or equal to MaxBtSizeY


  • qt_split_cu_flag is signalled

If qt_split_cu_flag is signalled as 0 (no QT split)

  • multi_type_tree is called and
  • allowSplitBtHor, allowSplitTtVer and allowSplitTtHor=false but allowSplitBtVer=true


  • mtt_split_cu_flag is signalled although it should be inferred to be equal to 1

A simple fix would

  1. add the following condition to the signalling of mtt_split_cu_flag:
  • if( ( allowSplitBtVer | | allowSplitBtHor | | allowSplitTtVer | | allowSplitTtHor ) && ( x0 + cbWidth <= pic_width_in_luma_samples ) && ( y0 + cbHeight <= pic_height_in_luma_samples ) )
  1. infer its value in case it is not present as:
  • If one or more of the following conditions are true, the value of mtt_split_cu_flag is inferred to be equal to 1.
    • x0 + cbWidth is greater than pic_width_in_luma_samples.
    • y0 + cbHeight is greater than pic_height_in_luma_samples.
  • Otherwise, the value of mtt_split_cu_vertical_flag is inferred to be equal to 0.

Thanks Virginie for spotting this.

Change history (1)

comment:1 Changed 6 years ago by bbross

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

Fixed in VVC Draft 2 v2 (JVET-K1001-v2)

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