Opened 9 years ago

Closed 9 years ago

#433 closed defect (fixed)

Subclause 8.5 bugs, wording, typos, cross references

Reported by: mwi Owned by: bbross
Priority: minor Milestone: D7
Component: Text Version: D6 (H1003) dI/dJ/dK
Keywords: Cc: bbross, wjhan, jct-vc@…


Subclause 8.5:

  • Step 2.: The decoding process for the residual signal of coding units in inter prediction mode is Subclause 8.5.3 instead of

Subclause 8.5.1:

  • wording for inputs: add 'the' between 'specifying' and 'prediction'. (2x)
  • PartIdx is a local variable and should therefore be written as partIdx.
  • PartMode is a local variable and should therefore be written as partMode.
  • For the steps depending on partMode: If the prediction unit size is not the coding unit size, the decoding process for prediction units in inter prediction mode (subclause 8.5.2) should return _modified_ arrays predSample{L,Cb,Cr} since the same array is filled step-by-step.

Subclause 8.5.2:

  • specification of process output: wording/typo semicolon in "inter prediction samples (predSamples)/;/ which are ..."


  • Local variables should start lower case in second sentence after Input, Output spec: PredFlagL0, PredFlagL1.
  • Step 3 (after eq (8-94)): The derivation process for luma motion vector prediction is subclause (instead of (also reported in #340)


  • In step 3, the size of the current PU (nPSW,nPSH) is missing in the parameter set passed to subclause The text in subclause indicates the refIdx of the 'current prediction unit partition', while it is the refIdx of A1 or 0.
  • In step 7, the variable numNscaleMergeCand is not specified


  • Eqs (8-103)--(8-105) miss a "(" after the "=". Same comment for Eqs (8-141)--(8-143).
  • Harmonize expression for the location of A1 in and (top/bottom right pixel of PU, respectively)


  • Typo "dervied" should be "derived" before eq.(8-106), (8-115), (8-124)


  • Remove round brackets in statement "If (slice_type is equal to P)"


  • Step 2.: replace "subclause 5" by subclause "".


  • Figure 8-3 should be marked informative. The depicted positions of A1,B1,B2 correspond to the specification of A1,B1,B2 in, not to specification in this subclause.
  • Step 1 for mvLXA: Remove the sentence "The set of sample locations ( xAk, yAk ) represent the sample locations immediately to the left side of the left partition boundary and it’s extended line."
  • Step 2 for mvLXA: rephrase, remove 'initially'.
  • Steps 4,5 for mvLXA: repeated specification of yA1, remove this.


  • scaling motion vectors according to POC is specified three times, around eqs. (8-137),(8-145), and (8-155). --> Put into separate process.
  • Eq.(8-138,146,156): Fractional maximum MV length 8191.75? all other values are integer. (also ticket #341)

Subclause "Reference picture selection process" is not specified.


  • remove 'general' in "These variables are used only inside this subclause for specifying general fractional-sample locations inside the reference sample arrays ..."
  • Replace "0<=xL<nPSW" by "xL=0..nPSW", same for yL, xC, yC.


  • The sentence after eq.8-187) "The positions labelled with lower-case letters within un-shaded blocks represent luma samples at quarter-pel sample fractional locations" should be moved behind the sentence referencing Figure 8-4.
  • In the text above eq.(8-173), the term 'rules' should be replaced by 'equations'.


  • In the text above eq.(8-188), Figure 8-5 should be referenced instead of Figure 8-4.
  • The sentence after eq.8-187) "The positions labelled with lower-case letters within un-shaded blocks represent chroma samples at eighth-pel sample fractional locations." should be moved behind the sentence referencing (corrected) Figure 8-5.
  • In the text above eq.(8-173), the term 'rules' should be replaced by 'equations'.


  • replace "as described in subclause ..." with "as specified in subclause ..."
  • The wording "with the same inputs and outputs as ..." when calling a process is not used elsewhere The same applies to subclauses{1,2}.
  • The shift and offset values are derived here, but used in the sub-processes{1,2} without passing them.


The organization of the subclause seems to be broken.

  • the variables for weighted prediction logWDC, logWDC (doubled), w0C, w1C, o0C, o1C are not passed as input to the process in subclause but are then derived after eq.(8-220). The derivation might be moved after input/output and before the derivation of predSamples.
  • The variable name should be modified to log2WDC to indicate the base of the logarithm.

Question: is it specified somewhere that arrays like mvLX[][], refIdxLX[][], etc.,
represent their respective values for each pixel position of a CU/PU? E.g. in subclause,
different pixel positions are used for addressing a PU (top left, bottom right, top right pixel).

Change History (6)

comment:1 Changed 9 years ago by DefaultCC Plugin

  • Cc bbross wjhan jct-vc@… added

comment:2 Changed 9 years ago by iperroux

Additionnaly in the equation number for RefPicOrderCnt(picX, refIdx, LX)(8 141) is broken. It should be replaced by field codes and display (8-149) instead of (8 141).

comment:3 Changed 9 years ago by asimpson


  • Step 1 defines xB0, xB1 & xB2
  • Step 2 refines xB0, xB1 & xB2 for case where they are off the top of the LCU
  • Steps 4&6 redefine xB0, xB1 & xB2, as per step 1 ignoring changes made in step 2

comment:4 Changed 9 years ago by asimpson


  • Steps 2 & 3 use refIdxLX, along with other variables selected by X, and state that X is 0 or 1, but there does not appear to be a loop so that both values get used.

comment:5 Changed 9 years ago by bbross

  • Milestone changed from WD6 to D7

comment:6 Changed 9 years ago by bbross

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

Fixed in JCTVC-I1003_d6.

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  • Benjamin Bross(Owner, Subscriber, Participant)
  • Isabelle Perroux(Participant)
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  • Karsten Suehring(Always)
  • Mathias Wien(Reporter)
  • Woo-Jin Han(Subscriber)