In 8.5.2.1.6, when deriving mvLXB and availableFlagLXB, the step 2 specifies the condition to modify xBk by equations 8-131 to 8-133.

However, in the following step 4 and 6, xBk's are again set to the values specified in step 1 (say, xB0 = xP + nPbW, xB1 = xB0 − 1, and xB2 = xP − 1). This makes step2 phantom modification.

Hi, In chapter 8.5.2.1.7, the collocated coordinates are derived according to the vertical position "( yP >> Log2CtbSizeY ) is equal to ( yPRb >> Log2CtbSizeY )" to know whether to select central luma location or bottom-right luma location.

This force to work always with the same Ctb row in the collocated picture and in the current picture.

But it is not explained what to do when the collocated Pb cross the right picture boundary. For example the top-right Pb of the current Ctb can have its collocated Pb outside the picture boundary if the current Ctb is the last Ctb of a picture row and it respect the "( yP >> Log2CtbSizeY ) is equal to ( yPRb >> Log2CtbSizeY )" equation.

In this case I see 2 solutions : 1) Central luma location is used instead. 2) The collocated Pb is marked as unavailable.

Regards, Alexis

(Pb: prediction block, Ctb: coding tree block )

In chapter 8.5.2.1.7, mvCol, refIdxCol and listCol are derived according to following sentence:

"If PicOrderCnt( pic ) of every picture pic in every reference picture lists is less than or equal to PicOrderCntVal"

"Every reference picture lists" may refer to 1) picture lists L0 and L1 associated to the current luma prediction block 2) picture lists L0 and L1 associated to the collocated luma prediction block