Opened 4 years ago

Closed 4 years ago

# Indexing of predSamples in Section 8.5.6.1

Reported by: Owned by: bheng minor spec VVC D10 vE ksuehring, bbross, XiangLi, fbossen, jvet@…

### Description

In Section 8.5.6.1, the predSamples output is supposed to be a (cbWidth)x(cbHeight) array.

However, the derivation produces samples for the following range of index:

predSamples[ xL + xSb ][ yL + ySb ] with xL = 0..sbWidth − 1 and yL = 0..sbHeight − 1

Here, the location ( xSb, ySb ) is the top-left sample of the current subblock relative to the top left luma sample of the current picture.

Since they are relative to the picture, not the coding block, in general xSb and ySb will be completely outside the predSamples array.

### comment:1 Changed 4 years ago by jlchen

Really good catch, Brian.

To solve this issue, I would like to define ( xSbInCb, ySbInCb ) as follows, and use it instead of xSb as the array index of predSamples.

– The sample location ( xSbInCb, ySbInCb ) is set equal to ( xSbIdx * sbWidth, ySbIdx * sbHeight ).

### comment:2 Changed 4 years ago by jlchen

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

### comment:3 Changed 4 years ago by bheng

• Resolution fixed deleted
• Status changed from closed to reopened

Thanks for the fix!

Should probably use the new ( xSbInCb, ySbInCb ) location in this sentence as well:

"If cIdx is equal to 0, the prediction samples inside the current luma subblock, predSamples[ xL + xSb ][ yL + ySb ] with xL = 0..sbWidth − 1 and yL = 0..sbHeight − 1, are derived as follows"

### comment:4 Changed 4 years ago by bbross

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

Thansk for checking and reopening. The array indices will be fixed as follows in this sentence in JVET-S2001-vH:
predSamples[ xL + xSbInCb ][ yL + ySbInCb ]

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