Opened 5 years ago

Closed 5 years ago

#136 closed defect (fixed)

Potential bug in transform coefficient zero-out of large TUs

Reported by: zhou Owned by:
Priority: minor Milestone:
Component: VTM Version:
Keywords: Cc: ksuehring, XiangLi, fbossen, jvet@…


non-zero transform coefficients found on the decoder side in the area outside the top-left 32x32 region of large TUs. For example, in


which is the 3rd sub-stream of the sequence parallel coded in RA cfg with QP = 22.

The non-zero coefficient location is:

Frame POC: 20
Location of 64x64 CU inside the frame: x = 1024 y = 704
Location of non-zero COEF inside the TU: x = 32 y = 16
Non-zero COEF value: 14

Change history (2)

comment:1 Changed 5 years ago by mcoban

TCQ can flip a zero coefficient in the zero-out region to a non-zero coefficient during quantization. Scanning only the non zero-out regions or modifying the TCQ process for handling of the coefficients in the zero-out region could be potential fixes.

comment:2 Changed 5 years ago by fbossen

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

Addressed by JVET-M0257

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