Opened 7 years ago

Closed 7 years ago

#1094 closed defect (invalid)

Incorrect decode at bitdepth 14

Reported by: peterderivaz Owned by:
Priority: minor Milestone: HM-10.1
Component: HM Version: HM-10.0
Keywords: Cc: fbossen, ksuehring, davidf, jct-vc@…

Description

Does the HM software support bitdepths above 10?

Main and Main10 profile only use bitdepths 8,9, or 10 so perhaps high bitdepths are not supported?
However, the HEVC text allows bitdepths 8,9,10,11,12,13, or 14.

The HM software appears to decode incorrectly at high bitdepths.
For example, in the function TComTrQuant::xITransformSkip there is the line:

pResidual[j * uiStride + k] = plCoef[j*width+k] << transformSkipShift;

Suppose transformSkipShift = 1.
pResidual is a 16bit number, so shifting plCoef can result in integer overflow. (Also this scaling will mean that the residual is always an even number.)

Change History (4)

comment:1 Changed 7 years ago by DefaultCC Plugin

  • Cc fbossen ksuehring davidf jct-vc@… added

comment:2 Changed 7 years ago by karlsharman

The high bit depth support is covered by the remit of the HM range extension work, which is still under development by the committee.

comment:3 Changed 7 years ago by peterderivaz

My apologies. Please feel free to close this bug report as invalid.

comment:4 Changed 7 years ago by ksuehring

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