Opened 9 years ago

Closed 7 years ago

#501 closed enhancement (fixed)

Decoding part_mode with inter_4x4 can use CNU context

Reported by: pieterkapsenberg Owned by:
Priority: minor Milestone: HM-7.1
Component: HM Version: HM-7.0
Keywords: CNU context part_mode Cc: fbossen, ksuehring, davidf, jct-vc@…

Description

When disable_inter_4x4 is equal to 0, it is possible to decode a bin for part_mode with context increment of 2, which indexes a context state initialized with CNU (154). This should be explicitly called out, not left up to the default catch-all.

static const UChar 
INIT_PART_SIZE[3][NUM_PART_SIZE_CTX] =  
{
  { 184,  CNU,  CNU,  CNU, }, 
  { 154,  139,  '''CNU''',  CNU, }, 
  { 154,  139,  '''CNU''',  CNU, }, 
};

TDecSbac::parsePartSize 
....
for ( UInt ui = 0; ui < uiMaxNumBits; ui++ )
    {
      // ui could be 2 at here
      m_pcTDecBinIf->decodeBin( uiSymbol, m_cCUPartSizeSCModel.get( 0, 0, ui) );
      if ( uiSymbol )
      {
        break;
      }
      uiMode++;
    }

Change History (5)

comment:1 Changed 9 years ago by DefaultCC Plugin

  • Cc fbossen ksuehring davidf jct-vc@… added

comment:2 Changed 9 years ago by ksuehring

This is related to issue #436. Context initializations were only run for common test conditions.

Last edited 9 years ago by ksuehring (previous) (diff)

comment:3 Changed 9 years ago by pieterkapsenberg

  • Milestone changed from HM-6.2 to HM-7.1
  • Version changed from HM-6.1 to HM-7.0

comment:4 Changed 9 years ago by pieterkapsenberg

Actually Main Profile streams can have this problem too, when the min CU size is larger than 8x8, because then inter NxN is allowed.

comment:5 Changed 7 years ago by fbossen

  • Priority changed from major to minor
  • Resolution set to fixed
  • Status changed from new to closed
  • Type changed from defect to enhancement

Fixed in r3774

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