Opened 12 years ago

Closed 10 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 12 years ago by DefaultCC Plugin

  • Cc fbossen ksuehring davidf jct-vc@… added

comment:2 Changed 12 years ago by ksuehring

This is related to issue #435. Context initializations were only run for common test conditions.

Version 0, edited 12 years ago by ksuehring (next)

comment:3 Changed 12 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 12 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 10 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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