International organisation for standardisation organisation internationale de normalisation

Discussion

The proposal from the set of contributions is to choose between the following options:

• 
  DRC WD is fine as is (so we keep using spline interpolation)
  
• 
  Replace spline interpolation with linear interpolation with predictive coding
  

The issue will continue to be discussed.

Later Discussion

The Chair felt that there is no consensus for a decision on this CE at this time. After some discussion, experts from Sony indicated that they could provide the following additional information in a contribution to the next MPEG meeting:

• 
  If possible, obtain additional DRC gain sequences from a third party or from widely used commercial products.
  
• 
  Compare DRC coding bit rate of using
  
  • 
    DRC WD1 encoder and DRC WD1 decoder (spline coding)
    
  • 
    DRC WD1 encoder + Sony CE and DRC WD1 decoder + Sony CE (no spline coding)
    
• 
  Differences in bit rate should be relative to (i.e. Diff/Ref)
  
  • 
    Ref = DRC WD1 total rate
    
  • 
    Ref = DRC WD1 total rate + 320 kb/s (i.e. 5.1 channel program coded with AAC)
    
• 
  Previous listening tests have demonstrated that there is no difference in subjective performance between the two DRC coding methods, so it is felt that further listening tests are not necessary.
  

It is the consensus of the Audio subgroup to continue this CE.

3.