International organisation for standardisation organisation internationale de normalisation

Further Discussion

It was the consensus of the Audio subgroup to incorporate the capability to carry DRC information in uniDrc() format as a USAC3D extension element.

Figure 7: Integration of Dynamic Range Control, Loudness Normalization and Peak Limiting into the MPEG-H decoder

Recommendations and review of AhG Report

The AhG report was reviewed and was approved by the AhG members present.

4. Task group activities

   1. Joint Meetings

      1. Audio and Systems: File Format and CICP (Wed 1130-1230)

David Singer, Apple, presented

m32272

Improved audio support in the ISO base media file format (14496-12)

David Singer, Frank Baumgarte,

The contribution points out that DRC as used in 3D Audio requires quite a rich set of metadata. Furthermore, that metadata could be in the MP4-FF boxes or in the audio Track (i.e. Elementary Stream or ES). The presenter stated that, in principle, the DRC metada should not be stored twice in the MP4-FF (i.e. in the FF boxes and the Elementary Stream).

The contribution is a proposed amendment to 14496-12, with boxed defined to support DRC. There are a number of issues:

• 
  Define how to carry DRC in FF boxes (which is done)
  
• 
  Define how to carry DRC in ES (which will be done by Audio)
  
• 
  If DRC is in ES, define what might need to be duplicated in FF.
  
• 
  Consider how to use a FF Hint Track to dynamically move DRC in FF to DRC in ES.
  

Agreed action items:

• 
  Jointly approve new WD of this document
  
• 
  Workplan from Audio which contains “study points” for audio experts.
  
  • 
    Investigate tracked-changes comment in WD document
    
  • 
    Address minimum “redundant metadata” that is to be both FF and ES.
    
  • 
    Consider software that could use hint track to automatically take FF level information into ES.
    

Max Neuendorf, FhG-IIS, presented

m32183

Update to Audio part of ISO/IEC 23001-8 (CICP)

Max Neuendorf, Ingo Hofmann, Nikolaus Rettelbach, Christian Ertel

The contribution presents proposed changes to the audio portion of the CICP standard. Proposed changes are:

• 
  Clarify the terms “channel”, “channel configuration”, “loudspeaker”, “ loudspeaker layout”, etc.
  
  • 
    It proposed to add a “Definition of Terms” section to the audio part.
    
• 
  Add a loudspeaker location table.
  

If a current term in CICP is “replaced” as proposed in the contribution, the “legacy” term MUST be retained at least in in the definition of terms section.

2.