Organisation internationale de normalisation

Open Issues

A workplan for integration of RM4 integration was presented. This will be extended to support Phase II RM0 integration and examination and replacement of Phase I source code copyright headers.

The Chair presented the MPEG-H 3D Audio Performance Report.

4. Maintenance

MPEG-4

Masayuki Nishiguchi, Sony, presented

m34893

Reference Software of MPEG-4 Audio Synchronization

Shusuke Takahashi, Akira Inoue, Masayuki Nishiguchi, Toru Chinen

MP4

The contribution proposes a structure for the reference software for the Audio Synchronization technology. The Chair suggested that Sony experts prepare a “Software to add to DAM 37”

It was the consensus of the Audio subgroup that Sony experts prepare an output document “Reference Software of MPEG-4 Audio Synchronization” that has as text:

• 
  An introductory paragraph indicating that the associated reference software is to be added to ISO/IEC 14496-5:2001/AMD 37, MPEG-4 Part5: Reference software
  
• 
  The remaining text is the text in the contribution
  

and that the zip archive of the document contains a zip archive of the Audio Synchronization reference software. This document can have an 12 week editing period.

Stephan Schreiner, FhG-IIS, presented

m35073

Proposal for extended MPEG-4 Audio Conformance

Stephan Schreiner, Tobias Schwegler, Nikolaus Rettelbach

MP4

MPEG-4 Audio AMD4 introduced new loudspeaker layouts and associated additional bitstream elements. The contribution proposed to extend the MPEG-4 conformance vectors so that these new elements are tested.

New conformance data will test

• 
  New channel configurations
  
• 
  Extended downmix capabilities
  
• 
  Extended DRC
  

The contribution requests a workplan to develop and cross-check the conformance data.

USAC

Joe Hilpert, FhG-IIS, presented

m34882

Further corrections to MPEG-D USAC Text and RefSoft

Daniel Fischer, Matthias Felix, Max Neuendorf

USAC

The contribution proposes 4 corrections to the text. In every case, the proposed change aligns the text with the reference software.

• 
  Differential coding of the ACELP pitch lag is done incorrectly. The corrections permit the full use of the range of quantizer values.
  
• 
  ACELP excitation codebook did not use index 0 and index 63 values due to an error in the text.
  
• 
  In the ACELP tool, LPC0 is not defined in all situations. The correction is to indicate in those cases that LPC0 should be LPC4 of the prevous frame.
  
• 
  In the text the Bass post-filter tool is missing a factor that is present in the reference software.
  

The contribution proposes 2 corrections to both the text and reference software. However, these are “corner cases” that

• 
  It is not clear whether the Bass Postfilter should be active in some FAC signal areas.
  
• 
  In certain cases, the Bass Postfiter has a tap that uses signal values “in the future.” The proposal is to eliminate that filter tap for those cases.
  

It was the consensus of the Audio subgroup to incorporate these changes into the DCOR for text and reference software and issue both as COR at this meeting.

5.