Organisation internationale de normalisation

4Task group activities

4.1Joint meetings and documents from other groups

There were not joint meetings.

4.2Task Group discussions

4.2.1MPEG-4 audio, conformance, reference software

Markus Schnell, FhG, presented

m15151

Update on AAC-ELD Verification Test

Markus Schnell Ralf Geiger

This contribution is a draft of the AAC-ELD Verification Test Workplan. It proposes two tests, the first “application-driven” which asses performance in application-driven operating points for typical material, and the second “technology-driven” which asses performance over a range of operating points for critical material. All operating modes of AAC-ELD are being tested (e.g. block length, sampling rate).

For the first test, contribution proposes to use speech items from a wide range of languages from both male and female talkers. This may be “corrupted” using a set of representative office noise signals which were recorded by FhG.

There was much valuable discussion on test items and how to construct test items from the signal toolbox. The Chair urged the Audio Subgroup to help in the task of specifying a process to construct the final test items that represent best practice.

Tilman Liebchen, LG, presented

m15121

Update of ALS Conformance

Tilman Liebchen

This contribution reports

• 
  some bugfixes in the current set of conformance data
  
• 
  some new conformance data relating to MP4FF OAFI box
  
• 
  Update of ASL Conformance data
  

The contribution proposes to

• 
  Issue a DCOR on MPEG-4 Conformance to
  
  • 
    remove an equation from the spec and instead reference an equation in the MPEG-4 ALS specification.
    
  • 
    Replace incorrect ALS conformance data (due to a bug in the ASL reference software)
    
• 
  Conformance data for OAFI to be generated by a tool rather than as a pre-stored waveform.
  

It was the consensus of the Audio Subgroup to issue the DCOR from this meeting and to incorporate the new OAFI conformance data into the AAC-ELD Conformance amendment.

Andreas Schneider, Dolby, presented

m15161

Proposed correction to PS conformance and reference software

Andreas Schneider Heiko Purnhagen

This contribution corrects a restriction on how random access points interact with parapeter prediction in the combination of SBR and PS tools.

It also corrects a disagreement between the PS specification and the PS reference software, in which the reference software must be corrected. In addition, new conformance bitstreams will be generated that removed the “bug” situation such that the old and new decoder both produces the current reference waveforms

It was the consensus of the Audio Subgroup to issue the.DCOR on conformance at this meeting and a WD on an AAC-ELD Reference Software.

Pierfrancesco Bellini, University of Florence, presented

m15078

Editors Study on ISO/IEC 14496-4:2004/FPDAM 29, SMR Conformance

Pierfrancesco Bellini Paolo Nesi Giorgio Zoia Maurizio Capanai

This study presents corrections to the FPDAM text as requested by National Bodies.

Ralph Sperschneider, FhG, presented

m15180

WD on Audio part of MPEG-4 Conformance

Manuela Schinn Ralph Sperschneider

Since this is a large document, the presenter urged audio experts to review it as homework. Furthermore, he expects that this rollup of audio-related conformance may be complete at the April MPEG meeting.

Takehiro Moriya, NTT, presented

m15183

Proposed update of MPEG-4 ALS reference software for OAFI

Noboru Harada Takehiro Moriya Yutaka Kamamoto

This contribution proposes to add OAFI functionality to the ALS MPEG-4 Reference Software, and notes several bugs in the ALS reference software.

It was the consensus of the Audio Subgroup to issue a DCOR on MPEG-4 Reference Software that will include the bugfixes and which will bring the Reference Software in line with the MPEG-4 Specification by incorporating the OAFI code.