International organisation for standardisation

Further Discussion

There was considerable discussion of what additional information experts from Huawei, Orange Labs and Qualcomm wanted in order to address concerns on the profile.

Gregory Pallone (Orange Labs) stated that he approves the idea of creating the LD profile but would be more comfortable with the availability of subjective tests, bitstreams and reference software for the different levels in the proposition.

Bernhard Grill, FhG, noted that the issue under discussion is a profile and that there is no need to prove the performance of a profile since the performance of the constituent standardized parts have already been proven in a Verification Test.

The Chair made a list of requests and each request was discussed. Concerning requests from Orange Labs to check the bitstreams and decoder software, Bernhard Grill, FhG, stated that FhG can make available bitstreams conforming to the profile and guidance as to how to build a decoder that contains only the profile modules. In this way Orange Labs, or any other interested party, can check the bitstreams and decoder reference software.

There were requests from Huawi and Qualcomm for assessment of performance of over errored channels and the Chair noted that errored bitstreams are non-conformant and MPEG does not define the behaviour of the standard for non-conformant bitstreams. Therefore, MPEG is not able to provide a software implementation that mitigates bit errors. However, any ER AAC LD product that promotes error resilience as a feature would implement proprietary error mitigation functions. Bernhard Grill, FhG, offered to give a demonstration of the FhG ER AAC LD or ELD product performance over simulated errored channels.

The Audio subgroup agreed to draft an AhG workplan to in which FhG will provide bitstreams conformant to the Low Delay AAC V2 Profile, e.g. ER AAC ELD + MPS 212 at 32 kb/s, and Orange Labs will verify that the bitstreams can be decoded using the MPEG-4 Reference Software.

It was the consensus of the Audio subgroup to adopt the proposed profile into the ISO/IEC 14496-3:2009/DAM 3 text. Subsequently, it was discovered that there was no PDAM 3 ballot comment to authorize inclusion of the profile definition into the DAM 3 text. Hence, the profile definition text is found in an output document. It is expected that there will be such a comment in the DAM 3 ballot. The Chair stated in closing Audio plenary that the decision to adopt the profile was made at the 97^th meeting, and the question of adoption will not be reopened at future meetings.

Leon Terentiv, FhG, presented

m21248

Report on corrections and contributions for MPEG SAOC

Jonas Engdegard, Heiko Purnhagen, Oliver Hellmuth, Juergen Herre, Cornelia Falch, Leon Terentiv, Johannes Hilpert, Andreas Holzer, Werner Oomen

The contribution has two parts. The first part proposes to add corrections to the outstanding Defect Report on SAOC. Some changes are expressed as “delta” format, other are expressed as a change-control markup of the specification. These are clarifications on

• 
  How unquantized SAOC parameters can be transferred to an MPEG Surround decoder
  
• 
  Editorial clarifications of object or parameter naming (e.g. EAO, Epsilion-squared, etc.).
  
• 
  Editorial changes to the standard to permit a more compact description.
  

It was agreed to incorporate these proposed changes into a revised Defect Report on SAOC.

The second part is an update to ISO/IEC CD 23003-2:2010/PDAM 1, SAOC Conformance and also update to ISO/IEC CD 23003-2:2010/FCD, SAOC Reference Software.

It was agreed to incorporate these proposed changes into a DAM for Conformance and Reference Software.

Julien Robilliard, FhG, presented

m21258

Clarifications on MPEG Surround Text

Julien Robilliard, Andreas Hoelzer, Christian Ertel, Ferenc Kraemer, Heiko Purnhagen

The contribution proposes editorial corrections and pre- and post- gains as part of the MPEG Surround up-mix. It proposes to add a table to make it very clear when one should apply pre- and post- gains. The presenter proposes to some additional edits to the contribution during the week and to make it an output titled: “Defect Report on MPEG Surround,” which was agreed to by the Audio subgroup.

Ferenc Kraemer, Dolby, presented

m21238

Proposed New Conformance Sequences for MPEG Surround

Frans de Bont, Christian Ertel, Michael Haertl, Andreas Hoelzer, Ferenc Kraemer, Markus Lohwasser, Heiko Purnhagen

The contribution reviewed the history of MPEG Surround conformance, proposes corrections to the definition of two conformance sequences using residual coding and, most importantly, mittigates the high “max diff” values reported at the 95th MPEG meeting. The presenter requested that the contribution forms the basis of a DCOR 2 to issue from this meeting that defines the new and corrected conformance sequences. It is further proposed that the conformance “max diff” thresholds be defined within an editing period after this MPEG meeting, which was agreed to by the Audio subgroup.