International organisation for standardisation organisation internationale de normalisation

4Task group activities

4.1Joint meetings

There were none.

4.2Task Group discussions

4.2.1MPEG-2, MPEG-4, MPEG-26 Audio, Audio Conformance, reference software

Yuriy A. Reznik, Qualcomm, presented

m16441

Fast SBR filterbanks for AAC-ELD, HE-AAC, and USAC.

Yuriy A. Reznik Ravi K. Chivukula

This contribution presents fast implementations for SBR filterbanks. Qualcomm will make software for the implementations available to MPEG.

Yuriy A. Reznik, Qualcomm, presented

m16443

On complexity of size 960 transform in AAC and related codecs

Yuriy A. Reznik Ravi K. Chivukula

This contribution presents information on the complexity of 960 length MDCT (as compared to 1024 length transform). The contribution concludes that there exist quite fast forms of a 960 length MDCT such that, when considering a count of multiplies and adds, the 960 length is less complex than the 1024 length by nearly a factor of 2.

Ralph Sperschneider, FhG, presented

m16299

Defect report on ISO/IEC14496-26

[e-mail]

This contribution presents two issues that need correction in the new MPEG-4 part 26, Audio Conformance:

• 
  al15 should not have an independently switched coupling channel (but it does). It is proposed to remove this sequence.
  
• 
  For the PNS conformance test procedure, the analysis window must be made dependent on the frame length. This change impacts both the standard text which describes the conformance test procedure and the related conformance testing software.
  

It was the consensus of the Audio Subgroup to issue a Study on 14496-26/DCOR 1 that contains these changes.