International organisation for standardisation organisation internationale de normalisation

8.2Task Group discussions

8.2.1MPEG-2, MPEG-4, Audio Conformance, Reference Software, MPEG Surround

JungHoe Kim, Samsung, presented

m16609

Proposed study on BSAC Conformance for Broadcasting

Miyoung Kim, Eunmi Oh

The contribution defines one new conformance stream that uses the intensity stereo tool in combination with other tools. It is the consensus of the Audio Subgroup to produce a “Study on ISO/IEC 14496-26:2009/PDAM 2, BSAC Conformance for Broadcasting” containing the new bitstream.

Ferenc Kraemer, Dolby, presented

m16633

Proposed addition to ELD conformance

Andreas Schneider

The presentation notes that the AAC-ELD conformance suite did not have AAC-LD / SBR test sequences and no test procedure for such sequences. Hence is it proposed to submit an AAC-LD / SBR conformance tool and define four new AAC-LD / SBR conformance streams. Both the streams and the conformance tool are available now,

It is the consensus of the Audio Subgroup to add the new definitions to the 14496-26/AMD 1 FDAM text. The conformance criteria will be specified at a future date, most likely via corrigendum.

Heiko Purnghagen, Dolby, presented

m16683

Study on 23003-1:2007/DCOR.2, MPEG Surround

Heiko Purnhagen

The only changes with respect to the DCOR 2 document is that the proposed Study document incorporates “hard-wired” references so that a published Cor 2 document with print correctly. It is the consensus of the Audio Subgroup to produce a “Study on 23003-1:2007/DCOR.2, MPEG Surround” containing the printable references.

Takehiro Moriya, NTT, presented

m16649

Proposal of a new Profile for MPEG-4 ALS

Takehiro Moriya, Tilman Liebchen, Noboru Harada, Yutaka Kamamoto

The contribution proposes an “ALS Baseline Profile” entailing the following restrictions:

• 
  No RLS-LMS tool
  
• 
  No BGMC (block Gilbert-Moore code) tool
  
• 
  Maximum amplitude resolution: 16 bits
  
• 
  Maximum sampling frequency: 48 kHz
  
• 
  Maximum number of channels: 2
  
• 
  Maximum number of samples per frame: 4096
  
• 
  Maximum prediction order: 15
  
• 
  Maximum BS (block switching) stages: 3
  
• 
  Maximum MCC (multi-channel coding) stages: 1 (stop_flag=0 is allowed only once.）
  

With these restrictions, the ALS decoder has complexity comparable to an AAC-LC stereo decoder when operating on an ARM platform.

It is envisioned that the primary application are for this profile is music delivery to mobile phone or mobile player.

Companies that have pledged to support the proposed standard are:

• 
  NTT DOCOMO
  
• 
  LG Electronics
  
• 
  NTT Electronics
  
• 
  Napster/Tower Records
  
• 
  RIAA
  

This contribution will be reviewed in a joint meeting with Requirements.