[mpegaudsg] Re: Proposal for some Audio-related actions this week

  • From: Eunmi Oh <sait@xxxxxxxxxxx>
  • To: Schuyler Quackenbush <srq@xxxxxxxxxxxxxxxxxxxxx>, "mpeg-audio-call@xxxxxxxxxxxxx" <mpeg-audio-call@xxxxxxxxxxxxx>, "mpegaudsg@xxxxxxxxxxxxx" <mpegaudsg@xxxxxxxxxxxxx>
  • Date: Tue, 20 Apr 2010 11:37:51 +0000 (GMT)

Dear Schuyler and All,  

Thank you for your opinion on the candidate list of CEs that might be reviewed 
for making a decision at this meeting.  
I would like to share my view on M17494 (CE on improvements to low bitrate 
stereo in USAC). 

In this CE, wavforms were available in two conditions.  
One condition is new downmix only (C2: encoder change), 
and the other is new downmix & upmix at the same time (C3: encoder & decoder 

Main results based on our listening tests described in M17509 are: 
- Only with downmix changes (C2), the quality of 5 items and 1 item out of 20 
items was significantly improved 
at 24 and 32kbits/sec stereo with respect to WD6. 

- The quality of only 1 item (an artificial “Harmonics”) is improved by 
normative changes (C3)
 in addition to informative changes (C2) in the differential scores, as you can 
see in Fig 4 & 8.  
The normative change only appears to bring benefit to a very artificial test 
signal called “Harmonics”.  

We are wondering what is done when only downmix (C2) is changed. 
Please elaborate the change in downmix (C2). 
We strongly recommend that we should separate the effect of normative changes 
from that of informative and normative changes.  

Furthermore, all cross-check reports are not in total agreement. 

I kindly ask Audio Subgroup not to make a decision on this issue at this 

Best regards, 


------- Original Message -------
Sender : Schuyler Quackenbush<srq@xxxxxxxxxxxxxxxxxxxxx> 
Date   : 2010-04-18 19:52 (GMT+09:00)
Title  : [mpegaudsg] Proposal for some Audio-related actions this week

Dear audio experts:

I attach my plan of possible decisions for this week. The document contains
a table that shows
-Contribution number, title, author
-Whether the contribution asks for an action (the specific action requested
is indicated as table heading)
-Whether I, as Audio Chair, think the supporting evidence is sufficiently
strong and uncontrovercial (i.e. all cross-check reports are in total
agreement) that a decision could be made via email communication.
-What additional information the authors should bring in order to help
individual experts make a decision (please fill in this entry box and
communicate back to be via email)

As to the last or rightmost column -- I will gather all comments into
revisions of the table. The purpose is to aid the CE proponents so that we
can make progress at the next meeting. When a complete CE is not acted upon,
experts typically state why they cannot make a decision (i.e. I don't see
full complexity information), so this entry is a placeholder for those kind
of comments.

I would like to highlight that, for USAC, I think it is possible to make a
decision (or to record expert positions) on only the following CEs:
M17502  Report on Enhanced Temporal Envelope Shaping CE for USAC
M17557  Corrections to Unified Stereo Coding
M17494  CE on improvements to low bitrate stereo in USAC
M17534  FhG listening test report for CE on improved downmix/upmix for USAC

However, PLEASE study the more complete attached table, as there are many
other decisions indicated (e.g. MPEG-2, -4, MPEG Surround, SAOC and other
aspects of USAC).

I welcome all comments on my proposed course of action.

Dr. Schuyler Quackenbush, Audio Research Labs
336 Park Ave, Suite 200,  Scotch Plains, NJ 07076
office: 908 490 0700      srq@xxxxxxxxxxxxxxxxxxxxx
mobile: 908 612 9423
fax:    908 842 9151      www.audioresearchlabs.com  

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