[Mp4-tech] Re: [Audio] Conformance Test ER-AAC-LC profile

[Ralph Sperschneider]

lisa wrote:
> Hi all,
> 
>     1)Could you please explain the conformance test proccedure for the  
> ER-AAC-LC profile?
>     
>     2)For ER_AL_10 --> RMS procedure is mentioned but there is no such  
> requirement for the     other    files?
> 
>     3)How does one conduct the conformance test for the following files
>         a)ER_AL12
>         b)ER_AL15
>         c)ER_AL18
>         d)ER_AL21
>         e)ER_AL23
>         f)ER_AL26
> 
> 
> With Regards
> Lisa Jones

Hi Lisa,
the standard (ISO/IEC 14496-4) says:
"
If no test is specified, a check of conformance using appropriate measurements, 
e.g. the LSB criterion (for those sequences that do not utilize PNS) or 
objective perceptual measurement systems, is not mandatory but highly 
recommended. This also applies to bitstreams with non-meaningful window sequences.
"
So in fact no test is required for ER_AL1[258] and ER_AL2[136], but you should 
run the RMS/LSB test for all sequences that do not use PNS (that is why PNS is 
only used at either fs1 or fs2).
For ER_AL10 the RMS/LSB test is mandatory.
Background: The RMS/LSB test is mandatory only for the sine sweep (ER_AL10), but 
not for the other signals.
Best regards,
Ralph
-- 
Dipl.-Ing. Ralph Sperschneider  | Phone: +49 9131 776 344
Fraunhofer IIS                  | Fax:   +49 9131 776 398
Am Wolfsmantel 33               | mailto:ralph.sperschneider iis.fraunhofer.de
D 91058 Erlangen                | http://www.iis.fraunhofer.de/amm/