[M4IF Technotes] Re: how to verify AAC decoder output

[Ralph Sperschneider]

Jens Rennert wrote:
> Hello everyone,
> 
> I would like to know what the usual procedure is to verify the correctness of 
> an AAC decoder output. I would assume that there are reference audio files 
> (decoded with a reference decoder) which could be compared to the decoders 
> output. 
Yes, this is correct.
> Would this compare be a bit true compare?
There are several tests defined in ISO/IEC 14496-4. Bit exactness is not 
required, but there are RMS and LSB measures which have to be met at least for 
the sine sweeps and a special energy masure to test PNS.
> Where can I get reference streams 
> to compare my decoders output with?
ftp://mpaudconf:adif2mp4@ftp.iis.fhg.de/mpeg4audio-conformance
For a description of the test sequences and the assigned measures check out 
ISO/IEC 14496-4. For the appropriate tools allowing the comparison of the 
waveforms check out ISO/IEC 14496-5.
Best regards,
Ralph
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Dipl.-Ing. Ralph Sperschneider  | Phone: +49 9131 776 344
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