[Mp4-tech] Looking for general information on AAC

[James Pieszala]

To all,
In brief:  I'm looking to obtain more information on HE-AAC (reference code
ISO/IEC 14496-5:2001/Amd.6:2005), the extend of what is contained there and
what I can expect it to do. Right now I'm running the conformance bitstreams
from the publicly available standard:
ISO/IEC 14496-4:2004/Amd.8:2005(Information technology -- Coding of
audio-visual objects -- Part 4: Conformance testing -- Amendment 8: High
Efficiency Advanced Audio Coding, audio BIFS, and structured audio
conformance).
Some of the conformance test streams are not passing, and some do not s"line
up":
For example(1), I'm not sure why this .mp4 has four corresponding .wav files
associated with it:
sbr_conftool al_sbr_cm_48_4.mp4 al_sbr_hq_cm_48_4_f00.wav
 al_sbr_hq_cm_48_4_f00.wav
 al_sbr_hq_cm_48_4_f01.wav
 al_sbr_hq_cm_48_4_f02.wav
 al_sbr_hq_cm_48_4_f03.wav
(2) With this one I don't get a CONFORMANCE PASSED message.
sbr_conftool al_sbr_sr_16_2_fsaac08.mp4 al_sbr_hq_sr_16_2_fsaac08.wav
(Informative) QMF-TEST: Max Diff: 0.040 RMS Diff: 0.009
===  SBR-TEST: Max Diff: 0.072 RMS Diff: 0.011
More information that would be helpful would be: what the file name letter
combinations symbolize, what the directory SBR_CONFORMANCE_3 with the
_lp_ files is, does the ISO/IEC conformance standard that ISO sells have
documentation that the publicly available one does not have.
Also, I am under the impression that in order to have an official conforming
decoder, one must pass an SBR and an AAC conformance test.  If I am correct
and the aforementioned constitutes the SBR conformance test, does anyone
know where to find the plain AAC conformance bitstreams.
 Any documentation on any of  this would be invaluable.
Thanks
James
-------------- next part --------------
An HTML attachment was scrubbed...
URL: /pipermail/mp4-tech/attachments/20070817/5bd07b4c/attachment.html