[M4IF Technotes] AAC test streams using coupling channels

[Umang Garg]

Jens, Hi...
The AT&T bitstreams are no longer valid. Their is a latest release from 
FhG which may be used for Conformance Testing.
You may want to have a look at the Technotes Archives containing details 
of previous communication on MP4IF in June-July 2003, dealing with this 
matter. 
Regards,
Umang Garg
NeoMagic Design Center
NeoMagic Corporation, based in Santa Clara, California, enables new 
generations of handheld systems with Applications Processors that offer 
the lowest power, smallest form-factor and best multimedia features and 
performance. The Company has pioneered the integration of complex logic, 
memory and analog circuits into single-chip solutions. NeoMagic is 
mobilizing multimedia for the Internet age. Information on the Company 
may be found on the World Wide Web at www.neomagic.com .
Jens Rennert wrote:
>Experts,
>
>I compiled versions 1 and 2 of the mpeg4 reference software and both seemed 
>unable to deal with the L6_XXX.aac bitstreams from AT&T. I tried various 
>other decoders (among them the MP4Play from the IBM MPEG 4 tool kit) and so 
>far I have found nothing which can decode these streams. 
>I added the coupling channel functionality from the reference code into my own 
>implementation and get some strange parsing results:
>
>1:single_channel_element, window_sequence 0, window_shape 0,max_sfb 47
>2:channel_pair_element, window_sequence 1, window_shape 0,max_sfb 34
>3:channel_pair_element, window_sequence 0, window_shape 1, max_sfb 0
>4:coupling_channel_element, element instance tag 4, ind_sw_cc 1
>   num_coupled_elements 0
>
>According to the stream description this streams should only contain 
>dependently switched channels. 
>Why would the number of coupled elements be zero?
>
>Could somebody please shed some light on this.
>Is there something like an AAC stream analyzer software available?
>
>Thanks
>
>Jens Rennert
>
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