[M4IF Technotes] MPEG-4 AAC LTP Question

[mauri.vaananen nokia.com]

Dear Mr. Dimkovic,
This was an error in the (ISO 14496-3) standard. The reference software is
correct, and a correction to the specification is included in the text of
Draft Corrigendum approved in the last MPEG meeting.
Best Regards,
Mauri Vaananen
--------------------------------------------
mauri.vaananen   nokia.com
Nokia Research Center, Speech and Audio Systems Laboratory
Visiokatu 1 (P.O. Box 100), FIN-33721 Tampere, FINLAND
tel: +358 7180-35843 fax: -35899 mobile: +358 50 4835843
> -----Original Message-----
> From: Ivan Dimkovic [mailto:dim   psytel-research.co.yu]
> Sent: 07 December, 2001 19:24
> To: MPEG4 technical notes (E-mail)
> Subject: [M4IF Technotes] MPEG-4 AAC LTP Question
> 
> 
> Dear M4IF people,
> 
> I've found a constant that is used in 14496-5 reference software:
> NOK_MAX_LT_PRED_SFB, defining upper scalefactor band for long term
> prediction for long blocks.
> 
> This value is set to 40 in both encoder and decoder
> (nok_ltp_common_internal.h)
> 
> However, there is no such limit in the ISO 14496-5 standard. 
> The question
> is, is there a possibility to use scalefactor bands higher 
> than 40 for LTP?
> If that is the case, then ISO reference software decoder 
> wouldn't be able to
> decode such AAC bitstreams. We use this limit (40) in our encoder.
> 
> Best Regards,
> 
> *************************************************
> Ivan Dimkovic, Technical Manager
> 
> PsyTEL Research
> Multimedia Coding Solutions
> Belgrade Yugoslavia
> 
> phone:  +381 63 264 334
> phone:  +381 64 11 40 600
> fax:       +381 11 32 25 275
> 
> email:  dim   psytel-research.co.yu
> www:  http://www.psytel-research.co.yu
> *************************************************
> 
> 
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