[Mp4-tech] audio

[Ralph Sperschneider]

sabrina wrote:
> dear all  
>  
>  
> i need help  to understand the audio format in mpeg4 . it may  be with 
> extension acc
>  
> Can i find a coder wich compress me an audio file to ACC file
> and if it exist where can i find it
>  
> think  you  :)
>  
>  
> 
> 
> ------------------------------------------------------------------------
> Do You Yahoo!? -- Une adresse @yahoo.fr gratuite et en français !
> Testez le nouveau Yahoo! Mail <http://fr.mail.yahoo.com>
> 
> 
> ------------------------------------------------------------------------
> 
> _______________________________________________
> Mp4-tech mailing list
> Mp4-tech lists.mpegif.org
> http://lists.mpegif.org/mailman/listinfo/mp4-tech

Sabrina,
there is no such thing as an mpeg4 aac file format. With regard to mpeg4, the 
mpeg4 file format is usually used to store aac content. Beside this, there is 
the legacy format adif (audio data interchange format) as specified for MPEG-2 
AAC and reused in MPEG-4 Audio (but this allows the storage of AAC Main, AAC LC, 
AAC SSR and AAC LTP only). Beside this, there might be raw aac files around 
(with no header at all), but they are rather useless unless you know at least 
the sampling rate used during encoding.
You can download the audio reference software here: 
http://www.iso.ch/iso/en/ittf/PubliclyAvailableStandards/ISO_IEC_14496-5_2001_Software_Reference/
It comes with AAC encoder and decoder. Both encoder and decoder support the raw 
format (if you encode the file, you know the sampling frequency and hence you 
will be able to decode it). Please refer to my e-mails sent some days ago to 
this reflector toward questions on how to use this software.
Note, that the software is written to be understood by someone skilled in the 
art. It has definitely not the status of a product, i.e. you cannot expect that 
it runs out of the box at your computer system, and you even cannot expect that 
everything there is self-explaining.
Best regards,
Ralph
-- 
Dipl.-Ing. Ralph Sperschneider  | Phone: +49 9131 776 344
FhG IIS                         | Fax:   +49 9131 776 398
Am Wolfsmantel 33               | mailto:sps iis.fhg.de
D 91058 Erlangen                | http://www.iis.fhg.de/amm/