Re: MPEG audio

It seems that MPEG-2 AAC is not like MPEG-2 bitstreams. And so MPEG-4 
AAC as well :

 From http://www.aac-audio.com/technology/ :
'When AAC was first developed, it was sometimes referred to as "MPEG-2 
NBC" for "not backwards compatible."'

Interresting page :
http://www.tnt.uni-hannover.de/project/mpeg/audio/faq/mpeg2.html#2-9

What is the status of the standardisation process?

MPEG-2 was finalised in 1994 and resulted in the International Standard 
ISO/IEC 13818-3 which was published in 1995. MPEG-2 AAC was finalised in 
1997 and published as the International Standard ISO/IEC 13818-7.

Where can I find information on MPEG-2 licensing?

Information on licensing of MPEG-2 Layer I and Layer II can be found at:
http://www.audiompeg.com/     (SISVEL, Italy)
http://www.licensing.philips.com/information/mpeg/

Information on licensing of MPEG-2 Layer III can be found at:
http://www.mp3licensing.com/
http://www.iis.fhg.de/amm/legal/index.html

Information on licensing of MPEG AAC can be found at:
http://www.aac-audio.com/     (e-mail: [email protected])

AND ALSO :

MPEG-2 AAC on the contrary leaves the choice of audio transport syntax 
to the application, standardizing only the format of the encoded audio 
data. In addition, two typical examples of transport syntax have also 
been standardized:

     * ADIF = Audio Data Interchange Format
       The audio bitstream contains one single header with all 
information necessary to control the decoder such as the bitrate, the 
sampling frequency or the stereo mode. The main application of ADIF is 
exchange of audio files.
     * ADTS = Audio Data Transport Stream
The audio bitstream consists of a sequence of frames with headers 
similar to MPEG-1 audio frame headers. The encoded audio data of one 
frame is always contained between two sync words. The number of bits in 
a frame however can be variable.