MP-man po cesku ??? (MPEG 2.5)

[Puskajler Robert]

Zdravim,


>PS: Nevi nekdo co je to Mpeg Layer 2.5 ?

vyberam priamo z FAQ:
(http://www.iis.fhg.de/amm/techinf/layer3/layer3faq/index.html)

Q: In your footnotes, you indicate the use of some "non-ISO" 
extension inside your Fraunhofer codec, called "MPEG 2.5", 
to further improve the performance at very low bitrates 
(e.g. 8 kbps mono). What do you mean by this?   

 A: Oh, yes. Well, the MPEG-2 standard allows bitrates as low 
as 8 kbps, for the low sample rate extension. At such a low bitrate, 
the useful audio bandwidth has to be limited anyway, e.g. to 3 kHz. 
Therefore, the actual sample rate could be reduced, e.g. to 8 kHz. 
The lower the sample rate, the better the frequency resolution, 
the worse the time resolution, and the better the ratio between 
control information and audio payload inside the bitstream format. 
As the MPEG-2 standard defines 16 kHz as lowest sample rate, 
we introduced a further extension, again dividing the low sample 
rates of MPEG-2 by 2, i.e. we introduced 8, 11.025, and 
12 kHz - and we named this extension to the extension "MPEG 2.5". 
"Layer-3" performs significantly better with 8 kbps @ 8 kHz or 
16 kbps @ 11 kHz than with 8 or 16 kbps @ 16 kHz.  


Puskajler Robert