Re: [LAU] How bad is mp3/ogg

On 10/11/2011 11:36 PM, Fons Adriaensen wrote:

> There are at least two good reasons why such a test is
> not valid.
>
> 1. The difference signal doesn't tell you anything about
> audible differences between two signals. It's fairly easy
> to make a linear filter (no compression involved) with
> a perfectly flat response and that nobody would be able
> to hear. But when you take the difference between in and
> out it is 3 dB higher than both.
>
> 2. Lossy compression is based on combined temporal and
> spectral masking - some signals you can't hear in the
> presence of others. Of course when you take away the
> masking signal they become apparent...

Makes a lot of sense, thanks!

BTW: Apparently the guy in the link has lifted the idea from this clip:

http://www.youtube.com/watch?v=wzJbjHc6bRE

where George Massenburg does the same. I don't know George Massenburg,
but he supposedly is some kine of authority in the world of audio
engineering. Not that it makes the test more valid...

-- 
Atte
http://atte.dk   http://modlys.dk
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