Le 2011-10-22 à 15:29:00, martin brinkmann a écrit :
On 10/22/2011 02:39 PM, saskia diez wrote:
I just discover this since i bought a nice speakers, before i havent realize that sound editors add that hiss.
i could hardly believe that, but you are right! i have just created a file with writesf~, ensured that it contained only zeros (hexeditor), loaded it in audacity, exported as 16bit wav, and after normalizing, there was a lot of noise.
How much is a lot ? What's the amplitude in the noise ? If it's something like 1/65536 of the maximum level, that's not what I'd call « a lot »...
It could appear because of different conceptions of where the home volume is. Lots of code assumes that in a range going from -32768 to +32767, the middle is 0 ; but it's also possible to assume that the middle is -½, which is the average of -32768 and +32767. The latter makes it impossible to make a completely empty signal. However, that signal is still DC. It needs some kind of misinterpretation of 0 (using two different conceptions at once) to think that 0 really means ½ and that ½ has to be dithered because it's not a whole number.
Personally, I don't understand what's the point of dither in audio. Maybe it's just an evil plot to make CD quality sound like 8-track cartridges.
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