[vdr] Low volume on Pro7 ?

Dr. Werner Fink werner at suse.de
Mon Jun 13 16:43:23 CEST 2005


On Mon, Jun 13, 2005 at 04:08:47PM +0200, Prakash Punnoor wrote:
> 
> But what do you want to tell me? You are right or me? I am not an audio
> expert, but if I may quote following, I think it rather backs me up, as AFAIk
> noise shaping is a form of dithering, too. I understand:
> 
> 96kHz, 20 bit pcm ~ SACD ~ 96kHz, 16 bit pcm w/ noise shaping

IMHO you do not get bak the exact original shape/wave form regardless
how good the dithering is.  What you can do is IMHO a mostly perfect
guessing how it may look like at recording time and before quantization.
This is somewhat of a higher art of fitting.

> So dithering does help to reduce noise levels. Or did I completely
> misunderstand anything?

It helps to get the signal noise ratio as low as possible to avoid
the requantization noise.

> I am not suggesting to add dither later to a signal, but if you have a 20bit
> source and dither down to 16bit, you will have a better signal than 16 bit
> truncated/rounded - which was my original claim.

Hmmm ... IMHO the problem is: You may restore at most the original
wave form, nevertheless you are never sure that you find the correct
one without the ``forgotten'' information.


         Werner


-- 
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Howto http://www.vdr-portal.de/board/thread.php?threadid=1958
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