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Re: [fluid-dev] Purpose of dither?
From: |
Z F |
Subject: |
Re: [fluid-dev] Purpose of dither? |
Date: |
Fri, 11 May 2007 07:38:54 -0700 (PDT) |
--- Miguel Lobo <address@hidden> wrote:
>
> I'm with Mihail on this one: turning off dithering would serve no
> purpose.
> The moment you truncate certain signals without dithering you will be
> introducing high-energy harmonics and nothing you do later will get
> rid of
> them. Therefore, if you are going to truncate, you *always* want
> dithering.
It does not matter if you add random float to a float and truncate or
trancate and add a random bit, the outcome will be exactly the same
sequence of bits so it does not matter, you can always add dither
later.
Write it out...
trun(signal + noise) = trun(signal) + noise'
notice that noise' is not the same as noise, but the equality holds
so one can do what can not be done -- remove undesired harmonic
after truncation. (Or more specifically, for every noise you add before
truncation there exists a noise which can be added after truncation,
such that the equality holds. This follows from the properties of the
plus operation.)
Thus, my point --- do it at the last stage, otherwise you will be
dithering the noise too, which I do not think is the goal.
In other words,
SoundEffect(SoundEffect(signal)) + noise
is better than
SoundEffect(SoundEffect(signal+noise)+noise) + noise
See the difference? more noise in the latter case...
ZF
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- Re: [fluid-dev] Purpose of dither?, (continued)
- Re: [fluid-dev] Purpose of dither?, Josh Green, 2007/05/09
- Re: [fluid-dev] Purpose of dither?, Mihail Zenkov, 2007/05/09
- Re: [fluid-dev] Purpose of dither?, Z F, 2007/05/09
- Re: [fluid-dev] Purpose of dither?, Mihail Zenkov, 2007/05/10
- Re: [fluid-dev] Purpose of dither?, Z F, 2007/05/10
- Re: [fluid-dev] Purpose of dither?, Edenyard, 2007/05/10
- Re: [fluid-dev] Purpose of dither?, Z F, 2007/05/10
- Re: [fluid-dev] Purpose of dither?, Josh Green, 2007/05/11
- Re: [fluid-dev] Purpose of dither?, Z F, 2007/05/11
- Re: [fluid-dev] Purpose of dither?, Miguel Lobo, 2007/05/11
- Re: [fluid-dev] Purpose of dither?,
Z F <=
- Re: [fluid-dev] Purpose of dither?, Miguel Lobo, 2007/05/11
- Re: [fluid-dev] Purpose of dither?, Z F, 2007/05/11
- Re: [fluid-dev] Purpose of dither?, Miguel Lobo, 2007/05/11
- Re: [fluid-dev] Purpose of dither?, Z F, 2007/05/11
- Re: [fluid-dev] Purpose of dither?, Miguel Lobo, 2007/05/12
- Re: [fluid-dev] Purpose of dither?, Mihail Zenkov, 2007/05/11
- Re: [fluid-dev] Purpose of dither?, Mihail Zenkov, 2007/05/11