[FFmpeg-devel] [PATCH] AC3 volume options

Michael Niedermayer michaelni
Sun Dec 16 23:38:09 CET 2007

On Sun, Dec 16, 2007 at 05:21:42PM -0500, Justin Ruggles wrote:
> Michael Niedermayer wrote:
> > On Sun, Dec 16, 2007 at 10:20:12AM -0500, Justin Ruggles wrote:
> > [...]
> >> I like Andreas' suggestion to make the dialog normalization value more
> >> universal.  I think a floating-point decibel value for the dialog level
> >> would be appropriate.
> > 
> > i think a simple float scale factor is a better choice, its more readily
> > useable than a value in decibel
> > that is 
> > sample[x] * factor 
> > vs.
> > sample[x] * pow(10, decibel/10)
> Personally, I think it's more intuitive in decibels because it's not a
> scale factor to be applied to output, but rather a comparison between
> dialog level and maximum level.  To say that the dialog level is the
> maximum level * 0.028 makes less sense to me than to say that the dialog
> level is 31 decibels below the maximum level.

so you suggest to use the string "31db" instead of a float?
because "31db" is 0.028 or some other such value
anyway i wont fight on this but you will have to provide whatever is needed
to gurantee binary identical behavior with db scale (i dont think log/pow/exp
are binary identical between architectures and that would break any regression
tests involving normalization to dialog level) 

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

I am the wisest man alive, for I know one thing, and that is that I know
nothing. -- Socrates
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