SV: [speex-dev] Some simple questions

[Jean-Marc Valin]

It would probably *work*, but it would also be twice as slow as using
compiler-generated float emulation. 

        Jean-Marc

Le jeu 25/09/2003 à 21:33, Jonas Tärnström a écrit :
> Maybe this is plain stupid or off topic.
> Could an atleast working fixed-point implementation of Speex be made by
> using a C++ "faked float" class with overloaded operators?
> 
> Don't know if this is a common way to solve stuff like this, but my
> guess is that it would work.
> 
> //Best Regards, Jonas Tärnström.
> 
> 
> > > So just how much work are we talking about, here, to convert to
> fixed-
> > point?
> > > Seems like with some clever type substitution and a few inlines here
> and
> > > there it might maybe not be so horrible?  But, then, I haven't
> looked
> > inside
> > > of Speex yet, and don't have a sense of scale...
> > 
> > That's not as simple. With floating point, you can take any two
> numbers,
> > multiply them together and not risk an overflow (not quite but it's
> true
> > in the context of Speex). With integers, that's not the case. You have
> > to know the range for all the inputs and then (usually) do some
> shifting
> > according to that.
> > 
> > My estimation is that it would probably require in the order of 100
> > hours for someone (with prior experience) to convert Speex to
> > fixed-point. Anyone is up to the task?
> > 
> > 	Jean-Marc
> > 
> > --
> > Jean-Marc Valin, M.Sc.A., ing. jr.
> > LABORIUS (http://www.gel.usherb.ca/laborius)
> > Université de Sherbrooke, Québec, Canada
> 
> 
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-- 
Jean-Marc Valin, M.Sc.A., ing. jr.
LABORIUS (http://www.gel.usherb.ca/laborius)
Université de Sherbrooke, Québec, Canada


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