[music-dsp] Help (Mac): How to remove (bass) clipping

[Sampo Syreeni]

On Thu, 31 May 2001, Davor Pavuna wrote:

>... and, the answer seems to be: No, Santa Claus is not for real :-)

Actually this is quite an interesting problem, and I'm not satisfied that
the distortion could not indeed be mitigated.

If any fullscale values are taken as a sign of clipping, and there aren't
too many of those, one might consider this an instance of an interpolation
problem. Simply put, instead of considering the fullscale values as part of
the signal, you remove the instants of time when they occur from its domain,
and try to extend (interpolate) the newly restricted function to all
instants of time, minimizing some error measure. In this case we even have
some extra information, like the fact that all the interpolated values will
be beyond the appropriate fullscale value, and that the resulting function
will have to be bandlimited.

If we utilize all the knowledge we have about the possible values taken by
the interpolated signal, we will likely end up with a nasty nonlinear
interpolation formula, best solved by an iterative method. So it might be
sensible to start with something a bit less difficult, like a Chebyshev
approximation. Any ideas, anyone?

Sampo Syreeni, aka decoy, mailto:decoy at iki.fi, gsm: +358-50-5756111
student/math+cs/helsinki university, http://www.iki.fi/~decoy/front


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