| Dear Victor,
Once again thanks for the great instruments!! I am very excited about
these new pvs opcodes and cannot wait to try them out...
Many thanks
Peiman
On 15 May 2006, at 10:08, Victor Lazzarini wrote:
> Dear all,
>
> I have added two new streaming pv opcodes to csound5 CVS,
> which will be included in the upcoming (5.02) binary release next
> week. For those of you using cvs, you can check them out straight
> away.
>
> The opcodes are pvsfreeze, which, as requested on this list, freezes
> the spectral evolution of an input, and pvsmooth, which smooths
> the amp & freq spectral functions over time.
>
> Here's the summary:
>
> ===================================================
> pvsfreeze
>
> This opcodes 'freezes' the evolution of pvs stream by locking into
> steady amplitude and/or
> frequency values for each bin. The freezing is controlled,
> independently for amplitudes and
> frequencies, by a control-rate trigger, which switches the freezing
> 'on' if equal to or above
> 1 and 'off' if below 1.
>
> fsig pvsfreeze fsigin, kfreeza, kfreezf
>
> fsig -- output pv stream
> fsigin -- input pv stream.
> kfreeza -- freezing switch for amplitudes. Freezing is on if
> above or equal to 1 and off if below 1.
> kfcf -- freezing switch for frequencies. Freezing is on if above
> or equal to 1 and off if below 1.
>
> ========================================================
> pvsmooth
>
> Smooth the amplitude and frequency time functions of a pv stream
> using a 1st order
> lowpass IIR with time-varying cutoff frequency. This opcode uses
> the same filter
> as the 'tone' opcode, but this time acting separately on the
> amplitude and frequency
> time functions that make up a pv stream. The cutoff frequency
> parameter runs at the
> control-rate, but unlike tone and tonek, it is not specified in Hz,
> but as fractions
> of 1/2 frame-rate (actually the pv stream sampling rate), which is
> easier to
> understand. This means that the highest cutoff frequency is 1 and
> the lowest 0; the lower
> the frequency the smoother the functions and more pronounced the
> effect will be. This
> opcode produces effects that are more or less similar to pvsblur,
> but with two important
> differences: 1.smoothing of amplitudes and frequencies use separate
> sets of filters; and 2. there is
> no increase in computational cost when higher amounts of
> 'blurring' (smoothing) are desired.
>
> fsig pvsmooth fsigin, kacf, kfcf
>
> fsig -- output pv stream
> fsigin -- input pv stream.
> kacf -- amount of cutoff frequency for amplitude function
> filtering, between 0 and 1,
> in fractions of 1/2 frame-rate.
> kfcf -- amount of cutoff frequency for frequency function
> filtering, between 0 and 1,
> in fractions of 1/2 frame-rate.
>
>
>
> Victor Lazzarini
> Music Technology Laboratory
> Music Department
> National University of Ireland, Maynooth
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