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Fix for bug 849. Validates user selected frequency in Spectral Edit plugins to prevent Nyquist applying invalid frequency (greater than Nyquist frequency) parameters to filters.

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This does not address the broader question of how Spectral Selection should handle multiple sample rates.
This commit is contained in:
stevethefiddle@gmail.com
2015-02-02 01:46:34 +00:00
parent abda1166de
commit 2e562600af
3 changed files with 79 additions and 46 deletions
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39
plug-ins/SpectralEditShelves.ny
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@@ -17,6 +17,10 @@
(setf control-gain (min 24 (max -24 control-gain))) ; excessive settings may crash
(defmacro validate (hz)
"Ensure frequency is below Nyquist"
`(setf hz (min (/ *sound-srate* 2.0),hz)))
(defun mid-shelf (sig lf hf gain)
"Combines high shelf and low shelf filters"
(let* ((invg (- gain)))
@@ -24,38 +28,47 @@
(eq-highshelf (eq-lowshelf sig lf invg)
hf invg))))
(defun wet (sig gain)
(let ((f0 (get '*selection* 'low-hz))
(f1 (get '*selection* 'high-hz)))
(cond
((not (or f0 f1))
(throw 'debug-message (format nil "~aPlease select frequencies." p-err)))
((not f0) (eq-lowshelf sig f1 gain))
((not f1) (eq-highshelf sig f0 gain))
(t (mid-shelf sig f0 f1 gain)))))
(defun wet (sig gain f0 f1)
(cond
((not f0) ;low-shelf
(if (< f1 (/ *sound-srate* 2.0))
(eq-lowshelf sig f1 gain)
(mult sig gain))) ;frequency above Nyquist so amplify full spectrum
((not f1) (eq-highshelf sig f0 gain))
(t (mid-shelf sig f0 (validate f1) gain))))
(defun result (sig)
(let*
((tn (truncate len))
((f0 (get '*selection* 'low-hz))
(f1 (get '*selection* 'high-hz))
(tn (truncate len))
(rate (snd-srate sig))
(transition (truncate (* 0.01 rate))) ; 10 ms
(t1 (min transition (/ tn 2))) ; fade in length (samples)
(t2 (max (- tn transition) (/ tn 2))) ; length before fade out (samples)
(breakpoints (list t1 1.0 t2 1.0 tn))
(env (snd-pwl 0.0 rate breakpoints)))
(sum (prod env (wet sig control-gain)) (prod (diff 1.0 env) sig))))
(cond
((not (or f0 f1))
(throw 'error-message (format nil "~aPlease select frequencies." p-err)))
((and f0 f1 (= f0 f1)) (throw 'error-message
"Please select a frequency range."))
; shelf is above Nyquist frequency so do nothing
((and f0 (>= f0 (/ *sound-srate* 2.0))) nil)
(T (sum (prod env (wet sig control-gain f0 f1))
(prod (diff 1.0 env) sig))))))
(cond
((not (get '*TRACK* 'VIEW)) ; 'View is NIL during Preview
(setf p-err (format nil "This effect requires a frequency selection in the~%~
'Spectrogram' or 'Spectrogram (log f)' track view.~%~%"))
(catch 'debug-message
(catch 'error-message
(multichan-expand #'result *track*)))
((string-not-equal (get '*TRACK* 'VIEW) "spectrogram" :end1 4 :end2 4)
"Use this effect in the 'Spectrogram'\nor 'Spectrogram (log f)' view.")
(T (setf p-err "")
(if (= control-gain 0) ; Allow dry preview
"Gain is zero. Nothing to do."
(catch 'debug-message
(catch 'error-message
(multichan-expand #'result *track*)))))