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5684185+vsariola@users.noreply.github.com
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commit
655d736149
@ -18,13 +18,12 @@ type (
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SpecAnSettings struct {
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ChnMode SpecChnMode
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Smooth SpecSmoothing
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Smooth int
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Resolution int
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}
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SpecChnMode int
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SpecSmoothing int
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Spectrum [2][]float32
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SpecChnMode int
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Spectrum [2][]float32
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specTemp struct {
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power [2][]float32
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@ -42,38 +41,24 @@ type (
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)
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const (
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SpecResolutionMin = 7
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SpecResolutionMax = 16
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SpecResolutionMin = -3
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SpecResolutionMax = 3
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)
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const (
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SpecChnModeOff SpecChnMode = iota // no spectrum analysis is done to save CPU resources
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SpecChnModeCombine // calculate a single combined spectrum for both channels
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SpecSpeedMin = -3
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SpecSpeedMax = 3
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)
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const (
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SpecChnModeSum SpecChnMode = iota // calculate a single combined spectrum for both channels
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SpecChnModeSeparate // calculate separate spectrums for left and right channels
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NumSpecChnModes
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)
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const (
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SpecSmoothingMedium SpecSmoothing = iota
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SpecSmoothingFast
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SpecSmoothingSlow
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NumSpecSmoothing
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)
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var spectrumSmoothingMap map[SpecSmoothing]float32 = map[SpecSmoothing]float32{
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SpecSmoothingSlow: 0.1,
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SpecSmoothingMedium: 0.2,
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SpecSmoothingFast: 0.4,
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}
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func NewSpecAnalyzer(broker *Broker) *SpecAnalyzer {
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ret := &SpecAnalyzer{broker: broker}
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ret.init(SpecAnSettings{
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ChnMode: SpecChnModeCombine,
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Smooth: SpecSmoothingMedium,
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Resolution: 10,
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})
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ret.init(SpecAnSettings{})
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return ret
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}
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@ -87,23 +72,28 @@ func (m *Model) BiquadCoeffs() (coeffs BiquadCoeffs, ok bool) {
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case "filter":
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p := m.d.Song.Patch[i].Units[u].Parameters
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f := float32(p["frequency"]) / 128
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res := float32(p["resonance"]) / 128
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f2 := f * f
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g := f2 / (2 - f2)
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a1 := 2 * (g*g - 1)
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a2 := (1 - g*(g-res))
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f *= f
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r := float32(p["resonance"]) / 128
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// in state-space, the filter has the form:
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// s(n+1) = A*s(n)+B*u, where A = [1 f;-f 1-f*r-f*f] and B = [0;f]
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// y(n) = C*s(n)+D*u, where
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// C = [low band]
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//
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// The transfer function is then H(z) = C*(zI-A)^-1*B + D
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// z*I-A = [z-1 -f; f z+f*r+f*f-1]
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// Invert it:
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// (z*I-A)^-1 = 1/det * [z+f*r+f*f-1 f; -f z-1], where det = (z-1)*(z+f*r+f*f-1)+f^2 = z^2 + z * (f*r+f*f−2) + 1-f*r
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// (z*I-A)^-1*B = 1/det * [-f*f; f*z-f]
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var a0 float32 = 1
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var a1 float32 = r*f + f*f - 2
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var a2 float32 = 1 - r*f
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var b0, b1, b2 float32
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if p["low"] == 1 {
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b0 += g * g
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b1 += 2 * g * g
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b2 += g * g
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if p["lowpass"] == 1 {
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b2 = -f * f
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}
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b0 += float32(p["high"])
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b1 += -2 * float32(p["high"])
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b2 += float32(p["high"])
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b0 += g * float32(p["band"])
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b2 += -g * float32(p["band"])
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return BiquadCoeffs{a0: 1, a1: a1, a2: a2, b0: b0, b1: b1, b2: b2}, true
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b2 -= f * float32(p["bandpass"])
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b1 += f * float32(p["bandpass"])
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return BiquadCoeffs{a0: a0, a1: a1, a2: a2, b0: b0, b1: b1, b2: b2}, true
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case "belleq":
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f := float32(m.d.Song.Patch[i].Units[u].Parameters["frequency"]) / 128
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band := float32(m.d.Song.Patch[i].Units[u].Parameters["bandwidth"]) / 128
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@ -149,14 +139,12 @@ func (s *SpecAnalyzer) handleMsg(msg MsgToSpecAn) {
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}
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switch m := msg.Data.(type) {
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case *sointu.AudioBuffer:
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if s.settings.ChnMode != SpecChnModeOff {
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buf := *m
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l := len(s.temp.window)
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// 50% overlap with the windows
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s.chunker.Process(buf, l, l>>1, func(chunk sointu.AudioBuffer) {
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TrySend(s.broker.ToModel, MsgToModel{Data: s.update(chunk)})
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})
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}
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buf := *m
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l := len(s.temp.window)
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// 50% overlap with the windows
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s.chunker.Process(buf, l, l>>1, func(chunk sointu.AudioBuffer) {
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TrySend(s.broker.ToModel, MsgToModel{Data: s.update(chunk)})
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})
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s.broker.PutAudioBuffer(m)
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default:
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// unknown message type; ignore
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@ -164,7 +152,7 @@ func (s *SpecAnalyzer) handleMsg(msg MsgToSpecAn) {
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}
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func (a *SpecAnalyzer) init(s SpecAnSettings) {
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s.Resolution = min(max(s.Resolution, SpecResolutionMin), SpecResolutionMax)
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s.Resolution = min(max(s.Resolution, SpecResolutionMin), SpecResolutionMax) + 10
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a.settings = s
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n := 1 << s.Resolution
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a.temp = specTemp{
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@ -205,7 +193,7 @@ func (s *SpecAnalyzer) update(buf sointu.AudioBuffer) *Spectrum {
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s.process(buf, 1)
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ret[0] = append(ret[0], s.temp.power[0]...)
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ret[1] = append(ret[1], s.temp.power[1]...)
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case SpecChnModeCombine:
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case SpecChnModeSum:
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s.process(buf, 0)
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s.process(buf, 1)
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ret[0] = append(ret[0], s.temp.power[0]...)
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@ -260,7 +248,7 @@ func (sd *SpecAnalyzer) process(buf sointu.AudioBuffer, channel int) {
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vek32.MulNumber_Inplace(t2[:m-1], 2)
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// calculate difference to current spectrum and add back, multiplied by smoothing factor
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vek32.Sub_Inplace(t2, sd.temp.power[channel])
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alpha := spectrumSmoothingMap[sd.settings.Smooth]
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alpha := float32(math.Pow(2, float64(sd.settings.Smooth-SpecSpeedMax)))
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vek32.MulNumber_Inplace(t2, alpha)
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vek32.Add_Inplace(sd.temp.power[channel], t2)
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}
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