add preamp to EQ

backend/app.go

@@ -186,6 +186,7 @@ func (a *App) setupMPV() error {
 	a.Player.SetAudioExclusive(a.Config.LocalPlayback.AudioExclusive)
 
 	eq := &player.ISO15BandEqualizer{
+		EQPreamp: a.Config.LocalPlayback.EqualizerPreamp,
 		Disabled: !a.Config.LocalPlayback.EqualizerEnabled,
 	}
 	copy(eq.BandGains[:], a.Config.LocalPlayback.GraphicEqualizerBands)

backend/config.go

@@ -75,6 +75,7 @@ type LocalPlaybackConfig struct {
 	InMemoryCacheSizeMB   int
 	Volume                int
 	EqualizerEnabled      bool
+	EqualizerPreamp       float64
 	GraphicEqualizerBands []float64
 }
 
@@ -158,6 +159,7 @@ func DefaultConfig(appVersionTag string) *Config {
 			InMemoryCacheSizeMB:   30,
 			Volume:                100,
 			EqualizerEnabled:      false,
+			EqualizerPreamp:       0,
 			GraphicEqualizerBands: make([]float64, 15),
 		},
 		Scrobbling: ScrobbleConfig{

player/equalizer.go

@@ -10,6 +10,7 @@ import (
 
 type Equalizer interface {
 	IsEnabled() bool
+	Preamp() float64
 	Curve() EqualizerCurve
 	Type() string
 	// Returns the band frequencies as strings friendly for display
@@ -18,6 +19,7 @@ type Equalizer interface {
 
 type ISO15BandEqualizer struct {
 	Disabled  bool
+	EQPreamp  float64
 	BandGains [15]float64
 }
 
@@ -32,6 +34,10 @@ func (i *ISO15BandEqualizer) IsEnabled() bool {
 	return !i.Disabled
 }
 
+func (i *ISO15BandEqualizer) Preamp() float64 {
+	return i.EQPreamp
+}
+
 func (i *ISO15BandEqualizer) Curve() EqualizerCurve {
 	fC := float64(25)
 	curve := make([]EqualizerBand, 0, len(i.BandGains))

player/player.go

@@ -5,6 +5,7 @@ import (
 	"errors"
 	"fmt"
 	"log"
+	"math"
 	"strconv"
 
 	"github.com/dweymouth/go-mpv"
@@ -507,7 +508,17 @@ func (p *Player) SetEqualizer(eq Equalizer) error {
 	if eq == nil || !eq.IsEnabled() {
 		return p.mpv.SetPropertyString("af", "")
 	}
-	return p.mpv.SetPropertyString("af", eq.Curve().String())
+	af := ""
+	if math.Abs(eq.Preamp()) > 0.01 {
+		af = fmt.Sprintf("volume=volume=%0.1fdB", eq.Preamp())
+	}
+	eqAF := eq.Curve().String()
+	if af == "" {
+		af = eqAF
+	} else if eqAF != "" {
+		af = fmt.Sprintf("%s,%s", af, eqAF)
+	}
+	return p.mpv.SetPropertyString("af", af)
 }
 
 func (p *Player) Equalizer() Equalizer {

ui/controller/controller.go

@@ -464,6 +464,7 @@ func (c *Controller) ShowSettingsDialog(themeUpdateCallbk func(), themeFiles map
 		// currently we only have one equalizer type
 		eq := c.App.Player.Equalizer().(*player.ISO15BandEqualizer)
 		eq.Disabled = !c.App.Config.LocalPlayback.EqualizerEnabled
+		eq.EQPreamp = c.App.Config.LocalPlayback.EqualizerPreamp
 		copy(eq.BandGains[:], c.App.Config.LocalPlayback.GraphicEqualizerBands)
 		c.App.Player.SetEqualizer(eq)
 	}

ui/dialogs/graphicequalizer.go

@@ -15,19 +15,20 @@ type GraphicEqualizer struct {
 	widget.BaseWidget
 
 	OnChanged       func(band int, gain float64)
+	OnPreampChanged func(gain float64)
 
 	container *fyne.Container
 }
 
-func NewGraphicEqualizer(bandFreqs []string, bandGains []float64) *GraphicEqualizer {
+func NewGraphicEqualizer(preamp float64, bandFreqs []string, bandGains []float64) *GraphicEqualizer {
 	g := &GraphicEqualizer{}
 	g.ExtendBaseWidget(g)
-	g.buildSliders(bandFreqs, bandGains)
+	g.buildSliders(preamp, bandFreqs, bandGains)
 
 	return g
 }
 
-func (g *GraphicEqualizer) buildSliders(bands []string, bandGains []float64) {
+func (g *GraphicEqualizer) buildSliders(preamp float64, bands []string, bandGains []float64) {
 	rng := container.NewVBox(
 		newCaptionTextSizeLabel("+12", fyne.TextAlignTrailing),
 		layout.NewSpacer(),
@@ -35,7 +36,16 @@ func (g *GraphicEqualizer) buildSliders(bands []string, bandGains []float64) {
 		layout.NewSpacer(),
 		newCaptionTextSizeLabel("-12", fyne.TextAlignTrailing),
 	)
-	bandSliders := container.New(layouts.NewGridLayoutWithColumnsAndPadding(16, -16))
+	bandSliders := container.New(layouts.NewGridLayoutWithColumnsAndPadding(len(bands)+2, -16))
+	pre := newCaptionTextSizeLabel("Pre", fyne.TextAlignCenter)
+	preampSlider := newEQSlider()
+	preampSlider.SetValue(preamp)
+	preampSlider.OnChanged = func(f float64) {
+		if g.OnPreampChanged != nil {
+			g.OnPreampChanged(f)
+		}
+	}
+	bandSliders.Add(container.NewBorder(nil, pre, nil, nil, preampSlider))
 	bandSliders.Add(container.NewBorder(nil, widget.NewLabel(""), nil, nil, rng))
 	for i, band := range bands {
 		s := newEQSlider()
@@ -55,7 +65,7 @@ func (g *GraphicEqualizer) buildSliders(bands []string, bandGains []float64) {
 	}
 	g.container = container.NewMax(
 		container.NewBorder(nil, widget.NewLabel(""), nil, nil,
-			container.NewBorder(nil, nil, util.NewHSpace(35), util.NewHSpace(5),
+			container.NewBorder(nil, nil, util.NewHSpace(5), util.NewHSpace(5),
 				container.NewVBox(
 					layout.NewSpacer(),
 					myTheme.NewThemedRectangle(theme.ColorNameInputBackground),

ui/dialogs/settingsdialog.go

@@ -337,8 +337,10 @@ func (s *SettingsDialog) createEqualizerTab(eqBands []string) *container.TabItem
 		}
 	})
 	enabled.Checked = s.config.LocalPlayback.EqualizerEnabled
-	geq := NewGraphicEqualizer(eqBands, s.config.LocalPlayback.GraphicEqualizerBands) // TODO: This should probably be an argument?
+	geq := NewGraphicEqualizer(s.config.LocalPlayback.EqualizerPreamp,
-	debouncer := util.NewDebouncer(200*time.Millisecond, func() {
+		eqBands,
+		s.config.LocalPlayback.GraphicEqualizerBands)
+	debouncer := util.NewDebouncer(350*time.Millisecond, func() {
 		if s.OnEqualizerSettingsChanged != nil {
 			s.OnEqualizerSettingsChanged()
 		}
@@ -347,6 +349,10 @@ func (s *SettingsDialog) createEqualizerTab(eqBands []string) *container.TabItem
 		s.config.LocalPlayback.GraphicEqualizerBands[b] = g
 		debouncer()
 	}
+	geq.OnPreampChanged = func(g float64) {
+		s.config.LocalPlayback.EqualizerPreamp = g
+		debouncer()
+	}
 	cont := container.NewBorder(container.NewHBox(enabled), nil, nil, nil, geq)
 	return container.NewTabItem("Equalizer", cont)
 }