add preamp to EQ

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 {