feat: Add audio equalizer with UI

app/src/main/java/com/cappielloantonio/tempo/service/EqualizerManager.kt

@@ -0,0 +1,47 @@
+package com.cappielloantonio.tempo.service
+
+import android.media.audiofx.Equalizer
+
+class EqualizerManager {
+
+    private var equalizer: Equalizer? = null
+
+    fun attachToSession(audioSessionId: Int): Boolean {
+        release()
+        if (audioSessionId != 0 && audioSessionId != -1) {
+            try {
+                equalizer = Equalizer(0, audioSessionId).apply {
+                    enabled = true
+                }
+                return true
+            } catch (e: Exception) {
+                // Some devices may not support Equalizer or audio session may be invalid
+                equalizer = null
+            }
+        }
+        return false
+    }
+
+    fun setBandLevel(band: Short, level: Short) {
+        equalizer?.setBandLevel(band, level)
+    }
+
+    fun getNumberOfBands(): Short = equalizer?.numberOfBands ?: 0
+
+    fun getBandLevelRange(): ShortArray? = equalizer?.bandLevelRange
+
+    fun getCenterFreq(band: Short): Int? =
+        equalizer?.getCenterFreq(band)?.div(1000)
+
+    fun getBandLevel(band: Short): Short? =
+        equalizer?.getBandLevel(band)
+
+    fun setEnabled(enabled: Boolean) {
+        equalizer?.enabled = enabled
+    }
+
+    fun release() {
+        equalizer?.release()
+        equalizer = null
+    }
+}

app/src/main/java/com/cappielloantonio/tempo/ui/fragment/EqualizerFragment.kt

@@ -0,0 +1,225 @@
+package com.cappielloantonio.tempo.ui.fragment
+
+import android.content.ComponentName
+import android.content.Context
+import android.content.Intent
+import android.content.ServiceConnection
+import android.os.Bundle
+import android.os.IBinder
+import android.view.Gravity
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import android.widget.*
+import androidx.annotation.OptIn
+import androidx.fragment.app.Fragment
+import androidx.media3.common.util.UnstableApi
+import com.cappielloantonio.tempo.R
+import com.cappielloantonio.tempo.service.EqualizerManager
+import com.cappielloantonio.tempo.service.MediaService
+import com.cappielloantonio.tempo.util.Preferences
+
+class EqualizerFragment : Fragment() {
+
+    private var equalizerManager: EqualizerManager? = null
+    private lateinit var eqBandsContainer: LinearLayout
+    private lateinit var eqSwitch: Switch
+    private lateinit var resetButton: Button
+    private lateinit var safeSpace: Space
+    private val bandSeekBars = mutableListOf<SeekBar>()
+
+    private val connection = object : ServiceConnection {
+        @OptIn(UnstableApi::class)
+        override fun onServiceConnected(className: ComponentName, service: IBinder) {
+            val binder = service as MediaService.LocalBinder
+            equalizerManager = binder.getEqualizerManager()
+            initUI()
+            restoreEqualizerPreferences()
+        }
+
+        override fun onServiceDisconnected(arg0: ComponentName) {
+            equalizerManager = null
+        }
+    }
+
+    @OptIn(UnstableApi::class)
+    override fun onStart() {
+        super.onStart()
+        Intent(requireContext(), MediaService::class.java).also { intent ->
+            intent.action = MediaService.ACTION_BIND_EQUALIZER
+            requireActivity().bindService(intent, connection, Context.BIND_AUTO_CREATE)
+        }
+    }
+
+    override fun onStop() {
+        super.onStop()
+        requireActivity().unbindService(connection)
+        equalizerManager = null
+    }
+
+    override fun onCreateView(
+        inflater: LayoutInflater, container: ViewGroup?,
+        savedInstanceState: Bundle?
+    ): View? {
+        return inflater.inflate(R.layout.fragment_equalizer, container, false)
+    }
+
+    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
+        super.onViewCreated(view, savedInstanceState)
+        eqBandsContainer = view.findViewById(R.id.eq_bands_container)
+        eqSwitch = view.findViewById(R.id.equalizer_switch)
+        resetButton = view.findViewById(R.id.equalizer_reset_button)
+        safeSpace = view.findViewById(R.id.equalizer_bottom_space)
+    }
+
+    private fun initUI() {
+        val manager = equalizerManager
+        val notSupportedView = view?.findViewById<LinearLayout>(R.id.equalizer_not_supported_container)
+        val switchRow = view?.findViewById<View>(R.id.equalizer_switch_row)
+
+        if (manager == null || manager.getNumberOfBands().toInt() == 0) {
+            switchRow?.visibility = View.GONE
+            resetButton.visibility = View.GONE
+            eqBandsContainer.visibility = View.GONE
+            safeSpace.visibility = View.GONE
+            notSupportedView?.visibility = View.VISIBLE
+            return
+        }
+
+        notSupportedView?.visibility = View.GONE
+        switchRow?.visibility = View.VISIBLE
+        resetButton.visibility = View.VISIBLE
+        eqBandsContainer.visibility = View.VISIBLE
+        safeSpace.visibility = View.VISIBLE
+
+        eqSwitch.setOnCheckedChangeListener(null)
+        eqSwitch.isChecked = Preferences.isEqualizerEnabled()
+        updateUiEnabledState(eqSwitch.isChecked)
+        eqSwitch.setOnCheckedChangeListener { _, isChecked ->
+            manager.setEnabled(isChecked)
+            Preferences.setEqualizerEnabled(isChecked)
+            updateUiEnabledState(isChecked)
+        }
+
+        createBandSliders()
+
+        resetButton.setOnClickListener {
+            resetEqualizer()
+            saveBandLevelsToPreferences()
+        }
+    }
+
+    private fun updateUiEnabledState(isEnabled: Boolean) {
+        resetButton.isEnabled = isEnabled
+        bandSeekBars.forEach { it.isEnabled = isEnabled }
+    }
+
+    private fun createBandSliders() {
+        val manager = equalizerManager ?: return
+        eqBandsContainer.removeAllViews()
+        bandSeekBars.clear()
+        val bands = manager.getNumberOfBands()
+        val bandLevelRange = manager.getBandLevelRange() ?: shortArrayOf(-1500, 1500)
+        val minLevel = bandLevelRange[0].toInt()
+        val maxLevel = bandLevelRange[1].toInt()
+
+        val savedLevels = Preferences.getEqualizerBandLevels(bands)
+        for (i in 0 until bands) {
+            val band = i.toShort()
+            val freq = manager.getCenterFreq(band) ?: 0
+
+            val row = LinearLayout(requireContext()).apply {
+                orientation = LinearLayout.HORIZONTAL
+                layoutParams = LinearLayout.LayoutParams(
+                    LinearLayout.LayoutParams.MATCH_PARENT,
+                    LinearLayout.LayoutParams.WRAP_CONTENT
+                ).apply {
+                    topMargin = 24
+                    bottomMargin = 24
+                }
+                setPadding(0, 8, 0, 8)
+            }
+
+            val freqLabel = TextView(requireContext(), null, 0, R.style.LabelSmall).apply {
+                text = if (freq >= 1000) {
+                    if (freq % 1000 == 0) {
+                        "${freq / 1000} kHz"
+                    } else {
+                        String.format("%.1f kHz", freq / 1000f)
+                    }
+                } else {
+                    "$freq Hz"
+                }
+                width = 120
+            }
+            row.addView(freqLabel)
+
+            val initialLevel = savedLevels.getOrNull(i) ?: (manager.getBandLevel(band)?.toInt() ?: 0)
+            val dbLabel = TextView(requireContext(), null, 0, R.style.LabelSmall).apply {
+                text = "${(initialLevel.toInt() / 100)} dB"
+                setPadding(12, 0, 0, 0)
+                width = 120
+                gravity = Gravity.END
+            }
+
+            val seekBar = SeekBar(requireContext()).apply {
+                max = maxLevel - minLevel
+                progress = initialLevel.toInt() - minLevel
+                layoutParams = LinearLayout.LayoutParams(0, LinearLayout.LayoutParams.WRAP_CONTENT, 1f)
+                setOnSeekBarChangeListener(object : SeekBar.OnSeekBarChangeListener {
+                    override fun onProgressChanged(seekBar: SeekBar, progress: Int, fromUser: Boolean) {
+                        val thisLevel = (progress + minLevel).toShort()
+                        if (fromUser) {
+                            manager.setBandLevel(band, thisLevel)
+                            saveBandLevelsToPreferences()
+                        }
+                        dbLabel.text = "${((progress + minLevel) / 100)} dB"
+                    }
+
+                    override fun onStartTrackingTouch(seekBar: SeekBar) {}
+                    override fun onStopTrackingTouch(seekBar: SeekBar) {}
+                })
+            }
+            bandSeekBars.add(seekBar)
+            row.addView(seekBar)
+            row.addView(dbLabel)
+            eqBandsContainer.addView(row)
+        }
+    }
+
+    private fun resetEqualizer() {
+        val manager = equalizerManager ?: return
+        val bands = manager.getNumberOfBands()
+        val bandLevelRange = manager.getBandLevelRange() ?: shortArrayOf(-1500, 1500)
+        val minLevel = bandLevelRange[0].toInt()
+        val midLevel = 0
+        for (i in 0 until bands) {
+            manager.setBandLevel(i.toShort(), midLevel.toShort())
+            bandSeekBars.getOrNull(i)?.progress = midLevel - minLevel
+        }
+        Preferences.setEqualizerBandLevels(ShortArray(bands.toInt()))
+    }
+
+    private fun saveBandLevelsToPreferences() {
+        val manager = equalizerManager ?: return
+        val bands = manager.getNumberOfBands()
+        val levels = ShortArray(bands.toInt()) { i -> manager.getBandLevel(i.toShort()) ?: 0 }
+        Preferences.setEqualizerBandLevels(levels)
+    }
+
+    private fun restoreEqualizerPreferences() {
+        val manager = equalizerManager ?: return
+        eqSwitch.isChecked = Preferences.isEqualizerEnabled()
+        updateUiEnabledState(eqSwitch.isChecked)
+        val bands = manager.getNumberOfBands()
+        val bandLevelRange = manager.getBandLevelRange() ?: shortArrayOf(-1500, 1500)
+        val minLevel = bandLevelRange[0].toInt()
+        val savedLevels = Preferences.getEqualizerBandLevels(bands)
+        if (savedLevels != null) {
+            for (i in 0 until bands) {
+                manager.setBandLevel(i.toShort(), savedLevels[i])
+                bandSeekBars.getOrNull(i)?.progress = savedLevels[i] - minLevel
+            }
+        }
+    }
+}

app/src/main/java/com/cappielloantonio/tempo/ui/fragment/PlayerControllerFragment.java

@@ -24,6 +24,8 @@ import androidx.media3.common.util.RepeatModeUtil;
 import androidx.media3.common.util.UnstableApi;
 import androidx.media3.session.MediaBrowser;
 import androidx.media3.session.SessionToken;
+import androidx.navigation.NavController;
+import androidx.navigation.NavOptions;
 import androidx.navigation.fragment.NavHostFragment;
 import androidx.viewpager2.widget.ViewPager2;
 
@@ -68,6 +70,7 @@ public class PlayerControllerFragment extends Fragment {
     private ImageButton playerOpenQueueButton;
     private ImageButton playerTrackInfo;
     private LinearLayout ratingContainer;
+    private ImageButton equalizerButton;
 
     private MainActivity activity;
     private PlayerBottomSheetViewModel playerBottomSheetViewModel;
@@ -89,6 +92,7 @@ public class PlayerControllerFragment extends Fragment {
         initMediaListenable();
         initMediaLabelButton();
         initArtistLabelButton();
+        initEqualizerButton();
 
         return view;
     }
@@ -126,6 +130,7 @@ public class PlayerControllerFragment extends Fragment {
         playerTrackInfo = bind.getRoot().findViewById(R.id.player_info_track);
         songRatingBar =  bind.getRoot().findViewById(R.id.song_rating_bar);
         ratingContainer = bind.getRoot().findViewById(R.id.rating_container);
+        equalizerButton = bind.getRoot().findViewById(R.id.player_open_equalizer_button);
         checkAndSetRatingContainerVisibility();
     }
 
@@ -426,6 +431,18 @@ public class PlayerControllerFragment extends Fragment {
         });
     }
 
+    private void initEqualizerButton() {
+        equalizerButton.setOnClickListener(v -> {
+            NavController navController = NavHostFragment.findNavController(this);
+            NavOptions navOptions = new NavOptions.Builder()
+                    .setLaunchSingleTop(true)
+                    .setPopUpTo(R.id.equalizerFragment, true)
+                    .build();
+            navController.navigate(R.id.equalizerFragment, null, navOptions);
+            if (activity != null) activity.collapseBottomSheetDelayed();
+        });
+    }
+
     public void goToControllerPage() {
         playerMediaCoverViewPager.setCurrentItem(0, false);
     }

app/src/main/java/com/cappielloantonio/tempo/ui/fragment/SettingsFragment.java

@@ -18,6 +18,9 @@ import androidx.appcompat.app.AppCompatDelegate;
 import androidx.core.os.LocaleListCompat;
 import androidx.lifecycle.ViewModelProvider;
 import androidx.media3.common.util.UnstableApi;
+import androidx.navigation.NavController;
+import androidx.navigation.NavOptions;
+import androidx.navigation.fragment.NavHostFragment;
 import androidx.preference.ListPreference;
 import androidx.preference.Preference;
 import androidx.preference.PreferenceFragmentCompat;
@@ -86,7 +89,7 @@ public class SettingsFragment extends PreferenceFragmentCompat {
     public void onResume() {
         super.onResume();
 
-        checkEqualizer();
+        checkSystemEqualizer();
         checkCacheStorage();
         checkStorage();
 
@@ -102,6 +105,7 @@ public class SettingsFragment extends PreferenceFragmentCompat {
         actionChangeDownloadStorage();
         actionDeleteDownloadStorage();
         actionKeepScreenOn();
+        actionAppEqualizer();
     }
 
     @Override
@@ -124,8 +128,8 @@ public class SettingsFragment extends PreferenceFragmentCompat {
         }
     }
 
-    private void checkEqualizer() {
+    private void checkSystemEqualizer() {
-        Preference equalizer = findPreference("equalizer");
+        Preference equalizer = findPreference("system_equalizer");
 
         if (equalizer == null) return;
 
@@ -353,4 +357,21 @@ public class SettingsFragment extends PreferenceFragmentCompat {
             return true;
         });
     }
+
+    private void actionAppEqualizer() {
+        Preference appEqualizer = findPreference("app_equalizer");
+        if (appEqualizer != null) {
+            appEqualizer.setOnPreferenceClickListener(preference -> {
+                NavController navController = NavHostFragment.findNavController(this);
+                NavOptions navOptions = new NavOptions.Builder()
+                        .setLaunchSingleTop(true)
+                        .setPopUpTo(R.id.equalizerFragment, true)
+                        .build();
+                activity.setBottomNavigationBarVisibility(true);
+                activity.setBottomSheetVisibility(true);
+                navController.navigate(R.id.equalizerFragment, null, navOptions);
+                return true;
+            });
+        }
+    }
 }

app/src/main/java/com/cappielloantonio/tempo/util/Preferences.kt

@@ -69,7 +69,8 @@ object Preferences {
     private const val NEXT_UPDATE_CHECK = "next_update_check"
     private const val CONTINUOUS_PLAY = "continuous_play"
     private const val LAST_INSTANT_MIX = "last_instant_mix"
-
+    private const val EQUALIZER_ENABLED = "equalizer_enabled"
+    private const val EQUALIZER_BAND_LEVELS = "equalizer_band_levels"
 
     @JvmStatic
     fun getServer(): String? {
@@ -538,4 +539,31 @@ object Preferences {
                 LAST_INSTANT_MIX, 0
         ) + 5000 < System.currentTimeMillis()
     }
+
+    @JvmStatic
+    fun setEqualizerEnabled(enabled: Boolean) {
+        App.getInstance().preferences.edit().putBoolean(EQUALIZER_ENABLED, enabled).apply()
+    }
+
+    @JvmStatic
+    fun isEqualizerEnabled(): Boolean {
+        return App.getInstance().preferences.getBoolean(EQUALIZER_ENABLED, false)
+    }
+
+    @JvmStatic
+    fun setEqualizerBandLevels(bandLevels: ShortArray) {
+        val asString = bandLevels.joinToString(",")
+        App.getInstance().preferences.edit().putString(EQUALIZER_BAND_LEVELS, asString).apply()
+    }
+
+    @JvmStatic
+    fun getEqualizerBandLevels(bandCount: Short): ShortArray {
+        val str = App.getInstance().preferences.getString(EQUALIZER_BAND_LEVELS, null)
+        if (str.isNullOrBlank()) {
+            return ShortArray(bandCount.toInt())
+        }
+        val parts = str.split(",")
+        if (parts.size < bandCount) return ShortArray(bandCount.toInt())
+        return ShortArray(bandCount.toInt()) { i -> parts[i].toShortOrNull() ?: 0 }
+    }
 }

app/src/main/res/drawable/ic_eq.xml

@@ -0,0 +1,11 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="960"
+    android:viewportHeight="960"
+    android:autoMirrored="true">
+
+    <path
+        android:fillColor="@color/titleTextColor"
+        android:pathData="M160,800L160,480L320,480L320,800L160,800ZM400,800L400,160L560,160L560,800L400,800ZM640,800L640,360L800,360L800,800L640,800Z"/>
+</vector>

app/src/main/res/drawable/ui_eq_not_supported.xml

@@ -0,0 +1,93 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="757.96dp"
+    android:height="743.73dp"
+    android:viewportWidth="757.96"
+    android:viewportHeight="743.73">
+  <path
+      android:pathData="M91.45,0a32.04,32.04 0,0 0,-32 32L59.45,710.43a32.04,32.04 0,0 0,32 32h297a32.04,32.04 0,0 0,32 -32L420.45,32a32.04,32.04 0,0 0,-32 -32Z"
+      android:fillColor="#e6e6e6"/>
+  <path
+      android:pathData="M400.66,156.98v-54.44a125.25,125.25 0,0 1,-80.86 -60.19h0a23.79,23.79 0,0 1,-14.22 4.68L262.35,47.03A178.55,178.55 0,0 0,400.66 156.98Z"
+      android:fillColor="#fff"/>
+  <path
+      android:pathData="M400.66,99.42v-52.3a29.12,29.12 0,0 0,-29.13 -29.13h-41.97v5.05a23.92,23.92 0,0 1,-7.4 17.33,122.3 122.3,0 0,0 78.5,59.05Z"
+      android:fillColor="#fff"/>
+  <path
+      android:pathData="M198.77,47.03L171.74,47.03a23.99,23.99 0,0 1,-23.98 -23.99v-5.05L108.38,17.99a29.13,29.13 0,0 0,-29.13 29.13v648.2a29.08,29.08 0,0 0,29.13 29.11h263.15a28.36,28.36 0,0 0,3.59 -0.22,29.15 29.15,0 0,0 25.54,-28.89L400.66,218.15C304.95,207.07 225.2,138.77 198.77,47.03Z"
+      android:fillColor="#fff"/>
+  <path
+      android:pathData="M259.07,47.03h-57.14c26.3,90.04 104.68,157.03 198.73,168.07v-55.02A181.67,181.67 0,0 1,259.07 47.03Z"
+      android:fillColor="#fff"/>
+  <path
+      android:pathData="M380.61,532.78h-270a5.01,5.01 0,0 1,-5 -5L105.61,460.81a5.01,5.01 0,0 1,5 -5h270a5.01,5.01 0,0 1,5 5v66.98A5.01,5.01 0,0 1,380.61 532.78ZM110.61,457.8a3,3 0,0 0,-3 3v66.98a3,3 0,0 0,3 3h270a3,3 0,0 0,3 -3L383.61,460.81a3,3 0,0 0,-3 -3Z"
+      android:fillColor="#e6e6e6"/>
+  <path
+      android:pathData="M145.61,494.29m-21,0a21,21 0,1 1,42 0a21,21 0,1 1,-42 0"
+      android:fillColor="#3f3d56"/>
+  <path
+      android:pathData="M194.11,480.29a3.5,3.5 0,0 0,0 7h165a3.5,3.5 0,1 0,0 -7Z"
+      android:fillColor="#e6e6e6"/>
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+      android:fillColor="#e6e6e6"/>
+  <path
+      android:pathData="M145.61,606.29m-21,0a21,21 0,1 1,42 0a21,21 0,1 1,-42 0"
+      android:fillColor="#3f3d56"/>
+  <path
+      android:pathData="M194.11,592.29a3.5,3.5 0,0 0,0 7h165a3.5,3.5 0,1 0,0 -7Z"
+      android:fillColor="#e6e6e6"/>
+  <path
+      android:pathData="M194.11,613.29a3.5,3.5 0,0 0,0 7h165a3.5,3.5 0,1 0,0 -7Z"
+      android:fillColor="#e6e6e6"/>
+  <path
+      android:pathData="M239.93,394a94.96,94.96 0,0 1,-95 -95c0,-0.2 0,-0.41 0.01,-0.61 0.29,-52.03 42.9,-94.39 94.99,-94.39a95,95 0,1 1,0 190ZM239.93,206a93.2,93.2 0,0 0,-92.99 92.46c-0.01,0.21 -0.01,0.38 -0.01,0.54a93.01,93.01 0,1 0,93 -93Z"
+      android:fillColor="#3f3d56"/>
+  <path
+      android:pathData="M282.95,296.81l-65.02,-37.54a2,2 0,0 0,-3 1.73L214.93,336.08a2,2 0,0 0,3 1.73l65.02,-37.54a2,2 0,0 0,0 -3.46l-65.02,-37.54a2,2 0,0 0,-3 1.73L214.93,336.08a2,2 0,0 0,3 1.73l65.02,-37.54a2,2 0,0 0,0 -3.46Z"
+      android:fillColor="#6c63ff"/>
+  <path
+      android:pathData="M757.57,743.73H0v-2.18H757.96Z"
+      android:fillColor="#3f3d56"/>
+  <path
+      android:pathData="M590.68,338.14m-27.94,0a27.94,27.94 0,1 1,55.87 0a27.94,27.94 0,1 1,-55.87 0"
+      android:fillColor="#ffb8b8"/>
+  <path
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+      android:fillColor="#ffb8b8"/>
+  <path
+      android:pathData="M544.67,726.93L530.72,726.93l-6.63,-53.79 20.58,0Z"
+      android:fillColor="#ffb8b8"/>
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+  <path
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+      android:fillColor="#ffb8b8"/>
+  <path
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+      android:pathData="M522.33,703.25c-9.34,-109.99 -14.9,-212.18 19.25,-253.86l0.26,-0.32 57.47,22.99 0.09,0.2c0.19,0.42 19.31,42.46 14.85,70.74l14.18,65.21 46.22,77.39a5.12,5.12 0,0 1,-2.33 7.31l-20.09,8.84a5.14,5.14 0,0 1,-6.42 -2.01L595.53,617.75l-28.4,-62.88a1.71,1.71 0,0 0,-3.25 0.52L548.14,703.36a5.11,5.11 0,0 1,-5.09 4.58L527.43,707.94A5.15,5.15 0,0 1,522.33 703.25Z"
+      android:fillColor="#2f2e41"/>
+  <path
+      android:pathData="M541.77,450.26l-0.27,-0.13 -0.04,-0.3c-2.15,-15.02 0.39,-31.72 7.55,-49.62a39.4,39.4 0,0 1,45.73 -23.59h0a39.35,39.35 0,0 1,25.09 19.3,38.92 38.92,0 0,1 2.7,31.19c-9.02,26.39 -20.73,51.08 -20.85,51.32l-0.25,0.51Z"
+      android:fillColor="#6c63ff"/>
+  <path
+      android:pathData="M500.42,512.57a12.78,12.78 0,0 1,9.16 -13.94l53.74,-103.17a10.3,10.3 0,1 1,17.52 10.82L525.84,508.73a12.42,12.42 0,0 1,0.2 1.89,12.86 12.86,0 0,1 -13.03,13.21h0a12.87,12.87 0,0 1,-9.87 -4.83,12.71 12.71,0 0,1 -2.71,-6.43Z"
+      android:fillColor="#ffb8b8"/>
+  <path
+      android:pathData="M556.81,322.35h44.36L601.16,303.02c-9.74,-3.87 -19.26,-7.16 -25.02,0a19.34,19.34 0,0 0,-19.34 19.34Z"
+      android:fillColor="#2f2e41"/>
+  <path
+      android:pathData="M603.62,299.61c26.52,0 33.94,33.24 33.94,51.99 0,10.46 -4.73,14.2 -12.16,15.46l-2.63,-14 -6.15,14.6c-2.09,0.01 -4.28,-0.03 -6.55,-0.07l-2.08,-4.29 -4.65,4.22c-18.62,0.03 -33.66,2.74 -33.66,-15.92C569.68,332.85 576.19,299.61 603.62,299.61Z"
+      android:fillColor="#2f2e41"/>
+  <path
+      android:pathData="M595.72,327L595.72,301.13a2.33,2.33 0,0 0,-2.33 -2.33h-4.67a2.33,2.33 0,0 0,-2.33 2.33L586.39,325.44a14.74,14.74 0,1 0,9.33 1.56Z"
+      android:fillColor="#6c63ff"/>
+  <path
+      android:pathData="M589.5,340.01m-7,0a7,7 0,1 1,14 0a7,7 0,1 1,-14 0"
+      android:fillColor="#fff"/>
+</vector>

app/src/main/res/layout-land/inner_fragment_player_controller_layout.xml

@@ -382,11 +382,23 @@
             android:layout_height="wrap_content"
             android:padding="16dp"
             android:background="?attr/selectableItemBackgroundBorderless"
-            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintStart_toEndOf="@+id/player_open_equalizer_button"
             app:layout_constraintEnd_toEndOf="parent"
             app:layout_constraintTop_toTopOf="parent"
             app:layout_constraintBottom_toBottomOf="parent"
             app:srcCompat="@drawable/ic_queue" />
 
+        <ImageButton
+            android:id="@+id/player_open_equalizer_button"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:padding="16dp"
+            android:background="?attr/selectableItemBackgroundBorderless"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintEnd_toStartOf="@+id/player_open_queue_button"
+            app:layout_constraintTop_toTopOf="parent"
+            app:layout_constraintBottom_toBottomOf="parent"
+            app:srcCompat="@drawable/ic_eq" />
+
     </androidx.constraintlayout.widget.ConstraintLayout>
 </androidx.constraintlayout.widget.ConstraintLayout>

app/src/main/res/layout/fragment_equalizer.xml

@@ -0,0 +1,105 @@
+<?xml version="1.0" encoding="utf-8"?>
+<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:id="@+id/eq_frame_layout"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent">
+
+    <ScrollView
+        android:id="@+id/eq_scroll_view"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:fillViewport="true"
+        android:padding="16dp">
+
+        <LinearLayout
+            android:id="@+id/eq_root_layout"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:orientation="vertical">
+
+            <TextView
+                android:id="@+id/equalizer_title"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:text="@string/equalizer_fragment_title"
+                style="@style/HeadlineSmall"
+                android:layout_gravity="center_horizontal"
+                android:paddingBottom="16dp" />
+
+            <LinearLayout
+                android:id="@+id/equalizer_switch_row"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:orientation="horizontal"
+                android:gravity="center_vertical"
+                android:paddingBottom="16dp">
+
+                <TextView
+                    android:id="@+id/equalizer_switch_label"
+                    android:layout_width="0dp"
+                    android:layout_height="wrap_content"
+                    android:layout_weight="1"
+                    style="@style/LabelMedium"
+                    android:text="@string/equalizer_enable" />
+
+                <Switch
+                    android:id="@+id/equalizer_switch"
+                    android:layout_width="wrap_content"
+                    android:layout_height="wrap_content"/>
+            </LinearLayout>
+
+            <LinearLayout
+                android:id="@+id/eq_bands_container"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:orientation="vertical">
+            </LinearLayout>
+
+            <Button
+                android:id="@+id/equalizer_reset_button"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:text="@string/equalizer_reset"
+                android:layout_gravity="center_horizontal"
+                style="@style/Widget.Material3.Button.TextButton"
+                android:layout_marginTop="24dp"/>
+
+            <Space
+                android:id="@+id/equalizer_bottom_space"
+                android:layout_width="match_parent"
+                android:layout_height="128dp"
+                android:layout_marginTop="0dp" />
+
+        </LinearLayout>
+    </ScrollView>
+
+    <LinearLayout
+        android:id="@+id/equalizer_not_supported_container"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:orientation="vertical"
+        android:gravity="center"
+        android:layout_gravity="center"
+        android:visibility="gone">
+
+        <ImageView
+            android:id="@+id/equalizer_not_supported_image"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:adjustViewBounds="true"
+            android:maxWidth="240dp"
+            android:maxHeight="240dp"
+            android:scaleType="centerInside"
+            android:src="@drawable/ui_eq_not_supported" />
+
+        <TextView
+            android:id="@+id/equalizer_not_supported_text"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:text="@string/equalizer_not_supported"
+            android:gravity="center"
+            style="@style/BodyMedium"
+            android:layout_marginTop="16dp"/>
+    </LinearLayout>
+
+</FrameLayout>

app/src/main/res/layout/inner_fragment_player_controller_layout.xml

@@ -381,11 +381,23 @@
             android:layout_height="wrap_content"
             android:padding="16dp"
             android:background="?attr/selectableItemBackgroundBorderless"
-            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintStart_toEndOf="@+id/player_open_equalizer_button"
             app:layout_constraintEnd_toEndOf="parent"
             app:layout_constraintTop_toTopOf="parent"
             app:layout_constraintBottom_toBottomOf="parent"
             app:srcCompat="@drawable/ic_queue" />
 
+        <ImageButton
+            android:id="@+id/player_open_equalizer_button"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:padding="16dp"
+            android:background="?attr/selectableItemBackgroundBorderless"
+            app:layout_constraintStart_toStartOf="parent"
+            app:layout_constraintEnd_toStartOf="@+id/player_open_queue_button"
+            app:layout_constraintTop_toTopOf="parent"
+            app:layout_constraintBottom_toBottomOf="parent"
+            app:srcCompat="@drawable/ic_eq" />
+
     </androidx.constraintlayout.widget.ConstraintLayout>
 </androidx.constraintlayout.widget.ConstraintLayout>

app/src/main/res/navigation/nav_graph.xml

@@ -151,6 +151,9 @@
             app:destination="@id/loginFragment"
             app:popUpTo="@id/homeFragment"
             app:popUpToInclusive="true" />
+        <action
+            android:id="@+id/action_settingsFragment_to_equalizerFragment"
+            app:destination="@id/equalizerFragment" />
     </fragment>
     <fragment
         android:id="@+id/searchFragment"
@@ -300,6 +303,20 @@
             android:id="@+id/action_indexFragment_to_directoryFragment"
             app:destination="@id/directoryFragment" />
     </fragment>
+    <fragment
+        android:id="@+id/playerControllerFragment"
+        android:name="com.cappielloantonio.tempo.ui.fragment.PlayerControllerFragment"
+        android:label="PlayerControllerFragment"
+        tools:layout="@layout/inner_fragment_player_controller">
+        <action
+            android:id="@+id/action_playerControllerFragment_to_equalizerFragment"
+            app:destination="@id/equalizerFragment"/>
+    </fragment>
+    <fragment
+        android:id="@+id/equalizerFragment"
+        android:name="com.cappielloantonio.tempo.ui.fragment.EqualizerFragment"
+        android:label="EqualizerFragment"
+        tools:layout="@layout/fragment_equalizer" />
     <dialog
         android:id="@+id/songBottomSheetDialog"
         android:name="com.cappielloantonio.tempo.ui.fragment.bottomsheetdialog.SongBottomSheetDialog"

app/src/main/res/values-de/strings.xml

@@ -282,8 +282,8 @@
     <string name="settings_delete_download_storage_summary">Wenn Du weitermachst werden alle gespeicherten Inhalte unwiderruflich gelöscht.</string>
     <string name="settings_delete_download_storage_title">Gespeicherte Inhalte löschen</string>
     <string name="settings_download_storage_title">Download storage</string>
-    <string name="settings_equalizer_summary">Audio Einstellungen anpassen</string>
+    <string name="settings_system_equalizer_summary">Audio Einstellungen anpassen</string>
-    <string name="settings_equalizer_title">Equalizer</string>
+    <string name="settings_system_equalizer_title">System-Equalizer</string>
     <string name="settings_github_link">https://github.com/eddyizm/tempo</string>
     <string name="settings_github_summary">Verfolge die Entwicklung</string>
     <string name="settings_github_title">Github</string>

app/src/main/res/values-es-rES/strings.xml

@@ -257,8 +257,8 @@
     <string name="search_hint">Buscar pista, artistas o álbumes</string>
     <string name="search_info_minimum_characters">Introduzca al menos tres caracteres</string>
     <string name="search_title_album">Álbumes</string>
-    <string name="settings_equalizer_summary">Ajustes de audio</string>
+    <string name="settings_system_equalizer_summary">Ajustes de audio</string>
-    <string name="settings_equalizer_title">Ecualizador</string>
+    <string name="settings_system_equalizer_title">Ecualizador del sistema</string>
     <string name="search_title_artist">Artistas</string>
     <string name="search_title_song">Pistas</string>
     <string name="server_signup_dialog_action_low_security">Baja seguridad</string>
@@ -435,4 +435,10 @@
     <string name="home_sync_starred_albums_title">Sincronizar álbumes favoritos</string>
     <string name="settings_sync_starred_albums_for_offline_use_summary">Si está habilitada, los álbumes favoritos se descargarán para uso sin conexión.</string>
     <string name="starred_album_sync_dialog_summary">Descargar los álbumes favoritos puede consumir una gran cantidad de datos.</string>
+    <string name="equalizer_fragment_title">Ecualizador</string>
+    <string name="equalizer_reset">Restablecer</string>
+    <string name="equalizer_enable">Habilitar</string>
+    <string name="equalizer_not_supported">No disponible en este dispositivo</string>
+    <string name="settings_app_equalizer">Ecualizador</string>
+    <string name="settings_app_equalizer_summary">Abrir el ecualizador incorporado</string>
 </resources>

app/src/main/res/values-fr/strings.xml

@@ -296,8 +296,8 @@
     <string name="settings_delete_download_storage_summary">Continuer entraînera la suppression irréversible de tous les éléments sauvegardés.</string>
     <string name="settings_delete_download_storage_title">Supprimer les éléments sauvegardés</string>
     <string name="settings_download_storage_title">Stockage des téléchargements</string>
-    <string name="settings_equalizer_summary">Ajuster les paramètres audios</string>
+    <string name="settings_system_equalizer_summary">Ajuster les paramètres audios</string>
-    <string name="settings_equalizer_title">Égaliseur</string>
+    <string name="settings_system_equalizer_title">Égaliseur du système</string>
     <string name="settings_github_link">https://github.com/eddyizm/tempo</string>
     <string name="settings_github_summary">Suivre le développement</string>
     <string name="settings_github_title">Github</string>

app/src/main/res/values-it/strings.xml

@@ -282,8 +282,8 @@
 	<string name="settings_delete_download_storage_summary">Continuando, tutti gli elementi salvati verranno eliminati in modo irreversibile.</string>
 	<string name="settings_delete_download_storage_title">Elimina elementi salvati</string>
 	<string name="settings_download_storage_title">Archivio download</string>
-	<string name="settings_equalizer_summary">Regola le impostazioni audio</string>
+	<string name="settings_system_equalizer_summary">Regola le impostazioni audio</string>
-	<string name="settings_equalizer_title">Equalizzatore</string>
+	<string name="settings_system_equalizer_title">Equalizzatore di sistema</string>
 	<string name="settings_github_link">https://github.com/eddyizm/tempo</string>
 	<string name="settings_github_summary">Segui lo sviluppo</string>
 	<string name="settings_github_title">Github</string>

app/src/main/res/values-ko/strings.xml

@@ -248,8 +248,8 @@
     <string name="settings_delete_download_storage_summary">계속하면 저장된 모든 항목을 완전히 삭제합니다.</string>
     <string name="settings_delete_download_storage_title">저장된 항목 삭제</string>
     <string name="settings_download_storage_title">스토리지 다운로드</string>
-    <string name="settings_equalizer_summary">오디오 설정 적용</string>
+    <string name="settings_system_equalizer_summary">오디오 설정 적용</string>
-    <string name="settings_equalizer_title">이퀄라이저</string>
+    <string name="settings_system_equalizer_title">시스템 이퀄라이저</string>
     <string name="settings_github_link">https://github.com/eddyizm/tempo</string>
     <string name="settings_github_summary">Follow the development</string>
     <string name="settings_github_title">Github</string>

app/src/main/res/values-pl/strings.xml

@@ -289,8 +289,8 @@
     <string name="settings_delete_download_storage_summary">Zatwierdzenie nieodwracalnie usunie wszystkie zapisane elementy</string>
     <string name="settings_delete_download_storage_title">Usuń zapisane elementy</string>
     <string name="settings_download_storage_title">Pamięć do pobierania</string>
-    <string name="settings_equalizer_summary">Zmień ustawienia audio</string>
+    <string name="settings_system_equalizer_summary">Zmień ustawienia audio</string>
-    <string name="settings_equalizer_title">Equalizer</string>
+    <string name="settings_system_equalizer_title">Korektor systemowy</string>
     <string name="settings_github_link">https://github.com/eddyizm/tempo</string>
     <string name="settings_github_summary">Śledź tworzenie aplikacji</string>
     <string name="settings_github_title">GitHub</string>

app/src/main/res/values-pt/strings.xml

@@ -248,8 +248,8 @@
     <string name="settings_delete_download_storage_summary">O processo resultará na exclusão irreversível de todos os itens salvos.</string>
     <string name="settings_delete_download_storage_title">Excluir itens salvos</string>
     <string name="settings_download_storage_title">Armazenamento dos downloads</string>
-    <string name="settings_equalizer_summary">Ajustar configurações de áudio</string>
+    <string name="settings_system_equalizer_summary">Ajustar configurações de áudio</string>
-    <string name="settings_equalizer_title">Equalizador</string>
+    <string name="settings_system_equalizer_title">Equalizador do sistema</string>
     <string name="settings_github_link">https://github.com/eddyizm/tempo</string>
     <string name="settings_github_summary">Acompanhe o desenvolvimento</string>
     <string name="settings_github_title">Github</string>

app/src/main/res/values-ru/strings.xml

@@ -294,8 +294,8 @@
     <string name="settings_delete_download_storage_summary">Продолжение приведет к необратимому удалению всех сохраненных элементов.</string>
     <string name="settings_delete_download_storage_title">Удалить сохраненные элементы</string>
     <string name="settings_download_storage_title">Загрузить хранилище</string>
-    <string name="settings_equalizer_summary">Отрегулируйте настройки звука</string>
+    <string name="settings_system_equalizer_summary">Отрегулируйте настройки звука</string>
-    <string name="settings_equalizer_title">Эквалайзер</string>
+    <string name="settings_system_equalizer_title">Системный эквалайзер</string>
     <string name="settings_github_link">https://github.com/eddyizm/tempo</string>
     <string name="settings_github_summary">Следите за развитием</string>
     <string name="settings_github_title">Github</string>

app/src/main/res/values-tr/strings.xml

@@ -293,8 +293,8 @@
     <string name="settings_delete_download_storage_summary">Devam ederseniz tüm kayıtlı öğeler geri alınamaz şekilde silinecektir.</string>
     <string name="settings_delete_download_storage_title">Kayıtlı öğeleri sil</string>
     <string name="settings_download_storage_title">İndirme depolaması</string>
-    <string name="settings_equalizer_summary">Ses ayarlarını düzenle</string>
+    <string name="settings_system_equalizer_summary">Ses ayarlarını düzenle</string>
-    <string name="settings_equalizer_title">Ekolayzır</string>
+    <string name="settings_system_equalizer_title">Sistem ekolayzır</string>
     <string name="settings_github_link">https://github.com/eddyizm/tempo</string>
     <string name="settings_github_summary">Gelişmeleri takip et</string>
     <string name="settings_github_title">Github</string>

app/src/main/res/values-zh/strings.xml

@@ -255,8 +255,8 @@
     <string name="settings_delete_download_storage_summary">继续当前操作将导致所有已保存的项目被永久删除。</string>
     <string name="settings_delete_download_storage_title">删除已保存的项目</string>
     <string name="settings_download_storage_title">下载存储</string>
-    <string name="settings_equalizer_summary">调整音频设置</string>
+    <string name="settings_system_equalizer_summary">调整音频设置</string>
-    <string name="settings_equalizer_title">均衡器</string>
+    <string name="settings_system_equalizer_title">系统均衡器</string>
     <string name="settings_github_link">https://github.com/eddyizm/tempo</string>
     <string name="settings_github_summary">关注开发进展</string>
     <string name="settings_github_title">Github</string>

app/src/main/res/values/strings.xml

@@ -298,8 +298,8 @@
     <string name="settings_delete_download_storage_summary">Proceeding will result in the irreversible deletion of all saved items.</string>
     <string name="settings_delete_download_storage_title">Delete saved items</string>
     <string name="settings_download_storage_title">Download storage</string>
-    <string name="settings_equalizer_summary">Adjust audio settings</string>
+    <string name="settings_system_equalizer_summary">Adjust audio settings</string>
-    <string name="settings_equalizer_title">Equalizer</string>
+    <string name="settings_system_equalizer_title">System equalizer</string>
     <string name="settings_github_link">https://github.com/eddyizm/tempo</string>
     <string name="settings_github_summary">Follow the development</string>
     <string name="settings_github_title">Github</string>
@@ -443,4 +443,10 @@
         <item quantity="one">%d album to sync</item>
         <item quantity="other">%d albums to sync</item>
     </plurals>
+    <string name="equalizer_fragment_title">Equalizer</string>
+    <string name="equalizer_reset">Reset</string>
+    <string name="equalizer_enable">Enable</string>
+    <string name="equalizer_not_supported">Not supported on this device</string>
+    <string name="settings_app_equalizer">Equalizer</string>
+    <string name="settings_app_equalizer_summary">Open the built-in equalizer</string>
 </resources>

app/src/main/res/xml/global_preferences.xml

@@ -2,9 +2,14 @@
     xmlns:app="http://schemas.android.com/apk/res-auto">
     <PreferenceCategory app:title="@string/settings_title_general">
         <Preference
-            android:key="equalizer"
+            android:key="system_equalizer"
-            android:title="@string/settings_equalizer_title"
+            android:title="@string/settings_system_equalizer_title"
-            android:summary="@string/settings_equalizer_summary" />
+            android:summary="@string/settings_system_equalizer_summary" />
+
+        <Preference
+            android:key="app_equalizer"
+            android:title="@string/settings_app_equalizer"
+            android:summary="@string/settings_app_equalizer_summary" />
 
         <Preference
             android:key="scan_library"

app/src/notquitemy/java/com/cappielloantonio/tempo/service/MediaService.kt

@@ -5,7 +5,9 @@ import android.app.PendingIntent.FLAG_IMMUTABLE
 import android.app.PendingIntent.FLAG_UPDATE_CURRENT
 import android.app.TaskStackBuilder
 import android.content.Intent
+import android.os.Binder
 import android.os.Bundle
+import android.os.IBinder
 import androidx.media3.common.*
 import androidx.media3.common.util.UnstableApi
 import androidx.media3.exoplayer.DefaultLoadControl
@@ -34,9 +36,18 @@ class MediaService : MediaLibraryService() {
     private lateinit var mediaLibrarySession: MediaLibrarySession
     private lateinit var shuffleCommands: List<CommandButton>
     private lateinit var repeatCommands: List<CommandButton>
+    lateinit var equalizerManager: EqualizerManager
 
     private var customLayout = ImmutableList.of<CommandButton>()
 
+    inner class LocalBinder : Binder() {
+        fun getEqualizerManager(): EqualizerManager {
+            return this@MediaService.equalizerManager
+        }
+    }
+
+    private val binder = LocalBinder()
+
     companion object {
         private const val CUSTOM_COMMAND_TOGGLE_SHUFFLE_MODE_ON =
             "android.media3.session.demo.SHUFFLE_ON"
@@ -48,6 +59,7 @@ class MediaService : MediaLibraryService() {
             "android.media3.session.demo.REPEAT_ONE"
         private const val CUSTOM_COMMAND_TOGGLE_REPEAT_MODE_ALL =
             "android.media3.session.demo.REPEAT_ALL"
+        const val ACTION_BIND_EQUALIZER = "com.cappielloantonio.tempo.service.BIND_EQUALIZER"
     }
 
     override fun onCreate() {
@@ -57,6 +69,7 @@ class MediaService : MediaLibraryService() {
         initializePlayer()
         initializeMediaLibrarySession()
         initializePlayerListener()
+        initializeEqualizerManager()
 
         setPlayer(player)
     }
@@ -66,10 +79,20 @@ class MediaService : MediaLibraryService() {
     }
 
     override fun onDestroy() {
+        equalizerManager.release()
         releasePlayer()
         super.onDestroy()
     }
 
+    override fun onBind(intent: Intent?): IBinder? {
+        // Check if the intent is for our custom equalizer binder
+        if (intent?.action == ACTION_BIND_EQUALIZER) {
+            return binder
+        }
+        // Otherwise, handle it as a normal MediaLibraryService connection
+        return super.onBind(intent)
+    }
+
     private inner class CustomMediaLibrarySessionCallback : MediaLibrarySession.Callback {
 
         override fun onConnect(
@@ -197,6 +220,23 @@ class MediaService : MediaLibraryService() {
         player.repeatMode = Preferences.getRepeatMode()
     }
 
+    private fun initializeEqualizerManager() {
+        equalizerManager = EqualizerManager()
+        val audioSessionId = player.audioSessionId
+        if (equalizerManager.attachToSession(audioSessionId)) {
+            val enabled = Preferences.isEqualizerEnabled()
+            equalizerManager.setEnabled(enabled)
+
+            val bands = equalizerManager.getNumberOfBands()
+            val savedLevels = Preferences.getEqualizerBandLevels(bands)
+            if (savedLevels != null) {
+                for (i in 0 until bands) {
+                    equalizerManager.setBandLevel(i.toShort(), savedLevels[i])
+                }
+            }
+        }
+    }
+
     private fun initializeMediaLibrarySession() {
         val sessionActivityPendingIntent =
             TaskStackBuilder.create(this).run {

app/src/play/java/com/cappielloantonio/tempo/service/MediaService.kt

@@ -4,6 +4,8 @@ import android.app.PendingIntent.FLAG_IMMUTABLE
 import android.app.PendingIntent.FLAG_UPDATE_CURRENT
 import android.app.TaskStackBuilder
 import android.content.Intent
+import android.os.Binder
+import android.os.IBinder
 import androidx.media3.cast.CastPlayer
 import androidx.media3.cast.SessionAvailabilityListener
 import androidx.media3.common.AudioAttributes
@@ -34,6 +36,19 @@ class MediaService : MediaLibraryService(), SessionAvailabilityListener {
     private lateinit var castPlayer: CastPlayer
     private lateinit var mediaLibrarySession: MediaLibrarySession
     private lateinit var librarySessionCallback: MediaLibrarySessionCallback
+    lateinit var equalizerManager: EqualizerManager
+
+    inner class LocalBinder : Binder() {
+        fun getEqualizerManager(): EqualizerManager {
+            return this@MediaService.equalizerManager
+        }
+    }
+
+    private val binder = LocalBinder()
+
+    companion object {
+        const val ACTION_BIND_EQUALIZER = "com.cappielloantonio.tempo.service.BIND_EQUALIZER"
+    }
 
     override fun onCreate() {
         super.onCreate()
@@ -43,6 +58,7 @@ class MediaService : MediaLibraryService(), SessionAvailabilityListener {
         initializeCastPlayer()
         initializeMediaLibrarySession()
         initializePlayerListener()
+        initializeEqualizerManager()
 
         setPlayer(
                 null,
@@ -63,10 +79,20 @@ class MediaService : MediaLibraryService(), SessionAvailabilityListener {
     }
 
     override fun onDestroy() {
+        equalizerManager.release()
         releasePlayer()
         super.onDestroy()
     }
 
+    override fun onBind(intent: Intent?): IBinder? {
+        // Check if the intent is for our custom equalizer binder
+        if (intent?.action == ACTION_BIND_EQUALIZER) {
+            return binder
+        }
+        // Otherwise, handle it as a normal MediaLibraryService connection
+        return super.onBind(intent)
+    }
+
     private fun initializeRepository() {
         automotiveRepository = AutomotiveRepository()
     }
@@ -85,6 +111,23 @@ class MediaService : MediaLibraryService(), SessionAvailabilityListener {
         player.repeatMode = Preferences.getRepeatMode()
     }
 
+    private fun initializeEqualizerManager() {
+        equalizerManager = EqualizerManager()
+        val audioSessionId = player.audioSessionId
+        if (equalizerManager.attachToSession(audioSessionId)) {
+            val enabled = Preferences.isEqualizerEnabled()
+            equalizerManager.setEnabled(enabled)
+
+            val bands = equalizerManager.getNumberOfBands()
+            val savedLevels = Preferences.getEqualizerBandLevels(bands)
+            if (savedLevels != null) {
+                for (i in 0 until bands) {
+                    equalizerManager.setBandLevel(i.toShort(), savedLevels[i])
+                }
+            }
+        }
+    }
+
     private fun initializeCastPlayer() {
         if (GoogleApiAvailability.getInstance()
                         .isGooglePlayServicesAvailable(this) == ConnectionResult.SUCCESS

app/src/tempo/java/com/cappielloantonio/tempo/service/MediaService.kt

@@ -4,6 +4,8 @@ import android.app.PendingIntent.FLAG_IMMUTABLE
 import android.app.PendingIntent.FLAG_UPDATE_CURRENT
 import android.app.TaskStackBuilder
 import android.content.Intent
+import android.os.Binder
+import android.os.IBinder
 import androidx.media3.cast.CastPlayer
 import androidx.media3.cast.SessionAvailabilityListener
 import androidx.media3.common.AudioAttributes
@@ -34,6 +36,19 @@ class MediaService : MediaLibraryService(), SessionAvailabilityListener {
     private lateinit var castPlayer: CastPlayer
     private lateinit var mediaLibrarySession: MediaLibrarySession
     private lateinit var librarySessionCallback: MediaLibrarySessionCallback
+    lateinit var equalizerManager: EqualizerManager
+
+    inner class LocalBinder : Binder() {
+        fun getEqualizerManager(): EqualizerManager {
+            return this@MediaService.equalizerManager
+        }
+    }
+
+    private val binder = LocalBinder()
+
+    companion object {
+        const val ACTION_BIND_EQUALIZER = "com.cappielloantonio.tempo.service.BIND_EQUALIZER"
+    }
 
     override fun onCreate() {
         super.onCreate()
@@ -43,6 +58,7 @@ class MediaService : MediaLibraryService(), SessionAvailabilityListener {
         initializeCastPlayer()
         initializeMediaLibrarySession()
         initializePlayerListener()
+        initializeEqualizerManager()
 
         setPlayer(
                 null,
@@ -63,14 +79,41 @@ class MediaService : MediaLibraryService(), SessionAvailabilityListener {
     }
 
     override fun onDestroy() {
+        equalizerManager.release()
         releasePlayer()
         super.onDestroy()
     }
 
+    override fun onBind(intent: Intent?): IBinder? {
+        // Check if the intent is for our custom equalizer binder
+        if (intent?.action == ACTION_BIND_EQUALIZER) {
+            return binder
+        }
+        // Otherwise, handle it as a normal MediaLibraryService connection
+        return super.onBind(intent)
+    }
+
     private fun initializeRepository() {
         automotiveRepository = AutomotiveRepository()
     }
 
+    private fun initializeEqualizerManager() {
+        equalizerManager = EqualizerManager()
+        val audioSessionId = player.audioSessionId
+        if (equalizerManager.attachToSession(audioSessionId)) {
+            val enabled = Preferences.isEqualizerEnabled()
+            equalizerManager.setEnabled(enabled)
+
+            val bands = equalizerManager.getNumberOfBands()
+            val savedLevels = Preferences.getEqualizerBandLevels(bands)
+            if (savedLevels != null) {
+                for (i in 0 until bands) {
+                    equalizerManager.setBandLevel(i.toShort(), savedLevels[i])
+                }
+            }
+        }
+    }
+
     private fun initializePlayer() {
         player = ExoPlayer.Builder(this)
                 .setRenderersFactory(getRenderersFactory())