dolby: Introduce graphical equalizer

Squashed: dolby: Refresh preset name on main screen Change-Id: I96783e2a03c384f031787f4cc9140f7d64dadb2f Signed-off-by: Pranav Vashi <neobuddy89@gmail.com> Change-Id: I38ee6ce594e5671af42afc3d4bf0f004329482b9
2024-08-03 08:36:46 +05:30 · 2024-08-03 08:36:46 +05:30 · b10f3eefc6
commit b10f3eefc6
parent ab222058f5
22 changed files with 1156 additions and 21 deletions
--- a/dolby/Android.bp
+++ b/dolby/Android.bp
@ -18,6 +18,10 @@ android_app {
    overrides: ["MusicFX"],
    static_libs: [
        "SettingsLib",
+        "SpaLib",
+        "androidx.activity_activity-compose",
+        "androidx.compose.material3_material3",
+        "androidx.compose.runtime_runtime",
        "androidx.preference_preference",
    ],
 }
--- a/dolby/AndroidManifest.xml
+++ b/dolby/AndroidManifest.xml
@ -47,6 +47,17 @@
                       android:value="content://co.aospa.dolby.xiaomi.summary/dolby" />
        </activity>

+        <activity
+            android:name=".geq.EqualizerActivity"
+            android:label="@string/dolby_preset"
+            android:theme="@style/Theme.SubSettingsBase"
+            android:exported="true" >
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+                <category android:name="android.intent.category.DEFAULT" />
+            </intent-filter>
+        </activity>
+
        <service
            android:name=".DolbyTileService"
            android:icon="@drawable/ic_dolby_qs"
--- a/dolby/res/drawable/reset_settings_24px.xml
+++ b/dolby/res/drawable/reset_settings_24px.xml
@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="960"
+    android:viewportHeight="960">
+    <path
+        android:fillColor="?android:attr/colorControlNormal"
+        android:pathData="M520,630L520,570L680,570L680,630L520,630ZM580,840L580,790L520,790L520,730L580,730L580,680L640,680L640,840L580,840ZM680,790L680,730L840,730L840,790L680,790ZM720,680L720,520L780,520L780,570L840,570L840,630L780,630L780,680L720,680ZM831,400L748,400Q722,312 649,256Q576,200 480,200Q363,200 281.5,281.5Q200,363 200,480Q200,552 232.5,612Q265,672 320,710L320,600L400,600L400,840L160,840L160,760L254,760Q192,710 156,637.5Q120,565 120,480Q120,405 148.5,339.5Q177,274 225.5,225.5Q274,177 339.5,148.5Q405,120 480,120Q609,120 706.5,199.5Q804,279 831,400Z" />
+</vector>
--- a/dolby/res/drawable/save_as_24px.xml
+++ b/dolby/res/drawable/save_as_24px.xml
@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="960"
+    android:viewportHeight="960">
+  <path
+      android:fillColor="?android:attr/colorControlNormal"
+      android:pathData="M200,840Q167,840 143.5,816.5Q120,793 120,760L120,200Q120,167 143.5,143.5Q167,120 200,120L680,120L840,280L840,492Q821,484 800.5,481.5Q780,479 760,482L760,313L647,200L200,200Q200,200 200,200Q200,200 200,200L200,760Q200,760 200,760Q200,760 200,760L440,760L440,764L440,840L200,840ZM200,200L200,313L200,482Q200,485 200,494.5Q200,504 200,519L200,760L200,760L200,760Q200,760 200,760Q200,760 200,760L200,200Q200,200 200,200Q200,200 200,200ZM520,920L520,797L741,577Q750,568 761,564Q772,560 783,560Q795,560 806,564.5Q817,569 826,578L863,615Q871,624 875.5,635Q880,646 880,657Q880,668 876,679.5Q872,691 863,700L643,920L520,920ZM820,657L820,657L783,620L783,620L820,657ZM580,860L618,860L739,738L721,719L702,701L580,822L580,860ZM721,719L702,701L702,701L739,738L739,738L721,719ZM240,400L600,400L600,240L240,240L240,400ZM480,720Q481,720 482,720Q483,720 484,720L600,605Q600,603 600,602.5Q600,602 600,600Q600,550 565,515Q530,480 480,480Q430,480 395,515Q360,550 360,600Q360,650 395,685Q430,720 480,720Z"/>
+</vector>
--- a/dolby/res/values/strings.xml
+++ b/dolby/res/values/strings.xml
@ -9,7 +9,7 @@
    <string name="dolby_title">Dolby Atmos</string>
    <string name="dolby_enable">Use Dolby Atmos</string>
    <string name="dolby_profile_title">Choose a profile</string>
-    <string name="dolby_preset">Equalizer preset</string>
+    <string name="dolby_preset">Graphic equalizer</string>
    <string name="dolby_off">Off</string>
    <string name="dolby_on">On</string>
    <string name="dolby_low">Low</string>
@ -36,7 +36,7 @@
    <string name="dolby_profile_voice">Voice</string>

    <!-- Dolby equalizer presets -->
-    <string name="dolby_preset_default">Default</string>
+    <string name="dolby_preset_default">Flat (off)</string>
    <string name="dolby_preset_rock">Rock</string>
    <string name="dolby_preset_jazz">Jazz</string>
    <string name="dolby_preset_pop">Pop</string>
@ -48,4 +48,17 @@
    <string name="dolby_preset_dance">Dance</string>
    <string name="dolby_preset_metal">Metal</string>

+    <!-- Dolby equalizer UI -->
+    <string name="dolby_geq_slider_label_gain">Gain</string>
+    <string name="dolby_geq_preset">Preset</string>
+    <string name="dolby_geq_preset_name">Preset name</string>
+    <string name="dolby_geq_new_preset">New preset</string>
+    <string name="dolby_geq_rename_preset">Rename preset</string>
+    <string name="dolby_geq_delete_preset">Delete preset</string>
+    <string name="dolby_geq_delete_preset_prompt">Do you want to delete this preset?</string>
+    <string name="dolby_geq_reset_gains">Reset gains</string>
+    <string name="dolby_geq_reset_gains_prompt">Do you want to reset this preset to defaults?</string>
+    <string name="dolby_geq_preset_name_exists">Preset name already exists!</string>
+    <string name="dolby_geq_preset_name_too_long">Preset name is too long!</string>
+
 </resources>
--- a/dolby/res/xml/dolby_settings.xml
+++ b/dolby/res/xml/dolby_settings.xml
@ -24,11 +24,14 @@
    <PreferenceCategory
        android:title="@string/dolby_category_settings">

-        <ListPreference
+        <Preference
            android:key="dolby_preset"
-            android:entries="@array/dolby_preset_entries"
-            android:entryValues="@array/dolby_preset_values"
-            android:title="@string/dolby_preset" />
+            android:title="@string/dolby_preset">
+            <intent
+                android:action="android.intent.action.MAIN"
+                android:targetPackage="co.aospa.dolby.xiaomi"
+                android:targetClass="co.aospa.dolby.xiaomi.geq.EqualizerActivity" />
+        </Preference>

        <SwitchPreference
            android:key="dolby_spk_virtualizer"
--- a/dolby/src/co/aospa/dolby/xiaomi/DolbyController.kt
+++ b/dolby/src/co/aospa/dolby/xiaomi/DolbyController.kt
@ -200,6 +200,18 @@ internal class DolbyController private constructor(
        dolbyEffect.setDapParameter(DsParam.GEQ_BAND_GAINS, gains, profile)
    }

+    fun getPresetName(): String {
+        val presets = context.resources.getStringArray(R.array.dolby_preset_values)
+        val presetIndex = presets.indexOf(getPreset())
+        return if (presetIndex == -1) {
+            "Custom"
+        } else {
+            context.resources.getStringArray(
+                R.array.dolby_preset_entries
+            )[presetIndex]
+        }
+    }
+
    fun getHeadphoneVirtEnabled(profile: Int = this.profile) =
        dolbyEffect.getDapParameterBool(DsParam.HEADPHONE_VIRTUALIZER, profile).also {
            dlog(TAG, "getHeadphoneVirtEnabled: $it")
--- a/dolby/src/co/aospa/dolby/xiaomi/DolbySettingsFragment.kt
+++ b/dolby/src/co/aospa/dolby/xiaomi/DolbySettingsFragment.kt
@ -34,7 +34,7 @@ class DolbySettingsFragment : PreferenceFragment(),
        findPreference<ListPreference>(DolbyConstants.PREF_PROFILE)!!
    }
    private val presetPref by lazy {
-        findPreference<ListPreference>(DolbyConstants.PREF_PRESET)!!
+        findPreference<Preference>(DolbyConstants.PREF_PRESET)!!
    }
    private val stereoPref by lazy {
        findPreference<ListPreference>(DolbyConstants.PREF_STEREO)!!
@ -106,7 +106,6 @@ class DolbySettingsFragment : PreferenceFragment(),
            }
        }

-        presetPref.onPreferenceChangeListener = this
        hpVirtPref.onPreferenceChangeListener = this
        spkVirtPref.onPreferenceChangeListener = this
        stereoPref.onPreferenceChangeListener = this
@ -136,6 +135,11 @@ class DolbySettingsFragment : PreferenceFragment(),
        super.onDestroyView()
    }

+    override fun onResume() {
+        super.onResume()
+        updateProfileSpecificPrefs()
+    }
+
    override fun onPreferenceChange(preference: Preference, newValue: Any): Boolean {
        dlog(TAG, "onPreferenceChange: key=${preference.key} value=$newValue")
        when (preference.key) {
@ -146,10 +150,6 @@ class DolbySettingsFragment : PreferenceFragment(),
                updateProfileSpecificPrefs()
            }

-            DolbyConstants.PREF_PRESET -> {
-                dolbyController.setPreset(newValue.toString())
-            }
-
            DolbyConstants.PREF_SPK_VIRTUALIZER -> {
                dolbyController.setSpeakerVirtEnabled(newValue as Boolean)
            }
@ -214,15 +214,7 @@ class DolbySettingsFragment : PreferenceFragment(),

        if (!enable) return

-        val preset = dolbyController.getPreset(currentProfile)
-        presetPref.apply {
-            if (entryValues.contains(preset)) {
-                summary = "%s"
-                value = preset
-            } else {
-                summary = unknownRes
-            }
-        }
+        presetPref.summary = dolbyController.getPresetName()

        val deValue = dolbyController.getDialogueEnhancerAmount(currentProfile).toString()
        dialoguePref.apply {
--- a/dolby/src/co/aospa/dolby/xiaomi/geq/EqualizerActivity.kt
+++ b/dolby/src/co/aospa/dolby/xiaomi/geq/EqualizerActivity.kt
@ -0,0 +1,53 @@
+/*
+ * Copyright (C) 2024 Paranoid Android
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package co.aospa.dolby.xiaomi.geq
+
+import android.os.Bundle
+import androidx.activity.ComponentActivity
+import androidx.activity.compose.setContent
+import androidx.activity.viewModels
+import androidx.compose.foundation.layout.padding
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.CompositionLocalProvider
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.res.stringResource
+import androidx.navigation.compose.rememberNavController
+import co.aospa.dolby.xiaomi.R
+import co.aospa.dolby.xiaomi.geq.ui.EqualizerScreen
+import co.aospa.dolby.xiaomi.geq.ui.EqualizerViewModel
+import com.android.settingslib.spa.framework.compose.localNavController
+import com.android.settingslib.spa.framework.theme.SettingsTheme
+import com.android.settingslib.spa.widget.scaffold.SettingsScaffold
+
+class EqualizerActivity : ComponentActivity() {
+
+    private val viewModel: EqualizerViewModel by viewModels { EqualizerViewModel.Factory }
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        setContent {
+            SettingsTheme {
+                MainContent()
+            }
+        }
+    }
+
+    @Composable
+    private fun MainContent() {
+        val navController = rememberNavController()
+        CompositionLocalProvider(navController.localNavController()) {
+            SettingsScaffold(
+                title = stringResource(id = R.string.dolby_preset)
+            ) { paddingValues ->
+                EqualizerScreen(
+                    viewModel = viewModel,
+                    modifier = Modifier.padding(paddingValues)
+                )
+            }
+        }
+    }
+}
--- a/dolby/src/co/aospa/dolby/xiaomi/geq/data/BandGain.kt
+++ b/dolby/src/co/aospa/dolby/xiaomi/geq/data/BandGain.kt
@ -0,0 +1,12 @@
+/*
+ * Copyright (C) 2024 Paranoid Android
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package co.aospa.dolby.xiaomi.geq.data
+
+data class BandGain(
+    val band: Int,
+    var gain: Int = 0
+)
--- a/dolby/src/co/aospa/dolby/xiaomi/geq/data/EqualizerRepository.kt
+++ b/dolby/src/co/aospa/dolby/xiaomi/geq/data/EqualizerRepository.kt
@ -0,0 +1,183 @@
+/*
+ * Copyright (C) 2024 Paranoid Android
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package co.aospa.dolby.xiaomi.geq.data
+
+import android.content.Context
+import android.content.SharedPreferences
+import android.util.Log
+import co.aospa.dolby.xiaomi.DolbyConstants.Companion.PREF_PRESET
+import co.aospa.dolby.xiaomi.DolbyConstants.Companion.dlog
+import co.aospa.dolby.xiaomi.DolbyController
+import co.aospa.dolby.xiaomi.R
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.channels.awaitClose
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.callbackFlow
+import kotlinx.coroutines.withContext
+
+class EqualizerRepository(
+    private val context: Context
+) {
+
+    private val dolbyController by lazy { DolbyController.getInstance(context) }
+
+    // Preset is saved as a string of comma separated gains in SharedPreferences
+    // and is unique to each profile ID
+    private val profile = dolbyController.profile
+    private val profileSharedPrefs by lazy {
+        context.getSharedPreferences(
+            "profile_$profile",
+            Context.MODE_PRIVATE
+        )
+    }
+
+    private val presetsSharedPrefs by lazy {
+        context.getSharedPreferences(
+            "presets",
+            Context.MODE_PRIVATE
+        )
+    }
+
+    val builtInPresets: List<Preset> by lazy {
+        val names = context.resources.getStringArray(
+            R.array.dolby_preset_entries
+        )
+        val presets = context.resources.getStringArray(
+            R.array.dolby_preset_values
+        )
+        List(names.size) { index ->
+            Preset(
+                name = names[index],
+                bandGains = deserializeGains(presets[index]),
+            )
+        }
+    }
+
+    val defaultPreset by lazy { builtInPresets[0] } // Flat
+
+    // User defined presets are stored in a SharedPreferences as
+    // key - preset name
+    // value - comma separated string of gains
+    val userPresets: Flow<List<Preset>> = callbackFlow {
+        val listener = SharedPreferences.OnSharedPreferenceChangeListener { _, _ ->
+            dlog(TAG, "presetsSharedPrefs changed")
+            trySend(
+                presetsSharedPrefs.all.map { (key, value) ->
+                    Preset(
+                        name = key,
+                        bandGains = deserializeGains(value.toString()),
+                        isUserDefined = true
+                    )
+                }
+            )
+        }
+
+        presetsSharedPrefs.registerOnSharedPreferenceChangeListener(listener)
+        dlog(TAG, "presetsSharedPrefs registered listener")
+        // trigger an initial emission
+        listener.onSharedPreferenceChanged(presetsSharedPrefs, null)
+
+        awaitClose {
+            presetsSharedPrefs.unregisterOnSharedPreferenceChangeListener(listener)
+            dlog(TAG, "presetsSharedPrefs unregistered listener")
+        }
+    }
+
+    suspend fun getBandGains(): List<BandGain> = withContext(Dispatchers.IO) {
+        val gains = profileSharedPrefs.getString(PREF_PRESET, dolbyController.getPreset())
+        return@withContext if (gains.isNullOrEmpty()) {
+            defaultPreset.bandGains
+        } else {
+            deserializeGains(gains)
+        }.also {
+            dlog(TAG, "getBandGains: $it")
+        }
+    }
+
+    suspend fun setBandGains(bandGains: List<BandGain>) = withContext(Dispatchers.IO) {
+        dlog(TAG, "setBandGains($bandGains)")
+        val gains = serializeGains(bandGains)
+        dolbyController.setPreset(gains)
+        profileSharedPrefs.edit()
+            .putString(PREF_PRESET, gains)
+            .apply()
+    }
+
+    suspend fun addPreset(preset: Preset) = withContext(Dispatchers.IO) {
+        dlog(TAG, "addPreset($preset)")
+        presetsSharedPrefs.edit()
+            .putString(preset.name, serializeGains(preset.bandGains))
+            .apply()
+    }
+
+    suspend fun removePreset(preset: Preset) = withContext(Dispatchers.IO) {
+        dlog(TAG, "removePreset($preset)")
+        presetsSharedPrefs.edit()
+            .remove(preset.name)
+            .apply()
+    }
+
+    private companion object {
+        const val TAG = "EqRepository"
+
+        val tenBandFreqs = intArrayOf(
+            32,
+            64,
+            125,
+            250,
+            500,
+            1000,
+            2000,
+            4000,
+            8000,
+            16000
+        )
+
+        fun deserializeGains(bandGains: String): List<BandGain> {
+            val gains: List<Int> =
+                bandGains.split(",").runCatching {
+                    require(size == 20) {
+                        "Preset must have 20 elements, has only $size!"
+                    }
+                    map { it.toInt() }
+                        .twentyToTenBandGains()
+                }.onFailure { exception ->
+                    Log.e(TAG, "Failed to parse preset", exception)
+                }.getOrDefault(
+                    // fallback to flat
+                    List<Int>(10) { 0 }
+                )
+            return List(10) { index ->
+                BandGain(
+                    band = tenBandFreqs[index],
+                    gain = gains[index]
+                )
+            }
+        }
+
+        fun serializeGains(bandGains: List<BandGain>): String {
+            return bandGains.map { it.gain }
+                .tenToTwentyBandGains()
+                .joinToString(",")
+        }
+
+        // we show only 10 bands in UI however backend requires 20 bands
+        fun List<Int>.tenToTwentyBandGains() =
+            List<Int>(20) { index ->
+                if (index % 2 == 1 && index < 19) {
+                    // every odd element is the average of its surrounding elements
+                    (this[(index - 1) / 2] + this[(index + 1) / 2]) / 2
+                } else {
+                    this[index / 2]
+                }
+            }
+
+        fun List<Int>.twentyToTenBandGains() =
+            // skip every odd element
+            filterIndexed { index, _ -> index % 2 == 0 }
+    }
+}
--- a/dolby/src/co/aospa/dolby/xiaomi/geq/data/Preset.kt
+++ b/dolby/src/co/aospa/dolby/xiaomi/geq/data/Preset.kt
@ -0,0 +1,14 @@
+/*
+ * Copyright (C) 2024 Paranoid Android
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package co.aospa.dolby.xiaomi.geq.data
+
+data class Preset(
+    var name: String,
+    val bandGains: List<BandGain>,
+    var isUserDefined: Boolean = false,
+    var isMutated: Boolean = false
+)
--- a/dolby/src/co/aospa/dolby/xiaomi/geq/ui/BandGainSlider.kt
+++ b/dolby/src/co/aospa/dolby/xiaomi/geq/ui/BandGainSlider.kt
@ -0,0 +1,101 @@
+/*
+ * Copyright (C) 2024 Paranoid Android
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package co.aospa.dolby.xiaomi.geq.ui
+
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.width
+import androidx.compose.material3.Slider
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableFloatStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.TransformOrigin
+import androidx.compose.ui.graphics.graphicsLayer
+import androidx.compose.ui.layout.layout
+import androidx.compose.ui.unit.Constraints
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.unit.sp
+import co.aospa.dolby.xiaomi.geq.data.BandGain
+
+@Composable
+fun BandGainSlider(
+    bandGain: BandGain,
+    onValueChangeFinished: (Int) -> Unit
+) {
+    // Gain range is of -1->1 in UI, -100->100 in backend, but actually is -10->10 dB.
+
+    // Ensure we update the slider when gain is changed,
+    // for eg. when changing the preset
+    var sliderPosition by remember(bandGain.gain) {
+        mutableFloatStateOf(bandGain.gain / 100f)
+    }
+
+    Column(
+        horizontalAlignment = Alignment.CenterHorizontally,
+    ) {
+        SliderText(
+            "%.1f".format(sliderPosition * 10f)
+        )
+        Slider(
+            value = sliderPosition,
+            onValueChange = { sliderPosition = it },
+            onValueChangeFinished = {
+                onValueChangeFinished((sliderPosition * 100f).toInt())
+            },
+            valueRange = -1f..1f,
+            modifier = Modifier
+                .graphicsLayer {
+                    rotationZ = 270f
+                    transformOrigin = TransformOrigin(0f, 0f)
+                }
+                .layout { measurable, constraints ->
+                    val placeable = measurable.measure(
+                        Constraints(
+                            minWidth = constraints.minHeight,
+                            maxWidth = constraints.maxHeight,
+                            minHeight = constraints.minWidth,
+                            maxHeight = constraints.maxHeight,
+                        )
+                    )
+                    layout(placeable.height, placeable.width) {
+                        placeable.place(-placeable.width, 0)
+                    }
+                }
+                // horizontal and vertical dimensions are inverted due to rotation
+                .width(200.dp)
+                .height(40.dp)
+                .padding(8.dp)
+        )
+        SliderText(
+            with(bandGain.band) {
+                if (this >= 1000) {
+                    "${this / 1000}k"
+                } else {
+                    "$this"
+                }
+            }
+        )
+    }
+}
+
+@Composable
+fun SliderText(
+    text: String,
+    modifier: Modifier = Modifier
+) {
+    Text(
+        text = text,
+        modifier = modifier,
+        fontSize = 12.sp
+    )
+}
--- a/dolby/src/co/aospa/dolby/xiaomi/geq/ui/BandGainSliderLabels.kt
+++ b/dolby/src/co/aospa/dolby/xiaomi/geq/ui/BandGainSliderLabels.kt
@ -0,0 +1,71 @@
+/*
+ * Copyright (C) 2024 Paranoid Android
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package co.aospa.dolby.xiaomi.geq.ui
+
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.unit.sp
+import co.aospa.dolby.xiaomi.R
+
+@Composable
+fun BandGainSliderLabels() {
+    Column(
+        horizontalAlignment = Alignment.End,
+        modifier = Modifier.padding(end = 8.dp)
+    ) {
+        LabelText(
+            stringResource(id = R.string.dolby_geq_slider_label_gain)
+        )
+        Column(
+            modifier = Modifier.height(200.dp),
+            horizontalAlignment = Alignment.End
+        ) {
+            LabelText(
+                "+10 dB",
+                modifier = Modifier.padding(
+                    top = 10.dp
+                )
+            )
+            Spacer(
+                modifier = Modifier.weight(1f)
+            )
+            LabelText("0 dB")
+            Spacer(
+                modifier = Modifier.weight(1f)
+            )
+            LabelText(
+                "-10 dB",
+                modifier = Modifier.padding(
+                    bottom = 10.dp
+                )
+            )
+        }
+        LabelText("Hz")
+    }
+}
+
+@Composable
+fun LabelText(
+    text: String,
+    modifier: Modifier = Modifier
+) {
+    Text(
+        text = text,
+        modifier = modifier,
+        color = MaterialTheme.colorScheme.secondary,
+        fontSize = 12.sp
+    )
+}
--- a/dolby/src/co/aospa/dolby/xiaomi/geq/ui/ConfirmationDialog.kt
+++ b/dolby/src/co/aospa/dolby/xiaomi/geq/ui/ConfirmationDialog.kt
@ -0,0 +1,58 @@
+/*
+ * Copyright (C) 2024 Paranoid Android
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package co.aospa.dolby.xiaomi.geq.ui
+
+import androidx.compose.material3.AlertDialog
+import androidx.compose.material3.Text
+import androidx.compose.material3.TextButton
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.res.stringResource
+
+@Composable
+fun ConfirmationDialog(
+    text: String,
+    onConfirm: () -> Unit,
+    onDismiss: () -> Unit
+) {
+    var showDialog by remember { mutableStateOf(true) }
+    if (!showDialog) {
+        onDismiss()
+        return
+    }
+
+    AlertDialog(
+        onDismissRequest = { showDialog = false },
+        confirmButton = {
+            TextButton(
+                onClick = {
+                    showDialog = false
+                    onConfirm()
+                }
+            ) {
+                Text(
+                    stringResource(id = android.R.string.ok)
+                )
+            }
+        },
+        dismissButton = {
+            TextButton(
+                onClick = { showDialog = false }
+            ) {
+                Text(
+                    stringResource(id = android.R.string.cancel)
+                )
+            }
+        },
+        text = {
+            Text(text)
+        }
+    )
+}
--- a/dolby/src/co/aospa/dolby/xiaomi/geq/ui/EqualizerBands.kt
+++ b/dolby/src/co/aospa/dolby/xiaomi/geq/ui/EqualizerBands.kt
@ -0,0 +1,39 @@
+/*
+ * Copyright (C) 2024 Paranoid Android
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package co.aospa.dolby.xiaomi.geq.ui
+
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.lazy.LazyRow
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+
+@Composable
+fun EqualizerBands(viewModel: EqualizerViewModel) {
+    val preset by viewModel.preset.collectAsState()
+    val bandGains = preset.bandGains
+
+    LazyRow(
+        verticalAlignment = Alignment.CenterVertically,
+        modifier = Modifier.fillMaxWidth()
+    ) {
+        item {
+            BandGainSliderLabels()
+        }
+        items(bandGains.size) { index ->
+            BandGainSlider(
+                bandGains[index],
+                onValueChangeFinished = {
+                    viewModel.setGain(index, it)
+                }
+            )
+        }
+    }
+}
--- a/dolby/src/co/aospa/dolby/xiaomi/geq/ui/EqualizerScreen.kt
+++ b/dolby/src/co/aospa/dolby/xiaomi/geq/ui/EqualizerScreen.kt
@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2024 Paranoid Android
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package co.aospa.dolby.xiaomi.geq.ui
+
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.fillMaxHeight
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material3.Surface
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.unit.dp
+import com.android.settingslib.spa.framework.theme.SettingsDimension
+import com.android.settingslib.spa.framework.theme.SettingsTheme
+
+@Composable
+fun EqualizerScreen(
+    viewModel: EqualizerViewModel,
+    modifier: Modifier = Modifier
+) {
+    Surface(
+        modifier = Modifier
+            .fillMaxSize()
+            .padding(SettingsDimension.itemPadding)
+            .then(modifier),
+        color = SettingsTheme.colorScheme.background
+    ) {
+        Column(
+            verticalArrangement = Arrangement.Top,
+            modifier = Modifier.fillMaxHeight()
+        ) {
+            PresetSelector(viewModel = viewModel)
+            EqualizerBands(viewModel = viewModel)
+        }
+    }
+}
--- a/dolby/src/co/aospa/dolby/xiaomi/geq/ui/EqualizerViewModel.kt
+++ b/dolby/src/co/aospa/dolby/xiaomi/geq/ui/EqualizerViewModel.kt
@ -0,0 +1,175 @@
+/*
+ * Copyright (C) 2024 Paranoid Android
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package co.aospa.dolby.xiaomi.geq.ui
+
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.ViewModelProvider
+import androidx.lifecycle.viewModelScope
+import androidx.lifecycle.viewmodel.initializer
+import androidx.lifecycle.viewmodel.viewModelFactory
+import co.aospa.dolby.xiaomi.geq.data.EqualizerRepository
+import co.aospa.dolby.xiaomi.geq.data.Preset
+import co.aospa.dolby.xiaomi.DolbyConstants.Companion.dlog
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.flow.drop
+import kotlinx.coroutines.flow.launchIn
+import kotlinx.coroutines.flow.onEach
+import kotlinx.coroutines.launch
+
+const val TAG = "EqViewModel"
+
+class EqualizerViewModel(
+    private val repository: EqualizerRepository
+) : ViewModel() {
+
+    private val _presets = MutableStateFlow(repository.builtInPresets)
+    val presets = _presets.asStateFlow()
+
+    private val _preset = MutableStateFlow(repository.defaultPreset)
+    val preset = _preset.asStateFlow()
+
+    private var presetRestored = false
+
+    init {
+        // Update the list of presets: combined list of user defined presets if any,
+        // and then the built in presets.
+        repository.userPresets
+            .onEach { presets ->
+                dlog(TAG, "updated userPresets: $presets")
+                _presets.value = mutableListOf<Preset>().apply {
+                    addAll(presets)
+                    addAll(repository.builtInPresets)
+                }.toList()
+
+                // We can restore the active preset only after the presets list is populated,
+                // since we do not save the preset name but only its gains.
+                if (!presetRestored) {
+                    val bandGains = repository.getBandGains()
+                    _preset.value = _presets.value.find {
+                        bandGains == it.bandGains
+                    } ?: Preset(
+                        name = "Custom",
+                        bandGains = bandGains
+                    )
+                    dlog(TAG, "restored preset: ${_preset.value}")
+                    presetRestored = true
+                }
+            }
+            .launchIn(viewModelScope)
+
+        // Update the preset in repository everytime we set it here
+        _preset
+            .drop(1) // skip the initial value
+            .onEach {
+                // wait till the active preset is restored
+                if (!presetRestored) {
+                    return@onEach
+                }
+                dlog(TAG, "updated preset: $it")
+                repository.setBandGains(it.bandGains)
+                if (it.isUserDefined) {
+                    repository.addPreset(it)
+                }
+            }
+            .launchIn(viewModelScope)
+    }
+
+    fun reset() {
+        dlog(TAG, "reset()")
+        if (_preset.value.isUserDefined) {
+            // Reset gains to 0
+            _preset.value = _preset.value.copy(
+                bandGains = repository.defaultPreset.bandGains
+            )
+        } else {
+            // Switch to flat preset
+            _preset.value = repository.defaultPreset
+        }
+    }
+
+    fun setPreset(preset: Preset) {
+        dlog(TAG, "setPreset($preset)")
+        _preset.value = preset
+    }
+
+    fun setGain(index: Int, gain: Int) {
+        dlog(TAG, "setGain($index, $gain)")
+        _preset.value = _preset.value.run {
+            copy(
+                name = if (!isUserDefined) "Custom" else name,
+                bandGains = bandGains
+                    .toMutableList()
+                    // create a new object to ensure the flow emits an update.
+                    .apply { this[index] = this[index].copy(gain = gain) }
+                    .toList(),
+                isMutated = true
+            )
+        }
+    }
+
+    // Returns string containing the error message if it failed, otherwise null
+    private fun validatePresetName(name: String): PresetNameValidationError? {
+        // Ensure we don't have another preset with the same name
+        return if (
+            _presets.value
+            .any { it.name.equals(name.trim(), ignoreCase = true) }
+        ) {
+            PresetNameValidationError.NAME_EXISTS
+        } else if (name.length > 50) {
+            PresetNameValidationError.NAME_TOO_LONG
+        } else null
+    }
+
+    fun createNewPreset(name: String): PresetNameValidationError? {
+        dlog(TAG, "createNewPreset($name)")
+        validatePresetName(name)?.let {
+            dlog(TAG, "createNewPreset failed: $it")
+            return it
+        }
+        _preset.value = _preset.value.copy(
+            name = name.trim(),
+            isUserDefined = true,
+            isMutated = false
+        )
+        return null
+    }
+
+    fun renamePreset(preset: Preset, name: String): PresetNameValidationError? {
+        dlog(TAG, "renamePreset($preset, $name)")
+        // create a preset with the new name and same gains
+        createNewPreset(name = name)?.let {
+            dlog(TAG, "renamePreset failed")
+            return it
+        }
+        // and delete the old one.
+        deletePreset(preset, shouldReset = false)
+        return null
+    }
+
+    fun deletePreset(preset: Preset, shouldReset: Boolean = true) {
+        dlog(TAG, "deletePreset($preset)")
+        viewModelScope.launch {
+            repository.removePreset(preset)
+        }
+        if (shouldReset) {
+            _preset.value = repository.defaultPreset
+        }
+    }
+
+    companion object {
+        val Factory = viewModelFactory {
+            initializer {
+                EqualizerViewModel(
+                    repository = EqualizerRepository(
+                        this[ViewModelProvider.AndroidViewModelFactory.APPLICATION_KEY]!!
+                    )
+                )
+            }
+        }
+    }
+}
--- a/dolby/src/co/aospa/dolby/xiaomi/geq/ui/PresetNameDialog.kt
+++ b/dolby/src/co/aospa/dolby/xiaomi/geq/ui/PresetNameDialog.kt
@ -0,0 +1,94 @@
+/*
+ * Copyright (C) 2024 Paranoid Android
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package co.aospa.dolby.xiaomi.geq.ui
+
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material3.AlertDialog
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.OutlinedTextField
+import androidx.compose.material3.Text
+import androidx.compose.material3.TextButton
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.unit.dp
+import co.aospa.dolby.xiaomi.R
+
+@Composable
+fun PresetNameDialog(
+    title: String,
+    presetName: String = "",
+    onPresetNameSet: (String) -> PresetNameValidationError?,
+    onDismissDialog: () -> Unit
+) {
+    var showDialog by remember { mutableStateOf(true) }
+    if (!showDialog) {
+        onDismissDialog()
+        return
+    }
+    var text by remember { mutableStateOf(presetName) }
+    var error by remember { mutableStateOf<PresetNameValidationError?>(null) }
+
+    AlertDialog(
+        onDismissRequest = { showDialog = false },
+        confirmButton = {
+            TextButton(
+                onClick = {
+                    onPresetNameSet(text)?.let {
+                        // validation failed
+                        error = it
+                        return@TextButton
+                    }
+                    // succeeded
+                    showDialog = false
+                    error = null
+                }
+            ) {
+                Text(
+                    stringResource(id = android.R.string.ok)
+                )
+            }
+        },
+        dismissButton = {
+            TextButton(
+                onClick = { showDialog = false }
+            ) {
+                Text(
+                    stringResource(id = android.R.string.cancel)
+                )
+            }
+        },
+        title = { Text(title) },
+        text = {
+            Column {
+                OutlinedTextField(
+                    value = text,
+                    onValueChange = { text = it },
+                    label = {
+                        Text(
+                            stringResource(id = R.string.dolby_geq_preset_name)
+                        )
+                    },
+                    isError = error != null,
+                    singleLine = true
+                )
+                error?.let {
+                    Text(
+                        text = it.toErrorMessage(),
+                        color = MaterialTheme.colorScheme.error,
+                        modifier = Modifier.padding(top = 8.dp)
+                    )
+                }
+            }
+        }
+    )
+}
--- a/dolby/src/co/aospa/dolby/xiaomi/geq/ui/PresetNameValidationError.kt
+++ b/dolby/src/co/aospa/dolby/xiaomi/geq/ui/PresetNameValidationError.kt
@ -0,0 +1,25 @@
+/*
+ * Copyright (C) 2024 Paranoid Android
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package co.aospa.dolby.xiaomi.geq.ui
+
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.res.stringResource
+import co.aospa.dolby.xiaomi.R
+
+enum class PresetNameValidationError {
+    NAME_EXISTS,
+    NAME_TOO_LONG;
+
+    @Composable
+    fun toErrorMessage() =
+        stringResource(
+            id = when (this) {
+                NAME_EXISTS -> R.string.dolby_geq_preset_name_exists
+                NAME_TOO_LONG -> R.string.dolby_geq_preset_name_too_long
+            }
+        )
+}
--- a/dolby/src/co/aospa/dolby/xiaomi/geq/ui/PresetSelector.kt
+++ b/dolby/src/co/aospa/dolby/xiaomi/geq/ui/PresetSelector.kt
@ -0,0 +1,176 @@
+/*
+ * Copyright (C) 2024 Paranoid Android
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package co.aospa.dolby.xiaomi.geq.ui
+
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Add
+import androidx.compose.material.icons.filled.Delete
+import androidx.compose.material.icons.filled.Edit
+import androidx.compose.material3.DropdownMenuItem
+import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.material3.ExposedDropdownMenuBox
+import androidx.compose.material3.ExposedDropdownMenuDefaults
+import androidx.compose.material3.Text
+import androidx.compose.material3.TextField
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.focus.focusProperties
+import androidx.compose.ui.graphics.vector.ImageVector
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.res.vectorResource
+import androidx.compose.ui.unit.dp
+import co.aospa.dolby.xiaomi.R
+
+@OptIn(ExperimentalMaterial3Api::class)
+@Composable
+fun PresetSelector(viewModel: EqualizerViewModel) {
+    val presets by viewModel.presets.collectAsState()
+    val currentPreset by viewModel.preset.collectAsState()
+    var expanded by remember { mutableStateOf(false) }
+    var showNewPresetDialog by remember { mutableStateOf(false) }
+    var showRenamePresetDialog by remember { mutableStateOf(false) }
+    var showDeleteConfirmDialog by remember { mutableStateOf(false) }
+    var showResetConfirmDialog by remember { mutableStateOf(false) }
+
+    Row(
+        modifier = Modifier
+            .fillMaxWidth()
+            .padding(bottom = 24.dp),
+        horizontalArrangement = Arrangement.Start,
+        verticalAlignment = Alignment.CenterVertically
+    ) {
+        ExposedDropdownMenuBox(
+            expanded = expanded,
+            onExpandedChange = { expanded = !expanded },
+            modifier = Modifier
+                .padding(end = 8.dp)
+                .weight(1f)
+        ) {
+            TextField(
+                value = currentPreset.name,
+                onValueChange = { },
+                readOnly = true,
+                label = {
+                    Text(
+                        stringResource(id = R.string.dolby_geq_preset)
+                    )
+                },
+                singleLine = true,
+                trailingIcon = {
+                    ExposedDropdownMenuDefaults.TrailingIcon(
+                        expanded = expanded
+                    )
+                },
+                colors = ExposedDropdownMenuDefaults.textFieldColors(),
+                modifier = Modifier.menuAnchor()
+                    // prevent keyboard from popping up
+                    .focusProperties { canFocus = false }
+            )
+            ExposedDropdownMenu(
+                expanded = expanded,
+                onDismissRequest = { expanded = false }
+            ) {
+                presets.forEach { preset ->
+                    DropdownMenuItem(
+                        text = { Text(text = preset.name) },
+                        onClick = {
+                            viewModel.setPreset(preset)
+                            expanded = false
+                        }
+                    )
+                }
+            }
+        }
+
+        TooltipIconButton(
+            icon = ImageVector.vectorResource(
+                id = R.drawable.save_as_24px
+            ),
+            text = stringResource(id = R.string.dolby_geq_new_preset),
+            onClick = { showNewPresetDialog = true }
+        )
+
+        if (currentPreset.isUserDefined) {
+            TooltipIconButton(
+                icon = Icons.Default.Edit,
+                text = stringResource(id = R.string.dolby_geq_rename_preset),
+                onClick = { showRenamePresetDialog = true }
+            )
+            TooltipIconButton(
+                icon = Icons.Default.Delete,
+                text = stringResource(id = R.string.dolby_geq_delete_preset),
+                onClick = { showDeleteConfirmDialog = true }
+            )
+        }
+
+        TooltipIconButton(
+            icon = ImageVector.vectorResource(
+                id = R.drawable.reset_settings_24px
+            ),
+            text = stringResource(id = R.string.dolby_geq_reset_gains),
+            onClick = {
+                if (currentPreset.isUserDefined) {
+                    showResetConfirmDialog = true
+                } else {
+                    viewModel.reset()
+                }
+            }
+        )
+    }
+
+    // Dialogs
+
+    if (showNewPresetDialog) {
+        PresetNameDialog(
+            title = stringResource(id = R.string.dolby_geq_new_preset),
+            onPresetNameSet = {
+                return@PresetNameDialog viewModel.createNewPreset(name = it)
+            },
+            onDismissDialog = { showNewPresetDialog = false }
+        )
+    }
+
+    if (showRenamePresetDialog) {
+        PresetNameDialog(
+            title = stringResource(id = R.string.dolby_geq_rename_preset),
+            presetName = currentPreset.name,
+            onPresetNameSet = {
+                return@PresetNameDialog viewModel.renamePreset(
+                    preset = currentPreset,
+                    name = it
+                )
+            },
+            onDismissDialog = { showRenamePresetDialog = false }
+        )
+    }
+
+    if (showDeleteConfirmDialog) {
+        ConfirmationDialog(
+            text = stringResource(id = R.string.dolby_geq_delete_preset_prompt),
+            onConfirm = { viewModel.deletePreset(currentPreset) },
+            onDismiss = { showDeleteConfirmDialog = false }
+        )
+    }
+
+    if (showResetConfirmDialog) {
+        ConfirmationDialog(
+            text = stringResource(id = R.string.dolby_geq_reset_gains_prompt),
+            onConfirm = { viewModel.reset() },
+            onDismiss = { showResetConfirmDialog = false }
+        )
+    }
+}
--- a/dolby/src/co/aospa/dolby/xiaomi/geq/ui/TooltipIconButton.kt
+++ b/dolby/src/co/aospa/dolby/xiaomi/geq/ui/TooltipIconButton.kt
@ -0,0 +1,40 @@
+/*
+ * Copyright (C) 2024 Paranoid Android
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package co.aospa.dolby.xiaomi.geq.ui
+
+import androidx.compose.foundation.layout.size
+import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.material3.Icon
+import androidx.compose.material3.IconButton
+import androidx.compose.material3.PlainTooltipBox
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.vector.ImageVector
+import androidx.compose.ui.unit.dp
+
+@OptIn(ExperimentalMaterial3Api::class)
+@Composable
+fun TooltipIconButton(
+    icon: ImageVector,
+    text: String,
+    onClick: () -> Unit
+) {
+    PlainTooltipBox(
+        tooltip = { Text(text) }
+    ) {
+        IconButton(
+            onClick = onClick
+        ) {
+            Icon(
+                imageVector = icon,
+                contentDescription = text,
+                modifier = Modifier.size(24.dp)
+            )
+        }
+    }
+}