Merge "Fix haptics scaling to match VibrationEffect function" into main

7 files changed, 510 insertions, 7 deletions

diff --git a/libs/vibrator/Android.bp b/libs/vibrator/Android.bp
index 2af51a722c..d3b3a734f9 100644
--- a/libs/vibrator/Android.bp
+++ b/libs/vibrator/Android.bp
@@ -24,6 +24,10 @@ package {
 cc_defaults {
     name: "libvibrator_defaults",
 
+    defaults: [
+        "aconfig_lib_cc_shared_link.defaults",
+    ],
+
     cflags: [
         "-Wall",
         "-Werror",
@@ -50,9 +54,11 @@ cc_library {
         "libbinder",
         "liblog",
         "libutils",
+        "server_configurable_flags",
     ],
 
     whole_static_libs: [
+        "android.os.vibrator.flags-aconfig-cc",
         "libvibratorutils",
     ],
 
@@ -79,8 +85,14 @@ cc_library {
     vendor_available: true,
     double_loadable: true,
 
+    static_libs: [
+        "android.os.vibrator.flags-aconfig-cc",
+    ],
+
     shared_libs: [
+        "liblog",
         "libutils",
+        "server_configurable_flags",
     ],
 
     srcs: [
@@ -89,6 +101,7 @@ cc_library {
 
     visibility: [
         "//frameworks/native/libs/vibrator",
+        "//frameworks/native/libs/vibrator/tests",
         "//frameworks/av/media/libeffects/hapticgenerator",
     ],
 }
diff --git a/libs/vibrator/ExternalVibrationUtils.cpp b/libs/vibrator/ExternalVibrationUtils.cpp
index 761ac1bf3b..706f3d7a56 100644
--- a/libs/vibrator/ExternalVibrationUtils.cpp
+++ b/libs/vibrator/ExternalVibrationUtils.cpp
@@ -15,6 +15,9 @@
  */
 #include <cstring>
 
+#include <android_os_vibrator.h>
+
+#include <algorithm>
 #include <math.h>
 
 #include <vibrator/ExternalVibrationUtils.h>
@@ -25,8 +28,9 @@ namespace {
 static constexpr float HAPTIC_SCALE_VERY_LOW_RATIO = 2.0f / 3.0f;
 static constexpr float HAPTIC_SCALE_LOW_RATIO = 3.0f / 4.0f;
 static constexpr float HAPTIC_MAX_AMPLITUDE_FLOAT = 1.0f;
+static constexpr float SCALE_GAMMA = 0.65f; // Same as VibrationEffect.SCALE_GAMMA
 
-float getHapticScaleGamma(HapticLevel level) {
+float getOldHapticScaleGamma(HapticLevel level) {
     switch (level) {
     case HapticLevel::VERY_LOW:
         return 2.0f;
@@ -41,7 +45,7 @@ float getHapticScaleGamma(HapticLevel level) {
     }
 }
 
-float getHapticMaxAmplitudeRatio(HapticLevel level) {
+float getOldHapticMaxAmplitudeRatio(HapticLevel level) {
     switch (level) {
     case HapticLevel::VERY_LOW:
         return HAPTIC_SCALE_VERY_LOW_RATIO;
@@ -56,6 +60,52 @@ float getHapticMaxAmplitudeRatio(HapticLevel level) {
     }
 }
 
+/* Same as VibrationScaler.SCALE_LEVEL_* */
+float getHapticScaleFactor(HapticLevel level) {
+    switch (level) {
+        case HapticLevel::VERY_LOW:
+            return 0.6f;
+        case HapticLevel::LOW:
+            return 0.8f;
+        case HapticLevel::HIGH:
+            return 1.2f;
+        case HapticLevel::VERY_HIGH:
+            return 1.4f;
+        default:
+            return 1.0f;
+    }
+}
+
+float applyOldHapticScale(float value, float gamma, float maxAmplitudeRatio) {
+    float sign = value >= 0 ? 1.0 : -1.0;
+    return powf(fabsf(value / HAPTIC_MAX_AMPLITUDE_FLOAT), gamma)
+                * maxAmplitudeRatio * HAPTIC_MAX_AMPLITUDE_FLOAT * sign;
+}
+
+float applyNewHapticScale(float value, float scaleFactor) {
+    float scale = powf(scaleFactor, 1.0f / SCALE_GAMMA);
+    if (scaleFactor <= 1) {
+        // Scale down is simply a gamma corrected application of scaleFactor to the intensity.
+        // Scale up requires a different curve to ensure the intensity will not become > 1.
+        return value * scale;
+    }
+
+    float sign = value >= 0 ? 1.0f : -1.0f;
+    float extraScale = powf(scaleFactor, 4.0f - scaleFactor);
+    float x = fabsf(value) * scale * extraScale;
+    float maxX = scale * extraScale; // scaled x for intensity == 1
+
+    float expX = expf(x);
+    float expMaxX = expf(maxX);
+
+    // Using f = tanh as the scale up function so the max value will converge.
+    // a = 1/f(maxX), used to scale f so that a*f(maxX) = 1 (the value will converge to 1).
+    float a = (expMaxX + 1.0f) / (expMaxX - 1.0f);
+    float fx = (expX - 1.0f) / (expX + 1.0f);
+
+    return sign * std::clamp(a * fx, 0.0f, 1.0f);
+}
+
 void applyHapticScale(float* buffer, size_t length, HapticScale scale) {
     if (scale.isScaleMute()) {
         memset(buffer, 0, length * sizeof(float));
@@ -65,15 +115,18 @@ void applyHapticScale(float* buffer, size_t length, HapticScale scale) {
         return;
     }
     HapticLevel hapticLevel = scale.getLevel();
+    float scaleFactor = getHapticScaleFactor(hapticLevel);
     float adaptiveScaleFactor = scale.getAdaptiveScaleFactor();
-    float gamma = getHapticScaleGamma(hapticLevel);
-    float maxAmplitudeRatio = getHapticMaxAmplitudeRatio(hapticLevel);
+    float oldGamma = getOldHapticScaleGamma(hapticLevel);
+    float oldMaxAmplitudeRatio = getOldHapticMaxAmplitudeRatio(hapticLevel);
 
     for (size_t i = 0; i < length; i++) {
         if (hapticLevel != HapticLevel::NONE) {
-            float sign = buffer[i] >= 0 ? 1.0 : -1.0;
-            buffer[i] = powf(fabsf(buffer[i] / HAPTIC_MAX_AMPLITUDE_FLOAT), gamma)
-                        * maxAmplitudeRatio * HAPTIC_MAX_AMPLITUDE_FLOAT * sign;
+            if (android_os_vibrator_fix_audio_coupled_haptics_scaling()) {
+                buffer[i] = applyNewHapticScale(buffer[i], scaleFactor);
+            } else {
+                buffer[i] = applyOldHapticScale(buffer[i], oldGamma, oldMaxAmplitudeRatio);
+            }
         }
 
         if (adaptiveScaleFactor != 1.0f) {
diff --git a/libs/vibrator/TEST_MAPPING b/libs/vibrator/TEST_MAPPING
new file mode 100644
index 0000000000..d782b43b57
--- /dev/null
+++ b/libs/vibrator/TEST_MAPPING
@@ -0,0 +1,7 @@
+{
+  "postsubmit": [
+    {
+      "name": "libvibrator_test"
+    }
+  ]
+}
diff --git a/libs/vibrator/tests/Android.bp b/libs/vibrator/tests/Android.bp
new file mode 100644
index 0000000000..2921a6275b
--- /dev/null
+++ b/libs/vibrator/tests/Android.bp
@@ -0,0 +1,53 @@
+// Copyright (C) 2024 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+package {
+    default_team: "trendy_team_haptics_framework",
+    // See: http://go/android-license-faq
+    // A large-scale-change added 'default_applicable_licenses' to import
+    // all of the 'license_kinds' from "frameworks_native_license"
+    // to get the below license kinds:
+    //   SPDX-license-identifier-Apache-2.0
+    default_applicable_licenses: ["frameworks_native_license"],
+}
+
+cc_test {
+    name: "libvibrator_test",
+    test_suites: ["general-tests"],
+    defaults: [
+        "aconfig_lib_cc_shared_link.defaults",
+    ],
+    srcs: [
+        "ExternalVibrationTest.cpp",
+        "ExternalVibrationUtilsTest.cpp",
+    ],
+    cflags: [
+        "-Wall",
+        "-Werror",
+        "-Wextra",
+    ],
+    static_libs: [
+        "android.os.vibrator.flags-aconfig-cc",
+        "libflagtest",
+        "libgtest",
+        "liblog",
+        "libvibrator",
+        "libvibratorutils",
+    ],
+    shared_libs: [
+        "libbase",
+        "libbinder",
+        "libutils",
+        "server_configurable_flags",
+    ],
+}
diff --git a/libs/vibrator/tests/ExternalVibrationTest.cpp b/libs/vibrator/tests/ExternalVibrationTest.cpp
new file mode 100644
index 0000000000..3141380219
--- /dev/null
+++ b/libs/vibrator/tests/ExternalVibrationTest.cpp
@@ -0,0 +1,109 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *            http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <binder/Parcel.h>
+#include <gtest/gtest.h>
+#include <vibrator/ExternalVibration.h>
+
+using namespace android;
+using namespace testing;
+
+using HapticLevel = os::HapticLevel;
+using ScaleLevel = os::ExternalVibrationScale::ScaleLevel;
+
+class TestVibrationController : public os::IExternalVibrationController {
+public:
+    explicit TestVibrationController() {}
+    IBinder *onAsBinder() override { return nullptr; }
+    binder::Status mute(/*out*/ bool *ret) override {
+        *ret = false;
+        return binder::Status::ok();
+    };
+    binder::Status unmute(/*out*/ bool *ret) override {
+        *ret = false;
+        return binder::Status::ok();
+    };
+};
+
+class ExternalVibrationTest : public Test {
+protected:
+    HapticLevel toHapticLevel(ScaleLevel level) {
+        os::ExternalVibrationScale externalVibrationScale;
+        externalVibrationScale.scaleLevel = level;
+        os::HapticScale hapticScale =
+                os::ExternalVibration::externalVibrationScaleToHapticScale(externalVibrationScale);
+        return hapticScale.getLevel();
+    }
+};
+
+TEST_F(ExternalVibrationTest, TestReadAndWriteToParcel) {
+    int32_t uid = 1;
+    std::string pkg("package.name");
+    audio_attributes_t originalAttrs;
+    originalAttrs.content_type = AUDIO_CONTENT_TYPE_SONIFICATION;
+    originalAttrs.usage = AUDIO_USAGE_ASSISTANCE_SONIFICATION;
+    originalAttrs.source = AUDIO_SOURCE_VOICE_COMMUNICATION;
+    originalAttrs.flags = AUDIO_FLAG_BYPASS_MUTE;
+    sp<TestVibrationController> vibrationController = new TestVibrationController();
+    ASSERT_NE(vibrationController, nullptr);
+    sp<os::ExternalVibration> original =
+            new os::ExternalVibration(uid, pkg, originalAttrs, vibrationController);
+    ASSERT_NE(original, nullptr);
+    EXPECT_EQ(original->getUid(), uid);
+    EXPECT_EQ(original->getPackage(), pkg);
+    EXPECT_EQ(original->getAudioAttributes().content_type, originalAttrs.content_type);
+    EXPECT_EQ(original->getAudioAttributes().usage, originalAttrs.usage);
+    EXPECT_EQ(original->getAudioAttributes().source, originalAttrs.source);
+    EXPECT_EQ(original->getAudioAttributes().flags, originalAttrs.flags);
+    EXPECT_EQ(original->getController(), vibrationController);
+    audio_attributes_t defaultAttrs;
+    defaultAttrs.content_type = AUDIO_CONTENT_TYPE_UNKNOWN;
+    defaultAttrs.usage = AUDIO_USAGE_UNKNOWN;
+    defaultAttrs.source = AUDIO_SOURCE_DEFAULT;
+    defaultAttrs.flags = AUDIO_FLAG_NONE;
+    sp<os::ExternalVibration> parceled =
+            new os::ExternalVibration(0, std::string(""), defaultAttrs, nullptr);
+    ASSERT_NE(parceled, nullptr);
+    Parcel parcel;
+    original->writeToParcel(&parcel);
+    parcel.setDataPosition(0);
+    parceled->readFromParcel(&parcel);
+    EXPECT_EQ(parceled->getUid(), uid);
+    EXPECT_EQ(parceled->getPackage(), pkg);
+    EXPECT_EQ(parceled->getAudioAttributes().content_type, originalAttrs.content_type);
+    EXPECT_EQ(parceled->getAudioAttributes().usage, originalAttrs.usage);
+    EXPECT_EQ(parceled->getAudioAttributes().source, originalAttrs.source);
+    EXPECT_EQ(parceled->getAudioAttributes().flags, originalAttrs.flags);
+    // TestVibrationController does not implement onAsBinder, skip controller parcel in this test.
+}
+
+TEST_F(ExternalVibrationTest, TestExternalVibrationScaleToHapticScale) {
+    os::ExternalVibrationScale externalVibrationScale;
+    externalVibrationScale.scaleLevel = ScaleLevel::SCALE_HIGH;
+    externalVibrationScale.adaptiveHapticsScale = 0.8f;
+    os::HapticScale hapticScale =
+            os::ExternalVibration::externalVibrationScaleToHapticScale(externalVibrationScale);
+    // Check scale factor is forwarded.
+    EXPECT_EQ(hapticScale.getLevel(), HapticLevel::HIGH);
+    EXPECT_EQ(hapticScale.getAdaptiveScaleFactor(), 0.8f);
+    // Check conversion for all levels.
+    EXPECT_EQ(toHapticLevel(ScaleLevel::SCALE_MUTE), HapticLevel::MUTE);
+    EXPECT_EQ(toHapticLevel(ScaleLevel::SCALE_VERY_LOW), HapticLevel::VERY_LOW);
+    EXPECT_EQ(toHapticLevel(ScaleLevel::SCALE_LOW), HapticLevel::LOW);
+    EXPECT_EQ(toHapticLevel(ScaleLevel::SCALE_NONE), HapticLevel::NONE);
+    EXPECT_EQ(toHapticLevel(ScaleLevel::SCALE_HIGH), HapticLevel::HIGH);
+    EXPECT_EQ(toHapticLevel(ScaleLevel::SCALE_VERY_HIGH), HapticLevel::VERY_HIGH);
+}
diff --git a/libs/vibrator/tests/ExternalVibrationUtilsTest.cpp b/libs/vibrator/tests/ExternalVibrationUtilsTest.cpp
new file mode 100644
index 0000000000..3d8dd9cb5b
--- /dev/null
+++ b/libs/vibrator/tests/ExternalVibrationUtilsTest.cpp
@@ -0,0 +1,237 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *            http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <android_os_vibrator.h>
+#include <flag_macros.h>
+#include <gtest/gtest.h>
+#include <vibrator/ExternalVibrationUtils.h>
+
+#include "test_utils.h"
+
+#define FLAG_NS android::os::vibrator
+
+using namespace android;
+using namespace testing;
+
+using HapticScale = os::HapticScale;
+using HapticLevel = os::HapticLevel;
+
+static constexpr float TEST_TOLERANCE = 1e-2f;
+static constexpr size_t TEST_BUFFER_LENGTH = 4;
+static float TEST_BUFFER[TEST_BUFFER_LENGTH] = { 1, -1, 0.5f, -0.2f };
+
+class ExternalVibrationUtilsTest : public Test {
+public:
+    void SetUp() override {
+        std::copy(std::begin(TEST_BUFFER), std::end(TEST_BUFFER), std::begin(mBuffer));
+    }
+
+protected:
+    void scaleBuffer(HapticLevel hapticLevel) {
+        scaleBuffer(HapticScale(hapticLevel), 0 /* limit */);
+    }
+
+    void scaleBuffer(HapticLevel hapticLevel, float adaptiveScaleFactor) {
+        scaleBuffer(hapticLevel, adaptiveScaleFactor, 0 /* limit */);
+    }
+
+    void scaleBuffer(HapticLevel hapticLevel, float adaptiveScaleFactor, float limit) {
+        scaleBuffer(HapticScale(hapticLevel, adaptiveScaleFactor), limit);
+    }
+
+    void scaleBuffer(HapticScale hapticScale, float limit) {
+        std::copy(std::begin(TEST_BUFFER), std::end(TEST_BUFFER), std::begin(mBuffer));
+        os::scaleHapticData(&mBuffer[0], TEST_BUFFER_LENGTH, hapticScale, limit);
+    }
+
+    float mBuffer[TEST_BUFFER_LENGTH];
+};
+
+TEST_F_WITH_FLAGS(
+        ExternalVibrationUtilsTest,
+        TestLegacyScaleMute,
+        REQUIRES_FLAGS_DISABLED(ACONFIG_FLAG(FLAG_NS, fix_audio_coupled_haptics_scaling))
+) {
+    float expected[TEST_BUFFER_LENGTH];
+    std::fill(std::begin(expected), std::end(expected), 0);
+
+    scaleBuffer(HapticLevel::MUTE);
+    EXPECT_FLOATS_NEARLY_EQ(expected, mBuffer, TEST_BUFFER_LENGTH, TEST_TOLERANCE);
+}
+
+TEST_F_WITH_FLAGS(
+        ExternalVibrationUtilsTest,
+        TestFixedScaleMute,
+        REQUIRES_FLAGS_ENABLED(ACONFIG_FLAG(FLAG_NS, fix_audio_coupled_haptics_scaling))
+) {
+    float expected[TEST_BUFFER_LENGTH];
+    std::fill(std::begin(expected), std::end(expected), 0);
+
+    scaleBuffer(HapticLevel::MUTE);
+    EXPECT_FLOATS_NEARLY_EQ(expected, mBuffer, TEST_BUFFER_LENGTH, TEST_TOLERANCE);
+}
+
+TEST_F_WITH_FLAGS(
+        ExternalVibrationUtilsTest,
+        TestLegacyScaleNone,
+        REQUIRES_FLAGS_DISABLED(ACONFIG_FLAG(FLAG_NS, fix_audio_coupled_haptics_scaling))
+) {
+    float expected[TEST_BUFFER_LENGTH];
+    std::copy(std::begin(TEST_BUFFER), std::end(TEST_BUFFER), std::begin(expected));
+
+    scaleBuffer(HapticLevel::NONE);
+    EXPECT_FLOATS_NEARLY_EQ(expected, mBuffer, TEST_BUFFER_LENGTH, TEST_TOLERANCE);
+}
+
+TEST_F_WITH_FLAGS(
+        ExternalVibrationUtilsTest,
+        TestFixedScaleNone,
+        REQUIRES_FLAGS_ENABLED(ACONFIG_FLAG(FLAG_NS, fix_audio_coupled_haptics_scaling))
+) {
+    float expected[TEST_BUFFER_LENGTH];
+    std::copy(std::begin(TEST_BUFFER), std::end(TEST_BUFFER), std::begin(expected));
+
+    scaleBuffer(HapticLevel::NONE);
+    EXPECT_FLOATS_NEARLY_EQ(expected, mBuffer, TEST_BUFFER_LENGTH, TEST_TOLERANCE);
+}
+
+TEST_F_WITH_FLAGS(
+    ExternalVibrationUtilsTest,
+    TestLegacyScaleToHapticLevel,
+    REQUIRES_FLAGS_DISABLED(ACONFIG_FLAG(FLAG_NS, fix_audio_coupled_haptics_scaling))
+) {
+    float expectedVeryHigh[TEST_BUFFER_LENGTH] = { 1, -1, 0.84f, -0.66f };
+    scaleBuffer(HapticLevel::VERY_HIGH);
+    EXPECT_FLOATS_NEARLY_EQ(expectedVeryHigh, mBuffer, TEST_BUFFER_LENGTH, TEST_TOLERANCE);
+
+    float expectedHigh[TEST_BUFFER_LENGTH] = { 1, -1, 0.7f, -0.44f };
+    scaleBuffer(HapticLevel::HIGH);
+    EXPECT_FLOATS_NEARLY_EQ(expectedHigh, mBuffer, TEST_BUFFER_LENGTH, TEST_TOLERANCE);
+
+    float expectedLow[TEST_BUFFER_LENGTH] = { 0.75f, -0.75f, 0.26f, -0.06f };
+    scaleBuffer(HapticLevel::LOW);
+    EXPECT_FLOATS_NEARLY_EQ(expectedLow, mBuffer, TEST_BUFFER_LENGTH, TEST_TOLERANCE);
+
+    float expectedVeryLow[TEST_BUFFER_LENGTH] = { 0.66f, -0.66f, 0.16f, -0.02f };
+    scaleBuffer(HapticLevel::VERY_LOW);
+    EXPECT_FLOATS_NEARLY_EQ(expectedVeryLow, mBuffer, TEST_BUFFER_LENGTH, TEST_TOLERANCE);
+}
+
+TEST_F_WITH_FLAGS(
+        ExternalVibrationUtilsTest,
+        TestFixedScaleToHapticLevel,
+        REQUIRES_FLAGS_ENABLED(ACONFIG_FLAG(FLAG_NS, fix_audio_coupled_haptics_scaling))
+) {
+    float expectedVeryHigh[TEST_BUFFER_LENGTH] = { 1, -1, 0.79f, -0.39f };
+    scaleBuffer(HapticLevel::VERY_HIGH);
+    EXPECT_FLOATS_NEARLY_EQ(expectedVeryHigh, mBuffer, TEST_BUFFER_LENGTH, TEST_TOLERANCE);
+
+    float expectedHigh[TEST_BUFFER_LENGTH] = { 1, -1, 0.62f, -0.27f };
+    scaleBuffer(HapticLevel::HIGH);
+    EXPECT_FLOATS_NEARLY_EQ(expectedHigh, mBuffer, TEST_BUFFER_LENGTH, TEST_TOLERANCE);
+
+    float expectedLow[TEST_BUFFER_LENGTH] = { 0.70f, -0.70f, 0.35f, -0.14f };
+    scaleBuffer(HapticLevel::LOW);
+    EXPECT_FLOATS_NEARLY_EQ(expectedLow, mBuffer, TEST_BUFFER_LENGTH, TEST_TOLERANCE);
+
+    float expectedVeryLow[TEST_BUFFER_LENGTH] = { 0.45f, -0.45f, 0.22f, -0.09f };
+    scaleBuffer(HapticLevel::VERY_LOW);
+    EXPECT_FLOATS_NEARLY_EQ(expectedVeryLow, mBuffer, TEST_BUFFER_LENGTH, TEST_TOLERANCE);
+}
+
+TEST_F_WITH_FLAGS(
+        ExternalVibrationUtilsTest,
+        TestAdaptiveScaleFactorAppliedAfterLegacyScale,
+        REQUIRES_FLAGS_DISABLED(ACONFIG_FLAG(FLAG_NS, fix_audio_coupled_haptics_scaling))
+) {
+    // Haptic level scale up then adaptive scale down
+    float expectedVeryHigh[TEST_BUFFER_LENGTH] = { 0.2, -0.2, 0.16f, -0.13f };
+    scaleBuffer(HapticLevel::VERY_HIGH, 0.2f /* adaptiveScaleFactor */);
+    EXPECT_FLOATS_NEARLY_EQ(expectedVeryHigh, mBuffer, TEST_BUFFER_LENGTH, TEST_TOLERANCE);
+
+    // Haptic level scale up then adaptive scale up
+    float expectedHigh[TEST_BUFFER_LENGTH] = { 1.5f, -1.5f, 1.06f, -0.67f };
+    scaleBuffer(HapticLevel::HIGH, 1.5f /* adaptiveScaleFactor */);
+    EXPECT_FLOATS_NEARLY_EQ(expectedHigh, mBuffer, TEST_BUFFER_LENGTH, TEST_TOLERANCE);
+
+    // Haptic level scale down then adaptive scale down
+    float expectedLow[TEST_BUFFER_LENGTH] = { 0.45f, -0.45f, 0.15f, -0.04f };
+    scaleBuffer(HapticLevel::LOW, 0.6f /* adaptiveScaleFactor */);
+    EXPECT_FLOATS_NEARLY_EQ(expectedLow, mBuffer, TEST_BUFFER_LENGTH, TEST_TOLERANCE);
+
+    // Haptic level scale down then adaptive scale up
+    float expectedVeryLow[TEST_BUFFER_LENGTH] = { 1.33f, -1.33f, 0.33f, -0.05f };
+    scaleBuffer(HapticLevel::VERY_LOW, 2 /* adaptiveScaleFactor */);
+    EXPECT_FLOATS_NEARLY_EQ(expectedVeryLow, mBuffer, TEST_BUFFER_LENGTH, TEST_TOLERANCE);
+}
+
+TEST_F_WITH_FLAGS(
+        ExternalVibrationUtilsTest,
+        TestAdaptiveScaleFactorAppliedAfterFixedScale,
+        REQUIRES_FLAGS_ENABLED(ACONFIG_FLAG(FLAG_NS, fix_audio_coupled_haptics_scaling))
+) {
+    // Haptic level scale up then adaptive scale down
+    float expectedVeryHigh[TEST_BUFFER_LENGTH] = { 0.2, -0.2, 0.16f, -0.07f };
+    scaleBuffer(HapticLevel::VERY_HIGH, 0.2f /* adaptiveScaleFactor */);
+    EXPECT_FLOATS_NEARLY_EQ(expectedVeryHigh, mBuffer, TEST_BUFFER_LENGTH, TEST_TOLERANCE);
+
+    // Haptic level scale up then adaptive scale up
+    float expectedHigh[TEST_BUFFER_LENGTH] = { 1.5f, -1.5f, 0.93f, -0.41f };
+    scaleBuffer(HapticLevel::HIGH, 1.5f /* adaptiveScaleFactor */);
+    EXPECT_FLOATS_NEARLY_EQ(expectedHigh, mBuffer, TEST_BUFFER_LENGTH, TEST_TOLERANCE);
+
+    // Haptic level scale down then adaptive scale down
+    float expectedLow[TEST_BUFFER_LENGTH] = { 0.42f, -0.42f, 0.21f, -0.08f };
+    scaleBuffer(HapticLevel::LOW, 0.6f /* adaptiveScaleFactor */);
+    EXPECT_FLOATS_NEARLY_EQ(expectedLow, mBuffer, TEST_BUFFER_LENGTH, TEST_TOLERANCE);
+
+    // Haptic level scale down then adaptive scale up
+    float expectedVeryLow[TEST_BUFFER_LENGTH] = { 0.91f, -0.91f, 0.45f, -0.18f };
+    scaleBuffer(HapticLevel::VERY_LOW, 2 /* adaptiveScaleFactor */);
+    EXPECT_FLOATS_NEARLY_EQ(expectedVeryLow, mBuffer, TEST_BUFFER_LENGTH, TEST_TOLERANCE);
+}
+
+TEST_F_WITH_FLAGS(
+        ExternalVibrationUtilsTest,
+        TestLimitAppliedAfterLegacyScale,
+        REQUIRES_FLAGS_DISABLED(ACONFIG_FLAG(FLAG_NS, fix_audio_coupled_haptics_scaling))
+) {
+    // Scaled = { 0.2, -0.2, 0.16f, -0.13f };
+    float expectedClippedVeryHigh[TEST_BUFFER_LENGTH] = { 0.15f, -0.15f, 0.15f, -0.13f };
+    scaleBuffer(HapticLevel::VERY_HIGH, 0.2f /* adaptiveScaleFactor */, 0.15f /* limit */);
+    EXPECT_FLOATS_NEARLY_EQ(expectedClippedVeryHigh, mBuffer, TEST_BUFFER_LENGTH, TEST_TOLERANCE);
+
+    // Scaled = { 1, -1, 0.5f, -0.2f };
+    float expectedClippedVeryLow[TEST_BUFFER_LENGTH] = { 0.7f, -0.7f, 0.33f, -0.05f };
+    scaleBuffer(HapticLevel::VERY_LOW, 2 /* adaptiveScaleFactor */, 0.7f /* limit */);
+    EXPECT_FLOATS_NEARLY_EQ(expectedClippedVeryLow, mBuffer, TEST_BUFFER_LENGTH, TEST_TOLERANCE);
+}
+
+TEST_F_WITH_FLAGS(
+        ExternalVibrationUtilsTest,
+        TestLimitAppliedAfterFixedScale,
+        REQUIRES_FLAGS_ENABLED(ACONFIG_FLAG(FLAG_NS, fix_audio_coupled_haptics_scaling))
+) {
+    // Scaled = { 0.2, -0.2, 0.16f, -0.13f };
+    float expectedClippedVeryHigh[TEST_BUFFER_LENGTH] = { 0.15f, -0.15f, 0.15f, -0.07f };
+    scaleBuffer(HapticLevel::VERY_HIGH, 0.2f /* adaptiveScaleFactor */, 0.15f /* limit */);
+    EXPECT_FLOATS_NEARLY_EQ(expectedClippedVeryHigh, mBuffer, TEST_BUFFER_LENGTH, TEST_TOLERANCE);
+
+    // Scaled = { 1, -1, 0.5f, -0.2f };
+    float expectedClippedVeryLow[TEST_BUFFER_LENGTH] = { 0.7f, -0.7f, 0.45f, -0.18f };
+    scaleBuffer(HapticLevel::VERY_LOW, 2 /* adaptiveScaleFactor */, 0.7f /* limit */);
+    EXPECT_FLOATS_NEARLY_EQ(expectedClippedVeryLow, mBuffer, TEST_BUFFER_LENGTH, TEST_TOLERANCE);
+}
diff --git a/libs/vibrator/tests/test_utils.h b/libs/vibrator/tests/test_utils.h
new file mode 100644
index 0000000000..f491ea1f49
--- /dev/null
+++ b/libs/vibrator/tests/test_utils.h
@@ -0,0 +1,31 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *            http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef LIBVIBRATOR_TEST_UTILS_H
+#define LIBVIBRATOR_TEST_UTILS_H
+
+#include <gtest/gtest.h>
+
+#if !defined(EXPECT_FLOATS_NEARLY_EQ)
+#define EXPECT_FLOATS_NEARLY_EQ(expected, actual, length, epsilon)              \
+        for (size_t i = 0; i < length; i++) {                                   \
+            EXPECT_NEAR(expected[i], actual[i], epsilon) << " at Index: " << i; \
+        }
+#else
+#error Macro EXPECT_FLOATS_NEARLY_EQ already defined
+#endif
+
+#endif //LIBVIBRATOR_TEST_UTILS_H