diff --git a/vibrator/aidl/android/hardware/vibrator/CompositeEffect.aidl b/vibrator/aidl/android/hardware/vibrator/CompositeEffect.aidl
new file mode 100644
index 0000000..84556b5
--- /dev/null
+++ b/vibrator/aidl/android/hardware/vibrator/CompositeEffect.aidl
@@ -0,0 +1,28 @@
+/*
+ * Copyright (C) 2019 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 android.hardware.vibrator;
+
+import android.hardware.vibrator.CompositePrimitive;
+
+@VintfStability
+parcelable CompositeEffect {
+    /* Period of silence preceding primitive. */
+    int delayMs;
+    CompositePrimitive primitive;
+    /* 0.0 (exclusive) - 1.0 (inclusive) */
+    float scale;
+}
diff --git a/vibrator/aidl/android/hardware/vibrator/CompositePrimitive.aidl b/vibrator/aidl/android/hardware/vibrator/CompositePrimitive.aidl
new file mode 100644
index 0000000..2a9d0be
--- /dev/null
+++ b/vibrator/aidl/android/hardware/vibrator/CompositePrimitive.aidl
@@ -0,0 +1,29 @@
+/*
+ * Copyright (C) 2019 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 android.hardware.vibrator;
+
+@VintfStability
+@Backing(type="int")
+enum CompositePrimitive {
+    NOOP,
+    CLICK,
+    THUD,
+    SPIN,
+    QUICK_RISE,
+    SLOW_RISE,
+    QUICK_FALL,
+}
diff --git a/vibrator/aidl/android/hardware/vibrator/IVibrator.aidl b/vibrator/aidl/android/hardware/vibrator/IVibrator.aidl
index 8c4fd05..ebf5faa 100644
--- a/vibrator/aidl/android/hardware/vibrator/IVibrator.aidl
+++ b/vibrator/aidl/android/hardware/vibrator/IVibrator.aidl
@@ -19,6 +19,8 @@
 import android.hardware.vibrator.IVibratorCallback;
 import android.hardware.vibrator.Effect;
 import android.hardware.vibrator.EffectStrength;
+import android.hardware.vibrator.CompositeEffect;
+import android.hardware.vibrator.CompositePrimitive;
 
 @VintfStability
 interface IVibrator {
@@ -42,6 +44,10 @@
      * Whether setAmplitude is supported (when external control is enabled)
      */
     const int CAP_EXTERNAL_AMPLITUDE_CONTROL = 1 << 4;
+    /**
+     * Whether compose is supported.
+     */
+    const int CAP_COMPOSE_EFFECTS = 1 << 5;
 
     /**
      * Determine capabilities of the vibrator HAL (CAP_* mask)
@@ -107,11 +113,10 @@
      * CAP_EXTERNAL_AMPLITUDE_CONTROL.
      *
      * @param amplitude The unitless force setting. Note that this number must
-     *                  be between 1 and 255, inclusive. If the motor does not
-     *                  have exactly 255 steps, it must do it's best to map it
-     *                  onto the number of steps it does have.
+     *                  be between 0.0 (exclusive) and 1.0 (inclusive). It must
+     *                  do it's best to map it onto the number of steps it does have.
      */
-    void setAmplitude(in int amplitude);
+    void setAmplitude(in float amplitude);
 
     /**
      * Enables/disables control override of vibrator to audio.
@@ -128,4 +133,36 @@
      * @param enabled Whether external control should be enabled or disabled.
      */
     void setExternalControl(in boolean enabled);
+
+    /**
+     * Retrieve composition delay limit.
+     *
+     * Support is reflected in getCapabilities (CAP_COMPOSE_EFFECTS).
+     *
+     * @return Maximum delay for a single CompositeEffect[] entry.
+     */
+    int getCompositionDelayMax();
+
+    /**
+     * Retrieve composition size limit.
+     *
+     * Support is reflected in getCapabilities (CAP_COMPOSE_EFFECTS).
+     *
+     * @return Maximum number of entries in CompositeEffect[].
+     * @param maxDelayMs Maximum delay for a single CompositeEffect[] entry.
+     */
+    int getCompositionSizeMax();
+
+    /**
+     * Fire off a string of effect primitives, combined to perform richer effects.
+     *
+     * Support is reflected in getCapabilities (CAP_COMPOSE_EFFECTS).
+     *
+     * Doing this operation while the vibrator is already on is undefined behavior. Clients should
+     * explicitly call off.
+     *
+     * @param composite Array of composition parameters.
+     */
+    void compose(in CompositeEffect[] composite, in IVibratorCallback callback);
+
 }
diff --git a/vibrator/aidl/default/Vibrator.cpp b/vibrator/aidl/default/Vibrator.cpp
index 09cd234..a77c49a 100644
--- a/vibrator/aidl/default/Vibrator.cpp
+++ b/vibrator/aidl/default/Vibrator.cpp
@@ -24,11 +24,14 @@
 namespace hardware {
 namespace vibrator {
 
+static constexpr int32_t kComposeDelayMaxMs = 1000;
+static constexpr int32_t kComposeSizeMax = 256;
+
 ndk::ScopedAStatus Vibrator::getCapabilities(int32_t* _aidl_return) {
     LOG(INFO) << "Vibrator reporting capabilities";
     *_aidl_return = IVibrator::CAP_ON_CALLBACK | IVibrator::CAP_PERFORM_CALLBACK |
                     IVibrator::CAP_AMPLITUDE_CONTROL | IVibrator::CAP_EXTERNAL_CONTROL |
-                    IVibrator::CAP_EXTERNAL_AMPLITUDE_CONTROL;
+                    IVibrator::CAP_EXTERNAL_AMPLITUDE_CONTROL | IVibrator::CAP_COMPOSE_EFFECTS;
     return ndk::ScopedAStatus::ok();
 }
 
@@ -84,9 +87,9 @@
     return ndk::ScopedAStatus::ok();
 }
 
-ndk::ScopedAStatus Vibrator::setAmplitude(int32_t amplitude) {
+ndk::ScopedAStatus Vibrator::setAmplitude(float amplitude) {
     LOG(INFO) << "Vibrator set amplitude: " << amplitude;
-    if (amplitude <= 0 || amplitude > 255) {
+    if (amplitude <= 0.0f || amplitude > 1.0f) {
         return ndk::ScopedAStatus(AStatus_fromExceptionCode(EX_ILLEGAL_ARGUMENT));
     }
     return ndk::ScopedAStatus::ok();
@@ -97,6 +100,55 @@
     return ndk::ScopedAStatus::ok();
 }
 
+ndk::ScopedAStatus Vibrator::getCompositionDelayMax(int32_t* maxDelayMs) {
+    *maxDelayMs = kComposeDelayMaxMs;
+    return ndk::ScopedAStatus::ok();
+}
+
+ndk::ScopedAStatus Vibrator::getCompositionSizeMax(int32_t* maxSize) {
+    *maxSize = kComposeSizeMax;
+    return ndk::ScopedAStatus::ok();
+}
+
+ndk::ScopedAStatus Vibrator::compose(const std::vector<CompositeEffect>& composite,
+                                     const std::shared_ptr<IVibratorCallback>& callback) {
+    if (composite.size() > kComposeSizeMax) {
+        return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_ARGUMENT);
+    }
+
+    for (auto& e : composite) {
+        if (e.delayMs > kComposeDelayMaxMs) {
+            return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_ARGUMENT);
+        }
+        if (e.scale <= 0.0f || e.scale > 1.0f) {
+            return ndk::ScopedAStatus::fromExceptionCode(EX_ILLEGAL_ARGUMENT);
+        }
+        if (e.primitive < CompositePrimitive::NOOP ||
+            e.primitive > CompositePrimitive::QUICK_FALL) {
+            return ndk::ScopedAStatus::fromExceptionCode(EX_UNSUPPORTED_OPERATION);
+        }
+    }
+
+    std::thread([=] {
+        LOG(INFO) << "Starting compose on another thread";
+
+        for (auto& e : composite) {
+            if (e.delayMs) {
+                usleep(e.delayMs * 1000);
+            }
+            LOG(INFO) << "triggering primitive " << static_cast<int>(e.primitive) << " @ scale "
+                      << e.scale;
+        }
+
+        if (callback != nullptr) {
+            LOG(INFO) << "Notifying perform complete";
+            callback->onComplete();
+        }
+    }).detach();
+
+    return ndk::ScopedAStatus::ok();
+}
+
 }  // namespace vibrator
 }  // namespace hardware
 }  // namespace android
diff --git a/vibrator/aidl/default/include/vibrator-impl/Vibrator.h b/vibrator/aidl/default/include/vibrator-impl/Vibrator.h
index 14e7292..817ec80 100644
--- a/vibrator/aidl/default/include/vibrator-impl/Vibrator.h
+++ b/vibrator/aidl/default/include/vibrator-impl/Vibrator.h
@@ -32,8 +32,12 @@
                                const std::shared_ptr<IVibratorCallback>& callback,
                                int32_t* _aidl_return) override;
     ndk::ScopedAStatus getSupportedEffects(std::vector<Effect>* _aidl_return) override;
-    ndk::ScopedAStatus setAmplitude(int32_t amplitude) override;
+    ndk::ScopedAStatus setAmplitude(float amplitude) override;
     ndk::ScopedAStatus setExternalControl(bool enabled) override;
+    ndk::ScopedAStatus getCompositionDelayMax(int32_t* maxDelayMs);
+    ndk::ScopedAStatus getCompositionSizeMax(int32_t* maxSize);
+    ndk::ScopedAStatus compose(const std::vector<CompositeEffect>& composite,
+                               const std::shared_ptr<IVibratorCallback>& callback) override;
 };
 
 }  // namespace vibrator
diff --git a/vibrator/aidl/vts/VtsHalVibratorTargetTest.cpp b/vibrator/aidl/vts/VtsHalVibratorTargetTest.cpp
index b6aa9e2..5c6120b 100644
--- a/vibrator/aidl/vts/VtsHalVibratorTargetTest.cpp
+++ b/vibrator/aidl/vts/VtsHalVibratorTargetTest.cpp
@@ -28,6 +28,8 @@
 using android::String16;
 using android::binder::Status;
 using android::hardware::vibrator::BnVibratorCallback;
+using android::hardware::vibrator::CompositeEffect;
+using android::hardware::vibrator::CompositePrimitive;
 using android::hardware::vibrator::Effect;
 using android::hardware::vibrator::EffectStrength;
 using android::hardware::vibrator::IVibrator;
@@ -55,6 +57,20 @@
         static_cast<EffectStrength>(static_cast<int8_t>(kEffectStrengths.back()) + 1),
 };
 
+// TODO(b/143992652): autogenerate
+const std::vector<CompositePrimitive> kCompositePrimitives = {
+        CompositePrimitive::NOOP,       CompositePrimitive::CLICK,
+        CompositePrimitive::THUD,       CompositePrimitive::SPIN,
+        CompositePrimitive::QUICK_RISE, CompositePrimitive::SLOW_RISE,
+        CompositePrimitive::QUICK_FALL,
+};
+// TODO(b/143992652): autogenerate
+
+const std::vector<CompositePrimitive> kInvalidPrimitives = {
+        static_cast<CompositePrimitive>(static_cast<int32_t>(kCompositePrimitives.front()) - 1),
+        static_cast<CompositePrimitive>(static_cast<int32_t>(kCompositePrimitives.back()) + 1),
+};
+
 class CompletionCallback : public BnVibratorCallback {
   public:
     CompletionCallback(const std::function<void()>& callback) : mCallback(callback) {}
@@ -201,11 +217,11 @@
 
 TEST_P(VibratorAidl, ChangeVibrationAmplitude) {
     if (capabilities & IVibrator::CAP_AMPLITUDE_CONTROL) {
-        EXPECT_TRUE(vibrator->setAmplitude(1).isOk());
+        EXPECT_EQ(Status::EX_NONE, vibrator->setAmplitude(0.1f).exceptionCode());
         EXPECT_TRUE(vibrator->on(2000, nullptr /*callback*/).isOk());
-        EXPECT_TRUE(vibrator->setAmplitude(128).isOk());
+        EXPECT_EQ(Status::EX_NONE, vibrator->setAmplitude(0.5f).exceptionCode());
         sleep(1);
-        EXPECT_TRUE(vibrator->setAmplitude(255).isOk());
+        EXPECT_EQ(Status::EX_NONE, vibrator->setAmplitude(1.0f).exceptionCode());
         sleep(1);
     }
 }
@@ -214,7 +230,7 @@
     if (capabilities & IVibrator::CAP_AMPLITUDE_CONTROL) {
         EXPECT_EQ(Status::EX_ILLEGAL_ARGUMENT, vibrator->setAmplitude(-1).exceptionCode());
         EXPECT_EQ(Status::EX_ILLEGAL_ARGUMENT, vibrator->setAmplitude(0).exceptionCode());
-        EXPECT_EQ(Status::EX_ILLEGAL_ARGUMENT, vibrator->setAmplitude(256).exceptionCode());
+        EXPECT_EQ(Status::EX_ILLEGAL_ARGUMENT, vibrator->setAmplitude(1.1).exceptionCode());
     }
 }
 
@@ -240,7 +256,7 @@
     if (capabilities & IVibrator::CAP_EXTERNAL_CONTROL) {
         EXPECT_TRUE(vibrator->setExternalControl(true).isOk());
 
-        Status amplitudeStatus = vibrator->setAmplitude(128);
+        Status amplitudeStatus = vibrator->setAmplitude(0.5);
         if (supportsExternalAmplitudeControl) {
             EXPECT_TRUE(amplitudeStatus.isOk());
         } else {
@@ -259,6 +275,102 @@
     }
 }
 
+TEST_P(VibratorAidl, ComposeValidPrimitives) {
+    if (capabilities & IVibrator::CAP_COMPOSE_EFFECTS) {
+        int32_t maxDelay, maxSize;
+
+        EXPECT_EQ(Status::EX_NONE, vibrator->getCompositionDelayMax(&maxDelay).exceptionCode());
+        EXPECT_EQ(Status::EX_NONE, vibrator->getCompositionSizeMax(&maxSize).exceptionCode());
+
+        std::vector<CompositeEffect> composite;
+
+        for (auto primitive : kCompositePrimitives) {
+            CompositeEffect effect;
+
+            effect.delayMs = std::rand() % (maxDelay + 1);
+            effect.primitive = primitive;
+            effect.scale = static_cast<float>(std::rand()) / RAND_MAX ?: 1.0f;
+            composite.emplace_back(effect);
+
+            if (composite.size() == maxSize) {
+                EXPECT_EQ(Status::EX_NONE, vibrator->compose(composite, nullptr).exceptionCode());
+                composite.clear();
+                vibrator->off();
+            }
+        }
+
+        if (composite.size() != 0) {
+            EXPECT_EQ(Status::EX_NONE, vibrator->compose(composite, nullptr).exceptionCode());
+            vibrator->off();
+        }
+    }
+}
+
+TEST_P(VibratorAidl, ComposeUnsupportedPrimitives) {
+    if (capabilities & IVibrator::CAP_COMPOSE_EFFECTS) {
+        for (auto primitive : kInvalidPrimitives) {
+            std::vector<CompositeEffect> composite(1);
+
+            for (auto& effect : composite) {
+                effect.delayMs = 0;
+                effect.primitive = primitive;
+                effect.scale = 1.0f;
+            }
+            EXPECT_EQ(Status::EX_UNSUPPORTED_OPERATION,
+                      vibrator->compose(composite, nullptr).exceptionCode());
+            vibrator->off();
+        }
+    }
+}
+
+TEST_P(VibratorAidl, CompseDelayBoundary) {
+    if (capabilities & IVibrator::CAP_COMPOSE_EFFECTS) {
+        int32_t maxDelay;
+
+        EXPECT_EQ(Status::EX_NONE, vibrator->getCompositionDelayMax(&maxDelay).exceptionCode());
+
+        std::vector<CompositeEffect> composite(1);
+        CompositeEffect effect;
+
+        effect.delayMs = 1;
+        effect.primitive = CompositePrimitive::CLICK;
+        effect.scale = 1.0f;
+
+        std::fill(composite.begin(), composite.end(), effect);
+        EXPECT_EQ(Status::EX_NONE, vibrator->compose(composite, nullptr).exceptionCode());
+
+        effect.delayMs = maxDelay + 1;
+
+        std::fill(composite.begin(), composite.end(), effect);
+        EXPECT_EQ(Status::EX_ILLEGAL_ARGUMENT,
+                  vibrator->compose(composite, nullptr).exceptionCode());
+        vibrator->off();
+    }
+}
+
+TEST_P(VibratorAidl, CompseSizeBoundary) {
+    if (capabilities & IVibrator::CAP_COMPOSE_EFFECTS) {
+        int32_t maxSize;
+
+        EXPECT_EQ(Status::EX_NONE, vibrator->getCompositionSizeMax(&maxSize).exceptionCode());
+
+        std::vector<CompositeEffect> composite(maxSize);
+        CompositeEffect effect;
+
+        effect.delayMs = 1;
+        effect.primitive = CompositePrimitive::CLICK;
+        effect.scale = 1.0f;
+
+        std::fill(composite.begin(), composite.end(), effect);
+        EXPECT_EQ(Status::EX_NONE, vibrator->compose(composite, nullptr).exceptionCode());
+
+        composite.emplace_back(effect);
+        EXPECT_EQ(Status::EX_ILLEGAL_ARGUMENT,
+                  vibrator->compose(composite, nullptr).exceptionCode());
+        vibrator->off();
+    }
+}
+
 INSTANTIATE_TEST_SUITE_P(Vibrator, VibratorAidl,
                          testing::ValuesIn(android::getAidlHalInstanceNames(IVibrator::descriptor)),
                          android::PrintInstanceNameToString);