diff --git a/core/java/android/app/NotificationChannel.java b/core/java/android/app/NotificationChannel.java
index 3f6c81b..2d716ad 100644
--- a/core/java/android/app/NotificationChannel.java
+++ b/core/java/android/app/NotificationChannel.java
@@ -139,7 +139,11 @@
     /**
      * @hide
      */
-    public static final int MAX_VIBRATION_LENGTH = 1000;
+    public static final int MAX_VIBRATION_LENGTH = 500;
+    /**
+     * @hide
+     */
+    public static final int MAX_SERIALIZED_VIBRATION_LENGTH = 32_768;
 
     private static final String TAG_CHANNEL = "channel";
     private static final String ATT_NAME = "name";
@@ -339,6 +343,9 @@
         if (Flags.notificationChannelVibrationEffectApi()) {
             mVibrationEffect =
                     in.readInt() != 0 ? VibrationEffect.CREATOR.createFromParcel(in) : null;
+            if (mVibrationEffect != null) {
+                mVibrationEffect = getTrimmedVibrationEffect(mVibrationEffect);
+            }
         }
         mUserLockedFields = in.readInt();
         mUserVisibleTaskShown = in.readByte() != 0;
@@ -553,6 +560,23 @@
         return input;
     }
 
+    // Returns trimmed vibration effect or null if not trimmable.
+    private VibrationEffect getTrimmedVibrationEffect(VibrationEffect effect) {
+        if (effect == null) {
+            return null;
+        }
+        // trim if possible; check serialized length; reject if it is still too long
+        VibrationEffect result = effect;
+        VibrationEffect trimmed = effect.cropToLengthOrNull(MAX_VIBRATION_LENGTH);
+        if (trimmed != null) {
+            result = trimmed;
+        }
+        if (vibrationToString(result).length() > MAX_SERIALIZED_VIBRATION_LENGTH) {
+            return null;
+        }
+        return result;
+    }
+
     /**
      * @hide
      */
@@ -656,6 +680,9 @@
     public void setVibrationPattern(long[] vibrationPattern) {
         this.mVibrationEnabled = vibrationPattern != null && vibrationPattern.length > 0;
         this.mVibrationPattern = vibrationPattern;
+        if (vibrationPattern != null && vibrationPattern.length > MAX_VIBRATION_LENGTH) {
+            this.mVibrationPattern = Arrays.copyOf(vibrationPattern, MAX_VIBRATION_LENGTH);
+        }
         if (Flags.notificationChannelVibrationEffectApi()) {
             try {
                 this.mVibrationEffect =
@@ -702,9 +729,29 @@
     public void setVibrationEffect(@Nullable VibrationEffect effect) {
         this.mVibrationEnabled = effect != null;
         this.mVibrationEffect = effect;
-        this.mVibrationPattern =
-                effect == null
-                ? null : effect.computeCreateWaveformOffOnTimingsOrNull();
+        if (effect != null) {
+            long[] pattern = effect.computeCreateWaveformOffOnTimingsOrNull();
+            if (pattern != null) {
+                // If this effect has an equivalent pattern, AND the pattern needs to be truncated
+                // due to being too long, we delegate to setVibrationPattern to re-generate the
+                // effect as well. Otherwise, we use the effect (already set above) and converted
+                // pattern directly.
+                if (pattern.length > MAX_VIBRATION_LENGTH) {
+                    setVibrationPattern(pattern);
+                } else {
+                    this.mVibrationPattern = pattern;
+                }
+            } else {
+                // If not convertible to a pattern directly, try trimming the vibration effect if
+                // possible and storing that version instead.
+                this.mVibrationEffect = getTrimmedVibrationEffect(mVibrationEffect);
+                this.mVibrationPattern = null;
+            }
+        } else {
+            this.mVibrationPattern =
+                    mVibrationEffect == null
+                            ? null : mVibrationEffect.computeCreateWaveformOffOnTimingsOrNull();
+        }
     }
 
     /**
@@ -1138,7 +1185,8 @@
             if (vibrationEffect != null) {
                 // Restore the effect only if it is not null. This allows to avoid undoing a
                 // `setVibrationPattern` call above, if that was done with a non-null pattern
-                // (e.g. back up from a version that did not support `setVibrationEffect`).
+                // (e.g. back up from a version that did not support `setVibrationEffect`), or
+                // if there is an equivalent vibration pattern available.
                 setVibrationEffect(vibrationEffect);
             }
         }
@@ -1331,7 +1379,11 @@
             out.attribute(null, ATT_VIBRATION, longArrayToString(getVibrationPattern()));
         }
         if (getVibrationEffect() != null) {
-            out.attribute(null, ATT_VIBRATION_EFFECT, vibrationToString(getVibrationEffect()));
+            if (getVibrationPattern() == null) {
+                // Only serialize the vibration effect if we do not already have an equivalent
+                // vibration pattern.
+                out.attribute(null, ATT_VIBRATION_EFFECT, vibrationToString(getVibrationEffect()));
+            }
         }
         if (getUserLockedFields() != 0) {
             out.attributeInt(null, ATT_USER_LOCKED, getUserLockedFields());
diff --git a/core/java/android/os/VibrationEffect.java b/core/java/android/os/VibrationEffect.java
index efbd96b..c5236a7 100644
--- a/core/java/android/os/VibrationEffect.java
+++ b/core/java/android/os/VibrationEffect.java
@@ -504,6 +504,17 @@
     /** @hide */
     public abstract void validate();
 
+
+    /**
+     * If supported, truncate the length of this vibration effect to the provided length and return
+     * the result. Will always return null for repeating effects.
+     *
+     * @return The desired effect, or {@code null} if truncation is not applicable.
+     * @hide
+     */
+    @Nullable
+    public abstract VibrationEffect cropToLengthOrNull(int length);
+
     /**
      * Gets the estimated duration of the vibration in milliseconds.
      *
@@ -805,6 +816,30 @@
             }
         }
 
+        /** @hide */
+        @Override
+        @Nullable
+        public VibrationEffect cropToLengthOrNull(int length) {
+            // drop repeating effects
+            if (mRepeatIndex >= 0) {
+                return null;
+            }
+
+            int segmentCount = mSegments.size();
+            if (segmentCount <= length) {
+                return this;
+            }
+
+            ArrayList truncated = new ArrayList(mSegments.subList(0, length));
+            Composed updated = new Composed(truncated, mRepeatIndex);
+            try {
+                updated.validate();
+            } catch (IllegalArgumentException e) {
+                return null;
+            }
+            return updated;
+        }
+
         @Override
         public long getDuration() {
             if (mRepeatIndex >= 0) {
diff --git a/core/tests/coretests/src/android/app/NotificationChannelTest.java b/core/tests/coretests/src/android/app/NotificationChannelTest.java
index 504f98f..f666809 100644
--- a/core/tests/coretests/src/android/app/NotificationChannelTest.java
+++ b/core/tests/coretests/src/android/app/NotificationChannelTest.java
@@ -235,6 +235,32 @@
     }
 
     @Test
+    @EnableFlags(Flags.FLAG_NOTIFICATION_CHANNEL_VIBRATION_EFFECT_API)
+    public void testLongVibrationFields_canWriteToXml() throws Exception {
+        NotificationChannel channel = new NotificationChannel("id", "name", 3);
+        // populate pattern with contents
+        long[] pattern = new long[65550 / 2];
+        for (int i = 0; i < pattern.length; i++) {
+            pattern[i] = 100;
+        }
+        channel.setVibrationPattern(pattern);  // with flag on, also sets effect
+
+        // Send it through parceling & unparceling to simulate being passed through a binder call
+        NotificationChannel fromParcel = writeToAndReadFromParcel(channel);
+        assertThat(fromParcel.getVibrationPattern().length).isEqualTo(
+                NotificationChannel.MAX_VIBRATION_LENGTH);
+
+        // Confirm that this also survives writing to & restoring from XML
+        NotificationChannel result = backUpAndRestore(fromParcel);
+        assertThat(result.getVibrationPattern().length).isEqualTo(
+                NotificationChannel.MAX_VIBRATION_LENGTH);
+        assertThat(result.getVibrationEffect()).isNotNull();
+        assertThat(result.getVibrationEffect()
+                .computeCreateWaveformOffOnTimingsOrNull())
+                .isEqualTo(result.getVibrationPattern());
+    }
+
+    @Test
     public void testRestoreSoundUri_customLookup() throws Exception {
         Uri uriToBeRestoredUncanonicalized = Uri.parse("content://media/1");
         Uri uriToBeRestoredCanonicalized = Uri.parse("content://media/1?title=Song&canonical=1");
diff --git a/core/tests/vibrator/src/android/os/VibrationEffectTest.java b/core/tests/vibrator/src/android/os/VibrationEffectTest.java
index e875875..edb0d70 100644
--- a/core/tests/vibrator/src/android/os/VibrationEffectTest.java
+++ b/core/tests/vibrator/src/android/os/VibrationEffectTest.java
@@ -20,6 +20,8 @@
 import static android.os.VibrationEffect.VibrationParameter.targetAmplitude;
 import static android.os.VibrationEffect.VibrationParameter.targetFrequency;
 
+import static com.google.common.truth.Truth.assertThat;
+
 import static junit.framework.Assert.assertEquals;
 import static junit.framework.Assert.assertFalse;
 import static junit.framework.Assert.assertNotNull;
@@ -420,6 +422,76 @@
     }
 
     @Test
+    public void cropToLength_waveform_underLength() {
+        VibrationEffect effect = VibrationEffect.createWaveform(
+                /* timings= */ new long[]{0, 1, 2},
+                /* repeatIndex= */ -1);
+        VibrationEffect result = effect.cropToLengthOrNull(5);
+
+        assertThat(result).isEqualTo(effect); // unchanged
+    }
+
+    @Test
+    public void cropToLength_waveform_overLength() {
+        VibrationEffect effect = VibrationEffect.createWaveform(
+                /* timings= */ new long[]{0, 1, 2, 3, 4, 5, 6},
+                /* repeatIndex= */ -1);
+        VibrationEffect result = effect.cropToLengthOrNull(4);
+
+        assertThat(result).isEqualTo(VibrationEffect.createWaveform(
+                new long[]{0, 1, 2, 3},
+                -1));
+    }
+
+    @Test
+    public void cropToLength_waveform_repeating() {
+        // repeating waveforms cannot be truncated
+        VibrationEffect effect = VibrationEffect.createWaveform(
+                /* timings= */ new long[]{0, 1, 2, 3, 4, 5, 6},
+                /* repeatIndex= */ 2);
+        VibrationEffect result = effect.cropToLengthOrNull(3);
+
+        assertThat(result).isNull();
+    }
+
+    @Test
+    public void cropToLength_waveform_withAmplitudes() {
+        VibrationEffect effect = VibrationEffect.createWaveform(
+                /* timings= */ new long[]{0, 1, 2, 3, 4, 5, 6},
+                /* amplitudes= */ new int[]{10, 20, 40, 10, 20, 40, 10},
+                /* repeatIndex= */ -1);
+        VibrationEffect result = effect.cropToLengthOrNull(3);
+
+        assertThat(result).isEqualTo(VibrationEffect.createWaveform(
+                new long[]{0, 1, 2},
+                new int[]{10, 20, 40},
+                -1));
+    }
+
+    @Test
+    public void cropToLength_composed() {
+        VibrationEffect effect = VibrationEffect.startComposition()
+                .addPrimitive(VibrationEffect.Composition.PRIMITIVE_CLICK)
+                .addPrimitive(VibrationEffect.Composition.PRIMITIVE_TICK)
+                .compose();
+        VibrationEffect result = effect.cropToLengthOrNull(1);
+
+        assertThat(result).isNotNull();
+        assertThat(result).isEqualTo(VibrationEffect.startComposition()
+                        .addPrimitive(VibrationEffect.Composition.PRIMITIVE_CLICK)
+                        .compose());
+    }
+
+    @Test
+    public void cropToLength_composed_repeating() {
+        VibrationEffect effect = VibrationEffect.startComposition()
+                .addPrimitive(VibrationEffect.Composition.PRIMITIVE_CLICK)
+                .repeatEffectIndefinitely(TEST_ONE_SHOT)
+                .compose();
+        assertThat(effect.cropToLengthOrNull(1)).isNull();
+    }
+
+    @Test
     public void getRingtones_noPrebakedRingtones() {
         Resources r = mockRingtoneResources(new String[0]);
         Context context = mockContext(r);