diff --git a/android-studio-project/ExoPlayer-AirPlay-Receiver/src/main/java/com/github/warren_bank/exoplayer_airplay_receiver/ui/exoplayer2/MultiFieldTimePickerDialog.java b/android-studio-project/ExoPlayer-AirPlay-Receiver/src/main/java/com/github/warren_bank/exoplayer_airplay_receiver/ui/exoplayer2/MultiFieldTimePickerDialog.java
index 5b2fd21..6fbeb43 100644
--- a/android-studio-project/ExoPlayer-AirPlay-Receiver/src/main/java/com/github/warren_bank/exoplayer_airplay_receiver/ui/exoplayer2/MultiFieldTimePickerDialog.java
+++ b/android-studio-project/ExoPlayer-AirPlay-Receiver/src/main/java/com/github/warren_bank/exoplayer_airplay_receiver/ui/exoplayer2/MultiFieldTimePickerDialog.java
@@ -29,6 +29,7 @@
 public class MultiFieldTimePickerDialog
         extends AlertDialog implements OnClickListener {
 
+    private final NumberPicker mSignSpinner;
     private final NumberPicker mHourSpinner;
     private final NumberPicker mMinuteSpinner;
     private final NumberPicker mSecSpinner;
@@ -38,12 +39,13 @@ public class MultiFieldTimePickerDialog
     private final int mStep;
     private final int mBaseMilli;
     private final boolean mIs24hourFormat;
+    private final boolean mIsSigned;
 
     /**
      * Adds an onTimeSet() method.
      */
     public interface OnMultiFieldTimeSetListener {
-        void onTimeSet(int hourOfDay, int minute, int second, int milli);
+        void onTimeSet(boolean isNegative, int hourOfDay, int minute, int second, int milli);
     }
 
     private static final int SECOND_IN_MILLIS = 1000;
@@ -53,13 +55,15 @@ public interface OnMultiFieldTimeSetListener {
     public MultiFieldTimePickerDialog(
             Context context,
             int theme,
+            boolean isNegative,
             int hour, int minute, int second, int milli,
-            int min, int max, int step, boolean is24hourFormat,
+            int min, int max, int step, boolean is24hourFormat, boolean isSigned,
             OnMultiFieldTimeSetListener listener) {
         super(context, theme);
         mListener = listener;
         mStep = step;
         mIs24hourFormat = is24hourFormat;
+        mIsSigned = isSigned;
 
         if (min >= max) {
             min = 0;
@@ -75,6 +79,7 @@ public MultiFieldTimePickerDialog(
         View view = inflater.inflate(R.layout.multi_field_time_picker_dialog, null);
         setView(view);
 
+        mSignSpinner = (NumberPicker) view.findViewById(R.id.sign);
         mHourSpinner = (NumberPicker) view.findViewById(R.id.hour);
         mMinuteSpinner = (NumberPicker) view.findViewById(R.id.minute);
         mSecSpinner = (NumberPicker) view.findViewById(R.id.second);
@@ -91,6 +96,18 @@ public MultiFieldTimePickerDialog(
             hour = minHour;
         }
 
+        if (!isSigned) {
+            mSignSpinner.setVisibility(View.GONE);
+        } else {
+            int minSign = 0; // + positive
+            int maxSign = 1; // - negative
+            int iniSign = isNegative ? maxSign : minSign;
+            mSignSpinner.setMinValue(minSign);
+            mSignSpinner.setMaxValue(maxSign);
+            mSignSpinner.setDisplayedValues(new String[] { "+", "-" });
+            mSignSpinner.setValue(iniSign);
+        }
+
         if (is24hourFormat) {
             mAmPmSpinner.setVisibility(View.GONE);
         } else {
@@ -171,7 +188,7 @@ public MultiFieldTimePickerDialog(
 
         if (step >= MINUTE_IN_MILLIS) {
             // Remove the ':' in front of the second spinner as well.
-            view.findViewById(R.id.second_colon).setVisibility(View.GONE);
+            view.findViewById(R.id.second_sep).setVisibility(View.GONE);
             mSecSpinner.setVisibility(View.GONE);
         }
 
@@ -200,7 +217,7 @@ public MultiFieldTimePickerDialog(
 
         if (step >= SECOND_IN_MILLIS) {
             // Remove the '.' in front of the milli spinner as well.
-            view.findViewById(R.id.second_dot).setVisibility(View.GONE);
+            view.findViewById(R.id.milli_sep).setVisibility(View.GONE);
             mMilliSpinner.setVisibility(View.GONE);
         }
 
@@ -262,7 +279,13 @@ private void notifyDateSet() {
             }
             hour += ampm * 12;
         }
-        mListener.onTimeSet(hour, minute, sec, milli);
+        boolean isNegative = false;
+        if (mIsSigned) {
+          int sign = getPickerValue(mSignSpinner);
+          if (sign == 1)
+            isNegative = true;
+        }
+        mListener.onTimeSet(isNegative, hour, minute, sec, milli);
     }
 
     /**
diff --git a/android-studio-project/ExoPlayer-AirPlay-Receiver/src/main/java/com/github/warren_bank/exoplayer_airplay_receiver/ui/exoplayer2/MultiFieldTimePickerDialogContainer.java b/android-studio-project/ExoPlayer-AirPlay-Receiver/src/main/java/com/github/warren_bank/exoplayer_airplay_receiver/ui/exoplayer2/MultiFieldTimePickerDialogContainer.java
index f02da34..6bef0a3 100644
--- a/android-studio-project/ExoPlayer-AirPlay-Receiver/src/main/java/com/github/warren_bank/exoplayer_airplay_receiver/ui/exoplayer2/MultiFieldTimePickerDialogContainer.java
+++ b/android-studio-project/ExoPlayer-AirPlay-Receiver/src/main/java/com/github/warren_bank/exoplayer_airplay_receiver/ui/exoplayer2/MultiFieldTimePickerDialogContainer.java
@@ -25,10 +25,13 @@ private static class TextSynchronizerListener implements MultiFieldTimePickerDia
         }
 
         @Override
-        public void onTimeSet(int hourOfDay, int minute, int second, int milli) {
+        public void onTimeSet(boolean isNegative, int hourOfDay, int minute, int second, int milli) {
             long textOffsetMs = (milli) + (second * 1000) + (minute * 60 * 1000) + (hourOfDay * 60 * 60 * 1000);
             long textOffsetUs = (textOffsetMs * 1000);
 
+            if (isNegative)
+                textOffsetUs *= -1;
+
             textSynchronizer.setTextOffset(textOffsetUs);
         }
 
@@ -39,8 +42,9 @@ public void onTimeSet(long textOffsetUs) {
 
     private static void showPickerDialog(
         Context mContext,
+        boolean isNegative,
         int hourOfDay, int minute, int second, int millis,
-        int min, int max, int step, boolean is24hourFormat,
+        int min, int max, int step, boolean is24hourFormat, boolean isSigned,
         MultiFieldTimePickerDialog.OnMultiFieldTimeSetListener mListener,
         DialogInterface.OnDismissListener onDismissListener
     ) {
@@ -49,8 +53,9 @@ private static void showPickerDialog(
         mDialog = new MultiFieldTimePickerDialog(
             mContext,
             /* theme= */ 0,
+            isNegative,
             hourOfDay, minute, second, millis,
-            min, max, step, is24hourFormat,
+            min, max, step, is24hourFormat, isSigned,
             mListener
         );
 
@@ -96,6 +101,11 @@ public static void show(
 
         long offsetPositionUs = textSynchronizer.getTextOffset();
 
+        boolean isNegative = (offsetPositionUs < 0);
+
+        if (isNegative)
+          offsetPositionUs *= -1;
+
         int hourOfDay = (int)  TimeUnit.MICROSECONDS.toHours(offsetPositionUs);
         int minute    = (int) (TimeUnit.MICROSECONDS.toMinutes(offsetPositionUs) % 60);
         int second    = (int) (TimeUnit.MICROSECONDS.toSeconds(offsetPositionUs) % 60);
@@ -106,11 +116,13 @@ public static void show(
         int step      = 100; // 100 ms
 
         boolean is24hourFormat = true;
+        boolean isSigned = true;
 
         showPickerDialog(
             mContext,
+            isNegative,
             hourOfDay, minute, second, millis,
-            min, max, step, is24hourFormat,
+            min, max, step, is24hourFormat, isSigned,
             mListener,
             onDismissListener
         );
diff --git a/android-studio-project/ExoPlayer-AirPlay-Receiver/src/main/res/layout/multi_field_time_picker_dialog.xml b/android-studio-project/ExoPlayer-AirPlay-Receiver/src/main/res/layout/multi_field_time_picker_dialog.xml
index e037a09..f064485 100644
--- a/android-studio-project/ExoPlayer-AirPlay-Receiver/src/main/res/layout/multi_field_time_picker_dialog.xml
+++ b/android-studio-project/ExoPlayer-AirPlay-Receiver/src/main/res/layout/multi_field_time_picker_dialog.xml
@@ -39,6 +39,18 @@
     android:orientation="horizontal"
     android:gravity="center">
 
+    <NumberPicker
+        android:id="@+id/sign"
+        android:layout_width="0dp"
+        android:layout_weight=".2"
+        android:textSize="12sp"
+        android:layout_height="wrap_content"
+        android:layout_marginStart="4dp"
+        android:layout_marginEnd="4dp"
+        android:focusable="true"
+        android:focusableInTouchMode="true"
+        android:contentDescription="@string/accessibility_time_picker_sign"
+        />
     <NumberPicker
         android:id="@+id/hour"
         android:layout_width="0dp"
@@ -70,11 +82,12 @@
         android:contentDescription="@string/accessibility_time_picker_minute"
         />
     <TextView
-        android:id="@+id/second_colon"
+        android:id="@+id/second_sep"
         android:layout_width="wrap_content"
         android:textSize="12sp"
         android:layout_height="wrap_content"
-        android:text="@string/time_picker_dialog_minute_second_separator"	    />
+        android:text="@string/time_picker_dialog_minute_second_separator"
+        />
     <NumberPicker
         android:id="@+id/second"
         android:layout_width="0dp"
@@ -88,11 +101,11 @@
         android:contentDescription="@string/accessibility_time_picker_second"
         />
     <TextView
-        android:id="@+id/second_dot"
+        android:id="@+id/milli_sep"
         android:layout_width="wrap_content"
         android:textSize="12sp"
         android:layout_height="wrap_content"
-        android:text="@string/time_picker_dialog_second_subsecond_separator"
+        android:text="@string/time_picker_dialog_second_milli_separator"
         />
     <NumberPicker
         android:id="@+id/milli"
@@ -106,6 +119,13 @@
         android:focusableInTouchMode="true"
         android:contentDescription="@string/accessibility_time_picker_milli"
         />
+    <TextView
+        android:id="@+id/ampm_sep"
+        android:layout_width="wrap_content"
+        android:textSize="12sp"
+        android:layout_height="wrap_content"
+        android:text="@string/time_picker_dialog_milli_ampm_separator"
+        />
     <NumberPicker
         android:id="@+id/ampm"
         android:layout_width="0dp"
diff --git a/android-studio-project/ExoPlayer-AirPlay-Receiver/src/main/res/values/multi_field_time_picker_dialog.xml b/android-studio-project/ExoPlayer-AirPlay-Receiver/src/main/res/values/multi_field_time_picker_dialog.xml
index 2dd101d..66528cd 100644
--- a/android-studio-project/ExoPlayer-AirPlay-Receiver/src/main/res/values/multi_field_time_picker_dialog.xml
+++ b/android-studio-project/ExoPlayer-AirPlay-Receiver/src/main/res/values/multi_field_time_picker_dialog.xml
@@ -5,13 +5,15 @@
   <string name="time_picker_dialog_am">"a.m."</string>
   <string name="time_picker_dialog_pm">"p.m."</string>
 
+  <string name="accessibility_time_picker_sign">"Positive/Negative Sign"</string>
   <string name="accessibility_time_picker_hour">"Hour"</string>
   <string name="accessibility_time_picker_minute">"Minute"</string>
   <string name="accessibility_time_picker_second">"Second"</string>
   <string name="accessibility_time_picker_milli">"Millisecond"</string>
   <string name="accessibility_time_picker_ampm">"AM/PM"</string>
 
-  <string name="time_picker_dialog_hour_minute_separator">":"</string>
-  <string name="time_picker_dialog_minute_second_separator">":"</string>
-  <string name="time_picker_dialog_second_subsecond_separator">"."</string>
+  <string name="time_picker_dialog_hour_minute_separator">"hr :"</string>
+  <string name="time_picker_dialog_minute_second_separator">"min :"</string>
+  <string name="time_picker_dialog_second_milli_separator">"sec ."</string>
+  <string name="time_picker_dialog_milli_ampm_separator">"ms"</string>
 </resources>