diff --git a/osu.Game.Rulesets.Karaoke.Tests/IO/Serialization/Converters/TimeTagConverterTest.cs b/osu.Game.Rulesets.Karaoke.Tests/IO/Serialization/Converters/TimeTagConverterTest.cs
new file mode 100644
index 000000000..e581602b6
--- /dev/null
+++ b/osu.Game.Rulesets.Karaoke.Tests/IO/Serialization/Converters/TimeTagConverterTest.cs
@@ -0,0 +1,46 @@
+// Copyright (c) andy840119 <andy840119@gmail.com>. Licensed under the GPL Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using Newtonsoft.Json;
+using NUnit.Framework;
+using osu.Framework.Graphics.Sprites;
+using osu.Game.Rulesets.Karaoke.IO.Serialization.Converters;
+using osu.Game.Rulesets.Karaoke.Objects;
+
+namespace osu.Game.Rulesets.Karaoke.Tests.IO.Serialization.Converters
+{
+    [TestFixture]
+    public class TimeTagConverterTest : BaseSingleConverterTest<TimeTagConverter>
+    {
+        [TestCase(1, TimeTagIndex.IndexState.Start, 1000, "[1,start]:1000")]
+        [TestCase(1, TimeTagIndex.IndexState.End, 1000, "[1,end]:1000")]
+        [TestCase(-1, TimeTagIndex.IndexState.Start, 1000, "[-1,start]:1000")] // Should not check index is out of range in here.
+        [TestCase(1, TimeTagIndex.IndexState.Start, -1000, "[1,start]:-1000")] // Should not check if time is negative.
+        [TestCase(1, TimeTagIndex.IndexState.Start, null, "[1,start]:")]
+        public void TestSerialize(int index, TimeTagIndex.IndexState state, int? time, string json)
+        {
+            var timeTag = new TimeTag(new TimeTagIndex(index, state), time);
+
+            var result = JsonConvert.SerializeObject(timeTag, CreateSettings());
+            Assert.AreEqual(result, $"\"{json}\"");
+        }
+
+        [TestCase("[1,start]:1000", 1, TimeTagIndex.IndexState.Start, 1000)]
+        [TestCase("[1,end]:1000", 1, TimeTagIndex.IndexState.End, 1000)]
+        [TestCase("[-1,start]:1000", -1, TimeTagIndex.IndexState.Start, 1000)] // Should not check index is out of range in here.
+        [TestCase("[1,start]:-1000", 1, TimeTagIndex.IndexState.Start, -1000)] // Should not check if time is negative.
+        [TestCase("[1,start]:", 1, TimeTagIndex.IndexState.Start, null)]
+        [TestCase("", 0, TimeTagIndex.IndexState.Start, null)] // Test deal with format is not right below.
+        [TestCase("[1,???]:", 0, TimeTagIndex.IndexState.Start, null)]
+        [TestCase("[1,]", 0, TimeTagIndex.IndexState.Start, null)]
+        [TestCase("[,start]", 0, TimeTagIndex.IndexState.Start, null)]
+        [TestCase("[]", 0, TimeTagIndex.IndexState.Start, null)]
+        public void TestDeserialize(string json, int index, TimeTagIndex.IndexState state, int? time)
+        {
+            var result = JsonConvert.DeserializeObject<TimeTag>($"\"{json}\"", CreateSettings());
+            var actual = new TimeTag(new TimeTagIndex(index, state), time);
+            Assert.AreEqual(result.Index, actual.Index);
+            Assert.AreEqual(result.Time, actual.Time);
+        }
+    }
+}
diff --git a/osu.Game.Rulesets.Karaoke.Tests/IO/Serialization/Converters/TimeTagsConverterTest.cs b/osu.Game.Rulesets.Karaoke.Tests/IO/Serialization/Converters/TimeTagsConverterTest.cs
deleted file mode 100644
index b0ad17f0b..000000000
--- a/osu.Game.Rulesets.Karaoke.Tests/IO/Serialization/Converters/TimeTagsConverterTest.cs
+++ /dev/null
@@ -1,45 +0,0 @@
-// Copyright (c) andy840119 <andy840119@gmail.com>. Licensed under the GPL Licence.
-// See the LICENCE file in the repository root for full licence text.
-
-using System;
-using Newtonsoft.Json;
-using NUnit.Framework;
-using osu.Framework.Graphics.Sprites;
-using osu.Game.Rulesets.Karaoke.IO.Serialization.Converters;
-using osu.Game.Rulesets.Karaoke.Objects;
-using osu.Game.Rulesets.Karaoke.Utils;
-
-namespace osu.Game.Rulesets.Karaoke.Tests.IO.Serialization.Converters
-{
-    [TestFixture]
-    public class TimeTagsConverterTest : BaseSingleConverterTest<TimeTagsConverter>
-    {
-        [Test]
-        public void TestSerialize()
-        {
-            var rowTimeTag = new[]
-            {
-                new TimeTag(new TimeTagIndex(0), 1000d),
-                new TimeTag(new TimeTagIndex(0, TimeTagIndex.IndexState.End), 1100d),
-                new TimeTag(new TimeTagIndex(0, TimeTagIndex.IndexState.End), 1200d),
-            };
-
-            var result = JsonConvert.SerializeObject(rowTimeTag, CreateSettings());
-
-            Assert.AreEqual(result, "[\r\n  \"0,0,1000\",\r\n  \"0,1,1100\",\r\n  \"0,1,1200\"\r\n]");
-        }
-
-        [Test]
-        public void TestDeserialize()
-        {
-            const string json_string = "[\r\n  \"0,0,1000\",\r\n  \"0,1,1100\",\r\n  \"0,1,1200\"\r\n]";
-            var result = JsonConvert.DeserializeObject<TimeTag[]>(json_string, CreateSettings());
-
-            Assert.IsNotNull(result);
-            Assert.AreEqual(result.Length, 3);
-            Assert.AreEqual(result[0].Index.Index, 0);
-            Assert.AreEqual(result[0].Index.State, TimeTagIndex.IndexState.Start);
-            Assert.AreEqual(result[0].Time, 1000);
-        }
-    }
-}
diff --git a/osu.Game.Rulesets.Karaoke/IO/Serialization/Converters/RomajiTagConverter.cs b/osu.Game.Rulesets.Karaoke/IO/Serialization/Converters/RomajiTagConverter.cs
index 5c56a1155..ded067fe5 100644
--- a/osu.Game.Rulesets.Karaoke/IO/Serialization/Converters/RomajiTagConverter.cs
+++ b/osu.Game.Rulesets.Karaoke/IO/Serialization/Converters/RomajiTagConverter.cs
@@ -19,14 +19,14 @@ public override RomajiTag ReadJson(JsonReader reader, Type objectType, RomajiTag
             if (value == null || value == "")
                 return new RomajiTag();
 
-            var regux = new Regex("([-0-9]+),([-0-9]+)]:(.*$)");
+            var regux = new Regex("(?<start>[-0-9]+),(?<end>[-0-9]+)]:(?<romaji>.*$)");
             var result = regux.Match(value);
             if (!result.Success)
                 return new RomajiTag();
 
-            var startIndex = int.Parse(result.Groups[1].Value);
-            var endIndex = int.Parse(result.Groups[2].Value);
-            var text = result.Groups[3].Value;
+            var startIndex = int.Parse(result.Groups["start"]?.Value);
+            var endIndex = int.Parse(result.Groups["end"]?.Value);
+            var text = result.Groups["romaji"]?.Value;
 
             return new RomajiTag
             {
diff --git a/osu.Game.Rulesets.Karaoke/IO/Serialization/Converters/RubyTagConverter.cs b/osu.Game.Rulesets.Karaoke/IO/Serialization/Converters/RubyTagConverter.cs
index 22379cff9..a6fa381b6 100644
--- a/osu.Game.Rulesets.Karaoke/IO/Serialization/Converters/RubyTagConverter.cs
+++ b/osu.Game.Rulesets.Karaoke/IO/Serialization/Converters/RubyTagConverter.cs
@@ -19,14 +19,14 @@ public override RubyTag ReadJson(JsonReader reader, Type objectType, RubyTag exi
             if (value == null || value == "")
                 return new RubyTag();
 
-            var regux = new Regex("([-0-9]+),([-0-9]+)]:(.*$)");
+            var regux = new Regex("(?<start>[-0-9]+),(?<end>[-0-9]+)]:(?<ruby>.*$)");
             var result = regux.Match(value);
             if (!result.Success)
                 return new RubyTag();
 
-            var startIndex = int.Parse(result.Groups[1].Value);
-            var endIndex = int.Parse(result.Groups[2].Value);
-            var text = result.Groups[3].Value;
+            var startIndex = int.Parse(result.Groups["start"]?.Value);
+            var endIndex = int.Parse(result.Groups["end"]?.Value);
+            var text = result.Groups["ruby"]?.Value;
 
             return new RubyTag
             {
diff --git a/osu.Game.Rulesets.Karaoke/IO/Serialization/Converters/TimeTagConverter.cs b/osu.Game.Rulesets.Karaoke/IO/Serialization/Converters/TimeTagConverter.cs
new file mode 100644
index 000000000..96c0ef695
--- /dev/null
+++ b/osu.Game.Rulesets.Karaoke/IO/Serialization/Converters/TimeTagConverter.cs
@@ -0,0 +1,46 @@
+// Copyright (c) andy840119 <andy840119@gmail.com>. Licensed under the GPL Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System;
+using System.Text.RegularExpressions;
+using Newtonsoft.Json;
+using Newtonsoft.Json.Linq;
+using osu.Framework.Graphics.Sprites;
+using osu.Game.Rulesets.Karaoke.Objects;
+
+namespace osu.Game.Rulesets.Karaoke.IO.Serialization.Converters
+{
+    public class TimeTagConverter : JsonConverter<TimeTag>
+    {
+        public override TimeTag ReadJson(JsonReader reader, Type objectType, TimeTag existingValue, bool hasExistingValue, JsonSerializer serializer)
+        {
+            var obj = JToken.Load(reader);
+            var value = obj.Value<string>();
+
+            if (value == null || value == "")
+                return new TimeTag(new TimeTagIndex());
+
+            var regux = new Regex("(?<index>[-0-9]+),(?<state>start|end)]:(?<time>[-0-9]+|s*|)");
+            var result = regux.Match(value);
+            if (!result.Success)
+                return new TimeTag(new TimeTagIndex());
+
+            var index = int.Parse(result.Groups["index"]?.Value);
+            var state = result.Groups["state"]?.Value == "start" ? TimeTagIndex.IndexState.Start : TimeTagIndex.IndexState.End;
+            var timeStr = result.Groups["time"]?.Value;
+            var time = timeStr == "" ? default(int?) : int.Parse(timeStr);
+
+            return new TimeTag(new TimeTagIndex(index, state), time);
+        }
+
+        public override void WriteJson(JsonWriter writer, TimeTag value, JsonSerializer serializer)
+        {
+            var tag = value.Index;
+            var state = tag.State == TimeTagIndex.IndexState.Start ? "start" : "end";
+            var time = value.Time;
+
+            var str = $"[{tag.Index},{state}]:{time}";
+            writer.WriteValue(str);
+        }
+    }
+}
diff --git a/osu.Game.Rulesets.Karaoke/IO/Serialization/Converters/TimeTagsConverter.cs b/osu.Game.Rulesets.Karaoke/IO/Serialization/Converters/TimeTagsConverter.cs
deleted file mode 100644
index 133d544a1..000000000
--- a/osu.Game.Rulesets.Karaoke/IO/Serialization/Converters/TimeTagsConverter.cs
+++ /dev/null
@@ -1,56 +0,0 @@
-// Copyright (c) andy840119 <andy840119@gmail.com>. Licensed under the GPL Licence.
-// See the LICENCE file in the repository root for full licence text.
-
-using System;
-using System.Linq;
-using Newtonsoft.Json;
-using Newtonsoft.Json.Linq;
-using osu.Framework.Graphics.Sprites;
-using osu.Game.Rulesets.Karaoke.Objects;
-
-namespace osu.Game.Rulesets.Karaoke.IO.Serialization.Converters
-{
-    public class TimeTagsConverter : JsonConverter<TimeTag[]>
-    {
-        public override TimeTag[] ReadJson(JsonReader reader, Type objectType, TimeTag[] existingValues, bool hasExistingValue, JsonSerializer serializer)
-        {
-            var obj = JArray.Load(reader);
-
-            return obj.Select(line =>
-            {
-                var value = line.ToString();
-                return deserializeTuple(value);
-            }).ToArray();
-
-            TimeTag deserializeTuple(string str)
-            {
-                var strArray = str.Split(',');
-
-                var state = strArray[1] == "0" ? TimeTagIndex.IndexState.Start : TimeTagIndex.IndexState.End;
-                var timeTag = new TimeTagIndex(int.Parse(strArray[0]), state);
-                var time = strArray[2] != "" ? int.Parse(strArray[2]) : default(double?);
-                return new TimeTag(timeTag, time);
-            }
-        }
-
-        public override void WriteJson(JsonWriter writer, TimeTag[] values, JsonSerializer serializer)
-        {
-            writer.WriteStartArray();
-
-            foreach (var value in values)
-            {
-                writer.WriteValue(serializeTuple(value));
-            }
-
-            writer.WriteEndArray();
-
-            string serializeTuple(TimeTag timeTagTuple)
-            {
-                var tag = timeTagTuple.Index;
-                var state = tag.State == TimeTagIndex.IndexState.Start ? "0" : "1";
-                var time = timeTagTuple.Time;
-                return $"{tag.Index},{state},{time}";
-            }
-        }
-    }
-}
diff --git a/osu.Game.Rulesets.Karaoke/Objects/Lyric.cs b/osu.Game.Rulesets.Karaoke/Objects/Lyric.cs
index 0ccb8f6e9..261a12e85 100644
--- a/osu.Game.Rulesets.Karaoke/Objects/Lyric.cs
+++ b/osu.Game.Rulesets.Karaoke/Objects/Lyric.cs
@@ -1,14 +1,12 @@
 // Copyright (c) andy840119 <andy840119@gmail.com>. Licensed under the GPL Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-using System;
 using System.Collections.Generic;
 using System.Globalization;
 using System.Linq;
 using Newtonsoft.Json;
 using osu.Framework.Bindables;
 using osu.Framework.Extensions.IEnumerableExtensions;
-using osu.Framework.Graphics.Sprites;
 using osu.Game.Beatmaps;
 using osu.Game.Beatmaps.ControlPoints;
 using osu.Game.Rulesets.Judgements;