diff --git a/src/JT1078.FMp4.Test/JT1078ToFMp4Box_Test.cs b/src/JT1078.FMp4.Test/JT1078ToFMp4Box_Test.cs
index 58d9958..489fb93 100644
--- a/src/JT1078.FMp4.Test/JT1078ToFMp4Box_Test.cs
+++ b/src/JT1078.FMp4.Test/JT1078ToFMp4Box_Test.cs
@@ -473,7 +473,7 @@ namespace JT1078.FMp4.Test
                 var otherMdatBuffer = fMp4Encoder.EncoderMdatBox(otherNalus, package.Bodies.Length);
                 //var otherMoofBuffer = fMp4Encoder.EncoderMoofBox(filterOtherNalus, length, package.Timestamp, package.LastFrameInterval, package.LastIFrameInterval, flag);
                 //var otherMdatBuffer = fMp4Encoder.EncoderMdatBox(filterOtherNalus, length);
-                var otherSidxBuffer = fMp4Encoder.EncoderSidxBox(otherMoofBuffer.Length + otherMdatBuffer.Length, package.Timestamp, package.LastIFrameInterval, package.LastFrameInterval);
+                var otherSidxBuffer = fMp4Encoder.EncoderSidxBox(otherMoofBuffer.Length + otherMdatBuffer.Length, package.Timestamp, package.LastFrameInterval, package.LastIFrameInterval);
                 fileStream.Write(otherSidxBuffer);
                 fileStream.Write(otherMoofBuffer);
                 fileStream.Write(otherMdatBuffer);
@@ -525,6 +525,7 @@ namespace JT1078.FMp4.Test
                             var iStypBuffer = fMp4Encoder.EncoderStypBox();
                             fileStream.Write(iStypBuffer);
                             var firstNalu = nalus[0];
+                            var lastNalu = nalus[nalus.Count-1];
                             var flag = firstNalu.DataType == Protocol.Enums.JT1078DataType.视频I帧 ? 1u : 0u;
                             int iSize = nalus.Where(w => w.DataType == Protocol.Enums.JT1078DataType.视频I帧)
                                             .Sum(s => s.RawData.Length + s.StartCodePrefix.Length);
@@ -533,9 +534,10 @@ namespace JT1078.FMp4.Test
                             sizes = sizes.Concat(nalus.Where(w => w.DataType != Protocol.Enums.JT1078DataType.视频I帧)
                                                 .Select(s => s.RawData.Length + s.StartCodePrefix.Length).ToList())
                                                 .ToList();
-                            var iMoofBuffer = fMp4Encoder.EncoderMoofBox(sizes, firstNalu.Timestamp, firstNalu.LastFrameInterval, firstNalu.LastIFrameInterval, flag);
+                            var iMoofBuffer = fMp4Encoder.EncoderMoofBox(sizes, (uint)(nalus.Count * 48000), (uint)(lastNalu.LastIFrameInterval), firstNalu.LastIFrameInterval, flag);
                             var iMdatBuffer = fMp4Encoder.EncoderMdatBox(nalus.Select(s => s.RawData).ToList());
-                            var iSidxBuffer = fMp4Encoder.EncoderSidxBox(iMoofBuffer.Length + iMdatBuffer.Length, firstNalu.Timestamp, firstNalu.LastIFrameInterval, firstNalu.LastFrameInterval);
+                            var iSidxBuffer = fMp4Encoder.EncoderSidxBox(iMoofBuffer.Length + iMdatBuffer.Length, (uint)(nalus.Count*48000), (uint)(lastNalu.LastIFrameInterval), firstNalu.LastIFrameInterval);
+                            fMp4Encoder.timestampCache += (uint)(sizes.Count * 48000+ lastNalu.LastFrameInterval);
                             fileStream.Write(iSidxBuffer);
                             fileStream.Write(iMoofBuffer);
                             fileStream.Write(iMdatBuffer);
@@ -546,7 +548,7 @@ namespace JT1078.FMp4.Test
                 }
             }
             fileStream.Close();
-        }
+       }
 
         [Fact]
         public void tkhd_width_height_test()
diff --git a/src/JT1078.FMp4/Boxs/TrackRunBox.cs b/src/JT1078.FMp4/Boxs/TrackRunBox.cs
index 8ce43a2..4351a28 100644
--- a/src/JT1078.FMp4/Boxs/TrackRunBox.cs
+++ b/src/JT1078.FMp4/Boxs/TrackRunBox.cs
@@ -123,6 +123,7 @@ namespace JT1078.FMp4
             /// version == 0
             ///  0:uint
             /// >0:int
+            /// cts
             /// </summary>
             public long SampleCompositionTimeOffset { get; set; }
         }       
diff --git a/src/JT1078.FMp4/FMp4Encoder.cs b/src/JT1078.FMp4/FMp4Encoder.cs
index fe573f4..838887a 100644
--- a/src/JT1078.FMp4/FMp4Encoder.cs
+++ b/src/JT1078.FMp4/FMp4Encoder.cs
@@ -108,15 +108,11 @@ namespace JT1078.FMp4
             }
         }
 
-        ulong IframeIntervalCache = 259960;
-
-        ulong cts = 0;
-
         /// <summary>
         /// 编码sidx盒子
         /// </summary>
         /// <returns></returns>
-        public byte[] EncoderSidxBox(int moofAndMdatLength, ulong timestamp, uint IframeInterval, uint frameInterval)
+        public byte[] EncoderSidxBox(int moofAndMdatLength, ulong timestamp,uint frameInterval, uint IframeInterval)
         {
             byte[] buffer = FMp4ArrayPool.Rent(4096);
             FMp4MessagePackWriter writer = new FMp4MessagePackWriter(buffer);
@@ -124,9 +120,8 @@ namespace JT1078.FMp4
             {
                 SegmentIndexBox segmentIndexBox = new SegmentIndexBox(1);
                 segmentIndexBox.ReferenceID = 1;
-                cts = cts == 0 ? 2160000 : (cts + cts);
-                segmentIndexBox.EarliestPresentationTime = cts;
-                IframeIntervalCache += frameInterval;
+                segmentIndexBox.EarliestPresentationTime = timestampCache;
+                //segmentIndexBox.EarliestPresentationTime = IframeInterval * 1000*90;
                 segmentIndexBox.SegmentIndexs = new List<SegmentIndexBox.SegmentIndex>()
                 {
                      new SegmentIndexBox.SegmentIndex
@@ -337,7 +332,8 @@ namespace JT1078.FMp4
                 movieFragmentBox.TrackFragmentBox.TrackFragmentHeaderBox.DefaultSampleSize = (uint)naluLength;
                 movieFragmentBox.TrackFragmentBox.TrackFragmentHeaderBox.DefaultSampleFlags = 0x1010000;
                 movieFragmentBox.TrackFragmentBox.TrackFragmentBaseMediaDecodeTimeBox = new TrackFragmentBaseMediaDecodeTimeBox();
-                movieFragmentBox.TrackFragmentBox.TrackFragmentBaseMediaDecodeTimeBox.BaseMediaDecodeTime = timestamp*1000;
+                movieFragmentBox.TrackFragmentBox.TrackFragmentBaseMediaDecodeTimeBox.BaseMediaDecodeTime = timestamp;
+                //movieFragmentBox.TrackFragmentBox.TrackFragmentBaseMediaDecodeTimeBox.BaseMediaDecodeTime = timestamp*1000;
                 //trun
                 //0x39 写文件
                 //0x02 分段
@@ -369,6 +365,8 @@ namespace JT1078.FMp4
             }
         }
 
+        public ulong timestampCache = 0;
+
         /// <summary>
         /// 编码Moof盒子
         /// </summary>
@@ -389,12 +387,12 @@ namespace JT1078.FMp4
                 movieFragmentBox.TrackFragmentBox.TrackFragmentHeaderBox = new TrackFragmentHeaderBox(0x2003a);
                 movieFragmentBox.TrackFragmentBox.TrackFragmentHeaderBox.TrackID = 1;
                 movieFragmentBox.TrackFragmentBox.TrackFragmentHeaderBox.SampleDescriptionIndex = 1;
-                movieFragmentBox.TrackFragmentBox.TrackFragmentHeaderBox.DefaultSampleDuration = frameInterval;
-                //movieFragmentBox.TrackFragmentBox.TrackFragmentHeaderBox.DefaultSampleDuration = 48000;
+                //movieFragmentBox.TrackFragmentBox.TrackFragmentHeaderBox.DefaultSampleDuration = frameInterval;
+                movieFragmentBox.TrackFragmentBox.TrackFragmentHeaderBox.DefaultSampleDuration = 48000;
                 movieFragmentBox.TrackFragmentBox.TrackFragmentHeaderBox.DefaultSampleSize = (uint)naluSzies[0];
                 movieFragmentBox.TrackFragmentBox.TrackFragmentHeaderBox.DefaultSampleFlags = 0x1010000;
                 movieFragmentBox.TrackFragmentBox.TrackFragmentBaseMediaDecodeTimeBox = new TrackFragmentBaseMediaDecodeTimeBox();
-                movieFragmentBox.TrackFragmentBox.TrackFragmentBaseMediaDecodeTimeBox.BaseMediaDecodeTime = cts;
+                movieFragmentBox.TrackFragmentBox.TrackFragmentBaseMediaDecodeTimeBox.BaseMediaDecodeTime = timestampCache;
                 //trun
                 //0x39 写文件
                 //0x02 分段
diff --git a/src/JT1078.FMp4/JT1078.FMp4.xml b/src/JT1078.FMp4/JT1078.FMp4.xml
index 9513cbf..8c30c0c 100644
--- a/src/JT1078.FMp4/JT1078.FMp4.xml
+++ b/src/JT1078.FMp4/JT1078.FMp4.xml
@@ -1098,6 +1098,7 @@
             version == 0
              0:uint
             >0:int
+            cts
             </summary>
         </member>
         <member name="T:JT1078.FMp4.URIBox">
diff --git a/src/JT1078.SignalR.Test/Services/ToWebSocketService.cs b/src/JT1078.SignalR.Test/Services/ToWebSocketService.cs
index 0f0b0c3..0754b04 100644
--- a/src/JT1078.SignalR.Test/Services/ToWebSocketService.cs
+++ b/src/JT1078.SignalR.Test/Services/ToWebSocketService.cs
@@ -89,7 +89,7 @@ namespace JT1078.SignalR.Test.Services
                 var flag = package.Label3.DataType == Protocol.Enums.JT1078DataType.视频I帧 ? 1u : 0u;
                 var otherMoofBuffer = fMp4Encoder.EncoderMoofBox(otherNalus, package.Bodies.Length, package.Timestamp, package.LastFrameInterval, package.LastIFrameInterval, flag);
                 var otherMdatBuffer = fMp4Encoder.EncoderMdatBox(otherNalus, package.Bodies.Length);
-                var otherSidxBuffer = fMp4Encoder.EncoderSidxBox(otherMoofBuffer.Length + otherMdatBuffer.Length, package.Timestamp, package.LastIFrameInterval, package.LastFrameInterval);
+                var otherSidxBuffer = fMp4Encoder.EncoderSidxBox(otherMoofBuffer.Length + otherMdatBuffer.Length, package.Timestamp,package.LastFrameInterval, package.LastIFrameInterval);
                 other.Add(otherSidxBuffer);
                 other.Add(otherMoofBuffer);
                 other.Add(otherMdatBuffer);