From a3afe7c152a9ccdf64bc6a706a2f8321df9dbafc Mon Sep 17 00:00:00 2001
From: Bryan Biedenkapp <gatekeep@jmp.cx>
Date: Thu, 21 Dec 2023 08:20:41 -0500
Subject: [PATCH] correct RTP offset error; add helper routines;

---
 FneUtils.cs  | 44 ++++++++++++++++++++++++++++++++++++++++++++
 RtpHeader.cs |  2 +-
 2 files changed, 45 insertions(+), 1 deletion(-)

diff --git a/FneUtils.cs b/FneUtils.cs
index c4e465d..bdef8cb 100644
--- a/FneUtils.cs
+++ b/FneUtils.cs
@@ -21,6 +21,7 @@
 */
 
 using System;
+using System.Linq;
 using System.Security.Cryptography;
 using System.Reflection;
 using System.Reflection.Emit;
@@ -59,6 +60,49 @@ namespace fnecore
             memsetDelegate = (Action<IntPtr, byte, int>)dynamicMethod.CreateDelegate(typeof(Action<IntPtr, byte, int>));
         }
 
+        /// <summary>
+        /// 
+        /// </summary>
+        /// <param name="x"></param>
+        /// <returns></returns>
+        public static ushort DoReverseEndian(ushort x)
+        {
+            //return Convert.ToUInt16((x << 8 & 0xff00) | (x >> 8));
+            return BitConverter.ToUInt16(BitConverter.GetBytes(x).Reverse().ToArray(), 0);
+        }
+
+        /// <summary>
+        /// 
+        /// </summary>
+        /// <param name="x"></param>
+        /// <returns></returns>
+        public static uint DoReverseEndian(uint x)
+        {
+            //return (x << 24 | (x & 0xff00) << 8 | (x & 0xff0000) >> 8 | x >> 24);
+            return BitConverter.ToUInt32(BitConverter.GetBytes(x).Reverse().ToArray(), 0);
+        }
+
+        /// <summary>
+        /// 
+        /// </summary>
+        /// <param name="x"></param>
+        /// <returns></returns>
+        public static ulong DoReverseEndian(ulong x)
+        {
+            //return (x << 56 | (x & 0xff00) << 40 | (x & 0xff0000) << 24 | (x & 0xff000000) << 8 | (x & 0xff00000000) >> 8 | (x & 0xff0000000000) >> 24 | (x & 0xff000000000000) >> 40 | x >> 56);
+            return BitConverter.ToUInt64(BitConverter.GetBytes(x).Reverse().ToArray(), 0);
+        }
+
+        /// <summary>
+        /// 
+        /// </summary>
+        /// <param name="x"></param>
+        /// <returns></returns>
+        public static int DoReverseEndian(int x)
+        {
+            return BitConverter.ToInt32(BitConverter.GetBytes(x).Reverse().ToArray(), 0);
+        }
+
         /// <summary>
         /// 
         /// </summary>
diff --git a/RtpHeader.cs b/RtpHeader.cs
index 5eee816..6c2d0e6 100644
--- a/RtpHeader.cs
+++ b/RtpHeader.cs
@@ -129,7 +129,7 @@ namespace fnecore
             Sequence = (ushort)((data[2] << 8) | (data[3] << 0));               // Sequence
 
             Timestamp = FneUtils.ToUInt32(data, 4);                             // Timestamp
-            SSRC = FneUtils.ToUInt32(data, 6);                                  // Synchronization Source ID
+            SSRC = FneUtils.ToUInt32(data, 8);                                  // Synchronization Source ID
 
             return true;
         }