hawkeye camera support(not tested)

framework/Inspectron.HawkEye/RTSP/Sdp/Attribut.cs

@@ -0,0 +1,77 @@
+using System;
+using System.Collections.Generic;
+using System.Diagnostics.Contracts;
+using System.Linq;
+
+namespace Inspectron.HawkEye.RTSP.Sdp
+{
+    public class Attribut
+    {
+        private static readonly Dictionary<string, Type> attributMap = new Dictionary<string, Type>()
+        {
+            {AttributRtpMap.NAME,typeof(AttributRtpMap)},
+            {AttributFmtp.NAME,typeof(AttributFmtp)},
+        };
+
+
+        public virtual string Key { get; private set; }
+        public virtual string Value { get; protected set; }
+
+        public static void RegisterNewAttributeType(string key, Type attributType)
+        {
+            if(!attributType.IsSubclassOf(typeof(Attribut)))
+                throw new ArgumentException("Type must be subclass of Rtsp.Sdp.Attribut","attributType");
+
+            attributMap[key] = attributType;
+        }
+
+        
+
+        public Attribut()
+        {
+        }
+
+        public Attribut(string key)
+        {
+            Key = key;
+        }
+
+
+        public static Attribut ParseInvariant(string value)
+        {
+            if(value == null)
+                throw new ArgumentNullException("value");
+
+            Contract.EndContractBlock();
+
+            var listValues = value.Split(new char[] {':'}, 2);
+            
+
+            Attribut returnValue;
+
+            // Call parser of child type
+            Type childType;
+            attributMap.TryGetValue(listValues[0], out childType);
+            if (childType != null)
+            {
+                var defaultContructor = childType.GetConstructor(Type.EmptyTypes);
+                returnValue = defaultContructor.Invoke(Type.EmptyTypes) as Attribut;
+            }
+            else
+            {
+                returnValue = new Attribut(listValues[0]);
+            }
+            // Parse the value. Note most attributes have a value but recvonly does not have a value
+            if (listValues.Count() > 1) returnValue.ParseValue(listValues[1]);
+
+            return returnValue;
+        }
+
+        protected virtual void ParseValue(string value)
+        {
+            Value = value;
+        }
+
+        
+    }
+}