Added experimental NSpeex plugin for Network Chat demo. Currently not fully working. Had to create a .NET 3.5 build of NSpeex

NAudioDemo/NAudioDemo.csproj

@@ -54,6 +54,9 @@
     <CodeAnalysisRuleSet>AllRules.ruleset</CodeAnalysisRuleSet>
   </PropertyGroup>
   <ItemGroup>
+    <Reference Include="NSpeex">
+      <HintPath>..\Lib\NSpeex\NSpeex.dll</HintPath>
+    </Reference>
     <Reference Include="System" />
     <Reference Include="System.ComponentModel.Composition">
       <HintPath>..\Lib\MEF\System.ComponentModel.Composition.dll</HintPath>
@@ -122,6 +125,7 @@
     <Compile Include="NetworkChatDemo\NetworkChatPanel.Designer.cs">
       <DependentUpon>NetworkChatPanel.cs</DependentUpon>
     </Compile>
+    <Compile Include="NetworkChatDemo\SpeexChatCodec.cs" />
     <Compile Include="NetworkChatDemo\TrueSpeechChatCodec.cs" />
     <Compile Include="NetworkChatDemo\UncompressedPcmChatCodec.cs" />
     <Compile Include="Program.cs" />

NAudioDemo/NetworkChatDemo/NetworkChatPanel.cs

@@ -48,7 +48,8 @@ namespace NAudioDemo.NetworkChatDemo
                 new TrueSpeechChatCodec(),
                 new Gsm610ChatCodec(),
                 new MicrosoftAdpcmChatCodec(),
-                new G722ChatCodec()
+                new G722ChatCodec(),
+                // new SpeexChatCodec(), - still work in progress
             };
 
             var sorted = from codec in codecs orderby codec.BitsPerSecond ascending select codec;

NAudioDemo/NetworkChatDemo/SpeexChatCodec.cs

@@ -0,0 +1,65 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using NAudio.Wave;
+using NSpeex;
+
+namespace NAudioDemo.NetworkChatDemo
+{
+    class SpeexChatCodec : INetworkChatCodec
+    {
+        private WaveFormat recordingFormat;
+        private SpeexDecoder decoder;
+        private SpeexEncoder encoder;
+
+        public SpeexChatCodec()
+        {
+            this.decoder = new SpeexDecoder(BandMode.Narrow);
+            this.encoder = new SpeexEncoder(BandMode.Narrow);
+            this.recordingFormat = new WaveFormat(8000, 16, 1);
+        }
+
+        public string Name
+        {
+            get { return "Speex Narrow Band"; }
+        }
+
+        public int BitsPerSecond
+        {
+            // don't know yet
+            get { return 8000; }
+        }
+
+        public WaveFormat RecordFormat
+        {
+            get { return recordingFormat; }
+        }
+
+        public byte[] Encode(byte[] data, int offset, int length)
+        {
+            byte[] outputBufferTemp = new byte[length]; // easily big enough
+            WaveBuffer wb = new WaveBuffer(data);
+            int bytesWritten = encoder.Encode(wb.ShortBuffer, offset / 2, length / 2, outputBufferTemp, 0, length);
+            byte[] encoded = new byte[bytesWritten];
+            Array.Copy(outputBufferTemp, 0, encoded, 0, bytesWritten);
+            return encoded;
+        }
+
+        public byte[] Decode(byte[] data)
+        {
+            byte[] outputBufferTemp = new byte[data.Length * 16]; // easily big enough
+            WaveBuffer wb = new WaveBuffer(outputBufferTemp);
+            int samplesWritten = decoder.Decode(data, 0, data.Length, wb.ShortBuffer, 0, false);
+            int bytesWritten = samplesWritten * 2;
+            byte[] decoded = new byte[bytesWritten];
+            Array.Copy(outputBufferTemp, 0, decoded, 0, bytesWritten);
+            return decoded;
+        }
+
+        public void Dispose()
+        {
+            // nothing to do
+        }
+    }
+}