From cf22b2328bf0e255e9297ceb24f517513b8a19f4 Mon Sep 17 00:00:00 2001
From: Kjell Kernen <github@kernen.se>
Date: Sat, 22 Mar 2014 00:38:18 +0100
Subject: [PATCH] Added audio processing of recorded files.

---
 sound/recorder/MainWindow.xaml            |  19 ++-
 sound/recorder/MainWindow.xaml.cs         |  20 +--
 sound/recorder/OpenTXRecorder.csproj      |   1 +
 sound/recorder/Properties/AssemblyInfo.cs |   4 +-
 sound/recorder/WaveIn.cs                  |   8 +-
 sound/recorder/clsWaveProcessor.cs        | 163 ++++++++++++++++++++++
 6 files changed, 198 insertions(+), 17 deletions(-)
 create mode 100644 sound/recorder/clsWaveProcessor.cs

diff --git a/sound/recorder/MainWindow.xaml b/sound/recorder/MainWindow.xaml
index 8dc4626e9..3be9ace89 100644
--- a/sound/recorder/MainWindow.xaml
+++ b/sound/recorder/MainWindow.xaml
@@ -57,9 +57,7 @@
                               SelectionChanged="switchLanguage" 
                               Width="200" Height="23"  />
                 </StackPanel>
-
             </StackPanel>
-
             <Separator Height="5" />
             <TextBlock Text="Sentence" Margin="5,0,0,0" FontSize="18"   />
             <Grid Margin="10,0,0,0" DataContext="{Binding ElementName=lvSentences, Path=SelectedItem}" Width="Auto">
@@ -82,9 +80,24 @@
                 <TextBlock Text="Sentence" Grid.Row="2" Grid.Column="0" Margin="0,5,0,0"   />
                 <TextBox   Text="{Binding Path=voiceString}" Grid.Row="2" Grid.Column="1"  Margin="0,0,10,0"/>
             </Grid>
+            <Separator Height="5" Margin="0,5,0,0" />
 
+            <StackPanel Orientation="Horizontal" Margin="0,0,0,0">
+                <TextBlock Text="Cut Level" Width="70" Margin="10,10,0,0"   />
+                <Slider Name="noiceLevelSlider" 
+                        Value="800"
+                        Minimum="0" 
+                        Maximum="4000" 
+                        TickPlacement="BottomRight" 
+                        TickFrequency="100" 
+                        IsSnapToTickEnabled="True"
+                        Width="170" 
+                        Margin="10,10,10,0" ToolTip="Set Cut Level as low as possible" />
+                <TextBlock Text="{Binding ElementName=noiceLevelSlider, Path=Value}" Width="40" Margin="0,10,0,0"/>
+                <TextBlock Text="Voice Rate" Width="70" Margin="10,10,0,0"   />
+            </StackPanel>
 
-            <StackPanel Orientation="Horizontal" HorizontalAlignment="Center" Margin="0,5,0,0">
+             <StackPanel Orientation="Horizontal" HorizontalAlignment="Center" Margin="0,5,0,0">
                 <Button Content="New Sentence" Width="120" Height="32" Name="buttonAddItem" Click="addSentence"/>
                 <Button Name="btnRecord" ToolTip="Start recording" Click="record"  Margin="20,0,0,0" >
                     <Image Height="32" Source="/OpenTXrecorder;component/record.png"/>
diff --git a/sound/recorder/MainWindow.xaml.cs b/sound/recorder/MainWindow.xaml.cs
index 0e0ffb4a1..515d31e44 100644
--- a/sound/recorder/MainWindow.xaml.cs
+++ b/sound/recorder/MainWindow.xaml.cs
@@ -161,7 +161,7 @@ namespace OpenTXrecorder
             {
                 try
                 {
-                    SoundPlayer player = new SoundPlayer(sentence.fullPath());
+                    SoundPlayer player = new SoundPlayer(sentence.fullPath);
                     player.Play();
                 }
                 catch (Exception) { };  // Catch and disregard all media exceptions
@@ -180,7 +180,7 @@ namespace OpenTXrecorder
                 isRecording = true;
                 lblRecording.Visibility = System.Windows.Visibility.Visible;
                 Sentence sentence = (Sentence)this.lvSentences.SelectedItem;
-                string path = sentence.fullPath();
+                string path = sentence.fullPath;
                 Directory.CreateDirectory(Path.GetDirectoryName(path));  // Create directory if it doesn't exist
                 System.IO.File.WriteAllText(path, "");                   // Create and flush the file
 
@@ -199,11 +199,16 @@ namespace OpenTXrecorder
             recorder.Close();
             filewriter.Close();
 
+
             int index = this.lvSentences.SelectedIndex;
             lblRecording.Visibility = System.Windows.Visibility.Hidden;
             Sentence sentence = (Sentence)this.lvSentences.SelectedItem;
             loadLanguage();            // Called to refresh the sentence data of the current langugae
             this.lvSentences.SelectedIndex = index;
+
+            wavProcessor processor = new wavProcessor();
+            int noiceLevel = (int)this.noiceLevelSlider.Value;
+            processor.StripSilence(sentence.fullPath, noiceLevel );
         }
 
         private void DataArrived(IntPtr data, int size)
@@ -235,10 +240,9 @@ namespace OpenTXrecorder
             shortLanguage = str;
         }
     }
+    
+    // Data container classes
 
-    /* 
-     * Data container classes
-     */
     public class Languages : List<Language>
     {
         public void Add(string longer, string shorter)
@@ -276,12 +280,12 @@ namespace OpenTXrecorder
             description = words[1];
             voiceString = words[2].TrimEnd('\"', ',', ' ');
             path = dirPath;
-            fileExists = File.Exists(fullPath());
+            fileExists = File.Exists(fullPath);
         }
 
-        public string fullPath()
+        public string fullPath
         {
-            return System.AppDomain.CurrentDomain.BaseDirectory + path + fileName + ".wav";
+            get { return System.AppDomain.CurrentDomain.BaseDirectory + path + fileName + ".wav"; }
         }
 
         public string toRaw()
diff --git a/sound/recorder/OpenTXRecorder.csproj b/sound/recorder/OpenTXRecorder.csproj
index 78532dd3c..2070e1262 100644
--- a/sound/recorder/OpenTXRecorder.csproj
+++ b/sound/recorder/OpenTXRecorder.csproj
@@ -80,6 +80,7 @@
     <Compile Include="App.xaml.cs">
       <DependentUpon>App.xaml</DependentUpon>
     </Compile>
+    <Compile Include="clsWaveProcessor.cs" />
     <Compile Include="sentencetables.cs" />
     <Compile Include="WaveIn.cs" />
     <Compile Include="WaveNative.cs" />
diff --git a/sound/recorder/Properties/AssemblyInfo.cs b/sound/recorder/Properties/AssemblyInfo.cs
index 4b2343de5..6defc2da9 100644
--- a/sound/recorder/Properties/AssemblyInfo.cs
+++ b/sound/recorder/Properties/AssemblyInfo.cs
@@ -67,5 +67,5 @@ using System.Windows;
 // You can specify all the values or you can default the Build and Revision Numbers 
 // by using the '*' as shown below:
 // [assembly: AssemblyVersion("1.0.*")]
-[assembly: AssemblyVersion("0.2")]
-[assembly: AssemblyFileVersion("0.2")]
+[assembly: AssemblyVersion("0.3")]
+[assembly: AssemblyFileVersion("0.3")]
diff --git a/sound/recorder/WaveIn.cs b/sound/recorder/WaveIn.cs
index c1265c186..2a7fc12c6 100644
--- a/sound/recorder/WaveIn.cs
+++ b/sound/recorder/WaveIn.cs
@@ -1,5 +1,5 @@
-/* 
- * This is free software: you can redistribute it and/or modify
+/* This file is part of OpenTX Recorder.
+ * OpenTX Recorder is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation, either version 3 of the License, or
  * (at your option) any later version.
@@ -10,7 +10,7 @@
  * GNU General Public License for more details.
 
  * You should have received a copy of the GNU General Public License
- * along with the code.  If not, see <http://www.gnu.org/licenses/>. 
+ * along with OpenTX Recorder.  If not, see <http://www.gnu.org/licenses/>. 
  *
  * Copyright 2014 Tomas Andersson  */
 
@@ -91,7 +91,7 @@ namespace WaveLib
 		}
 	}
 
-    class WavFileWriter
+    public class WavFileWriter
     {
         BinaryWriter filewriter;
         long audiobyteswritten;
diff --git a/sound/recorder/clsWaveProcessor.cs b/sound/recorder/clsWaveProcessor.cs
new file mode 100644
index 000000000..b03c2065a
--- /dev/null
+++ b/sound/recorder/clsWaveProcessor.cs
@@ -0,0 +1,163 @@
+using System;
+using System.Text;
+using System.IO;
+using System.Runtime.InteropServices;
+using WaveLib;
+
+
+public class wavProcessor
+{
+    public int Length;
+    public short Channels;
+    public int SampleRate;
+    public int DataLength;
+    public short BitsPerSample;
+
+    /// Filter out silence or noise from start and end of wave file. 
+    public bool StripSilence(string strPath, int noiceLevel)
+    {
+        if (strPath == null) strPath = "";
+        if (strPath == "") return false;
+
+        wavProcessor wain = new wavProcessor();
+        wavProcessor waout = new wavProcessor();
+
+        waout.DataLength = waout.Length = 0;
+
+        if (!wain.WaveHeaderIN(@strPath)) return false;
+
+        waout.DataLength = wain.DataLength;
+        waout.Length = wain.Length;
+
+        waout.BitsPerSample = wain.BitsPerSample;
+        waout.Channels = wain.Channels;
+        waout.SampleRate = wain.SampleRate;
+
+        byte[] arrfile = GetWAVEData(strPath);
+
+        //check for silence
+        int startpos = 0;
+        int endpos = arrfile.Length - 1;
+        //At start
+        try
+        {
+            for (int j = 0; j < arrfile.Length; j += 2)
+            {
+                short snd = ComplementToSigned(ref arrfile, j);
+                if (snd > (-1 * noiceLevel) && snd < noiceLevel) startpos = j;
+                else
+                    break;
+            }
+        }
+        catch (Exception ex)
+        {
+            Console.Write(ex.Message);
+        }
+
+        //At end
+        for (int k = arrfile.Length - 1; k >= 0; k -= 2)
+        {
+            short snd = ComplementToSigned(ref arrfile, k - 1);
+            if (snd > (-1 * noiceLevel) && snd < noiceLevel)
+                endpos = k;
+            else
+                break;
+        }
+
+        if (startpos == endpos) return false;
+        if ((endpos - startpos) < 1) return false;
+
+        byte[] newarr = new byte[(endpos - startpos) + 1];
+
+        for (int ni = 0, m = startpos; m <= endpos; m++, ni++)
+            newarr[ni] = arrfile[m];
+
+        //write file
+        waout.DataLength = newarr.Length;
+
+        WavFileWriter wfWriter = new WavFileWriter(@strPath, wain.SampleRate, wain.BitsPerSample, wain.Channels);
+        wfWriter.Write(newarr);
+        wfWriter.Close();
+
+        return true;
+    }
+
+    /// <summary>
+    /// Read the wave file header and store the key values in public variable.
+    /// Adapted from - Concatenation Wave Files using C# 2005 by By Ehab Mohamed Essa
+    /// URL - http://www.codeproject.com/useritems/Concatenation_Wave_Files.asp
+    /// </summary>
+    /// <param name="strPath">The physical path of wave file incl. file name for reading</param>
+    /// <returns>True/False</returns>
+    private bool WaveHeaderIN(string strPath)
+    {
+        if (strPath == null) strPath = "";
+        if (strPath == "") return false;
+
+        FileStream fs = new FileStream(strPath, FileMode.Open, FileAccess.Read);
+
+        BinaryReader br = new BinaryReader(fs);
+        try
+        {
+            Length = (int)fs.Length - 8;
+            fs.Position = 22;
+            Channels = br.ReadInt16(); //1
+            fs.Position = 24;
+            SampleRate = br.ReadInt32(); //16000
+            fs.Position = 34;
+            BitsPerSample = br.ReadInt16(); //16
+            DataLength = (int)fs.Length - 44;
+            byte[] arrfile = new byte[fs.Length - 44];
+            fs.Position = 44;
+            fs.Read(arrfile, 0, arrfile.Length);
+        }
+        catch
+        {
+            return false;
+        }
+        finally
+        {
+            br.Close();
+            fs.Close();
+        }
+        return true;
+    }
+
+    /// <summary>
+    /// In stereo wave format, samples are stored in 2's complement. For Mono, it's necessary to 
+    /// convert those samples to their equivalent signed value. This method is used 
+    /// by other public methods to equilibrate wave formats of different files.
+    /// </summary>
+    /// <param name="bytArr">Sample data in array</param>
+    /// <param name="intPos">Array offset</param>
+    /// <returns>Mono value as signed short</returns>
+    private short ComplementToSigned(ref byte[] bytArr, int intPos) // 2's complement to normal signed value
+    {
+        short snd = BitConverter.ToInt16(bytArr, intPos);
+        if (snd != 0)
+            snd = Convert.ToInt16((~snd | 1));
+        return snd;
+    }
+
+    /// <summary>
+    /// Read the WAVE file then position to DADA segment and return the chunk as byte array 
+    /// </summary>
+    /// <param name="strWAVEPath">Path of WAVE file</param>
+    /// <returns>byte array</returns>
+    private byte[] GetWAVEData(string strWAVEPath)
+    {
+        try
+        {
+            FileStream fs = new FileStream(@strWAVEPath, FileMode.Open, FileAccess.Read);
+            byte[] arrfile = new byte[fs.Length - 44];
+            fs.Position = 44;
+            fs.Read(arrfile, 0, arrfile.Length);
+            fs.Close();
+            return arrfile;
+        }
+        catch (IOException ioex)
+        {
+            throw ioex;
+        }
+    }
+} // End of clsWaveProcessor class