Deprecating Signal's Samples and Channels properties in favor of Numb…

…erOfSamples and NumberOfChannels;

Adding a new NumberOfFrames property to report the number of samples at each signal channel;
Adding convertion overloads in the SampleConverter class to convert from float to double;
Adding a base class for audio signal generators;

Sources/Accord.Audio.DirectSound/Accord.Audio.DirectSound.csproj

@@ -12,7 +12,8 @@
     <CheckForOverflowUnderflow>True</CheckForOverflowUnderflow>
     <DefineConstants>DEBUG;TRACE</DefineConstants>
     <OutputPath>$(SolutionDir)..\Debug\</OutputPath>
-    <DocumentationFile></DocumentationFile>
+    <DocumentationFile>
+    </DocumentationFile>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'net35|AnyCPU' ">
     <DefineConstants>TRACE;NET35</DefineConstants>
@@ -40,8 +41,6 @@
     <TargetFrameworkVersion>v4.5</TargetFrameworkVersion>
   </PropertyGroup>
   <Import Project="$(MSBuildBinPath)\Microsoft.CSharp.Targets" />
-
-
   <Choose>
     <When Condition="'$(Configuration)' == 'net35'">
       <ItemGroup>
@@ -80,7 +79,6 @@
       </ItemGroup>
     </Otherwise>
   </Choose>
-
   <ItemGroup>
     <Reference Include="System" />
     <Reference Include="System.Core">
@@ -99,9 +97,9 @@
     <Compile Include="AudioOutputDevice.cs" />
     <Compile Include="AudioDeviceInfo.cs" />
     <Compile Include="Extensions.cs" />
+    <Compile Include="Formats\WaveEncoder.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
-    <Compile Include="WaveDecoder.cs" />
-    <Compile Include="WaveEncoder.cs" />
+    <Compile Include="Formats\WaveDecoder.cs" />
     <Compile Include="WaveFileAudioSource.cs" />
   </ItemGroup>
   <ItemGroup>

Sources/Accord.Audio.DirectSound/WaveEncoder.cs → Sources/Accord.Audio.DirectSound/Formats/WaveEncoder.cs

@@ -45,6 +45,7 @@ namespace Accord.Audio.Formats
     /// </code>
     /// </example>
     /// 
+    [FormatEncoder("wav")]
     public class WaveEncoder : IAudioEncoder
     {
         private Stream waveStream;
@@ -273,7 +274,7 @@ public void Encode(Signal signal)
             }
 
             // Update counters
-            numberOfSamples += signal.Samples;
+            numberOfSamples += signal.NumberOfSamples;
             numberOfFrames += signal.Length;
             bytes += signal.RawData.Length;
             duration += (int)signal.Duration.TotalMilliseconds;
@@ -339,7 +340,7 @@ private void firstWriteHeaders()
 
         private void initialize(Signal signal)
         {
-            this.channels = signal.Channels;
+            this.channels = signal.NumberOfChannels;
             this.sampleRate = signal.SampleRate;
             this.sampleFormat = signal.SampleFormat;
             this.bitsPerSample = Signal.GetSampleSize(signal.SampleFormat);

Sources/Accord.Audio/Accord.Audio.csproj

@@ -58,10 +58,12 @@
     <Compile Include="Features\IAudioFeatureExtractor.cs" />
     <Compile Include="Filters\AddFilter.cs" />
     <Compile Include="Filters\MonoFilter.cs" />
+    <Compile Include="Formats\AudioEncoder.cs" />
     <Compile Include="Formats\AudioDecoder.cs" />
     <Compile Include="Formats\FrameInfo.cs" />
     <Compile Include="Formats\IAudioDecoder.cs" />
     <Compile Include="Formats\IAudioEncoder.cs" />
+    <Compile Include="Generators\Base\BaseSignalGenerator.cs" />
     <Compile Include="Generators\SignalGenerator.cs" />
     <Compile Include="Generators\SineGenerator.cs" />
     <Compile Include="AudioSourceMixer.cs" />
@@ -100,7 +102,7 @@
     <Compile Include="Signals\Signal.cs" />
     <Compile Include="Signals\ComplexSignal.cs" />
     <Compile Include="Generators\CosineGenerator.cs" />
-    <Compile Include="Generators\ISignalGenerator.cs" />
+    <Compile Include="Generators\Base\ISignalGenerator.cs" />
     <Compile Include="Generators\SquareGenerator.cs" />
     <Compile Include="Filters\Base\IFilter.cs" />
     <Compile Include="IAudioSource.cs" />

Sources/Accord.Audio/AudioSourceMixer.cs

@@ -370,7 +370,7 @@ private unsafe void WorkerThread()
 
                             short* src = (short*)signal.Data.ToPointer();
 
-                            if (signal.Channels < channels)
+                            if (signal.NumberOfChannels < channels)
                             {
                                 for (int j = 0; j < frameSize; j += 2, src++)
                                 {

Sources/Accord.Audio/ComplexFilters/Base/BaseComplexFilter.cs

@@ -37,7 +37,7 @@ public abstract class BaseComplexFilter : IComplexFilter
         public ComplexSignal Apply(ComplexSignal complexSignal)
         {
             // get number of channels and samples
-            int channels = complexSignal.Channels;
+            int channels = complexSignal.NumberOfChannels;
             int samples = complexSignal.Length;
 
             // retrieve other information

Sources/Accord.Audio/ComplexFilters/CombFilter.cs

@@ -114,7 +114,7 @@ private void generateBaseSignal()
         /// 
         protected override void ProcessFilter(ComplexSignal sourceData, ComplexSignal destinationData)
         {
-            int samples = sourceData.Samples;
+            int samples = sourceData.NumberOfSamples;
 
             unsafe
             {

Sources/Accord.Audio/ComplexFilters/EnvelopeFilter.cs

@@ -63,7 +63,7 @@ protected unsafe override void ProcessFilter(ComplexSignal sourceData, ComplexSi
             if (sourceData.Status != ComplexSignalStatus.Analytic)
                 throw new ArgumentException("Signal must be in analytic form.", "sourceData");
 
-            int samples = sourceData.Samples;
+            int samples = sourceData.NumberOfSamples;
 
             Complex* src = (Complex*)sourceData.Data.ToPointer();
             Complex* dst = (Complex*)destinationData.Data.ToPointer();

Sources/Accord.Audio/Filters/AddFilter.cs

@@ -69,7 +69,7 @@ public AddFilter(Signal overlaySignal)
         protected unsafe override void ProcessFilter(Signal sourceData, Signal destinationData)
         {
             SampleFormat format = sourceData.SampleFormat;
-            int channels = sourceData.Channels;
+            int channels = sourceData.NumberOfChannels;
             int length = sourceData.Length;
 
             if (format == SampleFormat.Format32BitIeeeFloat)

Sources/Accord.Audio/Filters/Base/BaseFilter.cs

@@ -64,8 +64,8 @@ public Signal Apply(Signal signal)
             CheckSourceFormat(signal.SampleFormat);
 
             // get number of channels and samples
-            int channels = signal.Channels;
-            int samples = signal.Length;
+            int channels = signal.NumberOfChannels;
+            int samples = signal.NumberOfFrames;
 
             // retrieve other information
             int rate = signal.SampleRate;

Sources/Accord.Audio/Filters/Base/BaseInPlaceFilter.cs

@@ -64,8 +64,8 @@ public Signal Apply(Signal signal)
             CheckSourceFormat(signal.SampleFormat);
 
             // get number of channels and samples
-            int channels = signal.Channels;
-            int samples = signal.Length;
+            int channels = signal.NumberOfChannels;
+            int samples = signal.NumberOfFrames;
 
             // retrieve other information
             int rate = signal.SampleRate;

Sources/Accord.Audio/Filters/EnvelopeFilter.cs

@@ -67,7 +67,7 @@ public EnvelopeFilter(float alpha)
         protected unsafe override void ProcessFilter(Signal sourceData, Signal destinationData)
         {
             SampleFormat format = sourceData.SampleFormat;
-            int channels = sourceData.Channels;
+            int channels = sourceData.NumberOfChannels;
             int length = sourceData.Length;
 
             if (format == SampleFormat.Format32BitIeeeFloat)

Sources/Accord.Audio/Filters/ExtractChannel.cs

@@ -72,7 +72,7 @@ protected override Signal NewSignal(int channels, int samples, int rate, SampleF
         protected unsafe override void ProcessFilter(Signal sourceData, Signal destinationData)
         {
             SampleFormat format = sourceData.SampleFormat;
-            int channels = sourceData.Channels;
+            int channels = sourceData.NumberOfChannels;
             int length = sourceData.Length;
 
             if (Channel < 0 || Channel > channels)

Sources/Accord.Audio/Filters/HighPassFilter.cs

@@ -89,7 +89,7 @@ public HighPassFilter(float alpha)
         protected override void ProcessFilter(Signal sourceData, Signal destinationData)
         {
             SampleFormat format = sourceData.SampleFormat;
-            int channels = sourceData.Channels;
+            int channels = sourceData.NumberOfChannels;
             int length = sourceData.Length;
 
             if (format == SampleFormat.Format32BitIeeeFloat)

Sources/Accord.Audio/Filters/LowPassFilter.cs

@@ -96,7 +96,7 @@ public LowPassFilter(float alpha)
         protected override void ProcessFilter(Signal sourceData, Signal destinationData)
         {
             SampleFormat format = sourceData.SampleFormat;
-            int channels = sourceData.Channels;
+            int channels = sourceData.NumberOfChannels;
             int length = sourceData.Length;
 
             if (format == SampleFormat.Format32BitIeeeFloat)

Sources/Accord.Audio/Filters/MonoFilter.cs

@@ -22,6 +22,7 @@
 
 namespace Accord.Audio.Filters
 {
+    using Accord.Diagnostics;
     using System;
     using System.Collections.Generic;
 
@@ -61,8 +62,11 @@ protected override Signal NewSignal(int channels, int samples, int rate, SampleF
         protected unsafe override void ProcessFilter(Signal sourceData, Signal destinationData)
         {
             SampleFormat format = sourceData.SampleFormat;
-            int channels = sourceData.Channels;
-            int length = sourceData.Length;
+            int channels = sourceData.NumberOfChannels;
+            int length = sourceData.NumberOfFrames;
+
+            Debug.Assert(sourceData.NumberOfFrames == destinationData.NumberOfSamples);
+            Debug.Assert(destinationData.NumberOfChannels == 1);
 
             if (format == SampleFormat.Format32BitIeeeFloat)
             {

Sources/Accord.Audio/Filters/VolumeFilter.cs

@@ -59,7 +59,7 @@ public VolumeFilter(float volume)
         protected override void ProcessFilter(Signal sourceData, Signal destinationData)
         {
             SampleFormat format = sourceData.SampleFormat;
-            int channels = sourceData.Channels;
+            int channels = sourceData.NumberOfChannels;
             int length = sourceData.Length;
 
             if (format == SampleFormat.Format32BitIeeeFloat)

Sources/Accord.Audio/Filters/WaveRectifier.cs

@@ -58,7 +58,7 @@ public WaveRectifier(bool halfRectificationOnly)
         protected unsafe override void ProcessFilter(Signal sourceData, Signal destinationData)
         {
             SampleFormat format = sourceData.SampleFormat;
-            int samples = sourceData.Samples;
+            int samples = sourceData.NumberOfSamples;
 
             if (format == SampleFormat.Format32BitIeeeFloat)
             {

Sources/Accord.Audio/Formats/AudioDecoder.cs

@@ -36,7 +36,7 @@ namespace Accord.Audio.Formats
     /// </summary>
     /// 
     /// <remarks><para>The class represent a help class, which simplifies decoding of audio
-    /// files finding appropriate image decoder automatically (using list of registered
+    /// files finding appropriate audio decoder automatically (using list of registered
     /// audio decoders). Instead of using required audio decoder directly, users may use this
     /// class, which will find required decoder by file's extension.</para>
     /// 
@@ -84,7 +84,7 @@ public static Signal DecodeFromFile(string fileName, out FrameInfo frameInfo)
         {
             string fileExtension = FormatDecoderAttribute.GetNormalizedExtension(fileName);
 
-            IAudioDecoder decoder = FormatDecoderAttribute.GetDecoder(fileExtension, decoderTypes, decoders.Value);
+            IAudioDecoder decoder = FormatDecoderAttribute.GetDecoders(fileExtension, decoderTypes, decoders.Value);
 
             if (decoder != null)
             {
@@ -99,14 +99,15 @@ public static Signal DecodeFromFile(string fileName, out FrameInfo frameInfo)
 
                     decoder.Close();
 
-                    frameInfo = new FrameInfo(signal.Channels, signal.SampleRate, Signal.GetSampleSize(signal.SampleFormat), 0, signal.Length);
+                    frameInfo = new FrameInfo(signal.NumberOfChannels, signal.SampleRate, Signal.GetSampleSize(signal.SampleFormat), 0, signal.Length);
 
                     return signal;
                 }
             }
 
             throw new ArgumentException(String.Format("No suitable decoder has been found for the file format {0}. If ", fileExtension) +
-                "you are trying to decode .wav files, please add a reference to Accord.Audio.DirectSouond.", "fileName");
+                "you are trying to decode .wav files, please add a reference to Accord.Audio.DirectSound. You might need to instantiate" +
+                "at least one type from this assembly to make sure it has been loaded in the AppDomain of your applicatoin.", "fileName");
         }
 
     }

Sources/Accord.Audio/Formats/AudioEncoder.cs

@@ -0,0 +1,91 @@
+// Accord Audio Library
+// The Accord.NET Framework
+// http://accord-framework.net
+//
+// Copyright © César Souza, 2009-2017
+// cesarsouza at gmail.com
+//
+//    This library is free software; you can redistribute it and/or
+//    modify it under the terms of the GNU Lesser General Public
+//    License as published by the Free Software Foundation; either
+//    version 2.1 of the License, or (at your option) any later version.
+//
+//    This library is distributed in the hope that it will be useful,
+//    but WITHOUT ANY WARRANTY; without even the implied warranty of
+//    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+//    Lesser General Public License for more details.
+//
+//    You should have received a copy of the GNU Lesser General Public
+//    License along with this library; if not, write to the Free Software
+//    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+//
+
+namespace Accord.Audio.Formats
+{
+    using System;
+    using System.Collections.Generic;
+    using System.IO;
+    using System.Linq;
+    using System.Text;
+    using System.Threading;
+    using System.Threading.Tasks;
+    using Accord.Compat;
+
+    /// <summary>
+    /// Audio encoder to encode different custom audio file formats.
+    /// </summary>
+    /// 
+    /// <remarks><para>The class represent a help class, which simplifies encoding of audio
+    /// files finding appropriate audio encoder automatically (using list of registered
+    /// audio encoders). Instead of using required audio encoder directly, users may use this
+    /// class, which will find required encoder by file's extension.</para>
+    /// 
+    /// <para>
+    ///   By default the class will query all referenced assemblies for types that are marked
+    ///   with the <see cref="FormatEncoderAttribute"/>. If the user would like to implement
+    ///   a new encoder, all that is necessary is to mark a new class with the <see cref="FormatEncoderAttribute"/>
+    ///   and make it implement the <see cref="IAudioEncoder"/> interface.</para>
+    /// </remarks>
+    /// 
+    public class AudioEncoder
+    {
+        private static Dictionary<string, Type> encoderTypes = new Dictionary<string, Type>();
+        private static ThreadLocal<Dictionary<string, IAudioEncoder>> encoders = 
+            new ThreadLocal<Dictionary<string, IAudioEncoder>>(() => new Dictionary<string, IAudioEncoder>());
+
+        /// <summary>
+        /// Encodes a signal from the specified file.
+        /// </summary>
+        /// 
+        /// <param name="fileName">File name to save the signal to.</param>
+        /// <param name="signal">The audio signal that should be saved to disk.</param>
+        /// 
+        public static void EncodeToFile(string fileName, Signal signal)
+        {
+            string fileExtension = FormatHandlerAttribute.GetNormalizedExtension(fileName);
+
+            IAudioEncoder encoder = FormatEncoderAttribute.GetEncoder(fileExtension, encoderTypes, encoders.Value);
+
+            if (encoder != null)
+            {
+                // open stream
+                using (FileStream stream = new FileStream(fileName, FileMode.Create, FileAccess.Write))
+                {
+                    // open decoder
+                    encoder.Open(stream);
+
+                    // write all audio frames
+                    encoder.Encode(signal);
+
+                    encoder.Close();
+                }
+
+                return;
+            }
+
+            throw new ArgumentException(String.Format("No suitable encoder has been found for the file format {0}. If ", fileExtension) +
+                "you are trying to encode .wav files, please add a reference to Accord.Audio.DirectSound.", "fileName");
+        }
+
+    }
+}