Add toolkit interfaces

src/LabelVoice.Toolkit/LabelVoice.Toolkit.csproj

@@ -0,0 +1,13 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net6.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="NAudio.Core" Version="2.1.0" />
+  </ItemGroup>
+
+</Project>

src/LabelVoice.Toolkit/Slicer/IAdaptiveAudioSlicer.cs

@@ -0,0 +1,14 @@
+using NAudio.Wave;
+
+namespace LabelVoice.Toolkit.Slicer;
+
+/// <summary>
+/// An adaptive audio slicer slices audios with no knowledge or supervision other than the signal itself.
+/// </summary>
+public interface IAdaptiveAudioSlicer : IAudioSlicer
+{
+    /// <summary>
+    /// Initialize the audio slicer with signal provided by <paramref name="provider"/>.
+    /// </summary>
+    void Init(ISampleProvider provider);
+}

src/LabelVoice.Toolkit/Slicer/IAudioSlicer.cs

@@ -0,0 +1,28 @@
+using NAudio.Wave;
+
+namespace LabelVoice.Toolkit.Slicer;
+
+/// <summary>
+/// An audio slicer slices audios into multiple pieces in a streaming way.
+/// </summary>
+public interface IAudioSlicer
+{
+    /// <summary>
+    /// Try to get the next piece.
+    /// </summary>
+    /// <param name="range">When this method returns, contains the range of next piece in the given signal, or <code>null</code> if there are no more pieces to be sliced.</param>
+    /// <returns><see langword="true"/> if the next valid piece is sliced, otherwise <see langword="false"/>.</returns>
+    public bool TrySlice(out AudioRange? range);
+}
+
+public readonly struct AudioRange
+{
+    public readonly double In;
+    public readonly double Out;
+
+    public AudioRange(double inPoint, double outPoint)
+    {
+        In = inPoint;
+        Out = outPoint;
+    }
+}

src/LabelVoice.Toolkit/Slicer/ISupervisedAudioSlicer.cs

@@ -0,0 +1,17 @@
+using NAudio.Wave;
+
+namespace LabelVoice.Toolkit.Slicer;
+
+/// <summary>
+/// A supervised audio slicer slices audios with given knowledge or supervision such as transcriptions or subtitles.
+/// </summary>
+/// <typeparam name="T">The type of the instance carrying the supervision.</typeparam>
+public interface ISupervisedAudioSlicer<in T> : IAudioSlicer
+{
+    /// <summary>
+    /// Initialize the audio slicer with signal provided by <paramref name="provider"/> and knowledge carried by <paramref name="supervision"/>.
+    /// </summary>
+    /// <param name="provider"></param>
+    /// <param name="supervision"></param>
+    public void Init(ISampleProvider provider, T supervision);
+}

src/LabelVoice.Toolkit/Slicer/MonoAudioSlicerBase.cs

@@ -0,0 +1,39 @@
+using NAudio.Wave;
+using NAudio.Wave.SampleProviders;
+
+namespace LabelVoice.Toolkit.Slicer;
+
+/// <summary>
+/// This abstract class represents audio slicers that slices mono audio signals and provides property and conversion to ensure the given signal is mono.
+/// Any class that inherits this class gets the `Provider` property whose setter converts stereo providers into mono providers. Thus, the provider got from this property is guaranteed to be mono.<br/>
+/// Example:
+/// <code>
+/// public void Init(ISampleProvider provider)
+/// {
+///     Provider = provider;
+///     // Once assigned, the `Provider` property is guaranteed to provide mono signals.
+/// }
+/// </code>
+/// </summary>
+public abstract class MonoAudioSlicerBase : IAudioSlicer
+{
+    private ISampleProvider _provider;
+
+    /// <summary>
+    /// Represents the source provider which is guaranteed to provide mono signals.
+    /// </summary>
+    protected ISampleProvider Provider
+    {
+        get => _provider;
+        set => _provider = RequireMono(value);
+    }
+
+    private static ISampleProvider RequireMono(ISampleProvider provider)
+    {
+        return provider.WaveFormat.Channels >= 2
+            ? new StereoToMonoSampleProvider(provider)
+            : provider;
+    }
+
+    public abstract bool TrySlice(out AudioRange? range);
+}

src/LabelVoice.Toolkit/Slicer/SilenceDetectionSlicer.cs

@@ -0,0 +1,19 @@
+using NAudio.Wave;
+
+namespace LabelVoice.Toolkit.Slicer;
+
+/// <summary>
+/// A silence detection slicer slices audios via silence detection, i.e. cuts off audios from detected silence parts.
+/// </summary>
+public class SilenceDetectionSlicer : MonoAudioSlicerBase, IAdaptiveAudioSlicer
+{
+    public void Init(ISampleProvider provider)
+    {
+        Provider = provider;
+    }
+
+    public override bool TrySlice(out AudioRange? range)
+    {
+        throw new NotImplementedException();
+    }
+}

src/LabelVoice.sln

@@ -5,10 +5,12 @@ VisualStudioVersion = 17.4.32916.344
 MinimumVisualStudioVersion = 10.0.40219.1
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "LabelVoice", "LabelVoice\LabelVoice.csproj", "{C7639302-E10B-4FBC-AD48-A645E4403C67}"
 EndProject
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "LabelVoice.Core", "LabelVoice.Core\LabelVoice.Core.csproj", "{340ADDD3-5B13-4328-A836-34A87EC8DEC5}"
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "LabelVoice.Core", "LabelVoice.Core\LabelVoice.Core.csproj", "{340ADDD3-5B13-4328-A836-34A87EC8DEC5}"
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Test.Playback", "Test.Playback\Test.Playback.csproj", "{EFE88D45-1EFD-4E3A-879F-6A03ECFECCDB}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "LabelVoice.Toolkit", "LabelVoice.Toolkit\LabelVoice.Toolkit.csproj", "{09B69A2A-6F91-4CA6-8629-87BE08E26149}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -27,6 +29,10 @@ Global
 		{EFE88D45-1EFD-4E3A-879F-6A03ECFECCDB}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{EFE88D45-1EFD-4E3A-879F-6A03ECFECCDB}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{EFE88D45-1EFD-4E3A-879F-6A03ECFECCDB}.Release|Any CPU.Build.0 = Release|Any CPU
+		{09B69A2A-6F91-4CA6-8629-87BE08E26149}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{09B69A2A-6F91-4CA6-8629-87BE08E26149}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{09B69A2A-6F91-4CA6-8629-87BE08E26149}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{09B69A2A-6F91-4CA6-8629-87BE08E26149}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE