feat: refactor audio extraction to reusable class

.editorconfig

@@ -26,6 +26,7 @@ insert_final_newline = false
 # Diagnostic severity preferences
 dotnet_diagnostic.IDE0058.severity = none
 dotnet_diagnostic.IDE0100.severity = none
+dotnet_diagnostic.CA1848.severity = none
 
 # Organize usings
 dotnet_separate_import_directive_groups = true

src/Directory.packages.props

@@ -7,6 +7,7 @@
     <PackageVersion Include="Microsoft.Extensions.Configuration" Version="9.0.7" />
     <PackageVersion Include="Microsoft.Extensions.Configuration.Json" Version="9.0.7" />
     <PackageVersion Include="Microsoft.Extensions.Hosting" Version="9.0.7" />
+    <PackageVersion Include="Microsoft.Extensions.Logging" Version="9.0.7" />
     <PackageVersion Include="NAudio" Version="2.2.1" />
     <PackageVersion Include="Serilog" Version="4.3.0" />
     <PackageVersion Include="Serilog.Extensions.Hosting" Version="9.0.0" />

src/StreamShorts.Console/Commands/DefaultCommand.cs

@@ -2,11 +2,13 @@ namespace StreamShorts.Console.Commands;
 
 internal class DefaultCommand(
   IFileSystem fileSystem,
-  IAnsiConsole console
+  IAnsiConsole console,
+  IAudioExtractor audioExtractor
 ) : AsyncCommand<DefaultCommand.Settings>
 {
   private readonly IFileSystem _fileSystem = fileSystem ?? throw new ArgumentNullException(nameof(fileSystem));
   private readonly IAnsiConsole _console = console ?? throw new ArgumentNullException(nameof(console));
+  private readonly IAudioExtractor _audioExtractor = audioExtractor ?? throw new ArgumentNullException(nameof(audioExtractor));
 
   internal class Settings : CommandSettings
   {
@@ -37,9 +39,28 @@ internal class DefaultCommand(
     return base.Validate(context, settings);
   }
 
-  public override Task<int> ExecuteAsync(CommandContext context, Settings settings)
+  public override async Task<int> ExecuteAsync(CommandContext context, Settings settings)
   {
-    _console.Write($"[green]Processing stream:[/] {settings.Stream}");
-    return Task.FromResult(0);
+    _console.MarkupLine($"[blue]Processing stream:[/] {settings.Stream}");
+    var videoStream = _fileSystem.File.OpenRead(settings.Stream);
+
+    Stream? audioStream = null;
+
+    await _console.Status()
+      .Spinner(Spinner.Known.Dots)
+      .StartAsync("Extracting audio...", async ctx =>
+      {
+        audioStream = await _audioExtractor.ExtractMp3FromMp4Async(videoStream).ConfigureAwait(false);
+      });
+
+    if (audioStream is null)
+    {
+      _console.MarkupLine("[red]Failed[/] to extract audio from the stream.");
+      return 1;
+    }
+
+    _console.MarkupLine($"[blue]Audio extracted[/] [green]successfully![/]");
+
+    return 0;
   }
 }

src/StreamShorts.Console/Program.cs

@@ -10,6 +10,7 @@ using FFMpegCore.Pipes;
 
 using NAudio.Wave;
 
+
 using Whisper.net;
 using Whisper.net.Ggml;
 
@@ -35,6 +36,7 @@ try
     {
       services.AddSingleton(AnsiConsole.Console);
       services.AddSingleton<IFileSystem, FileSystem>();
+      services.AddSingleton<IAudioExtractor, AudioExtractor>();
     })
     .BuildApp()
     .RunAsync(args);
@@ -51,206 +53,206 @@ finally
   await Log.CloseAndFlushAsync();
 }
 
-using var mp3Stream = new MemoryStream();
-using var mp4Stream = new FileStream(args[0], FileMode.Open, FileAccess.Read);
+// using var mp3Stream = new MemoryStream();
+// using var mp4Stream = new FileStream(args[0], FileMode.Open, FileAccess.Read);
 
-var wasExtracted = await FFMpegArguments
-  .FromPipeInput(new StreamPipeSource(mp4Stream))
-  .OutputToPipe(
-    new StreamPipeSink(mp3Stream),
-    o => o.DisableChannel(Channel.Video).ForceFormat("mp3")
-  )
-  .ProcessAsynchronously();
+// var wasExtracted = await FFMpegArguments
+//   .FromPipeInput(new StreamPipeSource(mp4Stream))
+//   .OutputToPipe(
+//     new StreamPipeSink(mp3Stream),
+//     o => o.DisableChannel(Channel.Video).ForceFormat("mp3")
+//   )
+//   .ProcessAsynchronously();
 
-// Step 2: Convert MP3 stream to 16khz wave format
-mp3Stream.Position = 0;
-using var reader = new Mp3FileReader(mp3Stream);
-var outFormat = new WaveFormat(16000, reader.WaveFormat.Channels);
-using var resampler = new MediaFoundationResampler(reader, outFormat);
-using var waveStream = new MemoryStream();
-WaveFileWriter.WriteWavFileToStream(waveStream, resampler);
+// // Step 2: Convert MP3 stream to 16khz wave format
+// mp3Stream.Position = 0;
+// using var reader = new Mp3FileReader(mp3Stream);
+// var outFormat = new WaveFormat(16000, reader.WaveFormat.Channels);
+// using var resampler = new MediaFoundationResampler(reader, outFormat);
+// using var waveStream = new MemoryStream();
+// WaveFileWriter.WriteWavFileToStream(waveStream, resampler);
 
-// Step 3: Split the wave stream into 2 minute segments
-waveStream.Position = 0;
-var segmentDuration = TimeSpan.FromMinutes(2);
-var segments = new List<MemoryStream>();
-using var waveReader = new WaveFileReader(waveStream);
-var segmentCount = (int)Math.Ceiling(waveReader.TotalTime.TotalMilliseconds / segmentDuration.TotalMilliseconds);
+// // Step 3: Split the wave stream into 2 minute segments
+// waveStream.Position = 0;
+// var segmentDuration = TimeSpan.FromMinutes(2);
+// var segments = new List<MemoryStream>();
+// using var waveReader = new WaveFileReader(waveStream);
+// var segmentCount = (int)Math.Ceiling(waveReader.TotalTime.TotalMilliseconds / segmentDuration.TotalMilliseconds);
 
-Directory.CreateDirectory("segments");
+// Directory.CreateDirectory("segments");
 
-foreach (var i in Enumerable.Range(0, segmentCount))
-{
-  waveStream.Position = 0;
-  using var segmentWaveReader = new WaveFileReader(waveStream);
-  var segment = segmentWaveReader.ToSampleProvider()
-    .Skip(i * segmentDuration)
-    .Take(segmentDuration);
-  var segmentProvider = segment.ToWaveProvider16();
-  var segmentStream = new MemoryStream();
-  WaveFileWriter.WriteWavFileToStream(segmentStream, segmentProvider);
-  segmentStream.Position = 0;
-  segments.Add(segmentStream);
-}
+// foreach (var i in Enumerable.Range(0, segmentCount))
+// {
+//   waveStream.Position = 0;
+//   using var segmentWaveReader = new WaveFileReader(waveStream);
+//   var segment = segmentWaveReader.ToSampleProvider()
+//     .Skip(i * segmentDuration)
+//     .Take(segmentDuration);
+//   var segmentProvider = segment.ToWaveProvider16();
+//   var segmentStream = new MemoryStream();
+//   WaveFileWriter.WriteWavFileToStream(segmentStream, segmentProvider);
+//   segmentStream.Position = 0;
+//   segments.Add(segmentStream);
+// }
 
-// Step 4: Transcribe each segment using Whisper
-using var modelMemoryStream = new MemoryStream();
-var model = await WhisperGgmlDownloader.Default.GetGgmlModelAsync(GgmlType.TinyEn);
-await model.CopyToAsync(modelMemoryStream);
-var whisperFactory = WhisperFactory.FromBuffer(modelMemoryStream.ToArray());
-using var whisperProcessor = whisperFactory.CreateBuilder()
-  .WithLanguage("en")
-  .Build();
+// // Step 4: Transcribe each segment using Whisper
+// using var modelMemoryStream = new MemoryStream();
+// var model = await WhisperGgmlDownloader.Default.GetGgmlModelAsync(GgmlType.TinyEn);
+// await model.CopyToAsync(modelMemoryStream);
+// var whisperFactory = WhisperFactory.FromBuffer(modelMemoryStream.ToArray());
+// using var whisperProcessor = whisperFactory.CreateBuilder()
+//   .WithLanguage("en")
+//   .Build();
 
-var completeTranscription = new StringBuilder();
+// var completeTranscription = new StringBuilder();
 
-foreach (var (i, segment) in segments.Select((s, index) => (index, s)))
-{
-  var durationOffset = TimeSpan.FromMilliseconds(i * segmentDuration.TotalMilliseconds);
-  var segmentTranscription = new StringBuilder();
+// foreach (var (i, segment) in segments.Select((s, index) => (index, s)))
+// {
+//   var durationOffset = TimeSpan.FromMilliseconds(i * segmentDuration.TotalMilliseconds);
+//   var segmentTranscription = new StringBuilder();
 
-  await foreach (var result in whisperProcessor.ProcessAsync(segment, CancellationToken.None))
-  {
-    var startTime = result.Start + durationOffset;
-    var endTime = result.End + durationOffset;
-    segmentTranscription.AppendLine(CultureInfo.CurrentCulture, $"[{startTime:hh\\:mm\\:ss} - {endTime:hh\\:mm\\:ss}] {result.Text}");
-  }
+//   await foreach (var result in whisperProcessor.ProcessAsync(segment, CancellationToken.None))
+//   {
+//     var startTime = result.Start + durationOffset;
+//     var endTime = result.End + durationOffset;
+//     segmentTranscription.AppendLine(CultureInfo.CurrentCulture, $"[{startTime:hh\\:mm\\:ss} - {endTime:hh\\:mm\\:ss}] {result.Text}");
+//   }
 
-  completeTranscription.Append(segmentTranscription);
-}
+//   completeTranscription.Append(segmentTranscription);
+// }
 
-// Step 5: Send the transcription to LLM for analysis
-// TODO: Explore this prompt further...seems break
-// when transcription is long
-var prompt = $$"""
-I need your help to transform my YouTube live stream transcript into engaging YouTube Shorts. Act as my content editor and pinpoint **all potential candidate segments** that are perfect for short-form video. I'm looking for clips that are:
+// // Step 5: Send the transcription to LLM for analysis
+// // TODO: Explore this prompt further...seems break
+// // when transcription is long
+// var prompt = $$"""
+// I need your help to transform my YouTube live stream transcript into engaging YouTube Shorts. Act as my content editor and pinpoint **all potential candidate segments** that are perfect for short-form video. I'm looking for clips that are:
 
-  * **Funny:** Moments that will make viewers laugh.
-  * **Informative:** Sections packed with valuable information or tips.
-  * **Insightful:** Portions offering unique perspectives or 'aha\!' moments.
+//   * **Funny:** Moments that will make viewers laugh.
+//   * **Informative:** Sections packed with valuable information or tips.
+//   * **Insightful:** Portions offering unique perspectives or 'aha\!' moments.
 
-For each suggested short, please provide:
+// For each suggested short, please provide:
 
-  * The **start time** of the initial segment and the **end time** of the final segment. The duration of each short should be no longer than 3 minutes, but **aim for durations between 15 seconds and 60 seconds**. However, the short **must be as long as necessary to capture the complete thought or idea**, even if it means exceeding the target range or extending slightly to capture all necessary dialogue.
-  * A concise **title** that grabs attention.
-  * A brief **description** highlighting the short's content and its appeal.
-  * An **explanation** of why this particular segment is suitable for a YouTube Short, focusing on its potential for discoverability and engagement.
+//   * The **start time** of the initial segment and the **end time** of the final segment. The duration of each short should be no longer than 3 minutes, but **aim for durations between 15 seconds and 60 seconds**. However, the short **must be as long as necessary to capture the complete thought or idea**, even if it means exceeding the target range or extending slightly to capture all necessary dialogue.
+//   * A concise **title** that grabs attention.
+//   * A brief **description** highlighting the short's content and its appeal.
+//   * An **explanation** of why this particular segment is suitable for a YouTube Short, focusing on its potential for discoverability and engagement.
 
-Please format your response as a JSON array of objects with the following structure:
+// Please format your response as a JSON array of objects with the following structure:
 
-```json
-{
-  ""title"": ""string"",
-  "start_time": "string",
-  "end_time": "string",
-  "description": "string",
-  "explanation": "string"
-}
-```
+// ```json
+// {
+//   ""title"": ""string"",
+//   "start_time": "string",
+//   "end_time": "string",
+//   "description": "string",
+//   "explanation": "string"
+// }
+// ```
 
-Here is the transcript of my YouTube live stream:
+// Here is the transcript of my YouTube live stream:
 
-{{completeTranscription}}
-""";
+// {{completeTranscription}}
+// """;
 
-if (string.IsNullOrWhiteSpace(apiKey))
-{
-  throw new InvalidOperationException("GeminiApiKey is not configured in appsettings.json.");
-}
+// if (string.IsNullOrWhiteSpace(apiKey))
+// {
+//   throw new InvalidOperationException("GeminiApiKey is not configured in appsettings.json.");
+// }
 
-using var client = new HttpClient()
-{
-  Timeout = TimeSpan.FromMinutes(30)
-};
+// using var client = new HttpClient()
+// {
+//   Timeout = TimeSpan.FromMinutes(30)
+// };
 
-var requestUrl = $"https://generativelanguage.googleapis.com/v1beta/models/gemini-2.5-flash-lite:generateContent?key={apiKey}";
-using var request = new HttpRequestMessage(HttpMethod.Post, requestUrl)
-{
-  Content = new StringContent(
-    JsonSerializer.Serialize(new
-    {
-      contents = new[]
-      {
-        new
-        {
-          role = "user",
-          parts = new[]
-          {
-            new
-            {
-              text = prompt
-            }
-          },
-        }
-      },
-      generationConfig = new
-      {
-        responseMimeType = "application/json",
-      }
-    }),
-    Encoding.UTF8,
-    "application/json"
-  )
-};
-var response = await client.SendAsync(request);
-var responseContent = await response.Content.ReadAsStringAsync();
-var responseJson = JsonSerializer.Deserialize<LLMResponse>(responseContent);
-var candidatesText = responseJson?
-  .Candidates?
-  .FirstOrDefault()?
-  .Content
-  .Parts?.FirstOrDefault()?
-  .Text;
-var analysis = JsonSerializer.Deserialize<List<LLMAnalysis>>(candidatesText ?? string.Empty);
+// var requestUrl = $"https://generativelanguage.googleapis.com/v1beta/models/gemini-2.5-flash-lite:generateContent?key={apiKey}";
+// using var request = new HttpRequestMessage(HttpMethod.Post, requestUrl)
+// {
+//   Content = new StringContent(
+//     JsonSerializer.Serialize(new
+//     {
+//       contents = new[]
+//       {
+//         new
+//         {
+//           role = "user",
+//           parts = new[]
+//           {
+//             new
+//             {
+//               text = prompt
+//             }
+//           },
+//         }
+//       },
+//       generationConfig = new
+//       {
+//         responseMimeType = "application/json",
+//       }
+//     }),
+//     Encoding.UTF8,
+//     "application/json"
+//   )
+// };
+// var response = await client.SendAsync(request);
+// var responseContent = await response.Content.ReadAsStringAsync();
+// var responseJson = JsonSerializer.Deserialize<LLMResponse>(responseContent);
+// var candidatesText = responseJson?
+//   .Candidates?
+//   .FirstOrDefault()?
+//   .Content
+//   .Parts?.FirstOrDefault()?
+//   .Text;
+// var analysis = JsonSerializer.Deserialize<List<LLMAnalysis>>(candidatesText ?? string.Empty);
 
-if (analysis is null)
-{
-  Console.WriteLine(resourceManager.GetString("LLMAnalysisFailed", CultureInfo.CurrentCulture));
-  return;
-}
+// if (analysis is null)
+// {
+//   Console.WriteLine(resourceManager.GetString("LLMAnalysisFailed", CultureInfo.CurrentCulture));
+//   return;
+// }
 
-foreach (var result in analysis)
-{
-  var fileName = string.Concat(result.Title.Split(Path.GetInvalidFileNameChars()));
-  await FFMpeg.SubVideoAsync(
-    args[0],
-    $"{fileName}.mp4",
-    result.StartTime,
-    result.EndTime
-  );
-}
+// foreach (var result in analysis)
+// {
+//   var fileName = string.Concat(result.Title.Split(Path.GetInvalidFileNameChars()));
+//   await FFMpeg.SubVideoAsync(
+//     args[0],
+//     $"{fileName}.mp4",
+//     result.StartTime,
+//     result.EndTime
+//   );
+// }
 
-// Step 6: Use analysis to generate a short video
+// // Step 6: Use analysis to generate a short video
 
-record LLMAnalysis(
-  [property: JsonPropertyName("title")]
-  string Title,
-  [property: JsonPropertyName("description")]
-  string Description,
-  [property: JsonPropertyName("explanation")]
-  string Explanation,
-  [property: JsonPropertyName("start_time")]
-  TimeSpan StartTime,
-  [property: JsonPropertyName("end_time")]
-  TimeSpan EndTime
-);
+// record LLMAnalysis(
+//   [property: JsonPropertyName("title")]
+//   string Title,
+//   [property: JsonPropertyName("description")]
+//   string Description,
+//   [property: JsonPropertyName("explanation")]
+//   string Explanation,
+//   [property: JsonPropertyName("start_time")]
+//   TimeSpan StartTime,
+//   [property: JsonPropertyName("end_time")]
+//   TimeSpan EndTime
+// );
 
-record LLMResponse(
-  [property: JsonPropertyName("candidates")]
-  Candidate[] Candidates
-);
+// record LLMResponse(
+//   [property: JsonPropertyName("candidates")]
+//   Candidate[] Candidates
+// );
 
-record Candidate(
-  [property: JsonPropertyName("content")]
-  Content Content
-);
+// record Candidate(
+//   [property: JsonPropertyName("content")]
+//   Content Content
+// );
 
-record Content(
-  [property: JsonPropertyName("parts")]
-  Part[] Parts
-);
+// record Content(
+//   [property: JsonPropertyName("parts")]
+//   Part[] Parts
+// );
 
-record Part(
-  [property: JsonPropertyName("text")]
-  string Text
-);
+// record Part(
+//   [property: JsonPropertyName("text")]
+//   string Text
+// );

src/StreamShorts.Console/StreamShorts.Console.csproj

@@ -25,4 +25,8 @@
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </None>
   </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\StreamShorts.Library\StreamShorts.Library.csproj" />
+  </ItemGroup>
 </Project>

src/StreamShorts.Console/Usings.cs

@@ -2,7 +2,6 @@ global using System.ComponentModel;
 global using System.IO.Abstractions;
 global using System.Reflection;
 
-global using Microsoft.Extensions.Configuration;
 global using Microsoft.Extensions.DependencyInjection;
 global using Microsoft.Extensions.Hosting;
 global using Microsoft.Extensions.Logging;
@@ -16,3 +15,4 @@ global using Spectre.Console.Cli;
 
 global using StreamShorts.Console.Commands;
 global using StreamShorts.Console.Hosting;
+global using StreamShorts.Library.Media.Audio;

src/StreamShorts.Library/Media/Audio/AudioExtractor.cs

@@ -0,0 +1,63 @@
+using FFMpegCore;
+using FFMpegCore.Pipes;
+
+using Channel = FFMpegCore.Enums.Channel;
+
+namespace StreamShorts.Library.Media.Audio;
+
+/// <inheritdoc/>
+public class AudioExtractor : IAudioExtractor
+{
+  public async Task<Stream> ExtractMp3FromMp4Async(Stream video)
+  {
+    if (video is null)
+    {
+      throw new ArgumentNullException(nameof(video), "Video stream cannot be null");
+    }
+
+    if (video.CanRead is false)
+    {
+      throw new ArgumentException("Video stream must be readable", nameof(video));
+    }
+
+    if (video.CanSeek is false)
+    {
+      throw new ArgumentException("Video stream must be seekable", nameof(video));
+    }
+
+    var originalPosition = video.Position;
+
+    try
+    {
+      using var mp3Stream = new MemoryStream();
+      using var mp4Stream = new MemoryStream();
+
+      await video.CopyToAsync(mp4Stream).ConfigureAwait(false);
+      mp4Stream.Position = 0;
+
+      var wasExtracted = await FFMpegArguments
+        .FromPipeInput(new StreamPipeSource(mp4Stream))
+        .OutputToPipe(
+          new StreamPipeSink(mp3Stream),
+          o => o.DisableChannel(Channel.Video).ForceFormat("mp3")
+        )
+        .ProcessAsynchronously()
+        .ConfigureAwait(false);
+
+      if (wasExtracted is false)
+      {
+        throw new FailedAudioExtractionException("Failed to extract audio from the video stream.");
+      }
+
+      return mp3Stream;
+    }
+    catch (Exception e) when (e is not FailedAudioExtractionException)
+    {
+      throw new FailedAudioExtractionException("Failed to extract audio", e);
+    }
+    finally
+    {
+      video.Position = originalPosition;
+    }
+  }
+}

src/StreamShorts.Library/Media/Audio/FailedAudioExtractionException.cs

@@ -0,0 +1,16 @@
+namespace StreamShorts.Library.Media.Audio;
+
+public class FailedAudioExtractionException : Exception
+{
+  public FailedAudioExtractionException() : base()
+  {
+  }
+
+  public FailedAudioExtractionException(string message) : base(message)
+  {
+  }
+
+  public FailedAudioExtractionException(string message, Exception innerException) : base(message, innerException)
+  {
+  }
+}

src/StreamShorts.Library/Media/Audio/IAudioExtractor.cs

@@ -0,0 +1,19 @@
+namespace StreamShorts.Library.Media.Audio;
+
+/// <summary>
+/// Represents an interface for extracting audio from video streams.
+/// </summary>
+public interface IAudioExtractor
+{
+  /// <summary>
+  /// Extracts MP3 audio from an MP4 video stream.
+  /// </summary>
+  /// <param name="video">The input video stream.</param>
+  /// <returns>A stream containing the extracted MP3 audio.</returns>
+  /// <exception cref="ArgumentNullException">Thrown when the video stream is null.</exception>
+  /// <exception cref="ArgumentException">Thrown when the video stream is not readable.</exception>
+  /// <exception cref="ArgumentException">Thrown when the video stream is not seekable.</exception>
+  /// <exception cref="FailedAudioExtractionException">Thrown when the audio extraction fails.</exception>
+  /// <remarks>The method will preserve the passed video stream's data and position.</remarks>
+  Task<Stream> ExtractMp3FromMp4Async(Stream video);
+}

src/StreamShorts.Library/StreamShorts.Library.csproj

@@ -1,3 +1,5 @@
 <Project Sdk="Microsoft.NET.Sdk">
-
+  <ItemGroup>
+    <PackageReference Include="FFMpegCore" />
+  </ItemGroup>
 </Project>

tests/.editorconfig

@@ -1,2 +1,3 @@
 [*.cs]
 dotnet_diagnostic.CA1707.severity = none
+dotnet_diagnostic.CA2007.severity = none

tests/StreamShorts.Library.Tests/StreamShorts.Library.Tests.csproj

@@ -1,7 +1,9 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <ItemGroup>
+    <PackageReference Include="AwesomeAssertions" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" />
+    <PackageReference Include="Moq" />
     <PackageReference Include="xunit.v3" />
     <PackageReference Include="xunit.runner.visualstudio" />
   </ItemGroup>

tests/StreamShorts.Library.Tests/Unit/Media/Audio/AudioExtractorTests.cs

@@ -0,0 +1,36 @@
+namespace StreamShorts.Library.Tests.Unit.Media.Audio;
+
+public class AudioExtractorTests
+{
+  private readonly AudioExtractor _sut = new();
+
+  [Fact]
+  public async Task ExtractMp3FromMp4Async_WhenVideoIsNull_ItShouldThrow()
+  {
+    var action = async () => await _sut.ExtractMp3FromMp4Async(null!);
+
+    await action.Should().ThrowAsync<ArgumentNullException>();
+  }
+
+  [Fact]
+  public async Task ExtractMp3FromMp4Async_WhenVideoIsNotReadable_ItShouldThrow()
+  {
+    var mockStream = new Mock<Stream>();
+    mockStream.Setup(s => s.CanRead).Returns(false);
+
+    var action = async () => await _sut.ExtractMp3FromMp4Async(mockStream.Object);
+
+    await action.Should().ThrowAsync<ArgumentException>();
+  }
+
+  [Fact]
+  public async Task ExtractMp3FromMp4Async_WhenVideoIsNotSeekable_ItShouldThrow()
+  {
+    var mockStream = new Mock<Stream>();
+    mockStream.Setup(s => s.CanSeek).Returns(false);
+
+    var action = async () => await _sut.ExtractMp3FromMp4Async(mockStream.Object);
+
+    await action.Should().ThrowAsync<ArgumentException>();
+  }
+}

tests/StreamShorts.Library.Tests/Usings.cs

@@ -0,0 +1,5 @@
+global using AwesomeAssertions;
+
+global using Moq;
+
+global using StreamShorts.Library.Media.Audio;