20220702-NAudio 雜記 and VS Code 常用快速鍵 備忘

20220702-NAudio 雜記

VS Code 常用快速鍵 備忘

解決 NAudio 轉 mp3 檔案時出現的 COMException

• 執行 MediaFoundationEncoder.EncodeToMp3 時出現以下錯誤訊息

未處理的例外狀況: System.Runtime.InteropServices.COMException: 因為已呼叫 Shutdown()，所以要求無效。 (發生例外狀況於 HRESULT: 0xC00D3E85)
   於 NAudio.MediaFoundation.MediaFoundationInterop.MFCreateSinkWriterFromURL(String pwszOutputURL, IMFByteStream pByteStream, IMFAttributes pAttributes, IMFSinkWriter& ppSinkWriter)
   於 NAudio.Wave.MediaFoundationEncoder.CreateSinkWriter(String outputFile)
   於 NAudio.Wave.MediaFoundationEncoder.Encode(String outputFile, IWaveProvider inputProvider)
   於 NAudio.Wave.MediaFoundationEncoder.EncodeToMp3(IWaveProvider inputProvider, String outputFile, Int32 desiredBitRate)
   於 HccMsCognitiveServicesTester.Program.<>c__DisplayClass2_1.<ConvertWavToMp3Async>b__0()
   於 System.Threading.Tasks.Task.Execute()
--- 先前擲回例外狀況之位置中的堆疊追蹤結尾 ---
   於 System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   於 System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   於 System.Runtime.CompilerServices.TaskAwaiter.GetResult()
   於 HccMsCognitiveServicesTester.Program.<ConvertWavToMp3Async>d__2.MoveNext()
--- 先前擲回例外狀況之位置中的堆疊追蹤結尾 ---
   於 System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   於 System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   於 System.Runtime.CompilerServices.TaskAwaiter.GetResult()
   於 HccMsCognitiveServicesTester.Program.<Main>d__1.MoveNext()
--- 先前擲回例外狀況之位置中的堆疊追蹤結尾 ---
   於 System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   於 System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   於 System.Runtime.CompilerServices.TaskAwaiter.GetResult()
   於 HccMsCognitiveServicesTester.Program.<Main>(String[] args)

• 根據錯誤訊息，找到以下文章及解法
  The request is invalid because Shutdown() has been called. (Exception from HRESULT: 0xC00D3E85)

• 英文錯誤訊息

  System.Runtime.InteropServices.COMException: 'The request is invalid because Shutdown() has been called. (Exception from HRESULT: 0xC00D3E85)'

• 參考解法

  using (var wfr = new WaveFileReader(ms))
  {
      MediaFoundationApi.Startup();
      MediaFoundationEncoder.EncodeToMp3(wfr, @"C:\Temp\Test.mp3", 160000);
      MediaFoundationApi.Shutdown();
  }

Task / async 寫法練習

• 參考文章
  Is there a difference with Task.Run a void method and Task method returning null?

• 參考寫法

  private async void btnStart_Click(object sender, EventArgs e)
  {
      cts = new CancellationTokenSource();
      token = cts.Token;
      var task = Task.Run(() => WriteSomeLines(), token);
      await task;
      rtbLoops.Text += "Task complete";
  }

本日最終寫法

static async Task ConvertWavToMp3Async(string wavPath, string mp3Path)
{
    using (var reader = new WaveFileReader(wavPath))
    {
        try
        {
            await Task.Run(() =>
            {
                MediaFoundationApi.Startup();
                MediaFoundationEncoder.EncodeToMp3(reader, mp3Path);
                MediaFoundationApi.Shutdown();
            });
        }
        catch (InvalidOperationException ex)
        {
            Console.WriteLine(ex.Message);
        }
    }
}

VS Code 常用快速鍵 備忘

CodePen / VS Code 常用快速鍵
往前縮排： Shift + tab