Recherche avancée

Sur d’autres sites (9363)

• Ffmpeg only receives a piece of information from the pipe

  4 juillet 2017, par Maxim Fedorov

  First of all - my english is not very good, i`m sorry for that.

  I use ffmpeg from c# to convert images to video. To interact with ffmpeg, I use pipes.

  public async Task ExecuteCommand(
  
          string arguments,
  
          Action<namedpipeserverstream> sendDataUsingPipe)
  
      {
  
          var inStream = new NamedPipeServerStream(
  
              "from_ffmpeg",
  
              PipeDirection.In,
  
              1,
  
              PipeTransmissionMode.Byte,
  
              PipeOptions.Asynchronous,
  
              PipeBufferSize,
  
              PipeBufferSize);
  
  
  
          var outStream = new NamedPipeServerStream(
  
              "to_ffmpeg",
  
              PipeDirection.Out,
  
              1,
  
              PipeTransmissionMode.Byte,
  
              PipeOptions.Asynchronous,
  
              PipeBufferSize,
  
              PipeBufferSize);
  
  
  
          var waitInConnectionTask = inStream.WaitForConnectionAsync();
  
          var waitOutConnectionTask = outStream.WaitForConnectionAsync();
  
  
  
          byte[] byteData;
  
  
  
          using (inStream)
  
          using (outStream)
  
          using (var inStreamReader = new StreamReader(inStream))
  
          using (var process = new Process())
  
          {
  
              process.StartInfo = new ProcessStartInfo
  
              {
  
                  RedirectStandardOutput = true,
  
                  RedirectStandardError = true,
  
                  RedirectStandardInput = true,
  
                  FileName = PathToFfmpeg,
  
                  Arguments = arguments,
  
                  UseShellExecute = false,
  
                  CreateNoWindow = true
  
              };
  
  
  
              process.Start();
  
  
  
              await waitOutConnectionTask;
  
  
  
              sendDataUsingPipe.Invoke(outStream);
  
  
  
              outStream.Disconnect();
  
              outStream.Close();
  
  
  
              await waitInConnectionTask;
  
  
  
              var logTask = Task.Run(() => process.StandardError.ReadToEnd());
  
              var dataBuf = ReadAll(inStream);
  
  
  
              var shouldBeEmpty = inStreamReader.ReadToEnd();
  
              if (!string.IsNullOrEmpty(shouldBeEmpty))
  
                  throw new Exception();
  
  
  
              var processExitTask = Task.Run(() => process.WaitForExit());
  
              await Task.WhenAny(logTask, processExitTask);
  
              var log = logTask.Result;
  
  
  
              byteData = dataBuf;
  
  
  
              process.Close();
  
              inStream.Disconnect();
  
              inStream.Close();
  
          }
  
  
  
          return byteData;
  
      }
  
  </namedpipeserverstream>

  Action "sendDataUsingPipe" looks like

  Action<namedpipeserverstream> sendDataUsingPipe = stream =>
  
          {
  
              foreach (var imageBytes in data)
  
              {
  
                  using (var image = Image.FromStream(new MemoryStream(imageBytes)))
  
                  {
  
                      image.Save(stream, ImageFormat.Jpeg);
  
                  }
  
              }
  
          };
  
  </namedpipeserverstream>

  When I send 10/20/30 images (regardless of the size) ffmpeg processes everything.
  When I needed to transfer 600/700 / .. images, then in the ffmpeg log I see that it only received 189-192, and in the video there are also only 189-192 images.
  There are no errors in the logs or exceptions in the code.

  What could be the reason for this behavior ?

• What could be causing processes to be left behind ?

  11 novembre 2015, par Alex

  I’m using the Process class to spawn a process (in particular, I’m using ffmpeg.exe to convert some video files). This ffmpeg process spawns more processes (on my computer, the total is 4, I’m guessing one per CPU core ?). If it matters, I’m doing this in a Windows service, although the problem also occurs when just debugging in Visual Studio, so I don’t think it does matter.

  The main ffmpeg process runs as expected and exits, causing the WaitForExit() call to return. Except, unlike when run normally (i.e. in a command prompt), the three processes that were spawned hang around. And they keep hanging around until the process that spawned the original ffmpeg.exe process (i.e. my service) is ended.

  Any ideas what this could be about ?

  My `ProcessStartInfo looks like this :

  _processStartInfo = new ProcessStartInfo(process, string.Join(" ", parameters))
  
  {
  
      UseShellExecute = false,
  
      CreateNoWindow = true,
  
      RedirectStandardOutput = true,
  
      RedirectStandardError = true
  
  };

  I launch the Process like this :

  _process = Process.Start(_processStartInfo);
  
  
  
  _outputReceivedHandler = (sender, e) =>
  
  {
  
      if (OutputData != null) OutputData(e.Data);
  
  };
  
  _process.OutputDataReceived += _outputReceivedHandler;
  
  
  
  _errorReceivedHandler = (sender, e) =>
  
  {
  
      if (ErrorData != null) ErrorData(e.Data);
  
  };
  
  _process.ErrorDataReceived += _errorReceivedHandler;
  
  
  
  _exitHandler = (sender, e) =>
  
  {
  
      if (Exited != null) Exited();
  
  };
  
  _process.EnableRaisingEvents = true;
  
  _process.Exited += _exitHandler;
  
  
  
  _process.Start();
  
  
  
  _process.BeginOutputReadLine();
  
  _process.BeginErrorReadLine();

  If it’s relevant, OutputData, ErrorData and Exited are Action<string></string>, Action<string></string> and Action, respectively.

  The reason I’m keeping the various handlers around is so that I can do this :

  private bool _disposed;
  
  public void Dispose()
  
  {
  
      Dispose(true);
  
      GC.SuppressFinalize(this);
  
  }
  
  
  
  protected virtual void Dispose(bool disposing)
  
  {
  
      if (_disposed || !disposing) return;
  
  
  
      if (_outputReceivedHandler != null) _process.OutputDataReceived -= _outputReceivedHandler;
  
      if (_errorReceivedHandler != null) _process.ErrorDataReceived -= _errorReceivedHandler;
  
      if (_exitHandler != null) _process.Exited -= _exitHandler;
  
      if (_process != null) _process.Dispose();
  
  
  
      _disposed = true;
  
  }

  Though it hasn’t made a difference whether or not I use Dispose(), the problem still occurs.

• avcodec/movtextenc : Fix potential use of uninitialized value

  15 octobre 2020, par Andreas Rheinhardt

  avcodec/movtextenc : Fix potential use of uninitialized value
  Background colour was never initialized if no style was available.
  
  Use a sane default of zero (i.e. completely transparent).
  Fixes Coverity issue #1461471.
  Reviewed-by : Philip Langdale <philipl@overt.org>
  
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
  

  • [DH] libavcodec/movtextenc.c