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• Ways to create animations in python ?

  21 mai 2017, par Allison123

  What is the best way to create a small animation in python ?
  So far, I have tried : tkinter and FuncAnimation (from animation in matplotlib- this is what is used in A Student’s Guide to Python for Physical Modeling).

  The goal is to make a set of simple animations, but FuncAnimation is having me install apt-get so that I can get ffmpeg so I can run the animation. It seems like a lot of downloading, which I don’t prefer if there is a similarly powerful alternative.

  If possible, I was hoping to integrate these animations into Pygame at a later time. Will that be possible ?

  YES, this is a subjective question, but I am looking for guidance from experienced python animators. What are the objective strengths and weaknesses of different methods of animating in Python ?

• 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.

• online free media hosting for live streaming

  30 novembre 2013, par Abdul Ali

  wanted to ask two things :

  1- How can we put the output of FFMPEG to a stream (online address to put the stream).

  2- Is there any free service (for testing purpose) to use FFMPEG and pass the output to it for live streaming .

  apologies if am unable to explain properly what is intended.

  to summarize, wish to convert images to video using FFMPEG (have tried the image to video conversion locally and seems to be working) and put the output to an online resource for live streaming and possibly also have VOD (so users who later logon can view at least from some point behind which they have missed).

  regards,