title: c# how to correctly format an ffmpeg user input stream?
body: <p>So I'm writing a c# application which allows a user to scale a video in pixels to a custom dimension. I am strugeling to get the user input from a textbox for the mpeg psi arguments:</p>
  <p>Here is the code:</p>
  <pre><code> var localStoragePath = Path.Combine(Path.GetTempPath(), name);
                              var directoryPath = Path.GetDirectoryName(localStoragePath);
                              Directory.CreateDirectory(directoryPath);
                              File.WriteAllBytes(localStoragePath, bytes);
                              Progress.Text = ($&quot;File copy successful: {File.Exists(localStoragePath)}&quot;);
                              var readBack = File.ReadAllBytes(localStoragePath);
                              Progress.Text = ($&quot;Read file Back: {readBack.Length}, {localStoragePath}&quot;);
                              var resizedFolderPath = @&quot;C:\upscaledvideohere&quot;;
                              Directory.CreateDirectory(resizedFolderPath);
                              var resizedFiePath = Path.Combine(resizedFolderPath, Path.GetFileName(localStoragePath));
  
                              var psi = new ProcessStartInfo();
                              psi.FileName = @&quot;C:\ffmpeg-2020-12-27-git-bff6fbead8-full_build\bin\ffmpeg.exe&quot;;
                              psi.Arguments = $&quot;-i \&quot;{localStoragePath}\&quot; -vf scale=&quot; + pixelsheight.Text  &quot;\&quot;{resizedFiePath}\&quot;&quot;;
                              psi.RedirectStandardOutput = false;
                              psi.RedirectStandardError = false;
                              psi.UseShellExecute = true;
                              Progress.Text = ($&quot;Args: {psi.Arguments}&quot;);
  </code></pre>
  <p>For</p>
  <pre><code> psi.Arguments = $&quot;-i \&quot;{localStoragePath}\&quot; -vf scale=&quot; + pixelsheight.Text  &quot;\&quot;{resizedFiePath}\&quot;&quot;
  </code></pre>
  <p>What would be the correct way to input the text for what the user typedin the pixelsheight text box?</p>
  <p>Thanks very much.</p>