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How to determine when FFmpeg process completes

var origFilePath = "C:/MyOriginalFile.webm";
var processedFilePath = "C:/MyProcessedFile.webm";
RunFfmpeg($"-i \"{origFilePath}\" -af \"silenceremove=1:0.1:0.001, areverse, silenceremove=1:0.1:0.001, areverse\" \"{processedFilePath}\" -y");
// fails with IOException as the file presumably not been released by FFmpeg
System.IO.File.Delete(origFilePath);
When the file is deleted, the following exception is frequently (maybe 80% of the time) thrown:
IOException: The process cannot access the file 'C:\MyOriginalFile.webm' because it is being used by another process.
The call to create and run the FFmpeg process goes like this:
private List<string> RunFfmpeg(string arguments)
{
using (var process = new Process())
{
process.StartInfo.RedirectStandardOutput = true;
process.StartInfo.RedirectStandardError = true;
process.StartInfo.FileName = _hostingEnvironment.ContentRootPath + _settings.FfmpegPath;
process.StartInfo.Arguments = arguments;
process.StartInfo.UseShellExecute = false;
process.StartInfo.CreateNoWindow = true;
// ffmpeg only uses strerr for its output
var output = new List<string>();
process.ErrorDataReceived += new DataReceivedEventHandler((s, e) => {
if (e.Data != null)
output.Add(e.Data);
});
process.Start();
process.BeginErrorReadLine();
process.WaitForExit();
return output;
}
}
It appears that even though the process has completed when the file is deleted, FFmpeg is still processing or has otherwise not released it.
Is this behaviour expected? How do I go about ensuring that FFmpeg has finished processing the files before continuing?

If it were me I'd run this on a background thread and tap into the process.Exited event and try to delete the File in there.
The MSDN Documentation for the Process Exit Event uses this strategy and polls for 30 seconds till the Exited event fires and checks the ExitCode. Depending on the ExitCode, you could give it more time, check if the file is still locked or perform another action until process.ExitCode == 0
private Process myProcess = new Process();
private int elapsedTime;
private bool eventHandled;
public void RunFfmpeg(string arguments)
{
elapsedTime = 0;
eventHandled = false;
try
{
myProcess.StartInfo.FileName = _hostingEnvironment.ContentRootPath + _settings.FfmpegPath;
myProcess.StartInfo.Arguments = arguments;
myProcess.StartInfo.CreateNoWindow = true;
myProcess.EnableRaisingEvents = true;
myProcess.Exited += new EventHandler(myProcess_Exited);
myProcess.Start();
}
catch (Exception ex)
{
Console.WriteLine("An error occurred trying to print \"{0}\":" + "\n" + ex.Message, fileName);
return;
}
// Wait for Exited event, but not more than 30 seconds.
const int SLEEP_AMOUNT = 100;
while (!eventHandled)
{
elapsedTime += SLEEP_AMOUNT;
if (elapsedTime > 30000)
{
break;
}
Thread.Sleep(SLEEP_AMOUNT);
}
}
private void myProcess_Exited(object sender, System.EventArgs e)
{
eventHandled = true;
Console.WriteLine("Exit time: {0}\r\n" +
"Exit code: {1}\r\nElapsed time: {2}", myProcess.ExitTime, myProcess.ExitCode, elapsedTime);
}

C# FFMPEG Process and Multiple files

I am working on a C# Form tool that will help me convert all of my phone and DSLR video to HEVC, currently, i have a program that uploads the photos and videos to different directories in my home server each time i connect to the WiFi. Once a month or so, i manually convert all the videos, but thought I would automate the process.. I have the Form working perfectly for processing 1 file. but get into trouble when processing a Directory (with possible sub-directories) all at once..
Sorry, this is long, just want to be thorough. here is the button calls
private void processFile_Click(object sender, EventArgs e)
{
OpenFileDialog file = new OpenFileDialog();
file.InitialDirectory = baseMediaDirectory;
if (file.ShowDialog() == DialogResult.OK)
{
ProcessSinlgeFile(file.FileName);
}
}
(above)for one file and (below) for a directory
private void processDirectory_Click(object sender, EventArgs e)
{
FolderBrowserDialog file = new FolderBrowserDialog();
file.SelectedPath = baseMediaDirectory;
if(file.ShowDialog() == DialogResult.OK)
{
ProcessDirectoryOfFiles(file.SelectedPath);
}
}
private void ProcessDirectoryOfFiles(string selectedPath)
{
List<string> listOfFiles = GetAllFiles(selectedPath);
foreach (string s in listOfFiles)
{
ProcessSinlgeFile(s);
}
}
both ultimately call this method, to do some checks and setup
private void ProcessSinlgeFile(string fileName)
{
if (IsAcceptableMediaFile(fileName))
{
outputWindow.AppendText("File to Process: " + fileName);
processMediaFile =
new MediaFileWrapper(this.outputWindow, new MediaFile(fileName), new NReco.VideoInfo.FFProbe());
if (processMediaFile.OkToProcess)
{
int initialCRFValue = 15;
//ultrafast superfast veryfast faster fast medium slow slower veryslow placebo
string intialSpeed = "veryfast";
try {
ConvertToMPEG(processMediaFile.getFFMPEGCommand(initialCRFValue, intialSpeed), processMediaFile);
}
catch
{
// at somepoint, we'll catch a bad file size (or compression)
// then change the CRF value and/or compression speed
}
}
}
}
ultimately I get to this Method and run into trouble.
private async void ConvertToMPEG(string arguments, MediaFileWrapper processMediaFile)
{
startTime = DateTime.Now;
watch = new Stopwatch();
watch.Start();
progressBar1.Minimum = 0;
progressBar1.Maximum = processMediaFile.GetTotalMilliseconds();
// Start the child process.
p = new Process();
//Setup filename and arguments
outputWindow.AppendText("ffmpeg " + arguments);
p.StartInfo.Arguments = arguments;
p.StartInfo.FileName = "ffmpeg.exe";
p.StartInfo.UseShellExecute = false;
// Redirect the output stream of the child process.
p.StartInfo.RedirectStandardOutput = true;
p.StartInfo.RedirectStandardError = true;
p.StartInfo.RedirectStandardInput = true;
// capture the date for stdout and std error
// note FFMPEG uses Stderr exclusively
p.ErrorDataReceived += new DataReceivedEventHandler(ErrorDataReceived);
p.OutputDataReceived += new DataReceivedEventHandler(OutputDataReceived);
// Hide Console Window
p.StartInfo.CreateNoWindow = true;
p.StartInfo.WindowStyle = ProcessWindowStyle.Hidden;
p.Start();
p.BeginErrorReadLine();
p.BeginOutputReadLine();
await p.WaitForExitAsync();
}
and WaitForExitAsync is in another class because in can not be in here with a Form
public static Task WaitForExitAsync(this Process process,
CancellationToken cancellationToken = default(CancellationToken))
{
var tcs = new TaskCompletionSource<object>();
process.EnableRaisingEvents = true;
process.Exited += (sender, args) => tcs.TrySetResult(null);
if (cancellationToken != default(CancellationToken))
cancellationToken.Register(tcs.SetCanceled);
return tcs.Task;
}
however, single files work fine, when I call a directory through, it continuously starts processes for each file, trying to run them all at the same time. You can see I tried implementing this
process.WaitForExit() asynchronously
with no luck.

Execute multiple command lines with output

I want to perform some command lines to display the result after each input.
Process p = new Process();
ProcessStartInfo info = new ProcessStartInfo();
info.FileName = "cmd.exe";
info.RedirectStandardInput = true;
info.UseShellExecute = false;
p.StartInfo = info;
p.Start();
using (StreamWriter sw = p.StandardInput)
{
if (sw.BaseStream.CanWrite)
{
sw.WriteLine("ftp");
//output
sw.WriteLine("open ftp.server.com");
//output
sw.WriteLine("username");
//output
sw.WriteLine("password");
//output
}
}
Help me to understand how to make the output result after each sw.WriteLine(...)?
Updated
It is not working with ftp. Why?
Initialization:
Test test = new Test();
test.start();
Console.ReadKey();
Class Test:
class Test
{
static StringBuilder StdOutput = new StringBuilder();
Process p = null;
Queue<string> cmdQueue = new Queue<string>();
public void start(){
cmdQueue = new Queue<string>();
cmdQueue.Enqueue("cd c:\\");
cmdQueue.Enqueue("dir");
cmdQueue.Enqueue("ftp");
cmdQueue.Enqueue("open us1.hostedftp.com");
cmdQueue.Enqueue("z3r9#ya.ru");
cmdQueue.Enqueue("123456");
cmdQueue.Enqueue("dir");
setupProcess();
startProcess();
}
private void setupProcess()
{
p = new Process();
ProcessStartInfo info = new ProcessStartInfo();
info.FileName = "cmd";
info.CreateNoWindow = true;
info.RedirectStandardOutput = true;
info.RedirectStandardInput = true;
info.UseShellExecute = false;
p.OutputDataReceived += new DataReceivedEventHandler(OutputDataHandler);
StdOutput = new StringBuilder();
p.StartInfo = info;
}
private async void startProcess()
{
p.Start();
p.BeginOutputReadLine();
using (StreamWriter sw = p.StandardInput)
{
if (sw.BaseStream.CanWrite)
{
while (cmdQueue.Count > 0)
{
string cmd = cmdQueue.Dequeue();
if (cmd != null & cmd != "")
{
await sw.WriteLineAsync(cmd);
Thread.Sleep(100);
//System.Console.WriteLine(StdOutput);
}
else
{
break;
}
}
Console.WriteLine(StdOutput);
}
p.WaitForExit();
}
}
private static void OutputDataHandler(object sendingProcess, DataReceivedEventArgs outLine)
{
if (!String.IsNullOrEmpty(outLine.Data))
{
StdOutput.Append(Environment.NewLine + outLine.Data);
//System.Console.WriteLine(Environment.NewLine + outLine.Data);
}
}
}

I assume that you are actually asking about how to catch outputs from all the commands you want to have executed in the (one) process.
Here is a version of a solution I came up with a long time ago, when I was a rookie here..
The trick is to collect the output as is comes along by listening to events the Process will trigger whenever output gets created: OutputDataReceived and ErrorDataReceived. We need to run things async for this to work, so it will look a little more complicated than the usual examples, which only have one process executing one command..:
First a few variables:
Queue<string> cmdQueue = new Queue<string>();
static StringBuilder StdOutput = new StringBuilder();
static StringBuilder ErrOutput = new StringBuilder();
Process p = null;
Task processTask = null;
bool processIsRunning = false;
Here is a button click event that starts processing all commands from a multiline TextBox. Output gets collected in the two StringBuilders; when the queue is empty, I wait a little longer..:
private void button1_Click(object sender, EventArgs e)
{
cmdQueue = new Queue<string>(tb_commands.Lines.ToList());
setupProcess();
startProcessTask();
while (cmdQueue.Count > 0) Thread.Sleep(100);
Thread.Sleep(500);
tb_out.AppendText(StdOutput + "\r\n" + ErrOutput + "\r\n");
}
Here is the routine that set up the Process. Here we register two events that will notify us when there are lines in the output streams..:
private void setupProcess()
{
p = new Process();
ProcessStartInfo info = new ProcessStartInfo();
info.FileName = "cmd.exe";
info.CreateNoWindow = true;
info.RedirectStandardOutput = true;
info.RedirectStandardError = true;
info.RedirectStandardInput = true;
info.UseShellExecute = false;
p.OutputDataReceived += new DataReceivedEventHandler(OutputDataHandler);
p.ErrorDataReceived += new DataReceivedEventHandler(ErrorDataHandler);
StdOutput = new StringBuilder();
ErrOutput = new StringBuilder();
p.StartInfo = info;
}
After the setup we can start a Task that will start our Process asynchonously..:
private void startProcessTask()
{
var task = Task.Factory.StartNew(() => startProcess());
processTask = task;
}
..and finally here is the async method that after starting the Process and beginning with the asynchronous read operations on the redirected streams, keeps feeding it all lines from the command queue.
private async void startProcess()
{
try { p.Start(); processIsRunning = true; } catch
{
ErrOutput.Append("\r\nError starting cmd process.");
processIsRunning = false;
}
p.BeginOutputReadLine();
p.BeginErrorReadLine();
using (StreamWriter sw = p.StandardInput)
{
if (sw.BaseStream.CanWrite)
do
{
try
{
string cmd = cmdQueue.Dequeue();
if (cmd != null & cmd != "") await sw.WriteLineAsync(cmd);
} catch { }
} while (processIsRunning);
try { p.WaitForExit(); } catch { ErrOutput.Append("WaitForExit Error.\r\n"); }
}
}
The last pieces are the two events we have registered for reading the output from the two streams and adding them to the StringBuilders:
private static void OutputDataHandler(object sendingProcess, DataReceivedEventArgs outLine)
{
if (!String.IsNullOrEmpty(outLine.Data))
{
StdOutput.Append(Environment.NewLine + outLine.Data);
}
}
private static void ErrorDataHandler(object sendingProcess, DataReceivedEventArgs outLine)
{
if (!String.IsNullOrEmpty(outLine.Data))
{
ErrOutput.Append(Environment.NewLine + outLine.Data);
}
}
Note that this works fine for all sorts of commands you can feed into the process, including FTP. Here I change my codepage, show the images I have before, log in to an FTP server, call up the help page, cd and dir, download an image, close the connection and check the images I have now..:
One Caveat: There must be something wrong in the way I wrote this, as VS keeps complaining about a System.InvalidOperationException and the exe file hogs ~10% cpu. Helping me out would be very much appreciated..

RedirectStandard Output/Error wont call my event for Standard Output/Error

hi i'm trying to build a parser for my System to Manage my Tekkit Server i am using C# but i have RedirectStandardOutput on my Tekkit Server process and there is a method set-up to then send that output to my console after adding to a List but it's not adding to a List<string>
Here is my code:
public void StartServer(string maxMem, string minMem, string path)
{
ThreadStart server = new ThreadStart(delegate() { StartServerThread(maxMem, minMem, path); });
server.Invoke();
}
private void StartServerThread(string maxMem, string minMem, string TekkitPath)
{
try
{
TekkitServer.StartInfo.FileName = "java";
TekkitServer.StartInfo.Arguments = String.Format("-Xmx{0} -Xms{1} -jar \"" + TekkitPath + "\" -nojline nogui", maxMem, minMem);
TekkitServer.StartInfo.UseShellExecute = false;
TekkitServer.StartInfo.RedirectStandardInput = true;
TekkitServer.StartInfo.RedirectStandardOutput = true;
TekkitServer.OutputDataReceived += new DataReceivedEventHandler(TekkitServer_OutputDataReceived);
IsStarted = TekkitServer.Start();
TekkitServerInput = TekkitServer.StandardInput;
}
catch (Exception)
{
}
}
void TekkitServer_OutputDataReceived(object sender, DataReceivedEventArgs e)
{
/*B*/recordedData.Add(e.Data);
Console.Out.WriteLine(e.Data);
}
Where /*B*/ is a break point, the breakpoint is never activating

By default, the standard output is directed at the console window.
If you need to do something with it, you need to redirect it, hence, you need to set RedirectStandardOutput = true; for the event to be fired.
Edit: This is my working code (with error handling and logging omitted):
public int ExecuteCommand(CommandParameters parameters)
{
Process process = new Process();
process.StartInfo.RedirectStandardInput = true;
process.StartInfo.RedirectStandardOutput = true;
process.StartInfo.RedirectStandardError = true;
process.OutputDataReceived += StdOutputHandler;
process.ErrorDataReceived += StdErrorHandler;
process.StartInfo.UseShellExecute = false;
process.StartInfo.FileName = ...;
process.StartInfo.Arguments = ...;
process.Start();
process.BeginErrorReadLine();
process.BeginOutputReadLine();
process.WaitForExit(parameters.Timeout);
return process.ExitCode;
}
private void StdOutputHandler(object sendingProcess, DataReceivedEventArgs outdata)
{
if (!string.IsNullOrEmpty(outdata.Data))
{
OutputMessages.Add(outdata.Data);
}
}
Most likely the missing link in your code is the BeginOutputReadLine that actually gets the handler method on it's way.
Also, I use a fresh Process object and that I wait on it to finish it's job, so no interference with previous calls is possible.

C# Keeping Sub-Process Running

I wrote a small program in C# NET a while back to keep a Java process running. I am about to deploy it to a bunch of servers and I am working on fixing up some of the code now. As it stands, I don't think I have this setup right.
What would be the best way to keep the process running that I am creating in my LaunchMinecraft() function? I want to have it so as long as my process is running, it continues to restart this process if it crashes.
static void Main(string[] args)
{
// Launch the Application
LaunchMinecraft("minecraft_server.jar", "512");
}
public static void LaunchMinecraft(string file, string memory)
{
string memParams = "-Xms" + memory + "M" + " -Xmx" + memory + "M ";
string args = memParams + "-jar " + file + " nogui";
ProcessStartInfo processInfo = new ProcessStartInfo("java.exe", args);
processInfo.CreateNoWindow = true;
processInfo.UseShellExecute = false;
processInfo.RedirectStandardOutput = true;
processInfo.RedirectStandardInput = true;
processInfo.RedirectStandardError = true;
try
{
using (Process minecraftProcess = Process.Start(processInfo))
{
// Store Process Globally to access elsewhere
JavaProcess = minecraftProcess;
// Creates a Repeating Poll Timer (30 Seconds)
// Use this to keep the Minecraft's Process Affinity/Priority the same as the Daemon
PollTimer = new System.Timers.Timer();
PollTimer.Elapsed += new ElapsedEventHandler(Event_PollProcess);
PollTimer.Interval = 5000;
PollTimer.Start();
Console.WriteLine("Minecraft Process Started.");
// Setup Callback for Redirected Output/Error Streams
minecraftProcess.OutputDataReceived += new DataReceivedEventHandler(Handler_ProcessOutput);
minecraftProcess.ErrorDataReceived += new DataReceivedEventHandler(Handler_ProcessError);
// Steam Writer
streamWriter = minecraftProcess.StandardInput;
minecraftProcess.BeginOutputReadLine();
minecraftProcess.BeginErrorReadLine();
while (minecraftProcess.HasExited == false)
{
String strInput = Console.ReadLine();
SendProcessCmd(strInput);
}
minecraftProcess.WaitForExit();
}
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
}

The Process class itself cant prevent your external program from shutting down, you have to use the Exited event as #Jalal mentiones or poll the HasExited property of the process.