How can I send command "q" to FFMPEG with c#

Question

How can I send the command "q" to a FFMPEG process with C#?
I tried it like this:

var p = Process.GetProcessesByName("ffmpeg").FirstOrDefault();

if (p != null)
{
    p.StandardInput.Write("q");
}

But I got this error:

I tried this and get this error: StandardIn não foi redirecionado. — thiago.adriano26, Sep 15 '15 at 17:34
I don't think this will work because you don't "own" a handle to its stdin, since you didn't start the process...anyway see http://stackoverflow.com/a/32505963/32453 — rogerdpack, Sep 17 '15 at 15:15

score 4 · Accepted Answer · edited Jul 25 '23 at 01:39

You can use the SendMessage call of the user32 api.

[DllImport("user32.dll", EntryPoint = "FindWindowEx")]
public static extern IntPtr FindWindowEx(IntPtr hwndParent, IntPtr hwndChildAfter,          string lpszClass, string lpszWindow);

[DllImport("user32.dll")]
public static extern int SendMessage(IntPtr hWnd, int uMsg, int wParam, string lParam);

static void Send(string message)
{
    var notepads = Process.GetProcessesByName("notepad");
    
    if (notepads.Length == 0)
        return;

    if (notepads[0] != null)
    {
        var child = FindWindowEx(notepads[0].MainWindowHandle, new IntPtr(0), "Edit", null);
        SendMessage(child, 0x000C, 0, message);
    }
}

Change it as you need. I'm not sure it would work for your situation, but it's always good to try.

Goodluck.

How can I send command "q" to FFMPEG with c#

1 Answers1