vb.netffmpegbackgroundworkersendkeyspausing-execution

How to pause ffmpeg than runs without window?

I'm working on a video converter and I wanted to be able to stop or pause ffmpeg by pressing a button. Googleing I have found a way but it's not working. basically I Start ffmpeg on a background worker in this way:

Private Sub bw_DoWork(ByVal sender As Object, ByVal e As DoWorkEventArgs)

        Dim Proc As New Process

        Proc.StartInfo.UseShellExecute = False
        Proc.StartInfo.RedirectStandardError = True
        Proc.StartInfo.RedirectStandardOutput = True
        Proc.StartInfo.FileName = current_ffmpeg_path
        Proc.StartInfo.Arguments = input_params
        Proc.StartInfo.CreateNoWindow = True
        Proc.Start()

[do things...]

then inside a loop I place an if to pause ffmpeg:

If (pause = 1 Or pause = 2) Then
        AppActivate(Proc.Id)
        SendKeys.SendWait("^(s)")
        SetForegroundWindow(Me)
        pause = 0
    End If

but it's not working.. maybe cause of AppActivate that need a window to work while instead ffmpeg is running without it. There is another way? maybe not with sendkeys?

Solution

  • SOLVED. It's not possible use SendKeys for a process without a window.. use instead NtSuspendProcess and NtResumeProcess..

    More information googling about:

    p/invoke NtResumeProcess/NtSuspendProcess which are callable platform APIs