private async void RunSimpleButton_Click(object sender, RoutedEventArgs e) { if (Validate()) { ProcessOptionsFFmpeg Options = new ProcessOptionsFFmpeg(FFmpegDisplayMode.Interface, "Encoding to H264/AAC (Simple)"); string Src = SourceTextBox.Text; string Dst = DestinationTextBox.Text; await Task.Run(() => { encoder.Encode(Src, "h264", "aac", null, Dst, Options); }); } }