The below code captures console outputs and send it in real time to callback function, so the application can handle it such as displaying its progress by adding to memo, so end user may not think the application is hanging while program performing the command.
type TArg<T> = reference to procedure(const Arg: T); . . . procedure CaptureConsoleOutput(const ACommand: String; CallBack: TArg<PAnsiChar>); const CReadBuffer = 2400; var saSecurity: TSecurityAttributes; hRead: THandle; hWrite: THandle; suiStartup: TStartupInfo; piProcess: TProcessInformation; pBuffer: array [0 .. CReadBuffer] of AnsiChar; dBuffer: array [0 .. CReadBuffer] of AnsiChar; dRead: DWORD; dRunning: DWORD; dAvailable: DWORD; begin saSecurity.nLength := SizeOf(TSecurityAttributes); saSecurity.bInheritHandle := true; saSecurity.lpSecurityDescriptor := nil; if CreatePipe(hRead, hWrite, @saSecurity, 0) then try FillChar(suiStartup, SizeOf(TStartupInfo), #0); suiStartup.cb := SizeOf(TStartupInfo); suiStartup.hStdInput := hRead; suiStartup.hStdOutput := hWrite; suiStartup.hStdError := hWrite; suiStartup.dwFlags := STARTF_USESTDHANDLES or STARTF_USESHOWWINDOW; suiStartup.wShowWindow := SW_HIDE; if CreateProcess(nil, PChar(ACommand), @saSecurity, @saSecurity, true, NORMAL_PRIORITY_CLASS, nil, nil, suiStartup, piProcess) then try repeat dRunning := WaitForSingleObject(piProcess.hProcess, 100); PeekNamedPipe(hRead, nil, 0, nil, @dAvailable, nil); if (dAvailable > 0) then repeat dRead := 0; ReadFile(hRead, pBuffer[0], CReadBuffer, dRead, nil); pBuffer[dRead] := #0; OemToCharA(pBuffer, dBuffer); CallBack(dBuffer); until (dRead < CReadBuffer); Application.ProcessMessages; until (dRunning <> WAIT_TIMEOUT); finally CloseHandle(piProcess.hProcess); CloseHandle(piProcess.hThread); end; finally CloseHandle(hRead); CloseHandle(hWrite); end; end;
Example)
var strDir, strFFMPEG: string; begin strDir := GetCurrentDir; strFFMPEG := '"' + strDir + '\ffmpeg.exe"'; strFFMPEG := strFFMPEG + ' -y -i C:\test.mkv -vcodec h264 -acodec aac -f mp4 C:\test-2.mp4'; Memo1.Lines.Add(strFFMpeg); CaptureConsoleOutput(strFFMPEG, procedure(const Line: PAnsiChar) begin //Panel1.Caption := String(Line); Memo1.Lines.Add( String(Line)); end ); end;