Terminal text becomes invisible after terminating subprocess

Question

After terminating an ffmpeg subprocess, the terminal gets messed up - typed characters are invisible! The input still works in that commands can be executed, b

Answer 1

As stated in this answer, ffmpeg expects data from stdin. You can run ffmpeg with the -nostdin flag and it will keep your terminal from hiding keystrokes.

Answer 2

os.system('stty sane') worked for me. It reset settings making echo invisible.

Answer 3

Change the script so that proc.terminate() is not used. You can stop an ffmpeg subprocess more politely with

  proc.send_signal(signal.SIGINT)
  proc.wait()

This allows ffmpeg the chance to write whatever escape sequences it needs to restore the terminal.

---

edit: discovered later- another tip to make ffmpeg behave better with Popen is to provide it a subprocess.PIPE or open(os.devnull) in the stdin handle. Otherwise, it seems to try to get input from the parent's stdin which can cause weird terminal behaviour. A running ffmpeg process is listening for '?' and 'q' input on stdin.

Answer 4

do you communicate with the subprocess? in that case i would use pexpect which makes that type of setup very simple, perhaps you must wait for the command to finish? i.e.

 p = subprocess.Popen(argv, stdout=o, stderr=e)
 p.wait()
 if p.returncode != 0:
      print("problems")

that's what i use on a dvd2h264 script i wrote a while back, never had any problems with it, but i don't redirect stdin/stderr to tmpfiles..