Getting realtime output from ffmpeg to be used in progress bar (PyQt4, stdout)

Question

I\'ve looked at a number of questions but still can\'t quite figure this out. I\'m using PyQt, and am hoping to run ffmpeg -i file.mp4 file.avi and get the out

Answer 1

If you have the duration (Which you can also get from the FFMPEG output) you can calculate the progress by reading the elapsed time (time) output when encoding.

A simple example:

  pipe = subprocess.Popen(
        cmd,
        stderr=subprocess.PIPE,
        close_fds=True
  )
  fcntl.fcntl(
        pipe.stderr.fileno(),
        fcntl.F_SETFL,
        fcntl.fcntl(pipe.stderr.fileno(), fcntl.F_GETFL) | os.O_NONBLOCK,
  )
   while True:
            readx = select.select([pipe.stderr.fileno()], [], [])[0]

            if readx: 
                chunk = pipe.stderr.read()

                if not chunk:
                    break

                result = re.search(r'\stime=(?P\S+) ', chunk)
                elapsed_time = float(result.groupdict()['time'])

                # Assuming you have the duration in seconds
                progress = (elapsed_time / duration) * 100

                # Do something with progress here
                callback(progress)

        time.sleep(10)