1 Problem Description

Write a GUI program using PySide2, call ffmpeg command line tool, do simple batch video processing (adjust frame width, frame height, video speed, reduce video bitrate to limit video size), use ffmpeg, ffmpeg-python library;
It was easy, but I had a problem:

2 Solutions

Directly look anxiously 2.2 Hide the CMD black frame.

2.1 CMD black box is still in place, verbose information is not displayed (cure symptoms, cure diseases)

1. Use subprocess.call():

   When the CMD command is invoked, adding -loglevel quiet to the parameter after ffmpeg will only have a black box and will not show real-time progress information

2. Using ffmpeg, ffmpeg-python Libraries

   ffmpeg.run(quiet=True), set quiet to True, only the black box, do not display real-time progress information

2.2 Hide CMD black frame (Ah-ha-ha comfortable)

(I used the probe (call ffprobe.exe to get video stream information) and run (call ffmpeg.exe to perform operations) methods of the ffmpeg library)

1. Find the **_probe.py** and **_run.py** files for the ffmpeg Library

   Back up these two files, modify them, package them, and restore them to their original state

   Copy the two files to the desktop and modify them before you put them back. (It took me a while. win10 did not open the files with administrator privileges because the ffmpeg library is installed on the Program.. path on the C drive. The changes made in PyCharm have not been saved.)

2. Modify_probe.py

   Source: p = subprocess.Popen(args, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
   Popen parameter adds shell=True, stdin=subprocess.PIPE

   def probe(filename, cmd='ffprobe', **kwargs):
       """Run ffprobe on the specified file and return a JSON representation of the output.
   
       Raises:
           :class:`ffmpeg.Error`: if ffprobe returns a non-zero exit code,
               an :class:`Error` is returned with a generic error message.
               The stderr output can be retrieved by accessing the
               ``stderr`` property of the exception.
       """
       args = [cmd, '-show_format', '-show_streams', '-of', 'json']
       args += convert_kwargs_to_cmd_line_args(kwargs)
       args += [filename]
   
       # Source: p = subprocess.Popen(args, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
       # The Popen parameter adds shell=True, stdin=subprocess.PIPE,
   
       p = subprocess.Popen(args, shell=True, stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
       out, err = p.communicate()
       if p.returncode != 0:
           raise Error('ffprobe', out, err)
       p.wait()
       return json.loads(out.decode('utf-8'))

3. Modify_run.py

   Source: return subprocess.Popen(args, stdin=pipe_stdin, stdout=stdout_stream, stderr=stderr_stream)
   Add shell=True, modify stdin=subprocess.PIPE, or modify pipe_stdin=True

   def run_async(
           stream_spec,
           cmd='ffmpeg',
           pipe_stdin=False,
           pipe_stdout=False,
           pipe_stderr=False,
           quiet=False,
           overwrite_output=False,
   ):
       args = compile(stream_spec, cmd, overwrite_output=overwrite_output)
       stdin_stream = subprocess.PIPE if pipe_stdin else None
       stdout_stream = subprocess.PIPE if pipe_stdout or quiet else None
       stderr_stream = subprocess.PIPE if pipe_stderr or quiet else None
   
       # Source: return subprocess.Popen(
       #            args, stdin=pipe_stdin, stdout=stdout_stream, stderr=stderr_stream)    
       # Add shell=True, modify stdin=subprocess.PIPE, or modify pipe_stdin=True
   
       return subprocess.Popen(
           args, shell=True, stdin=subprocess.PIPE, stdout=stdout_stream, stderr=stderr_stream
       )

4. Put the modified_probe.py and_run.py back into the ffmpeg Library

5. When pyinstaller packages, add the -w or--noconsole parameter, and CMD black boxes will not appear

   ==The black box is gone, everything is comfortable==

Appendix 1: Instead of using the ffmpeg library, you can call ffmpeg.exe directly using subprocess by specifying the parameter shell=True and stdin=subprocess.PIPE when calling subprocess.Popen().

**Appendix 2: Pack up the program and restore the backup _probe.py and _run.py to the ffmpeg library. I don't know what's wrong with writing this, or restore it as it is**

Reference 1:https://blog.csdn.net/polyhedronx/article/details/82432148 ---- subprocess.Popen setting shell=True, stdin=subprocess.PIPE
Reference 2: https://my.oschina.net/u/2396236/blog/1610765 ---- subprocess.Popen setting shell=True, stdin=subprocess.PIPE
Reference 3:https://blog.csdn.net/iserfj/article/details/94487538 ---- creationflags=0x08000000 or creationflags=subprocess.CREAT_NO_WINDOW (this method I tried to be invalid)