Question

I am new to python and ffmpeg. I have a following question to ask.

If I run the following command from command-line and it works.

ffmpeg -i  1.flv  temp_filename

If I put it in a program

   temp_file_handle, temp_filename = tempfile.mkstemp('.flv')

   command = "ffmpeg -i " + newvideo.location + " "+ temp_filename

   out = subprocess.Popen(command, stdout=subprocess.PIPE, stderr=subprocess.PIPE, shell=True)
   res = out.communicate()

The generated video didn’t write to the tem_filename. Why?

Answer 1

mkstemp creates the file itself, not just the file name. So the file will already exist when ffmpeg attempts to write to it. Therefore it will ask whether you want to overwrite the file, or produce an error message, unless the ffmpeg -y option is used.