error during encoding

[fperdigon]

First of all, great work so far guys!!!

Following the environment and the error are described
The SO: Ubuntu 20.04
ffmpeg version 4.2.4-1ubuntu0.1 (the one that cames in the Ubuntu 20.04 repository)
Video-diet was installed in a conda main environment using pip according to the installation instructions on the readme of this repo
python interpreter version 3.7.7
Behavior: The program launch and convert a couple of files then it stops showing the following error:

Processing: /media/fco/STORAGE1/VIDEOS LYF_HDD/VIDEOS CLIPS/Adele/conv-Adele Skyfall Live Performance Oscar 2013[1].mp4
Traceback (most recent call last):
  File "/home/fco/miniconda3/bin/video-diet", line 8, in <module>
    sys.exit(app())
  File "/home/fco/miniconda3/lib/python3.7/site-packages/typer/main.py", line 214, in __call__
    return get_command(self)(*args, **kwargs)
  File "/home/fco/miniconda3/lib/python3.7/site-packages/click/core.py", line 829, in __call__
    return self.main(*args, **kwargs)
  File "/home/fco/miniconda3/lib/python3.7/site-packages/click/core.py", line 782, in main
    rv = self.invoke(ctx)
  File "/home/fco/miniconda3/lib/python3.7/site-packages/click/core.py", line 1259, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/home/fco/miniconda3/lib/python3.7/site-packages/click/core.py", line 1066, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/home/fco/miniconda3/lib/python3.7/site-packages/click/core.py", line 610, in invoke
    return callback(*args, **kwargs)
  File "/home/fco/miniconda3/lib/python3.7/site-packages/typer/main.py", line 497, in wrapper
    return callback(**use_params)  # type: ignore
  File "/home/fco/miniconda3/lib/python3.7/site-packages/video_diet/main.py", line 78, in folder
    convert_video_progress_bar(str(video), str(new_path), manager)
  File "/home/fco/miniconda3/lib/python3.7/site-packages/video_diet/__init__.py", line 37, in convert_video_progress_bar
    if get_bitdepth(source).is_10bit:
AttributeError: 'NoneType' object has no attribute 'is_10bit'

Files   4%|███▏                                                                     |   9/212 [04:41<1h 45:48, 0.03 files/s]
Adele Skyfall Live Performance Oscar 2013[1].mp4 100%|█████████████████████████████████| 100.0/100.0 [04:39<00:00, 0.36 %/s]