MineAudio | Midi & Wav & Lrc to Minecraft for Redstone music | Audio Utils library

I have a python script that I want to call from the windows file browser context menu (https://www.howtogeek.com/107965/how-to-add-any-application-shortcut-to-windows-explorers-context-menu/)

I am currently debugging calling it from the non-specific context (HKEY_CLASSES_ROOT\Directory\Background\shell) with the command "python "D:\toolbox\mineAudio.py" 0" (note python3 is on the path as python and the script is at D:\toolbox\mineAudio.py)

When I call the script from cmd it works as expected with that command, and when I make debug modifications to the script (adding os.system("pause") to random lines) I can verify it is running correctly up to the point it hits the line meta=cmd(['ffmpeg','-i',target]) (line 46) where it instantly and silently fails (note ffmpeg is also on the path)

EDIT: it actually gets as far as line 15 result = subprocess.run(command, stdout=subprocess.PIPE,stderr=subprocess.PIPE,startupinfo=startupinfo) I cant figure out why the program is failing there as that line works fine everywhere else I have tested the script from other than the context menu.

Here is the full script if you want to brows through it