Time stamp has invalid characters in Windows

In a Windows environment, the following characters cannot be used in a file or folder name:

< (less than)
> (greater than)
: (colon)
" (double quote)
/ (forward slash)
\ (backslash)
| (vertical bar or pipe)
? (question mark)
* (asterisk)
Microsoft Docs

So the colons in the date/time stamp should be changed to something more OS-agnostic. Perhaps hyphens.

mpv_slicing/slicing.lua

Line 30 in d09c112

return string.format("%02d:%02d:%02.03f", hours, minutes, seconds)

If these characters are not changed the FFmpeg command will not work in Windows.

Are you able to pull request that fix?

Oh uhm..., I have no idea how to do that 😂