Updating the situation:
I’d like to do the following: for the first 15 minutes, I want to play the video normally and then either not show the rest or display a frozen image instead.
I occasionally encounter corrupted videos that only show certain parts and not the entire content.
I was wondering if I could replicate such a situation based on my selection. However, I would also like the option to view the entire video normally if I choose to do so through an alternative method
the purpose of the partially locked portion is To share with others selectively and To let everyone to quickly preview the contents The reason I mentioned the cloud is not necessarily get the support of the cloud system, I store the files on the cloud. so ideally viewer runs the file on his/her computer via link with a video player to be able to see the preview whereas another person viewing the same file in full via some sort of password, I don’t care if a decrypted file is kept in the authorized guest computer or deleted