Folders in Program Files
or Program Files (x86)
will be limited to being written to only by System
groups or Administrator
groups by default. Quite often the Administrator
group or SYSTEM
will be the owner of the folder.
The default permissions will usually allow users in the Administrator
group full control:
But as you've spotted, your account is in the Administrator group, but you can't write in it.
For the simple reason that you aren't running with those elevated privileges. You are running your account as a normal user, which, if you check the first screenshot, only has Read & execute
permissions to the folder.
The "solution" is to not write in this folder, as it could cause problems updating, difficulty finding your files, or might work fine but it's not really a logical place to look for a video. That's not to mention the risk of accidentally overwriting a critical file needed by the application.
Of course, if you want to do so regardless, you can run the program in question as an administrator:
Now it'll be within the correct privilege group.
But as stated, this isn't typically a very good idea, and I'd recommend keeping programs and their data separated.