To understand why a "portable viewer" is impossible without actual hacking, look at the backend logic.
If you already have access to a video and want to download it for offline use, the following methods are widely used: thisvid private viewer portable
Many creators offer private access through supported memberships. To understand why a "portable viewer" is impossible
So, why should you choose ThisVid Private Viewer Portable for your private video viewing needs? Here are some benefits: thisvid private viewer portable