You log into your account, start playing the private video, and the extension "catches" the data stream, allowing you to save the full file.

This is a powerful, command-line tool that is widely considered the gold standard for video downloading. It is frequently updated to bypass site changes. By using the --cookies-from-browser command, YT-DLP can use your logged-in session to download private ThisVid content.

Unlike public videos, private content on ThisVid is usually protected by session-based authentication or paywalls. This means a standard "copy-paste URL" downloader often fails because it cannot "see" the content behind your login credentials.

There are numerous websites that claim to be a "ThisVid Downloader."

For many, the most effective "downloader" isn't a standalone app but a browser extension. Extensions like (for Firefox and Chrome) or Video Downloader Professional work by detecting the video stream as it plays in your browser.