I saw most of free url video downloader is for downloading the You Tube video and/or convert it to the other format. Is there a reliable video downloader for downloading any website video? Thank you for your answer.

They are usually specific to the browser you are using. Search their Add-ons area.

The following are the video downloader which downloads any websites video. You can download video downloader from below listed sites.
Ant.com/video-downloader
Speedbit.com/video-downloader-converter
Freemake.com/free_video_downloader/

I have tested Ant.com/video-downloader It's amazing that can dowload videos from most of web site and easy to use.

You can download and install Internet Download manager.
With it you can download audio and video from any website page.
You will see a download button when any audio or video is available to download from a web page.
Simply click on it and you can download the media.