Here is tutorial/guide on how to turn online streamed video into a local video file on a computer HDD.

Im not sure for which streams it works. But i assume all that VLC media player can stream.

1. Open webpage with the streamed video and mouse right click. Then click "Inspect element". If you do not have this option (Firefox browser does have by default), download some web browser extension that allow analyzing traffic / inspecting source code.

2. Once clicked Inspect element, click "Network" tab in the inspector window

3. Refresh/reload webpage (F5)

4. click on the video and once it start playing, stop it or pause it.

5. in the Network inspector you should see comming new entries and one of them should be the network stream URL.

6. Right click the entry that appears to be video stream (m3u8, flv, swf....) and copy it into clipboard.

7. Open VLC Media Player, click "Media" menu item and then click "Convert/Save". On the "Network" tab in VLC player, paste your stream URL and in the next step select location where video file should be saved.

Video tutorial: