You can find out the ip of your chromecast with the command "arp -a" and it should list Chromecast as one of the devices if its switched on and on the same wifi
Only works with VLC nightly builds 3.x.x. Also it is not very stable but gets the job done if you don't care about subtitles and scrolling through the video frequently.
THe best option is plex (works for many file formats). Second best option is videostream extension on Chrome (not on chromium). But videostream doesn't support all file formats. They keep updating though.
