I've seen that applications like Steam, Spotify, and others, are able to launch native applications from inside Chrome, after the user allows the invocation in the pop up box. How can I do this from my own website, for VLC, or failing that, the default system video streaming application.
Sure, Safari, for example, will open VLC for rtmp://
links like
<a target="_blank" href="rtmp://zozolala.com">text</a>
You can invoke video player from JavaScript:
window.open('rtmp://zozolala.com', '_blank');
You can specify URLs your OS X app can open by adding them to .plist:
<key>CFBundleURLTypes</key>
<array>
<dict>
<key>CFBundleTypeRole</key>
<string>Editor</string>
<key>CFBundleURLIconFile</key>
<string></string>
<key>CFBundleURLName</key>
<string>abc</string>
<key>CFBundleURLSchemes</key>
<array>
<string>abc</string>
</array>
</dict>
</array>
If you want to feed your VLC with HTTPS URI (this URI will be opened in Safari by default), you can do a trick: prepare .m3u
playlist file with https://
entry inside and make this file be available via some other protocol (for which default app is VLC), like RSTP or SFTP.