In order to open video in Lightbox/Shodow you have to have a plugin to do this job.
Install plugin and don't forget to enable it.
Then go to Youtube Gallery, create one gallery or open existing one.
Find "rel option" box.
If you type anything here, then the links of thumbnails would lead to a page without template and
thumbnails, only video player.
Set "Switch Video As" to "Same Window (_top)"
Some of the lightboxes require "lightbox" to be written in a "rel option" box some "shadowbox". It's
very depend on a plugin you installed.
Also you would need to pass a window size to plugin.
Here you have two options, one is to add it's size after lightbox name, example:
"lightbox;width=600;height=400".
Another option is to add this parameter to the link.
Let's take a ARI Sexy light box plugin for example.
http://www.ari-soft.com/vmchk/Joomla-Components/ARI-Sexy-Lightbox-Lite/Detailed-product-flyer.html
Type "sexylightbox" into "Rel Option" box
And
"&TB_iframe=true&width=600&height=400" into "HREF addon" box.
After all this you will get this type of link (URL) from thumbnails to video.
index.php/youtube-gallery-lightbox-example/gallery?videoid=2ErW6vewV2M&galleryid=6&tmpl=component&TB_iframe=true&width=600&height=400
Lets break it apart to explain:
- videoid=2ErW6vewV2M - Video ID
- galleryid=6 - Youtube Gallery ID
- tmpl=component - This to disable template
- TB_iframe=true - some parameter required by ARI Sexy light box plugin
- width=600 - Width
- height=400 - Height
Be careful with "?" and "&" characters, you probably have to type it in-front of whatever you have in HREF addon.
Again about ARI Sexy light box, probably you would need to change plugin parameter "Load assets" from "Auto detect" to "Always"
After Gallery being created it's time to make it visible.
Here is three options" plugin, component and module
If you choose component set "Allow Content Plugins" to "yes" in order to allow light box to workout the links.