You can capture Youtube videos using the Youtube API. While not particularly user-friendly the Youtube API page provides a vast set inputs to customize your query.
SocialMiner will work with all the defualt settings therefore you can all the settings and enter your desired search string in the "Search Query" field, then copy the Resulting URI.
For example, here is a YouTube search for "Cisco" http://gdata.youtube.com/feeds/base/videos?q=cisco&client=ytapi-youtube-search&v=2
The current Google search result does not include search of the comments, although this functionality is under development. You can see this in "TestTube" here: http://www.youtube.com/comment_search
- You can use typical Google Search parameters like quotes, AND, OR, etc.