@balbant from what i know you cannot
you need direct link to the video file , with you tube you only have a link to the embed page so ...
I'm pretty sure that would violate Youtube/Google's TOS and therefore probably Roku's as well.
If you are the content/copyright owner, you can move the videos to another CDN and stream them from the new location. You'll need to recode each video with a tool like Nero Video.
If, however, you are not the content owner, you must acquire permission from the content owner to stream their video content. Then, you'll need to follow the steps above.
I have successfully obtained permission (from my content owners) and moved videos to a CDN for streaming.