This webpage lets you turn any subreddit into a video playlist just by adding the reddit path to the url.
Example: http://example.com/r/hiphopheads will give you a playlist with all videos from the front page of r/hiphopheads.
You can use any reddit path: http://example.com/r/hiphopheads/top for example will use the tops posts on the subreddit.
If you don't pass any path to the url the app will play r/treemusic by default.