According to the video description/comments, the shark was spotted off Grand Manan Island in Canada and was several feet longer than the boat which was 26 feet. The videographer estimates the shark was around 30 feet in length.
In addition, this is the time of year that you would expect to encounter basking sharks in that area. According to Grand Manan Whale & Seabird Research Station, basking sharks are common this time of year but they will leave the Canadian Atlantic waters in November and travel as far south as the southern Caribbean Sea before returning to northern waters in late spring.
So everyone can relax, there is not a 30 foot great white lurking in Canadian waters. And for the record, the maximum size of a great white is around 21 feet give or take.
As for the video, in addition to offering a nice, yet brief, view of the magnificent basking shark, it provides some humor when the videographer's female companion sees the massive shark and says, "Oh my gosh, oh my gosh...let's get out of here." But the good news for her is that she can relax as basking sharks are filter feeders.
The video was posted by Blaine Brown and is 45 seconds in length. The shark appears at the 25 second mark.