Depends on the text, the video, and the person.
For maths teaching, the very popular Khan Academy have adopted the strategy of large numbers of short videos - with a blackboard showing formulas and diagrams - i.e. you're looking at text the whole time you're watching the video. In that case at least, it's not a question of either video or text.
My most direct experience comparing text and video learning is from a TED talk, 'My stroke of insight'. The talk is fantastic, the book a bit dry. Where there is emotion to be communicated along with technical information, and in that talk it is important, video is great. Where it is just technical understanding, in my view it is books, and ideally books with exercises to work through at your own pace, that shine.