To quote the "Reddiquette":
Feel free to post links to your own content (within reason). But if that's all you ever post, and it always seems to get voted down, take a good hard look in the mirror — you just might be a spammer. A widely used rule of thumb is the 9:1 ratio, i.e. only 1 out of every 10 of your submissions should be your own content.
As known, Reddit has several "subreddits" where one can post content related to various topics, so one could try to post a video in one of the subreddits dedicated to the video's theme, which may do well if your video is of good quality. The big difference between Reddit and other medias is that there's not only a "like" button, or upvote as it's called there, but the option to downvote. Anything not meeting Reddit's standards will get downvoted to oblivion by the hivemind, and there's generally a below-average attitude towards self-promotion. You should also be an active commenter and post other content too, or else you're easily labelled a spammer.
But yes, if you hit the niche correctly and make some excellent content, it's absolutely possible to get your work promoted there. I've done it a few times, gathering about 30-200 upvotes on some videos and over 800 upvotes on a post linking to a video. Just note; Reddit is a tough crowd to satisfy.