Is there a limit to the length of video I can upload?
Nope. You can upload any video of any length.
Technically, you should know that it does take time and bandwidth to upload video — and that your service provider usually gives you much slower upload speed than download. So be sure to keep your app in the foreground if you’re uploading from a mobile device until the upload is complete.
Also, if uploading from your Desktop computer, there is a maximum single file size of 2 GB. That’s enough for a feature length movie!