I've read some posts, but I don't find the answer I need: is it possible to play a video file or a video from a URL in a WatchKit app?
The current version of WatchKit (8.2) does not provide support for video. It is possible to create an animated series of images and play them on the Watch, but storage and transmission costs likely mean that this "video" would be short and at a low frame rate. It has been speculated that this is the kind of technique they used to show the garage door video in one of their keynote demos.