Prisma for iOS adds offline video filtering, Android version still in progress
The iOS app requires an update to iOS 10, though, so if you're holding onto iOS 9, you'll have to upgrade if you want to enjoy the feature. Also, transforming videos takes a fair bit longer than dealing with photos, as the app must process several hundred frames, rather than a single photo. The waiting time depends on the clip's length, resolution, and how recent your iOS device is.
Thankfully, the processing is done offline, which means slow connections are no possible bottlenecks. Moreover, the Prisma creators are working on adding a GIF creator, which might happen later in October. As for the Android version, the Prisma team wants to deal with implementing offline photo processing in the app first, which is supposed to happen in the coming weeks. The team will add video processing next.
Below, you can watch a music video by the band Tweed, which is edited with Prisma's video processing technology. It is much longer than 15 seconds, though, and it's not yet known whether this time limit will be removed for users as well.