We've never actually revealed this before, so I'll add one more juicy bit: The model ran on the phone's CPU, not GPU, because of weird memory management issues when you're trying to push the limits. The quality of images wound up being significantly better than open source.https://twitter.com/citnaj/status/1316789600531017728 …
I figure it's nice to at least throw it out there that yes, it is possible to engineer something this efficient for a task like this.