Well, I was talking about real time object detection on 640x480 video. Perhaps most users would be okay with a 5 second or so delay when processing an image and perhaps you could use Facebook's trick of fast, bad quality style transfer and better quality style transfer once the image is in the servers. But the point is that the current paradigm is very restrictive in terms of deep learning applications.
I think computing optical flow remains a major time bottleneck. Any attempt at temporal coherence would be great, and I'm sure there is some attempt on Messenger, but it really only works well for the last style transfer filter, all the way to the right in the app, and that one only really looks great in well lit scenes. Also, the phone seems to heat up a lot.
I you would downsize the frames first and work on multiple frames in parallel (e.g. however many nets I can fit in VRAM). I find it hard to believe that it wouldn't work after these things.
