Startup request: create a service where you could transcript just from videos, without voice. Ideally a mobile app. Some of the use cases are somewhat creepy,

Startup request: create a service where you could transcript just from videos, without voice. Ideally a mobile app. Some of the use cases are somewhat creepy, but there are quite a few legitimate ones. In particular, there are a lot of recording where sounds is broken/terrible and you could "restore" does. You could start it yourself, but later you could make some kind of marketplace.