[littlestymaar]

> Video Upload / Processing Service that saves the video into chunks

At this point you also need to chose what streaming protocol you want to use. You have mostly two choices, HLS if you want to get things done quick, or MPEG-DASH if you want more control (but you'd need a separate HLS pipeline for iOS anyway…)

> Build or use a video streaming library that can play video chunks as a stream

As someone who's worked on a web streaming player, I'd strongly recommend not to build one but to use an existing one (or, in short: use HLS.js)