I recently interviewed with Plex for a Senior Software Engineer role focused on low-level media streaming. As someone with prior experience in this space, I used the prep process to go deeper into the internals of how streaming actually works. The interview went well, but the role wasn't quite the right fit at the time. In an effort not let that knowledge go to waste, I thought I'd write an article to share what I learned during this period.
This article is the first in a series introducing how media streaming works on the client side: the steps involved in getting a piece of media from a server onto a client device over the internet, so off we go!
The Problem with Downloading
I believe at some point you've consume some sort of media on the internet today with either your phone, your laptop, maybe even a pager if you're reading this from 1998. Whether it's a short clip on Instagram or X(formerly Twitter), or a two-hour film on Netflix or Amazon Prime, or maybe even listening to your favourite music on Spotify that content had to get to your device somehow.
These media content can be delivered in various ways but we'd be looking at two of them. In the early days of the internet, there was really just one go-to option, downloading the entire file before playback actually starts. Yeah that's works fine for a few second clip, but where the problem lies is when a long form media content is being served to a user. Downloading an hour of 720p video over a 4G connection can take several minutes depending on your connection quality, now imagine how that scales when the media resolution is larger with a longer duration. Nobody wants to stare at a loading bar for ten minutes before a movie starts.
