[kossTKR]

Regarding 3. I've seen tiktok on an iPad and the quality is surprisingly good. High res and no artifacts. People can already film 4k with their phones, and that's what's shared.

Also young people scroll for hours (and adults, the average age is above 25 afaik) so watch-time isn't less than on YT, probably even more.

Lastly but most importantly, many people scroll through a huge pile of videos before watching even 10 seconds of an "interesting one" before doing the same thing over and over again, so in effect you are buffering a lot more video than on YT.

They must have absolutely massive infrastructure.

[dimmke]

I feel like I always comment on TikTok posts on here, but FWIW this is something I noticed early on about TikTok as well - the app felt well put together. There's even a web app that it is way better than it needs to be if you go on tiktok.com

I believe the videos are actually 720p, that may only be on mobile devices though.

I have strong and complicated feelings about how good UX/UI needs to be in software. It often gets ignored especially in B2B settings, but there are certain times where it's so clear how crucial it was to get something right. I think about Spotify compared to Apple Music and how Spotify had a way of preloading songs so they played immediately that Apple Music never quite captured. TikTok definitely had the chops.

The one big technical issue I have noticed with TikTok as a user though, is that their comments go down a lot. It's clear that comments are handled by a different service and it seems way less stable. It's somewhat common to be able to load videos but trying to load the comments leaves you with an endless spinner.

[sippeangelo]

In addition to buffering the next 10 or so videos in your feed, they also only buffer the first few seconds of each of them (likely driven by an individual metric of how quickly users tend to swipe off them, or how confident the algorithm is that you’ll be interested).

[nateb2022]

TikTok runs on top of AWS, and uses S3 to store uploaded videos. Each uploaded video is copied into several resolutions, copies of which are made available on each regional CDN.