Ask HN: Techwise, how did TikTok get so good? | Hacker News Reader

Ask HN: Techwise, how did TikTok get so good?

147 pointsgardenhedge141 comments

You may like or dislike Tiktok based on it's content and style of delivering that content but I think everyone has to admit that technically it is quite the achievement.

It's video based and delivers video really well. It rarely buffers or fails to load. Compare that to the Reddit video player or the Twitter video player or Vimeo. It's much better. Netflix loads poorly initially for me quite a bit (granted it's trying to load much higher quality).

How did they manage to get the engineering talent when seemingly FB, MS, Netflix, Amazon, Google are all fighting for that talent?

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I don’t have any unique insights into TikTok nor do I use the app, but TikTok has several product advantages over those other platforms:

1. They only have a queue of videos. That means there is one video playing and they know exactly what the next N videos are going to be, so they can start buffering them early

2. The video plays are high intent. If you launch TikTok, you are 100% going to watch videos. This is not true for Reddit or Twitter, making it harder for them to preemptively buffer content or over-optimize their architecture just for video playback.

3. As you noted, the videos are lower quality and shorter than YouTube or Netflix videos. They also are exclusively optimized for mobile, so don’t need to worry about streaming videos larger than a phone screen.

4. Most videos in your feed might be a similar style. This one is a stretch but I wouldn’t be shocked if TikTok uses some ML to extrapolate highly compressed videos early in the buffer.

5. Depending on who you believe, ByteDance might have financial backing and motivations that make it easier to throw more money at this problem than its American competitors.

I wonder for me at least, why Instagram Reels is super blurry compared to TikTok, like since they should have the all the same conditions except for #5.

Instagram uses DASH (chunked, adaptive streaming) and starts playing with a low res, and aggressively compresses video. Tiktok's api just returns a bunch of different CDN urls for different MP4s of the video (HQ often being 576P CRF24), and the client loads whatever bitrate it has detected it can load without hiccuping.

This list is focused on videos but the search is what is beyond good, it's one of the best searches I've ever seen for content. You can literally use it as you would google. I'm assuming they transcribe their videos as well as run some object detection or image to text models that generate some metadata as to what is happening and or who or what is in a clip.

Lots of people tagging the videos in the background for better algorithmic access.

You are talkabout tiktok? The search is terrible. You can't order by date, no filters. Has this magically improved overnight?

You can't order by date or filter on Google either. I think the fact that young people use it over google as a search says something.

You can order Google News by date and Search (at least in a desktop view) can be filtered to only include results from the past hour, day, week, month, or year.

Actually, google's paid search API can order by date, ascending or descending.

Checkout this example:

https://quackquackgo.net/?q=hacker+news&lr=&qqg-date=&qqg-ra...

I love this! Often when searching for some event I want the first report, not the spam that followed. Thank you for showing me this service.

I don't understand how the dates work on that. On the search you linked, the first result is an HN post with a date listed as "2000-09-18", but if you click the link, the post was from 3 months ago.

This is probably because the HN page doesn't contain the document date metadata. So google just picked a random date from that page.

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.

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.

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).

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.

Even ignoring these things, they seem to do pretty well. I only use TikTok by being linked to it, and the video always works. The same cannot be said of Reddit, which often just shows a spinner, or sometimes it gets stuck midway through the video, or sometimes keeps playing sound even when you navigate to a different page.

I think Reddit is just especially terrible. They had to write custom code for handling the viewport autoplay, and ... I guess didn't implement everything else correctly.

YouTube has been fine for ages, though, and have great keyboard shortcuts that no PM would ever think to ask people to add. They just added them in 2008 and kept them all working through 5 versions of HTML. Not bad.

The worst experience for me is trying to play videos in the google photos mobile app (or the website). It can take 1-2-3-4 minutes (or never) for it to finally play a video I uploaded from my phone a few days, weeks ago.

Yes! I've had the same experience but forgot to list it in my initial post.

My god the google photos mobile app is oblivious, if I select a photo and make the mistake of swiping to the previous or next one, is game over for me, only a black screen awaits my despair. I have to close and reopen the app (same for web version) and then, only if I select the video/photo correctly the first time, after a lot of waiting, I can finally view my content.

The fact that they kept the keyboard shortcuts working is something like a miracle in tech

Expanding on point #4, the videos are much shorter than other platforms like say for example, YouTube, so for the same X minutes that a user watches or interacts with content, tiktok has more points of observation for what type of stuff the user likes and therefore can learn using ML much faster.

> ByteDance might have financial backing and motivations that make it easier to throw more money at this problem than its American competitors.

American VC can provide almost unlimited money. What it can't do is focus its spending on things that actually work.

The original question frames this in terms of technical talent, but it's not that at all. There are all sorts of US firms and even HN posters who could, given the right spec, come up with as good a solution for the problem of low latency smooth delivery of various videos.

No, the problem is choosing to make the right product. TikTok is good for the same reason that original Whatsapp was good: it had to succeed on its merits, rather than being part of a giant tech company. Whereas how many products has Google launched and then canned in that time? Was Stadia great technologically? Doesn't matter, it's dead.

Conversely, the Reddit video player on web is bad for the same reason that all the rest of the web app is bad: it's supposed to be, because of the dark pattern monetization that's supposed to force you into using the app.

I'm sympathetic but remember failed start ups that too are trying to succeed[0] on their on merits are a dime a dozen. It explains somethings but not why they succeeded.

[0]...or at least until being bought out by the big players you mentioned

I think the idea behind Tik Tok being good is that it was designed with tech goals in mind, unlike monetization in apps based out of US companies. My bet is that Bytedance is building generative models for video/audio for propaganda purposes (with the government involved of course), and Tik Tok is essentially their data set generator, so they designed the system for throughput from the ground up.

Last week I was travelling on a different country. I was mostly without WiFi and I bought a prepaid SIM card with some GB. TikTok ate 2GB of "background data" in two days, even if I did not open the app.

So it's not hard for me to guess how they do it...

(Yes, background data is now disabled for TikTok on my phone... I learned my lesson)

Won't be long before some cell plans have special discounts for TikTok data like with WhatsApp. Unless it's a thing already.

It's a thing, especially in developing countries. You often get xGB data with an additional xGB social media data.

Yeah, constant reminder not to take the wide-open internet for granted.

its already a thing in some countries. Operators in my country have unlimited packages for social media and streaming services.

Portugal used to have that, but I think they stopped it because the EU said no. Thank god.

> Compare that to the Reddit video player

This is worthy of it's own question. Why is Reddit's player so uniquely bad? It's worse than any other video player on the entire internet.

It’s serverless

For someone who doesn’t know much about this stuff, what does that mean?

It means it has no server.

Yes, no server. It runs somewhere up in the clouds!

Ignore them, it's unlikely they know what they're talking about at multiple levels

I took it as a joke about cloud marketing speak.

It’s my understanding that Reddit video was PoC’d by one person using aws lambda.

Severless often gets touted as being the best way of doing things rather than just a way. My comment was a dig at that.

But it seems like my comment somehow exposes multiple levels of ignorance, would love to know what they all are!

It was unclear to me that you were being tongue-in-cheek. Were you serious, I'd point out for starters that A. You probably don't know whether it's serverless currently and B. Even if it were it's not a particularly uniquely likely explanation for consistent latency at scale

Usually that it works via "functions" like aws lambda that don't maintain a long running process, but instead start a new process for every request.

my understanding is that in a serverless architecture the dev does not manage the server, there still is one but its managed via third party cloud services who expose basic server or database functions which your app can plug into.

think a "like count" database, it needs to increment and persist. Both very simple, and its implementation is entirely decoupled from the client implementation. Firebase would manage that for you, youd just call firebase functions instead of updating a database yourself.

note: i dont know if this is how tiktok works

Indeed. The behavior I've seen consistently is that the first N seconds play, then buffering starts, and it _never recovers from buffering_. And it has been this way for at least a year. Astonishing.

This is what I get on the second play.

Without fail, my experience is:

Play video. Usually works.

Try to replay video. It stops at 4 seconds.

Refresh browser. Now the video is half the size? But it now plays, though tiny.

I don't know who wrote Reddit's video player, but it's obvious they are a masochist. That they still haven't fixed it speaks volumes of their eng org to an end user like myself.

> The behavior I've seen consistently is that the first N seconds play, then buffering starts, and it _never recovers from buffering_.

It's why on the Desktop, at least, I always have a https://redditsave.com/ tab opened. It's just way faster (and less frustrating). There's an FF extension that automates this : https://addons.mozilla.org/en-US/firefox/addon/downloader-4-... : which I haven't tested.

*update, a few minutes later: decided to install extension. Looks useful. Now the testing phase...

The fun part is that they completely botched an experience that iOS can delivery natively. I built a mini app to extract the HSL stream from a URL and have iOS play it. It usually solves my problems with it: https://arte.vercel.app/

Is Reddit what engineering at scale looks like when not funded by a surveillance monopoly?

Or not funded at all, which is both its curse and its blessing.

Don't fret, surveillance is still baked right in. The video player is bad so that one installs the app, whose video player, and ability to spy on the user, is much superior to that of the browser.

The various ol., old., and i. subdomains, which still allow access to a functional reddit with a functional video player, are there to keep the old-school power users from revolting, for now, anyway.

They want to encourage you to use their mobile app

I'm using the same 3rd party Reddit app as I have been since 2013, and not only do videos work fine, I can download them to storage as well. Here's hoping Musk doesn't turn his attention to them anytime soon.

I've noticed that TikTok will show you unfamiliar content about every 10 or so videos. I suspect this is to explore it's knowledge graph of categories you might be interested in, and also keeping things fresh. I've found this mechanism fantastic, as it's shown me videos of places around my hometown that I've gone out to visit that I would have no idea even existed in the first place. This on top of a more traditional learning algorithm makes it very addictive.

If you compare this to YouTube, you can tell they've resorted their algorithm back to a more curated list of recommended videos. This blocks new content creators out and keeps the recommended list stale. You can also tell they've weighted videos with the highest ad revenue, so you're more likely to get frustrating long ads with vapid click bait style content. It's no wonder why YouTube lost the top spot of video sites, as they've put advertising ahead of content creators and viewers.

I've bought several products from TikTok ads. I usually never buy things based on online ads. Because their ads are skippable, and have to demonstrate their use instantly, they're very effective. Again, compared to YouTube, their ads tend to focus on long droning corporate agendas and visions. These don't make me want to use the platform.

A 1/10 ratio sounds like a sensible explore/exploit ratio to me.

Here you go: https://arxiv.org/abs/2204.12954 .. not from TikTok but some researchers who reverse engineered some network aspects. Thought the paper is well worth the read.

Systems research people are not valued enough .. my understanding is a bunch (not sure about number) of ex-MSR folks went to ByteDance .. sizable pay bumps.

Most people don't realize that mobile app penetration in China happened earlier and to a much greater degree than in US/Europe, because many people skipped the PC stage and went straight to mobile. Apps like Weibo, Weixin (WeChat) and Zhifubao (Alipay), were used by a very large percentage of the population. It was very rare to meet someone anywhere in China who didn't have Weixin on their phone (and I left in 2017 so probably even more now). Tech was very mobile-first. All that to say, Chinese companies like Tencent had tons of experience creating very full-featured and well-designed mobile apps that could handle a LOT of traffic given the sheer numbers in China. So while I don't particularly like or use TikTok, it doesn't at all surprise me that it is so slick. People assume ByteDance was a new company but its Toutiao news aggregation app was extremely popular in China before it bought/merged Douyin + Musicaly to create TikTok.

People have answered about the inherent easiness of preloading videos. It's still a challenge. Users skip videos very frequently, right? And when you first open the app, it already has a video playing. Twitter's video player seems worse than it should be. Netflix has a harder job due to the quality, so I give them a pass.

IIRC TikTok for a long time wasn't even using TLS encryption for client-server traffic, which is rare. Whoever is cutting corners like that is very focused on just making the thing work and fixing the issues later, which has its pros and cons. In a US big tech company, experienced devs would throw a fit over things like this and slow down the project to catch those details. I work with people like that. I'm guessing (as not a TikTok employee) that TikTok is more top-down, plus video is its main focus. Maybe they're preloading aggressively, user's battery and data plan be darned.

If they weren't using TLS, I'd guess that this wasn't cutting corners but rather intentional to help caching. Ten people watching the same video can get the same data packets, ten people watching the same video over TLS have ten data streams with nothing in common.

TLS is usually terminated at the CDN, isn't it? I actually don't remember. If so, it's not a problem for caching.

Yes.

CDNs usually cache the plaintext object rather than the encrypted stream. What I’d believe is that they started with a CDN which charged more for HTTPS support - I believe they used Akamai at one point, which would make sense since they had some of the best presence in China in the 2000s and into the 2010s and DEFINITELY charged noticeably more for HTTPS unless you could negotiate well.

It used to be not uncommon for some ISPs and corporations/schools to run transparent caching HTTP proxies. I don't know how much of that still exists, but anything helps.

One of the benefits of HTTPS everywhere was breaking the bad versions of those systems: I remember Vodafone ES having one which cached resources far longer (months) than the Cache-Control headers allowed, and mobile ISPs used ByteMobile to over-compress images.

You still see opt-in proxies, which are at least better in the sense of the user being able to see the config & trust relationship when something breaks.

Yeah, feels good not having the ISP mess with that anymore.

To write something obvious: companies generally don’t succeed or fail based on their technology. A good user experience is necessary for TikTok to do well but it doesn’t matter whether they achieve because of ‘good’ tech, whatever that is, or in spite of it.

I think there were a few things for the business where tech was important:

- being good at serving/storing videos

- the recommendation engine. There are two parts, one is taking user preferences as a strong signal (not a tech decision) and another is recommendation algorithms which produce this effect (I think they’re rote a paper that suggested things about how this worked)

- being an app people wanted to use (weakly tech but mostly not)

I think a some of the explosive growth came from the app having been iterated on a bunch in China first so it seemed more polished when it reached the west. But I could be pretty wrong there.

To answer the question about engineering talent:

- Chinese people will go to the US, get great educations at US universities, some get denied work visas or otherwise choose to return to China. TikTok can employ them in a less competitive labour market and not fight companies like Google which don’t operate in China.

>But I could be pretty wrong there.

The history of TikTok is actually murkier than that. I listened to a podcast about this, I wish I could find it again. The narrative that seems to be popular is that ByteDance launched this app called Douyin in China and it was so successful they decided to launch it globally, and thus TikTok was born and hit the ground running.

But the podcast I listened to told the story from the perspective of the founders of Musical.ly - which was an app that was started by two Chinese software engineers that were living and working in silicon valley. Originally it was supposed to be a video app about teaching (?) but pivoted and gained a lot of traction with teenagers in the U.S. This is where the origins of TikTok being thought of as a "teen dancing/lip syncing app" came from. Musical.ly got acquired by ByteDance.

- Douyin launched in September 2016 - Musical.ly launched in 2014 and by June 2016 had over 90 million registered users. Around 2016-2017 is when I first remembered seeing videos with the Musically watermark (very similar to the TikTok mark) usually on r/cringe on Reddit. Here's an example: https://www.youtube.com/watch?v=rfT0jRYaovE - ByteDance acquired Musical.ly for almost 1 billion dollars a year after launching Douyin and merged them to create TikTok.

I never used Douyin or Musical.ly, but I think that a lot of Musical.ly's DNA was injected into TikTok and the idea that TikTok was a purely Chinese invention is a little revisionist.

The thing that really cements this to me is that Alex Zhu, one of the Musical.ly founders was the first CEO of TikTok. Also, looking at the type of content in those compilation videos definitely gives me the same vibe. So TikTok actually has roots in silicon valley way more than people think it does.

I think that noting this history is interesting because TikTok is touted as being so purely Chinese, and it's certainly owned entirely by a Chinese company now so I'm not saying any concerns about the Chinese government having access are unfounded. But I think part of the fear around TikTok comes from "How did they create this app that is beating our apps and seems to have the product/market fit of a glove in our society? Have they been planning this?"

But a lot of the iteration and pivoting happened with Musical.ly, in the U.S. and a Chinese company paid through the nose for it.

I thought this was common knowledge but I guess not. But then again I lived with my preteen siblings when the whole musically/TikTok merger happened so for them it was huge news

It's definitely not common knowledge- especially for people who don't use TikTok and only became aware of it in the last 2-3 years.

And I actually think it benefits the Chinese government for this revisionist history of the app to be the story that "wins" - because it portrays China as this mysterious force with previously unknown insight, power, and plans. When in reality the bones of TikTok came directly out of the same place as most new social apps do.

If you look at the Wikipedia article for Musical.ly - it goes through great effort to talk about how it was a Chinese company that happened to have a "Santa Monica office" but if you look at the Crunchbase profile for Musical.ly - the story is different. https://www.crunchbase.com/organization/musical-ly/company_f...

The companies that participated in those funding rounds are not blue chip VCs and do have foreign ties - but they are specifically focused on investing in US startups.

I would love to see a journalist at The Verge or somewhere that writes about tech in the same way tackle this topic. I think it's a missing piece in a lot of the discourse around TikTok.

> "TikTok can employ them in a less competitive labour market and not fight companies like Google which don’t operate in China."

Is this really true though? I imagine the market for SDEs in china is much more competitive and cut throat. There are only so many locals/immigrants to choose from in the US, hence the higher salaries. A lot of top talent in Silicon Valley have almost worked at all FAANG companies.

Competition between employers, I think.

I would say the Chinese market is MUCH more competitive than the US market. Do a few searches for the salaries of AI/engineers. Just because Chinese companies don't operate in the US doesn't mean they are small.

Half their country isn't up to US middle class standards yet, they still have plenty of cheap labor to acquire.

TikTok has offices all over the world and competes for SDEs in the traditional places like Seattle and San Francisco: https://careers.tiktok.com/position?keywords=&category=67098...

Any FAANG engineer or someone who looks at job postings in those areas would know this. The comments I see about TikTok on Hacker News in general are so much more low effort, low knowledge/low research than other areas it is genuinely concerning to me. There's so many blanket assumptions that go unresearched, unchallenged. It's bizarre.

I think a large number of HN comments are low effort/totally wrong in a lot of areas (including some of mine). I haven’t noticed this being particularly the case for TikTok but I do notice it more for subjects I know more about.

What sold me on Tik Tok (I'm a early 40 year old guy!) was realizing how their algo allowed you to drill in to a musical emotional trip like no other platform that I've seen to date.

You find a video, with a song, that you vibe with. Now, click on the bottom right sound graphic and you can watch ALL the videos produced with that sound and vibe.

It is part of the core product!

So good it's hard to describe :)

I also love how a creator can respond to a comment with another video and you are able to read the comment and click it in the new video to go back to the original comment and video they are responding to. Same with stiches and duets.

I think old YouTube had a similar feature, but killed it to become "the next cable tv"

I think technologies wise TikTok is similar to that of Youtube Shorts

Both seems to preload about 10 secs of next 4-5 videos.

I think here is the trick: if your recommendation gets sufficiently good, then user won't eagerly scrolling next just to get content they would actually watch, which makes serving less of noticeable problem. There is a feedback loop here.

On TikTok I rarely gets content that would skip at first sight, which speaks to strength of its algorithm.

Don't know about Reddit/Twitter, but Netflix's video is a whole different business overall, all the DRAM and stuff.

YouTube Shorts don't seem to operate on the same level as TikTok. Maybe I have a unique experience but every time I look at YouTube Shorts, it's literally the same batch of videos in the same order, day-to-day.

Same here. Same videos shown to me for weeks

TikTok’s parent co, bytedance, has multiple social video products in China. They have been genuinely investing in being good at serving and recommending video for a while.

If you search arxiv.org for bytedance you can see some of the work they have published. I’m sure there is lots more they haven’t.

I suspect a lot of learnings from other products went into the product design of tik tok as well in terms of how to balance exploiting a users knon interests with showing them novel stuff, how to give anything the chance to go viral etc.

It's hyper focused on the feed that is just videos' that it determines for you. Therefore it is able to prepare and buffer multiple videos ahead.

I also think that for the public feed, people so see similar videos based on demographic etc so there is a form of caching that is likely applied.

Videos are all small clips as well and they're being loaded from TikToks content servers. With reddit and twitter you are often watching a video linked from another website.

I agree, Reddits video player is garbage.

"It rarely buffers or fails to load" this is because the next 6 or so videos are known and buffered ahead of time. This isn't really the case on other sites.

You load a feed on Twitter. It knows what videos are coming up. You open a page on Reddit, it knows what videos are in the first few pages.

But Twitter/Reddit don't know if you'll play the videos, meanwhile TikTok can assume you will, so can already fetch them from the server.

You might skip the TikTok ones or not reach them. Every time you close the app or change contexts, it probably wastes ~5 preloaded video intros. Reddit and Twitter could do the same. It's not necessary to load the entire video, just the first few seconds. But since video isn't the main focus of those, I can see them not feeling the need to optimize it so much.

I think Twitter's video servers are also just slow.

There's a trick with Spotify, where they buffer a few seconds from expected next songs and load the rest once it picks which song is next. You can test this by cutting off internet, then pressing next song at the same time.

They featured this on the show The Playlist. Really fun show btw

I’m just going to answer this last part:

> How did they manage to get the engineering talent when seemingly FB, MS, Netflix, Amazon, Google are all fighting for that talent?

China is both a huge labor market along with the largest mobile phone market in the world. Add to that fact that the great firewall has created a parallel internet, it’s been fairly inevitable that China will end up with some tech giants. Even with all the money that American tech giants have, they are at a disadvantage when it comes to tapping the massive labor market and consumer market within China.

Note that the same thing is happening with EVs. In ten years, the auto market will have several dominant Chinese automakers a la what happened with Germany and Japan in the 70s and 80s.

Also the elephant in the room is that by design, Chinese companies aren't constrained by BlackRock's ESG rating. Western companies have to devote significant resources to "diversity, inclusion, and equity" while Chinese just hire by meritocracy. I bet they wake up and go to bed laughing at our ridiculousness.

I’m not sure that major tech companies are all that heavily driven by esg ratings, but you’re definitely correct that there’s a difference in work culture.

Chinese tech is notorious for the 996 work schedule, that wouldn’t fly in the west.

They have a gigantic pool of talented engineers to hire from in China.

This paper by various folks at Bytedance hints at their recommender architecture: https://arxiv.org/pdf/2209.07663.pdf

I'm amazed they are publishing anything about it. It would seem like that's an important trade secret.

new companies have structural advantages.

amazon for example is services architecture. many frameworks and solutions built once for shopping/seller use case. now you want to join Y space? incentive to reuse tooling and framework that already exist. get to market quickly. sound like big advantage but the tools were built for problem X. with problem Y, we have hacks on top of hacks to fit square into circle.

“you want to build mobile apps? okay. we only know how to do services really.” so even how you build code or how to branch and release strategy missing or expertise is only in some specific business division who did everything so custom when they invent it first time that it not really work for you.

so if you observe you company like amazon try do 100 different things at once. sound good and impressive and stock grow. but 98 thing executed very poorly and not close to best in class experience.

this my exact experience at two different company.

once you get over these problem, then u focus on optimization. N second videos? Okay.. let’s preload them..let use lower resolution..let’s have warm cache of recommendations if you like this vide, meaning you watch it for greater than S second..let invest in custom recommendation pipeline with online and offline training to expand dataset of video recommendation so u eyes stay on a video longer while we preload next one.

because we smaller nimble build what we need now without politic of tech alignment across orgs and ownership territory battle going up to separate director or VPs.

this me experience and me sure there are other things too.

Compared to Netflix and even YouTube, TikTok has an extremely tight dopamine feedback loop. Any buffering of a video after a scroll event could result in the user's attention being lost and the session ending. My guess is that they've spent a lot of time optimizing video load because of how correlated with their revenue it is. For Netflix doing this optimization might not be worth the increased infrastructure cost.

No one mentioned the UX design of Tiktok?

From what I can recall, TikTok was the first one to let you to swipe to watch/switch videos, so users can easily be stuck on it, no matter the short video's quality is good or bad, interesting or boring. Since one single swipe, you changed to another, the cost is very low for user even the video quality is not good.

Vine? Musical.ly?

I think it's eastern tech culture. East tends to assume everyone is interchangeable and not as intelligent, and tries to bring people up via education. Whereas West tends to just hire talent and let them figure it out.

Not everyone here speaks a common language, and if it is, it's almost certainly English. So documentation and communication is greatly simplified, smaller words, and a lot of conversing through code.

Let's compare two mature technologies between east and west, Google Maps vs Huawei Map SDK:

Google map quickstart: https://developers.google.com/maps/documentation/android-sdk...

Huawei map: https://developer.huawei.com/consumer/en/doc/development/HMS...

There's subtle differences here, but Google tends to use a lot more English words, and Huawei talks mostly in code.

System analysts are common, who act as living documentation. Basically people who you can always interrupt to ask questions. PM isn't sure if a feature is possible? Ask the analyst. Dev doesn't know the right endpoint or understand how something works? The analyst takes time to explain it to them. They generally don't hold the responsibility of development and during periods of low utilisation, they learn the architecture or do R&D.

In MMOs, they would be the tank, while the devs focus on being DPS.

So personally, I think the key is that they rely less on the skill of the individual, and focus heavily on teamwork. Also this is probably an analysis of Huawei more than ByteDance/TikTok, but I assume the culture is more similar.

> There's subtle differences here, but Google tends to use a lot more English words, and Huawei talks mostly in code.

I learned how well code speaks when working with remote web/mobile app contractors who hardly spoke English and had a 12hr time difference. If they didn't understand something right the first time, it could cost a day of progress. I started giving them code or cURL examples on how to use every backend call I implemented, often using multiple together. We ended up better oiled than some fully-localized teams I've been on.

Now I just work with other Americans in the Google offices, and I've seen success focusing our internal communications and docs more on examples. I often complain about how many English words our docs have, both internally and with customers. Nobody cares what my thing is or what philosophy it follows, they care how to use it. And like TikTok videos, brevity helps.

However, I don't think this explains TikTok's ability to load videos quickly.

I was mostly answering that last question, "How did they manage to get the engineering talent when seemingly FB, MS, Netflix, Amazon, Google are all fighting for that talent?"

which I think is a false assumption - they don't need as much engineering talent, they do more with less.

Oh yeah, they probably do. FAANG can throw really expensive engineers at simple problems and still get bad results, or they can accomplish great things.

Reddit is not a great comparison. It looks like the video elements of reddit were cobbled together quickly and just left in place since it sort of worked. It won't annoy too many users when most content doesn't use reddit's video player.

If TikTok did this, 100% of it's users would be affected.

I think most people here are vastly, vastly overestimating the size of the videos with all this talk about buffering in the comments.

The average video on tiktok, at least for the webapp version, appears to be around 1 megabit (0.125 megabytes) per second when the h264 option is used, and only half of that rate when using ByteDance's 'own' (essentially hevc) format.

I would reckon nearly all internet users, even many mobile ones, have more than enough bandwidth (and low enough latency and loss) to stream many of these tiktok videos in real time simultaneously, let alone a single one at a time.

Tiktok's backend infrastructure may be impressive, but the same could be said for the other companies you listed such as Google.

I don't think feeding those videos is a terribly hard engineering challenge for Engineers who are organized and are backed with the right financing. And who for one reason or another seem to be motivated to work almost 7 days a week.

Reddit is crap because of organizational history, and it's no a huge revenue-rich company, in a market with very high salaries.

TikTok has a a few magic ingredients, but 'dancing girls' as a starting point is one of them, the other is the learning algorithm. BTW I do not think that algorithm is magic - just good.

If you see how some Chinese companies have so many focused people and adapt so reactively to things, and they're backed by ample money.

Disclaimer: speculation

TikTok is a Chinese company. The source code is mostly written in China. I'd say that TikTok is the Chinese equivalent of a FAANG company.

They get the talent because the fight is happening in the FAANG space, they are not there.

Most of the tech jobs are not in China: https://jobs.bytedance.com/en/position?category=670421586260...

Chinese FAANG is probably geared more towards hardware, things like Xiaomi and Huawei.

Yes, they are. That's a link to the English language site, and it shows 310 openings under the R&D category.

Click the link for "Careers in China" in the footer and filter by R&D: 6526 job openings.

https://jobs.bytedance.com/experienced/position?category=670...

That was a perfect example of selection bias, lol. Thanks.

Heh, I only went and poked around because it has bitten me before. It seems to be a pattern with a lot of Chinese companies to have their own domestic facing sites, and then an entirely separate Western-facing presence.

I'm curious about this as well. Specially how their videos barely buffer and almost instant. you could say that they can preload them cause for you is mostly VOD, but they have live as well and it may not be as instant. its still feels pretty instant no matter how fast you scroll. I don't know how to inspect their app but their website version is using video/x-flv progressive download for playback. which surprised cause

1. I thought flash was deprecated by the browser and

2. I thought the industry has moved onto HLS/Dash or stream via websockets for live streaming.

> 2. I thought the industry has moved onto HLS/Dash or stream via websockets for live streaming.

Industry consensus doesn't mean best performance, unfortunately. Maybe it means works well enough for existing participants, but going your own way can be more efficient or less efficient, or a waste of time. Industry solutions tend to take more round trips in search of flexibility, and number of round trips is a big factor in download time if the round trip time is large, as is common on mobile.

HLS at least adds significant latency because it involves multiple round trips before you can get the first frame:

- request top level playlist (choice of bitrates, etc)

- request playlist for a particular bitrate

- actually request a segment with some frames in

In buffering, the first 20 (N) posts are pre-determined and can therefor be buffered when still on the first video. What I find amazing is their extremely accurate recommendation page that keeps you hooked to the application. Honestly I needed to delete it after the first week since I spent so much time on it.

How big is a typical TikTok video compared to a Vimeo one? And if "buffering" is your problem, perhaps it's caused by something other than the company serving the video.

Big in what way, resolution or length? I'm sure Vimeo can serve lower-resolution, and the length of the video doesn't affect how quickly it can buffer.

It's simple, they don't use their smartest developers to work on intrusive ways to bother the user with ads. They work on serving content to users instead.

Quite simply, TikTok is using (and paying for) A LOT of traffic. That allows them to cache the first X seconds of the next Y videos. If you choose the values correctly, it takes you longer to swipe up Y times than it takes them to cache the Y+1 th video, on average.

I'm sure if Reddit had government-level funding to burn, they'd also find some ways to improve their video player.

I think it preloads a shitload of stuff ahead, before you deciding to watch it. Predictive caching.

Engineering talent is historically mostly China based, and over there they can get Silicon Valley quality people for half the price and twice the working hours => order of magnitude engineering cost advantage over all the companies you mentioned.

I'm curious how cloud they are. Maybe they have an advantage by starting after the maturity of cloud platforms, using the latest and greatest, and avoiding all the redesign cycles? Or maybe they don't cloud at all and that is their advantage? Or maybe that has nothing to do with it.

> Compare that to the Reddit video player or the Twitter video player or Vimeo. It's much better.

The difference between TikTok and e.g. Reddit is that on TikTok the user wants some video, whereas on Reddit the user wants that video.

> How did they manage to get the engineering talent when seemingly FB, MS, Netflix, Amazon, Google are all fighting for that talent?

By hiring people in china? Not everyone wants to move to the US.

tiktok has exactly one video format, and the videos are small and can compromise on quality because they’re intended to be viewed on mobile. processing becomes a lot easier when you only need to transcode to one format. and also it’s a linear feed, so they can preload the next videos ahead of time. just open up your browser console and you can see for yourself how big each video is and their preloading.

i definitely wouldn’t call this evidence that their tech is good though.

There videos are tiny so buffering is less of an issue

A product being viral doesn't mean it's good, it's just sufficient for the usage.

never before seen so much cope in a HN comment section. lmao

Is the tiktok tech REALLY that good?

i don't know if TikTok's tech is that good or not, but it seems apparent that silicon valley was unable to compete with it until we got even more-massive direct assistance from Uncle Sam and other government entities.

Yep, YouTube had no real competitors until TikTok came out. Get too comfy, and this is what happens.

Then how come instagram's Reels (a copycat product) works as fast, as efficient and with the same kind of UX?

Are you saying instagram got "massive direct assistance from Uncle Sam and other government entities"? How would you even come up with that opinion?

did uncle same shut down reels too? i didn't see that.

Remember Vines?

As they say, "Good artists copy, great artists steal"...

Being headquartered in a jurisdiction that doesn't care for intellectual property sure must be convenient.

> Being headquartered in a jurisdiction that doesn't care for intellectual property sure must be convenient.

Like… YouTube with their shorts?

A continuous, infinite scroll stream of $media is everything but an original invention, and most likely not protected by any IP law.

Or Instagram reels, or Snapchat…whatever they call it that’s basically also a TikTok clone. It’s ironic that Meta is suing Snapchat for infringing IP when everyone and their brother ripped off the vertical video UI.

https://youtu.be/Km5XQxRrQvw?t=46

Difference is that Twitter threw Vine away...

Because while FB, MS, Netflix, Amazon, Google went woke, chinese look for talents.

And you probably haven’t seen other chinese apps like xiaolongshu - it's algorithms are amazing in showing you content of your interest. Ethically there may be some compromises across, but it does great things.

Here is your answer from a book called The American Trap:

Americans are very proud of their "process". ... Americans love their processes. In their jobs they rarely express their creativity. Conversely, they expend a lot of energy and time adhering to their processes.

Maybe?

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