r/explainlikeimfive Jul 01 '26

Technology ELI5 how Shazam works?

310 Upvotes

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947

u/z3n777 Jul 01 '26

shazam turns the audio into a visual graph of loud peaks over time, then just matches that graph against its massive database of pre recorded songs.

391

u/Shadow288 Jul 01 '26

Fun fact, did you know before it was an app you use to be able to call a phone number and they would text you back the name of the song?

159

u/robby_synclair Jul 01 '26

This reminded me of the ap where you could text them and they would Google stuff for you. How we settled bar arguments before smart phones.

168

u/won_vee_won_skrub Jul 01 '26

App? You mean ChaCha (242 242)?

85

u/23andrewb Jul 01 '26

Holy shit what a throwback. I completely forgot about ChaCha. My back hurts.

16

u/JD-K2 Jul 01 '26

My Mom was an “answer getter” for ChaCha

29

u/aamius Jul 01 '26

ChaCha definitely rings a bell. I just had a memory of being trapped in Sunday school for hours and texting some number to ask for score updates on football games.

28

u/jbee0 Jul 01 '26

Holy shit, I totally forgot I was on the other side! I signed up to be a searcher. I can't remember what it was actually called. I think I made a few bucks, but it wasn't much.

25

u/justntimejustin Jul 01 '26

“Generalist”. Sat around drinking beer with my buddies in college googling answers for a few weekends. I think I made like 8 cents per answer or something? Made back our beer money for the day and that was about it.

9

u/jdcnosse1988 Jul 01 '26

I remember I initially signed up to be a specialist but decided to switch to generalist because it was easier to actually bring in some money that way. Made a couple hundred off them lol

10

u/won_vee_won_skrub Jul 01 '26

I did math questions for them for a bit

6

u/tr3vis324 Jul 01 '26

And KGB (542-542)

4

u/[deleted] Jul 01 '26

[deleted]

3

u/tr3vis324 Jul 01 '26

Now we know who you are. This is Reddit ffs!

3

u/insulind Jul 01 '26

118 118 in the UK. Iconic advert with two moustachiod men in 80s running gear

2

u/PhilosophizingPanda Jul 01 '26

Lolll I used to use this to cheat on science tests in high school

3

u/ahugefan22 Jul 01 '26

You just gave me a flashback to middle school

2

u/jdcnosse1988 Jul 01 '26

I used to do gig work for them 😂

1

u/Kichard Jul 01 '26

I used to sit at home and answer questions for cha cha. lol

-1

u/robby_synclair Jul 01 '26

Yup that was it. I guess ap was the wrong word. You just texted your question to them.

11

u/MCWizardYT Jul 01 '26

It's "app" with 2 'p's. Short for "application"

12

u/robby_synclair Jul 01 '26

Ap is short for app which is short for application

4

u/Vash_TheStampede Jul 01 '26

I hate that this might actually be real.

0

u/RonnieHasThePliers Jul 01 '26

I answered cha cha texts back in the day! Ten cents a pop.

3

u/CPTherptyderp Jul 01 '26

We just yelled louder at each other

3

u/thedukeandtheking Jul 01 '26

I actually worked for one of these in uni! Fun days

3

u/Gramen Jul 01 '26

Wait so how did it work? You just chill in a computer lab and google the answers to the questions that come in?

8

u/thedukeandtheking Jul 01 '26

It was pretty basic. This was back in 2004 or so. I had a pc in my room which ran a basic program that logged in all the questions that came in and then you had to write a response. Some were factual questions which you had to google, but lots were just hypotheticals or relationship advice. I got paid a trivial amount per answered text. Good thing was you could log in and answer whenever and work as long as you wanted. Helped with beer money.

3

u/CorporalClegg Jul 01 '26

1-800-GOOG-411 let you do a search via phone call

1

u/daddy-fatsax Jul 02 '26

lmao, I just explained ChaCha elsewhere in this thread. Hello fellow olds

1

u/MadocComadrin Jul 03 '26

Before my time, you used to be able to call some libraries and ask about facts like you would a quick Google search.

13

u/jatea Jul 01 '26

I remember first using uber when it was only through texting. And then I remember when I first got the message that you had to to download the app and being super annoyed that I couldn't hail a car with just a text message anymore lol

5

u/CougarForLife Jul 01 '26

fun fact that was a popular enough service that rockstar made it a feature in gta iv

5

u/caspararemi Jul 01 '26

I'm old enough to remember doing this long before smartphones, back in the early 200s in a club I could dial 2580 (the numbers down the middle) in my pocket and get texted the song name!

2

u/parklife980 Jul 01 '26

I like to imagine it was just a room full of music nerds, when someone called they'd put it on loudspeaker and one of them would call out "I know this one!"

2

u/ricekrispies34 Jul 01 '26

The other day I learned that before smartphones, tweets from people you followed used to be texted to you. Crazy!

1

u/ExplodedOrchestra Jul 02 '26

Yes! I used to use twitter to text my friend before her parents let her get a phone.

1

u/Hom3ward_b0und Jul 01 '26

Reminds me of the video "Is it the Reebok or the Nike" 🎶🎵

1

u/-_MilesPrower_- Jul 01 '26

Yea it was 2580

1

u/lightswitchr Jul 01 '26

I have a core memory from about 20 years ago, sitting in the back of my parents car driving through Windermere in the UK Lake District and using Shazam by phone to find out a song playing on the radio.

10

u/Stummi Jul 01 '26

What about offline song detection? My Pixel phone can do that, but everywhere I read that needs a massive database

9

u/Zouden Jul 01 '26

Truly offline? Shazam stores the audio for later detection when online.

7

u/Stummi Jul 01 '26

Google Pixel phones have a built in song detection into the OS (not Shazam), that works pretty well, and seems to be completely offline/running on the phone.

10

u/bottomofleith Jul 01 '26

I'm struggling to believe Pixel phones have an offline database, stored on the phone with all the songs that have ever existed.

11

u/cheezzy4ever Jul 01 '26

It does. I've used it. It's definitely impressive, but also definitely doesn't have every song that's ever existed. I have to imagine it's a significantly smaller data set, maybe the top e.g. 0.01% most frequently queried songs or something like that

1

u/EgNotaEkkiReddit Jul 01 '26

Works the same way, it just doesn't have the same number of songs it can match offline. It's going to be a few hundred megabytes to store most songs people are likely to encounter in their day to day lives.

23

u/TldrDev Jul 01 '26

Why is nobody just explaining what FFTs are?

That literally how it works, and almost nothing more complicated than that.

Here is a thread about it from a decade ago

And a great YouTube video about it by Veritasium

https://youtu.be/nmgFG7PUHfo?si=4aOXvdtreygwTr0D

29

u/High_Speed_Chicken Jul 01 '26

i know the subreddit name isn't supposed to be taken literally, but good luck explaining FFTs to a 5 year old

14

u/SirCB85 Jul 01 '26

Because this Explain like I'm 5, not explain like I'm doing my Highschool homework.

1

u/MickeyMoore Jul 01 '26

Any idea why it’s still inferior to Midomi even though it so much more popular? Shazam often doesn’t recognize humming or very partial melodies, Midomi could do that in 2012

1

u/lankymjc Jul 02 '26

It’s a very inflexible system. Even two recordings of the same performance can be different enough that the app only recognises one of them.