8 ms·

How Spotify Works

162 points by rythie 15y ago

SuperChihuahua 15y ago
One should also discuss their revenue streams. Here in Sweden, we pay 99 SEK (about 14USD) each month, and I learned yesterday that the artists only get 5 SEK from that 99 SEK. 60 SEK goes to the record companies... Source (in Swedish so please use translate): http://jardenberg.se/b/lite-mer-spotify-siffror-hur-99-kronor-blir-en-femma/ http://jardenberg.se/b/lite-mer-spotify-siffror-hur-99-krono...
- estel 15y ago
  That's just how the record companies work. There was an interesting breakdown from the CEO of Mog discussed his revenue model on this pretty good Fast Company article: http://www.fastcompany.com/1796382/mog-ceo-on-artist-payments-its-like-a-black-hole http://www.fastcompany.com/1796382/mog-ceo-on-artist-payment...
  - mbesto 15y ago
    Which is why their business model is now flawed. If you look at what a music publisher actually does. From wikipedia: "In the music industry, a music publisher (or publishing company) is responsible for ensuring the songwriters and composers receive payment when their compositions are used commercially. Through an agreement called a publishing contract, a songwriter or composer "assigns" the copyright of their composition to a publishing company. In return, the company licenses compositions, helps monitor where compositions are used, collects royalties and distributes them to the composers. They also secure commissions for music and promote existing compositions to recording artists, film and television."[1] So basically the publisher is getting money (a large portion of it) to make sure they get paid and provide contract negotiations. Spotify can easily (1) ensure the artist gets paid and (2) provide negotiations (you get X for Y amount of plays). The excessive overhead of the middle man is unnecessary now. IMHO, recording labels should just provide artists access to studios/producers/etc and become glorified marketing (music specific) firms. Also it might still be interesting for publishers to collect royalties for things like tv-ads, inclusion to movies, etc. But to the mass public it's a service that's no longer needed. Lots of business models are built on assumptions. The assumptions have changed. [1]- http://en.wikipedia.org/wiki/Music_publisher_(popular_music) http://en.wikipedia.org/wiki/Music_publisher_(popular_music)
    - dansingerman 15y ago
      Just like Amazon are doing to publishers. Middle men are getting disintermediated left right and centre.
    - mikeknoop 15y ago
      I've thought about this. We aren't really getting rid of middle men. Rather, if what you proposes runs its course, we are shifting the middle man from old media distributors to... new media (internet) distributors. What's to say streaming services wouldn't run up the price on artists once record labels are out of the picture? You could argue that artists could simply take their music to another service but if one service has A LOT of users (ie, Spotify) that might not be a viable option.
      - jakubw 15y ago
        Because streaming services wouldn't own rights to artists' work and they wouldn't be tying them down with multirecord deals. With these constraints lifted, there'd only be free market mechanisms left, which would force the services to be nice both to artists and users.
        danieldk 15y ago
        Or spread artists amongst competitive services, forcing us users to subscribe to multiple services. I'd rather take a copy of the music, and own the copy the rest of my life, thank you.
      - jiggy2011 15y ago
        I thought the main advantage of the record companies was that they could loan artists large amounts of money to make and market a commercial record. Most musicians I know are poor and would make pretty poor business people. Unless spotify or apple decide to go into developing artists themselves.
- ra 15y ago
  And that's why the record companies are in a downward spiral, and why they are fighting so hard against online markets for recorded music.
EwanToo 15y ago
Site seems a bit unreliable to me, timing out, so here's the original research PDFs that the article is based on http://www.csc.kth.se/~gkreitz/spotify-p2p10/ http://www.csc.kth.se/~gkreitz/spotify-p2p10/
mzl 15y ago
There is a newer paper than the one described in the linked article available (http://www.csc.kth.se/~gkreitz/spotify-p2p11/ http://www.csc.kth.se/~gkreitz/spotify-p2p11/) that has some interesting measurements on the network.
huhtenberg 15y ago
Since it's p2p and it's TCP-based, I wonder if they do TCP hole punching for NAT'ed peers - not that this is hard to do [1], but it is far less common than UDP hole punching. [1] Just need to predict the Internet-facing ports for both peers and then instruct them to connect() towards each other at these ports. The rest is handled natively by TCP, via the simultaneous open scenario [2]. [2] http://www.ietf.org/rfc/rfc793.txt http://www.ietf.org/rfc/rfc793.txt, sect. 3.4, fig. 8
- vektor 15y ago
  They don't do any NAT traversal, but that use UPnP to open ports. During a talk Gunnar Kreitz said that they still got a 60% success rate for connections (if I remember correct, varied between countries also). And that this was good enough for them. More can be read in this paper: http://www.csc.kth.se/~gkreitz/spotify-p2p11/spotify-p2p11.pdf http://www.csc.kth.se/~gkreitz/spotify-p2p11/spotify-p2p11.p...
  - tjoff 15y ago
    Since I'm NATing my network and don't allow UPnP the statement that they don't do any NAT traversal seemed suspicious since I know spotify does stream to other peers from my machine (400 MB since last reboot (13 days)). Got the answer from the paper: When a client wishes to connect to a peer, a request is also forwarded through the Spotify server asking the connectee to attempt a TCP connection back to the connecter. This means that as long as one of the two peers can accept incoming connections, the connection will succeed.
speedracr 15y ago
500 Internal Server Error. Google Cache: http://webcache.googleusercontent.com/search?hl=de&source=hp&q=cache%3Apansentient.com%2F2011%2F04%2Fspotify-technology-some-stats-and-how-spotify-works%2F&meta=&aq=f&oq= http://webcache.googleusercontent.com/search?hl=de&sourc...
dhruvbird 15y ago
very insightful. esp. the bit about how they use a combination of server based and p2p based streaming to ensure a seamless experience.
stef25 15y ago
"79% of server requests were for the most popular 21% of all tracks on Spotify." Pareto principle, bang on!
zbowling 15y ago
All this technology and Rdio is still growing faster around these parts. Guess amazing technology doesn't always help you win the game.
- Stuk 15y ago
  I guess you're in the US, Canada or Brazil, because Rdio isn't available anywhere else. But Spotify is, and is doing well.
- gregschlom 15y ago
  As for me, I switched from the French competitor Deezer to Spotify in a heartbeat, when Spotify's client totally blew my expectations with zero latency. So I guess it does help you win the game. But of course it's not the only factor.
- megaman821 15y ago
  I choose Rdio over Spotify because it has a web client which probably means they couldn't leverage p2p even if they wanted to (without using a browser plugin).
  - Zirro 15y ago
    That's interesting. One of the main reasons I use* Spotify is because it has a native client and not a web interface. *I'm actually currently in a period when I listen to music which is likely to never show up at any professional music service, but when I feel the need for mainstream music again, Spotify will probably be my choice for several reasons including the above, despite their recent Facebook-login only policy (which doesn't affect me, but still bothers me a bit).
  - eps 15y ago
    Is there any Flash involved? One of the biggest features in Flash 10 was the addition of p2p streaming.
    - chrischen 15y ago
MarkMc 15y ago
I've always been very impressed with the Spotify client - instant streaming, quick searching, responsive UI, never crashes, near-seamless version updates, automatic syncing. And cross-platform too! The guys that wrote it know their stuff.
- daleharvey 15y ago
  I was really surprised trying out the ubuntu client, I am used to very sub par implementations on linux but it was identical
  - jiggy2011 15y ago
    It's fine.. If you use pulseaudio, if you hate pulseaudio's latency and have falled back to alsa then suddenly the volume control doesn't work. Luckily the windows version works fine under Wine , even though it does nag about "unsupported platform"
  - waterlesscloud 15y ago
    I find when I try to share songs with friends via the linux client, my friends never have the songs in their inboxes. But when I send the same songs via the windows client, they show up with no problems.
  - Derbasti 15y ago
    I am not quite sure but I think I spotted pieces of Qt in the Spotify client. That would explain a lot of its somewhat odd behavior on OSX (wrong focus states on some buttons, nothing serious) and its very consistent cross-platform looks. In Germany, its only competitor uses an AIR app. Since Spotify is not available in Germany and thus a slight pain to use, I would really like to use an alternative. But AIR vs. Qt... the AIR app does not work on case sensitive file systems (solvable), it does not recognize the Mac media keys, it is sluggish and playback is nowhere near instantaneous. And you have to install AIR and suffer through regular AIR updates and the like. Oh, and audio quality is noticeably worse.
    - 15y ago
sudonim 15y ago
One of the reasons I canceled my spotify subscription is that I learned I was participating in a p2p network without my knowledge. If I'm paying for it, I don't want to be a node in their network. Most users are probably clueless about that because they aren't up front at all.
- efraim 15y ago
  Why does it matter?
  - naz 15y ago
    Because most home connections are asymmetrical, and even a small amount of upstream bandwidth usage can degrade the performance of everything else.
    - Zirro 15y ago
      I seem to remember reading that the speed is of your connection is tested, and the amount of data sent is customized not to slow your connection down.
- eps 15y ago
  > If I'm paying for it, I don't want to be a node in their network. You are paying for music licensing and you get the delivery for free because of the p2p nature of their system. Traditional client-server delivery would've simply translated into higher monthly fees, which I am pretty sure would've not been any more popular among their average user base.
  - nhangen 15y ago
    Perhaps, but I agree they should be more up front about the way they use bandwidth.
  - cnunciato 15y ago
    Rhapsody, Rdio, etc. all do client-server and cost the same.
adaml_623 15y ago
"Only 8.8% of music playback comes from Spotify’s servers. The rest comes from the peer-to-peer network (35.8%) or your local cache (55.4%). The exception here is Spotify on smartphones, which gets all the music directly from the Spotify servers." That point about doesn't quite make sense. Most of the time on my phone I'm playing from the local cache in off line mode. So it all comes from the servers originally but 98% of it is repeated plays from the local cache.
- vecter 15y ago
  I'm assuming they mean, of the actual bits that have ever been downloaded, where does it come from?
- estel 15y ago
  There's a distinction between songs which are from playlists explicitly "available offline" and songs in Spotify's cache. Presumably the mobile version doesn't have a cache for non-downloaded songs.
  - bookwormAT 15y ago
    I think the Android version does have a cache beside the offline playlists. At least there is an option to set the size in settings.
esmevane 15y ago
A curious bit about the P2P stuff - although it's clever as can be, it makes bootstrapping on lighter network hardware excruciating. Such a shame.
mcao 15y ago
Doesn't matter how amazing their technology is when they leave critical bugs in the client unresolved for over 2 years: http://getsatisfaction.com/spotify/topics/error_message_offline_access_for_this_computer_device_has_been_withdrawn http://getsatisfaction.com/spotify/topics/error_message_offl...
nollkoll 15y ago
the star coder of spotify. the guy behind their p2p is ludvig. creator of µTorrent. in many ways a remarkable engineer. only in swedish. http://chalmersalumni.files.wordpress.com/2011/09/ludvig_strigeus_fkraft_2011.pdf http://chalmersalumni.files.wordpress.com/2011/09/ludvig_str...
- lucaspiller 15y ago
  He was also the guy who originally reverse-engineered Transport Tycoon Deluxe which led to OpenTTD. :)
kkolev 15y ago
Seeing this link on HN reminded me to give Spotify a try. Going to their website reminded me that they don't provide a non-Facebook option. That's a shame.
cshesse 15y ago
How much bandwidth are they saving by making a P2P network? I made up some numbers and got about 30k$ a month at S3 prices, is that worth building and maintaining this P2P network instead of just a bunch of servers?
- eurleif 15y ago
  Even if it's only $30k/month now, P2P is infinitely scalable for (essentially) free. That's pretty valuable

162 points by rythie 15y ago

One should also discuss their revenue streams. Here in Sweden, we pay 99 SEK (about 14USD) each month, and I learned yesterday that the artists only get 5 SEK from that 99 SEK. 60 SEK goes to the record companies... Source (in Swedish so please use translate): http://jardenberg.se/b/lite-mer-spotify-siffror-hur-99-kronor-blir-en-femma/ http://jardenberg.se/b/lite-mer-spotify-siffror-hur-99-krono...

estel 15y ago
That's just how the record companies work. There was an interesting breakdown from the CEO of Mog discussed his revenue model on this pretty good Fast Company article: http://www.fastcompany.com/1796382/mog-ceo-on-artist-payments-its-like-a-black-hole http://www.fastcompany.com/1796382/mog-ceo-on-artist-payment...
- mbesto 15y ago
  Which is why their business model is now flawed. If you look at what a music publisher actually does. From wikipedia: "In the music industry, a music publisher (or publishing company) is responsible for ensuring the songwriters and composers receive payment when their compositions are used commercially. Through an agreement called a publishing contract, a songwriter or composer "assigns" the copyright of their composition to a publishing company. In return, the company licenses compositions, helps monitor where compositions are used, collects royalties and distributes them to the composers. They also secure commissions for music and promote existing compositions to recording artists, film and television."[1] So basically the publisher is getting money (a large portion of it) to make sure they get paid and provide contract negotiations. Spotify can easily (1) ensure the artist gets paid and (2) provide negotiations (you get X for Y amount of plays). The excessive overhead of the middle man is unnecessary now. IMHO, recording labels should just provide artists access to studios/producers/etc and become glorified marketing (music specific) firms. Also it might still be interesting for publishers to collect royalties for things like tv-ads, inclusion to movies, etc. But to the mass public it's a service that's no longer needed. Lots of business models are built on assumptions. The assumptions have changed. [1]- http://en.wikipedia.org/wiki/Music_publisher_(popular_music) http://en.wikipedia.org/wiki/Music_publisher_(popular_music)
  - dansingerman 15y ago
    Just like Amazon are doing to publishers. Middle men are getting disintermediated left right and centre.
  - mikeknoop 15y ago
    I've thought about this. We aren't really getting rid of middle men. Rather, if what you proposes runs its course, we are shifting the middle man from old media distributors to... new media (internet) distributors. What's to say streaming services wouldn't run up the price on artists once record labels are out of the picture? You could argue that artists could simply take their music to another service but if one service has A LOT of users (ie, Spotify) that might not be a viable option.
    - jakubw 15y ago
      Because streaming services wouldn't own rights to artists' work and they wouldn't be tying them down with multirecord deals. With these constraints lifted, there'd only be free market mechanisms left, which would force the services to be nice both to artists and users.
      - danieldk 15y ago
        Or spread artists amongst competitive services, forcing us users to subscribe to multiple services. I'd rather take a copy of the music, and own the copy the rest of my life, thank you.
    - jiggy2011 15y ago
      I thought the main advantage of the record companies was that they could loan artists large amounts of money to make and market a commercial record. Most musicians I know are poor and would make pretty poor business people. Unless spotify or apple decide to go into developing artists themselves.
ra 15y ago
And that's why the record companies are in a downward spiral, and why they are fighting so hard against online markets for recorded music.

EwanToo 15y ago

Site seems a bit unreliable to me, timing out, so here's the original research PDFs that the article is based on http://www.csc.kth.se/~gkreitz/spotify-p2p10/ http://www.csc.kth.se/~gkreitz/spotify-p2p10/

mzl 15y ago

There is a newer paper than the one described in the linked article available (http://www.csc.kth.se/~gkreitz/spotify-p2p11/ http://www.csc.kth.se/~gkreitz/spotify-p2p11/) that has some interesting measurements on the network.

huhtenberg 15y ago

Since it's p2p and it's TCP-based, I wonder if they do TCP hole punching for NAT'ed peers - not that this is hard to do [1], but it is far less common than UDP hole punching. [1] Just need to predict the Internet-facing ports for both peers and then instruct them to connect() towards each other at these ports. The rest is handled natively by TCP, via the simultaneous open scenario [2]. [2] http://www.ietf.org/rfc/rfc793.txt http://www.ietf.org/rfc/rfc793.txt, sect. 3.4, fig. 8

vektor 15y ago
They don't do any NAT traversal, but that use UPnP to open ports. During a talk Gunnar Kreitz said that they still got a 60% success rate for connections (if I remember correct, varied between countries also). And that this was good enough for them. More can be read in this paper: http://www.csc.kth.se/~gkreitz/spotify-p2p11/spotify-p2p11.pdf http://www.csc.kth.se/~gkreitz/spotify-p2p11/spotify-p2p11.p...
- tjoff 15y ago
  Since I'm NATing my network and don't allow UPnP the statement that they don't do any NAT traversal seemed suspicious since I know spotify does stream to other peers from my machine (400 MB since last reboot (13 days)). Got the answer from the paper: When a client wishes to connect to a peer, a request is also forwarded through the Spotify server asking the connectee to attempt a TCP connection back to the connecter. This means that as long as one of the two peers can accept incoming connections, the connection will succeed.

speedracr 15y ago

500 Internal Server Error. Google Cache: http://webcache.googleusercontent.com/search?hl=de&source=hp&q=cache%3Apansentient.com%2F2011%2F04%2Fspotify-technology-some-stats-and-how-spotify-works%2F&meta=&aq=f&oq= http://webcache.googleusercontent.com/search?hl=de&sourc...

dhruvbird 15y ago

very insightful. esp. the bit about how they use a combination of server based and p2p based streaming to ensure a seamless experience.

stef25 15y ago

"79% of server requests were for the most popular 21% of all tracks on Spotify." Pareto principle, bang on!

zbowling 15y ago

All this technology and Rdio is still growing faster around these parts. Guess amazing technology doesn't always help you win the game.

Stuk 15y ago
I guess you're in the US, Canada or Brazil, because Rdio isn't available anywhere else. But Spotify is, and is doing well.
gregschlom 15y ago
As for me, I switched from the French competitor Deezer to Spotify in a heartbeat, when Spotify's client totally blew my expectations with zero latency. So I guess it does help you win the game. But of course it's not the only factor.
megaman821 15y ago
I choose Rdio over Spotify because it has a web client which probably means they couldn't leverage p2p even if they wanted to (without using a browser plugin).
- Zirro 15y ago
  That's interesting. One of the main reasons I use* Spotify is because it has a native client and not a web interface. *I'm actually currently in a period when I listen to music which is likely to never show up at any professional music service, but when I feel the need for mainstream music again, Spotify will probably be my choice for several reasons including the above, despite their recent Facebook-login only policy (which doesn't affect me, but still bothers me a bit).
- eps 15y ago
  Is there any Flash involved? One of the biggest features in Flash 10 was the addition of p2p streaming.
  - chrischen 15y ago

MarkMc 15y ago

I've always been very impressed with the Spotify client - instant streaming, quick searching, responsive UI, never crashes, near-seamless version updates, automatic syncing. And cross-platform too! The guys that wrote it know their stuff.

daleharvey 15y ago
I was really surprised trying out the ubuntu client, I am used to very sub par implementations on linux but it was identical
- jiggy2011 15y ago
  It's fine.. If you use pulseaudio, if you hate pulseaudio's latency and have falled back to alsa then suddenly the volume control doesn't work. Luckily the windows version works fine under Wine , even though it does nag about "unsupported platform"
- waterlesscloud 15y ago
  I find when I try to share songs with friends via the linux client, my friends never have the songs in their inboxes. But when I send the same songs via the windows client, they show up with no problems.
- Derbasti 15y ago
  I am not quite sure but I think I spotted pieces of Qt in the Spotify client. That would explain a lot of its somewhat odd behavior on OSX (wrong focus states on some buttons, nothing serious) and its very consistent cross-platform looks. In Germany, its only competitor uses an AIR app. Since Spotify is not available in Germany and thus a slight pain to use, I would really like to use an alternative. But AIR vs. Qt... the AIR app does not work on case sensitive file systems (solvable), it does not recognize the Mac media keys, it is sluggish and playback is nowhere near instantaneous. And you have to install AIR and suffer through regular AIR updates and the like. Oh, and audio quality is noticeably worse.
  - 15y ago

sudonim 15y ago

One of the reasons I canceled my spotify subscription is that I learned I was participating in a p2p network without my knowledge. If I'm paying for it, I don't want to be a node in their network. Most users are probably clueless about that because they aren't up front at all.

efraim 15y ago
Why does it matter?
- naz 15y ago
  Because most home connections are asymmetrical, and even a small amount of upstream bandwidth usage can degrade the performance of everything else.
  - Zirro 15y ago
    I seem to remember reading that the speed is of your connection is tested, and the amount of data sent is customized not to slow your connection down.
eps 15y ago
> If I'm paying for it, I don't want to be a node in their network. You are paying for music licensing and you get the delivery for free because of the p2p nature of their system. Traditional client-server delivery would've simply translated into higher monthly fees, which I am pretty sure would've not been any more popular among their average user base.
- nhangen 15y ago
  Perhaps, but I agree they should be more up front about the way they use bandwidth.
- cnunciato 15y ago
  Rhapsody, Rdio, etc. all do client-server and cost the same.

adaml_623 15y ago

"Only 8.8% of music playback comes from Spotify’s servers. The rest comes from the peer-to-peer network (35.8%) or your local cache (55.4%). The exception here is Spotify on smartphones, which gets all the music directly from the Spotify servers." That point about doesn't quite make sense. Most of the time on my phone I'm playing from the local cache in off line mode. So it all comes from the servers originally but 98% of it is repeated plays from the local cache.

vecter 15y ago
I'm assuming they mean, of the actual bits that have ever been downloaded, where does it come from?
estel 15y ago
There's a distinction between songs which are from playlists explicitly "available offline" and songs in Spotify's cache. Presumably the mobile version doesn't have a cache for non-downloaded songs.
- bookwormAT 15y ago
  I think the Android version does have a cache beside the offline playlists. At least there is an option to set the size in settings.

esmevane 15y ago

A curious bit about the P2P stuff - although it's clever as can be, it makes bootstrapping on lighter network hardware excruciating. Such a shame.

mcao 15y ago

Doesn't matter how amazing their technology is when they leave critical bugs in the client unresolved for over 2 years: http://getsatisfaction.com/spotify/topics/error_message_offline_access_for_this_computer_device_has_been_withdrawn http://getsatisfaction.com/spotify/topics/error_message_offl...

nollkoll 15y ago

the star coder of spotify. the guy behind their p2p is ludvig. creator of µTorrent. in many ways a remarkable engineer. only in swedish. http://chalmersalumni.files.wordpress.com/2011/09/ludvig_strigeus_fkraft_2011.pdf http://chalmersalumni.files.wordpress.com/2011/09/ludvig_str...

lucaspiller 15y ago
He was also the guy who originally reverse-engineered Transport Tycoon Deluxe which led to OpenTTD. :)

kkolev 15y ago

Seeing this link on HN reminded me to give Spotify a try. Going to their website reminded me that they don't provide a non-Facebook option. That's a shame.

cshesse 15y ago

How much bandwidth are they saving by making a P2P network? I made up some numbers and got about 30k$ a month at S3 prices, is that worth building and maintaining this P2P network instead of just a bunch of servers?

eurleif 15y ago
Even if it's only $30k/month now, P2P is infinitely scalable for (essentially) free. That's pretty valuable