May 13, 2013 at 3:20 pm

Spotify Uses Different Audio Formats Depending on Platform

Downloadify (icon pictured here) allowed Google Chrome to rip music from Spotify's web player.

Last week, CNET reported on an extension for Google’s Chrome web browser that let people scrape songs off of Spotify’s web player, for free, and save the music as MP3 files. This was obviously fairly problematic and possibly illegal, as far as browser extensions go, so Google hastily deleted the app from its Chrome app store in short order, and then Spotify closed the loophole.

We did learn something from the brief saga of Downloadify. The app let people save music from any web-embedded Spotify playlist as MP3s, which indicates that Spotify is streaming MP3s, rather than the Ogg Vorbis format it sends to the desktop. (Downloadify could have been transcoding the files, but we doubt that, in part due to Spotify’s response to our inquiries, and in part because that would have required more work and probable patent-licensing by Downloadify, whose creator was apparently just trying to make a point, not create something for people to use forever).

According to Spotify’s FAQ, Spotify streams the open-source Ogg Vorbis codec, rather than MP3. That appears to apply only to the desktop, or at least not to the web player, where the music appears to be in MP3, which has cost implications (see below).

Well before Spotify launched in the States, I suggested to Spotify co-founder and CEO Daniel Ek, that even the people who built Ogg Vorbis thought commercial companies would shy away from it for patent concerns, so Spotify might want a back-up plan behind Ogg Vorbis. The problem: Over 20 patents apply to the MP3 codec, and some of them might cover stuff that Ogg Vorbis does — even obvious stuff like losing frequencies outside of the human hearing range.

He said he wasn’t worried, because Spotify could easily switch formats — and it looks like that’s what has happened, in the case of the web player anyway, albeit not for patent concerns. Instead, it likely has to do with making sure the music plays on any computer with a web browser, and MP3 is the more widely-supported format.

When we asked a Spotify spokesman if Spotify had in fact switched away from Ogg Vorbis, the company responded:

“We use the simplest and best sounding codec for each platform.”

That’s not outright confirmation, but it’s more than we knew before, which was “Spotify uses Ogg Vorbis.”

The implications are not earth-shattering, unless you’re sort of a digital music dork. But it’s interesting that streaming music to the web likely costs Spotify more than streaming to its own desktop app — not just because the desktop app defrays bandwidth costs by rebroadcasting bits via P2P, but also because when Spotify streams to your desktop app, it can use the open-source Ogg Vorbis, which, unlike MP3, is free for services to use.

  • Anonymous

    I’d imagine it’s also due to the limited processing power on mobile devices, many of them have hardware mp3 decoding but ogg would have to be decoded through a slower software decoder without dedicated hardware acceleration.

  • Pascal Fiedler

    lol AAC (m4a) Isn’t compatible with the Desktop Application without an plugin…

  • Xavier Mendez

    Is the Web Player still there? I’ll try to update the Downloadify extension to work again. It’ll be an interesting task to do.

  • Alex

    you just need quicktime due to apple’s patenting rules. Not really a plugin imo.

  • Pascal Fiedler

    yepp. It works with Quicktime…