Weird Spotify Compression Artifacts

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Spotify Artifacts Showcase

I love Spotify. But I've noticed some weird artifacts on a few albums. It sounds like a fluttery warble noise in the midrange. It's most noticeable during big string or choir sections with broad spectral content.

The problem seems limited to certain albums. The worst album I've come across is this Pascal Roge Poulenc album.

Spotify uses Ogg Vorbis encoding. Free streaming accounts get Ogg Vorbis q5, 160kbps. I wonder if this is a normal Ogg Vorbis artifact, or something more complicated. Here are some audio samples. Can you hear it?

Michael Jackson - Ben / on Spotify
Poulenc - Piano Concerto Movement 2 (linked above)
Poulenc - Piano Concerto Movement 3
Poulenc - Piano Sonata Movement 1

And the worst example - yikes, is this intentional?
Three Doors Down - When You're Young / on Spotify

Update 1:

I just upgraded to Spotify Premium and switched to 320kbps high quality streaming. I'm sad to say the nasty artifacts are still audible on these songs.

Update 2:

Due to investigative effort by Ulysses at spotifyclassical.com, this is no longer a mystery but indeed just a case of bad compression; it turns out maybe 50 percent of the Spotify library is actually available at 320kbps.

If this is true then I don't like Ogg Vorbis, since their 160kbps rate seems to have far more annoying artifacts than any 160kbps MP3 I've ever heard. Ogg is supposed to be better.I have not been able to reproduce the artifacts with my own Ogg compressor.

Update 3:

I compared the latest Three Doors Down album on Spotify, Rdio, and FLAC original audio. It's pretty clear that sometimes, the labels just supply bad tracks to the streaming services. The Spotify and Rdio tracks were identical.  I heard the same artifacts at the same points in the song.  The FLAC was very different.  This changes some of my earlier conclusions. The artifacts are not Ogg 160kbps artifacts.

To answer my question above, the warbling noise is definitely not part of the original Three Doors Down - When You're Young  track.  Now the question is, exactly what format are these tracks provided in, and why is there such variance even among a single label's catalog? Are these differences intentional?

Update 4:

Finally, the source of all this consternation: Universal Media Group supplies heavily watermarked audio to all services. More.

12 ResponsesLeave a Reply

  1. The vorbis encoders I know of are:

    - The reference vorbis encoder (libvorbis)
    - Aoyume's modified version of the reference encoder (AOTUV)
    - The one in libavcodec (ffmpeg, mencoder, ....)

    IIRC, the ffmpeg one has had some quality issues on the past. A case of NIH syndrome, I think.

  2. Btw, http://www.hydrogenaudio.org/forums/ has conducted some comparisons between codecs in the past, they tend to prefer AoTuV for Vorbis (but AoTuV only has modifications to the tables for lower bitrates, IIRC).

  3. I've noticed the same thing on artists from Kiss to Stratvarius (both distorted electric guitars) to The Housemartins (a capella vocals). It's really annoying, and seems to be endemic to particular sources, but I don't have any sort of correlation yet.

    What I noticed with Stratovarius is that the songs from their albums have it, but that songs from compilation albums (which may have a different source) do not. This makes me wonder if it's some fundamental incompatibility with some studio's FLAC inputs and the Vorbis outputs, or if it's a reencoding setting that gets messed up.

  4. Interesting. Can you provide some Spotify links to the tracks from two different sources that have different artifacts? I was looking for an example like that myself.

  5. Hah, spelled my name wrong last time.

    Anyway, It's a horrible song, but it really shows the artifacting:

    Kiss - Lick It Up from Lick It Up album: http://open.spotify.com/track/3cXiUuiGpFmZ8OdAWKk8Ck

    Kiss - Lick It Up from Rock Star Soundtrack: http://open.spotify.com/track/3rfEkOyccbDSBNBi4xQLnm

  6. Tonio Roffo

     /  December 10, 2011 Quote

    Could it simply be the decoding part? Spotify windows app (especially with volume leveling active) decodes hot mastered tracks so loud it clips - a lot. Turn the function off.

    Listening on a 3rd party system (Squeezebox plugin) I get near perfect audio - except when of course, the source material is crappy.

  7. Tonio Roffo

     /  December 10, 2011 Quote

    The artifacts you talk about are not vorbis artifacts, it really seems like a bad case of digital clipping, which I think is caused by bad decoding in the spotify app ("play all songs at the same level") - putting volume slightly lower than 100% seems to help here (not windows volume, spotify volume)

  8. Hi Tonio, I don't think we are hearing the same thing. The artifacts I'm talking about are not clipping artifacts and I do not have "play songs at the same level" enabled. It's more of a swashing/warbling noise in the background.

  9. Thanks for the further investigation, Matt. As far as I know, labels send the same lossless files (normally flac, Apple Lossless or wav) to all streaming/download services. When Beach Boys' Smile Sessions first appears on Spotify, there were many crackles in Surf's Up and other tracks at the end of each disk, most likely caused by bad ripping process from CD to flac. It's a prominent new release so I guess many users complained, and Spotify/the label updated the album shortly. I've noticed a few crackles in some classical recordings as well, the crackle in Simon Rattle's Duke Ellington album on Spotify are identical with those in the iTunes version. What I don't understand is why the major labels still use CD ripping instead of encoding from the master wav files, since digital is now a more important distribution medium than CD.

    I assume some small labels might not be able to obtain part of their catalogue in lossless, so it's possible that they just transcode whatever they have to flac and upload to services like Spotify. It's not practical for Spotify to to test more than ten thousands tracks uploaded daily, but if you are right about the Poulenc recording that even Decca sometimes uploads fake lossless files, it would indeed be a problem. I will try to inform Spotify and Decca about this. Maybe they couldn't find a copy of the Poulenc CD, but they surely have the master files.

  10. Hi Ulysses,
    The problem I'm focused on is not pops or other ripping errors; it's a very distinct and consistent compression artifact. If I figure out what compressor produces this kind of artifact, I'll be able to illustrate it clearly.

    The problem isn't limited to Decca but also Mercury, Deutsche Grammophon, Universal, etc. It's as if content was encoded for distribution on some retail kiosk like RedDotNet and then repurposed for the streaming services.

  11. Martin Rubenstein

     /  August 25, 2014 Quote

    The problem I hear is far worse than your samples eg at around 1min50secs in

    http://open.spotify.com/track/66YQXX404d3z4q9DdymcPj

    I hear a rattle that sounds like amplitude clipping in my earphones. Turning the volume right down has no effect, so I can't blame the earphones. I hear most with singers and choirs. Is this also watermarking?

  12. Martin Rubenstein: The problem I hear is far worse than your samples eg at around 1min50secs inhttp://open.spotify.com/track/66YQXX404d3z4q9DdymcPjI hear a rattle that sounds like amplitude clippingin my earphones.Turning the volume right down has no effect, so I can't blame the earphones. I hear most with singers and choirs. Is this also watermarking?

    Hard to say, I don't hear any artifacts on that recording. It could be a problem with your earphones even if it persists at low volumes. Try a different pair?

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