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Are there any notoriously bad Ogg Vorbis encoders?, I think Spotify might be using one of them...
mmontag
post Aug 1 2011, 08:18
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I am wondering because I have noticed a particular disturbing artifact on many Spotify tracks. What could cause this? I'd like to reproduce this sound in order to back up my suspicions. I can't seem to reproduce the noise no matter how low quality I compress my test audio, so my first guess was that Spotify could have used a bad encoder, earlier version, etc. Much like some early MP3 encoders, such as Xing, were notorious for producing poor quality MP3s.

I have some samples available on my blog:

http://www.mattmontag.com/music/weird-spot...ssion-artifacts

Matt

This post has been edited by mmontag: Aug 1 2011, 08:19
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lvqcl
post Aug 1 2011, 15:18
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http://xiphmont.livejournal.com/51160.html
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mixminus1
post Aug 1 2011, 16:15
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Hmm, perhaps, but that was a year ago, and as the last post noted, current builds of ffmpeg throw an error if you try to use the internal Vorbis encoder...I would "hope" Spotify wouldn't be going out of their way to deliberately use it.

Might it be watermarking? Those artifacts sound quite similar to the ones found in the downloaded Deutsche Grammophon FLACs from Passionato.com in this thread.

Regardless of the source of the artifacts, if that's the kind of sound quality that Spotify offers - even from their paid stream - it would seem that their entry into the US market was much ado about nothing...I think I'll just stick to iTunes... rolleyes.gif


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saratoga
post Aug 1 2011, 18:50
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QUOTE (mixminus1 @ Aug 1 2011, 11:15) *
Hmm, perhaps, but that was a year ago, and as the last post noted, current builds of ffmpeg throw an error if you try to use the internal Vorbis encoder...I would "hope" Spotify wouldn't be going out of their way to deliberately use it.


You're assuming they've updated. Its quite common to see people using ancient ffmpeg builds.
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mixminus1
post Aug 1 2011, 19:08
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Heh, true that.


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saratoga
post Aug 1 2011, 19:35
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QUOTE (mixminus1 @ Aug 1 2011, 14:08) *
Heh, true that.


That said, its probably a good idea to capture a spotify track and verify what produced the vorbis stream.
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mixminus1
post Aug 1 2011, 21:50
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According to the spotifyclassical.com blog post linked on the OP's website, the stream is encrypted, so that could be tricky...I'm "assuming" that the WAVs Matt provided on his website were captures of the actual playback, either by sound card loop-back, or by grabbing the decompressed PCM stream via something like Total Recorder.

Matt, how did you create those WAV samples?

On a whim, I did some searching on Amazon, and it just so happens that all the tracks that Matt posted come from Universal Music Group labels...after what was discovered in my previously-linked thread, I'm going to double-down on watermarking, particularly since Matt says that the artifacts are still there on the 320 kbps stream.

Edit: added the last bit about the 320 kb stream

This post has been edited by mixminus1: Aug 1 2011, 21:59


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