Here's an MP3 I have.

  • My iPhone plays it back with no problems.
  • VLC on OS X plays it back with no problems.
  • iTunes plays it with annoying bleeps and bloops, some kind of errors or artifacts that are very noticeable at the beginning of the track.
  • Other OS X playback methods, like QuickTime Player or Quick Look, have tiny skips/gaps in the playback, in the same places where iTunes has the error bleeps.

The MP3 has a 32 kHz sampling rate instead of 44.1 kHz; is that the problem? When I use an OS X conversion tool like XLD, the tiny gaps are in the output, no matter what kind of conversion I do. Is the problem actually with the MP3 or with OS X/Core Audio?

This happens on multiple Macs running OS X 10.11.3 using iTunes

  • 1
    I'm no audio expert however based on the tests I did I could replicate the issue as expressed under different OS X and iTunes version until I changed the sampling rate by streaming it to a file at 44.1 kHz using VLC at which point it played without issue everywhere. FWIW looking at magnified waveform output in Audacity and the original file I see nothing that would account for the noise. So while not a highly scientific analysis by any means nonetheless it looks like native OS X methods of playing including, afplay, iTunes, etc. don't like the 32 kHz sampling rate. – user3439894 Jan 26 '16 at 21:19

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