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No lossy codec is perfectly gapless, Here is the killer sample
Pio2001
post Feb 1 2004, 20:42
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I found a problem sample for gapless encoding. Whatever I do, there is an audible click between the tracks. I've analyzed its cause, and found that it comes from edge effects. The termination of the waveform far from zero causes ringing, that manifests itself as an audible click, even when the files are played gapless.

I saw the problem with MP3 and MusePack.

MP3 : Lame 3.90.3 --alt-preset standard ; Foobar2000 disc writer
MPC : Mppenc 1.14 --xlevel ; Mppdec

You can get the file here : http://www.hydrogenaudio.org/forums/index....35&t=18207&st=0

Look at the attached picture to see the problem in the waveform.
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hujay
post Feb 2 2004, 13:32
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I'll be very interested to see what you can come up with Pio. With the step file you've certainly devised what must be the severest test of mp3 encoding.

The screen shot of a perfect 'cut and shut' (glitch.jpg) that I posted clearly shows the artefacts, and is audible because of the unvarying background. In a normal music file this will still be present (as shown be looking at the delta file) but will be masked out by the music itself. This is distinct from the louder artefact that will be generated by imperfect silence detection and shown in the attatched 'imperfect.jpg'.
Note the difference in scale !

UJ
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