[vorbis] Ogg artifacts

[Paul Martin]

On Thu, Jan 22, 2004 at 02:57:13PM -0700, Jon Pomrenke wrote:
> I'm having some difficulty getting into Ogg. Being my first time encoding to
> Ogg, I am left doubtful of the quality in reproduction. Hopefully, it is
> merely something that I am doing.
> 
> My original intentions were to go through my CD collection and rip
> everything out at 224kps VBR. I began with an album I was relatively
> familiar with. I used FreeRip 2.53 initially, but found that I had
> artifacts (clipping) in a couple places in a couple songs. Being suspicious

Problem:

Many modern CDs are mastered with clipped waveforms.

Ogg overshoots the waveform. (Take a theoretically pure square wave,
and try to synthesise it from sine waves which are odd harmonics of the
fundamental, and you'll see ringing at each rise and fall of the
waveform.)

This results in a harder clipping noise than on the original CD.

Solution:

Reduce the playback gain of these files.

References:

http://www.personal.uni-jena.de/~pfk/mpp/clipping.html
http://www.proaudiorx.com/dynamicrange.htm
http://www.broadcast.net/pipermail/radio-tech/2001-April/002684.html


-- 
Paul Martin <pm at zetnet.net> (work)
  <pm at nowster.zetnet.co.uk> (home)
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