[vorbis] just an idea about quality evaluation

Lorenzo Prince lorenzo at princenet.sytes.net
Sat Jan 25 17:40:19 PST 2003



I may want to leave this to someone who is more knowledgeable, but in my
opinion, there are arguments both for and against doing this.  Always,
however, the best thingis to just let your ears hear what they hear.  Do
whatever sounds good to you.  And, if you like, you can do listening tests
on the resulting files with other people and see what they like too.  The
ear is really the best tool for the job.  However, depending on the quality
you're aiming for, if you use a 256k or higher mp3, generally, the loss
won't be great enough to hear the difference unless you encode at less than
q6.  Just a thought.
Lorenzo

----- Original Message -----
From: "Daniel Schregenberger" <npfdd at gmx.net>
To: <vorbis at xiph.org>
Sent: Saturday, January 25, 2003 8:32 AM
Subject: Re: [vorbis] just an idea about quality evaluation

<p>> Lorenzo Prince wrote:
>
> > The problem with using technical methods to judge the quality of a
> > perceptual codec is that the codec is designed to be tuned to the human
ear.
>
> hmmm...maybe this is a bad idea too, but couldn't I use it then to see the
> difference of two lossy formats? I mean encode a wav with q4 and q5 and
see how
> different the output was with the method Stoffke described.
> Or maybe to find some decent quality settings to convert mp3s to ogg: If I
have
> a 256k mp3, what quality should I use to
>
> a) not lose to much (converting is bad I know, but 256k -> q10 shouldn't
be
> that bad)
> b) not waste too much space (maybe 256k -> q8 results in almost the same)
>
> -- Daniel
>
>
> "Not only is this incomprehensible, but the ink is ugly and the paper
> is from the wrong kind of tree."
> -- Professor W.
>
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