[vorbis] Archival quality for music

[Olaf Marzocchi]

OK, thank you all. Now I have every info I need to choose.
I will make some test with my hi-fi, then I will choose a quality level 
considering a future upgrade of my equipment.

Olaf

At 04.49 02/08/2002, you wrote:
>On Fri, 02 Aug 2002 05:47, Olaf Marzocchi wrote:
> > This mail depends upon the fact that I don't have a couple of good
> > earphones ;-)
> >
> > I read in the site that q=6 is a very high quality, but does it contain
> > perceivable differencies from the original? (for 95% of people, of course).
>
>I can hear differences between original and encoded applause segments at q6
>that go away at q7, but no one else on the list has claimed to hear what I'm
>hearing, so I expect I'm the 5% minority for that particular kind of
>artifact. For anything else, something over q4 is fine.
>
>What this illustrates is that even if you belive the claim that q6 is good
>enough for 95% of people (and there's not substantial evidence for this,
>though intuition would suggest somewhere in the region of q4-5 is more
>accurate), you still need to find out where in that 95% you are, and for what
>sort of music.
>
> > I also found q=6 to produce files slightly bigger (1/10 bigger) than those
> > produced with lame VBR q=2 (about 192 bps on average). I always thought
> > LAME VBR q=2 produced files with very little (if audible) differencies. May
> > OGG obtain better results than mp3 only at low bitrates? (I don't think so,
> > but I don't have enough skills to be sure).
> > I also think that ogg q=6 is the minimum quality level to use with ogg
> > because it has a better way to encode stereo than q=5.x.
>
>I believe lame's VBR mode tends to use joint stereo, while vorbis switchs to
>a lossless channel coupling method over q5-q6 region - this may account for
>the difference in size. I haven't heard of anyone claiming that lame vbr 2 is
>indistinquishable, quality-wise from the original, though that claim might be
>made for whateve the --r3mix switch sets these days.
>
>Certainly fatboy.wav sounds is pretty easy to ABX against lame at any vbr
>setting, the last time I checked.
>
> > To summarize, I need an advice about the quality level to set in order to
> > achieve comparable or better results than mp3s (LAME) at about 192 kbps or,
> > as preferred alternative, to produce files with very little perceivable
> > differencies form originals.
> > If this value has a nominal bitrate of more than 256 kbps please give me an
> > idea of the level of distorctions at 192 kbps nominal (OGG of course).
>
>I'm going to use q7 for 'hard to encode' stuff, which, for me is just a few
>live ablums, right now, and q4.99 for everything else - I can't really ABX
>anything past q4, but I'm adding a bit to account for future improvements in
>my hearing and equipment, and staying shy of 5.00 as there's still a large
>bitrate hop between 4.99 and 5.00.
>
>I suggest you do some ABX testing against the usual set of difficult to
>encode samples, and music you're familar with at various different quality
>levels to find one or two that suit you. If they happen to produce files with
>a better ABR than lame, use ogg, otherwise stick with lame.
>
>John

<p><p><p><olaf@ kjws.com> for every kind of mail, except spam! :-)

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