[vorbis] Why FLAC, why not MAC? [Off-Topic]
J C Fitzgerald
v7022 at wave.co.nz
Sat Aug 30 16:40:30 PDT 2003
On Sat, Aug 30, 2003 at 10:26:57AM +0100, John Denton wrote:
>
> > (Besides, I'm now quite happy with FLAC which is achieving file sizes
> > around 20% of the RIFFs from which they are sourced.
>
> Really? Why bother with Ogg? Several tracks I compressed to Ogg yesterday
> (at a quality setting of q6) weight in at about 15% of the original wav -
> the 5% saving on your figure hardly seems worth the effort.
>
This one point is constructive, and could even be valid if it didn't
compare apples to oranges.
My audios are mainly speech with little stereo content. I chose one at
random (a roughly half-hour segment of a committee meeting) and crunched
some numbers. The table below shows the relative file sizes of the
row compared to the column and shown as a percentage. (So, the FLAC is
23.1% of the RIFF file size.) The Speex figures have been adjusted for
a 32kHz sampling rate (ultra-wide band); except for FLAC --best and the
indicated Vorbis quality, default settings have been used throughout.
<p> Vorbis Vorbis Vorbis
RIFF FLAC (q6) (q4) (q2)
FLAC 23.1 -- -- -- --
Vorbis (q6) 9.5 41.0 -- -- --
Vorbis (q4) 6.2 26.9 -- -- --
Vorbis (q2) 5.0 21.8 -- -- --
Speex 3.7 14.9 31.7 48.3 58.7
<p>As we can see when we compare like with like, both Vorbis and Speex
do seem to have a /raison d'etre/ after all. It would be interesting
(but probably only to me) to see how MAC fares on this sort of material.
John
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