[vorbis] Why FLAC, why not MAC? [Off-Topic]

[J C Fitzgerald]

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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