[vorbis] Ogg Vorbis files can be compressed ?!?

[Michel Donais]

One of my friends and I made a 2GB "empty" file once. It was basically a
bunch of 0s.

We zipped it. It took a few megabytes.
We zipped the zip. It took a few Ks.
We zipped the zip. It took 4-5Ks.

I don't remember the exact number (we did this a long time ago). But my
point is even ZIP files can be recompressed sometimes.

For vorbis, I guess it's perfectly possible to be lucky and have a
re-compressible file, since Vorbis uses block compression. MP3s
recompress too, at least a few percents.

It could be a good idea to have a Vorbis stream compression, where any
random access would be prohibited, at the gain of a few K or Ms. (In the
"To do someday when I am really bored and when Vorbis is perfect" list
^_^ )

<p><p>But I understand it seems odd anyways.
Mike

<p><p><p>> -----Original Message-----
> From: owner-vorbis at xiph.org [mailto:owner-vorbis at xiph.org] On Behalf
Of
> Nescafe
> Sent: 17 janvier, 2003 13:19
> To: vorbis at xiph.org
> Cc: members at gwain.fr.st
> Subject: Re: [vorbis] Ogg Vorbis files can be compressed ?!?
> 
> > Can you tell us what program and options you used to make the Ogg
Vorbis
> > file? If there isn't a copyright issue, could you also post the
original
> > WAV file somewhere so others could try and see if they get the same
> > result?
> 
> I use oggenc downloaded from :
> http://www.vorbis.com/files/1.0/windows/vorbis-tools-1.0-win32.zip
> With single setting "-q 0"
> 
> I tried to use ReHuff, using <malloc.h> because
> I am on a windows platform, but the output stream
> seemed invalid. However, it was only 126'499 bytes
> but packed aswell to 102'693 (zip) or even as low
> as 98'520 (rar3), but I guess this is not a valid test
> even though the file looked just like an ogg vorbis
> when opened with notepad :)
> 
> So, lazy me, I posted the wave file, actually an .xm
> rendered through winamp, so that you can try to
> encode it with your own oggenc, or to rehuff with
> your own rehuff. I heard about a patch to get the
> stream valid, but it seems way too long to apply.
> Maybe I'll give it a try, it seems just as nice as it
> sounds.
> 
> http://gwaingroup.1.free.fr/2003/01/17/
> for WAV and XM version of the sample.
> 
> Nescafe
> 
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