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

[Stan Seibert]

Someone in a post several months ago reported a similar issue.  They
found they could bzip2 an Ogg Vorbis file and get compression ratios
like what you are reporting.  Upon further inspection, I don't think
anyone was able to reproduce his result, though.

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?


---
Stan Seibert

<p>On Fri, 2003-01-17 at 08:55, Nescafe wrote:
> Hi there.
> 
> I have a short .ogg with Vorbis stream @56kbps
> from a 44.1 16bits stereo sample, which weights
> exactly 135'781 bytes. Packed to ZIP, it goes
> down to 109'485 bytes, that's a 80% ratio !
> Even worse with latest RAR3 archive, with
> which the file size goes to 104'349 (76%).
> 
> <sceptical>
> I admit this sample is a bit repetitive, but I
> guess the probability of having the beats match
> exactly the window frame edge is relatively
> low, so is the one of having multiple similar
> stream frames. Even though, I don't know if
> the coding inside Vorbis would let this happen.
> This is just non-sense to me. Are OGG packets
> padded and too big ? Or is it Vorbis frames ?
> </sceptical>
> 
> So I did the same test with a Lame encoded
> mp3, with average bitrate at 56kbps too,
> keeping all frequency range, 44.1 joint-stereo.
> The results struck me : the source file is
> 136'028 bytes, which is quite like the ogg
> reference file. But the ZIP file was 128'287
> (94% as opposed to 80%), and the RAR3
> didn't do really better with 128'048 bytes
> (94% too versus 76%).
> 
> Why do I get such compression ratio with
> OGG Vorbis ? All files are there :
> http://gwaingroup.1.free.fr/2003/01/17/
> 
> <kidding>
> It's not a problem for me since my current
> project uses Ogg Vorbis in a RARed
> archive, so a better sounding format, which
> can be packed even more, that's a "twice"
> better format.
> </kidding>
> 
> This could just be done in a somehow better
> way, am I wrong ?
> 
> Thanx for any response.
> 
> 
> Nicolas "Nescafe" Le Gland
> 
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