[vorbis-dev] Re: lossless ogg encoding with good compression rate

[Christian Hack]

> -----Original Message-----
> From: owner-vorbis-dev at xiph.org 
> [mailto:owner-vorbis-dev at xiph.org] On Behalf Of Christian Buchner
> Sent: Thursday, 26 June 2003 2:25 PM
> To: vorbis-dev at xiph.org
> Subject: RE: [vorbis-dev] Re: lossless ogg encoding with good 
> compression rate
> 
> 
> 
> > you must obtain compression rate around 35% (28.53% -> 
> 34.58% for me)
> > 
> > +-----------+------------+------------+------------+-----------+
> > | ORIG      | 49.153.582 | 36.463.150 | 36.350.206 | 39.866.446|
> > +-----------+------------+------------+------------+-----------+
> > | ogg       | 8.031.545  | 5.675.553  | 5.717.410  | 6.155.756 |
> > | bz2 diff  | 8.961.170  | 6.934.106  | 6.713.344  | 5.216.487 |
> > +-----------+------------+------------+------------+-----------+
> > | SUM       | 16.992.715 | 12.609.659 | 12.430.754 | 11.372.243|
> > +-----------+------------+------------+------------+-----------+
> 
> This sounds too good to be true.
> 
> have you actually verified that you can get the original WAVE files
> back from the ogg and bz2 diffs?
> 
> If yes, then I attribute the good compression ratios to the style
> of music you chose. Must be classical or something else that 
> compressed
> well.
> 

I just tried one myself. I just picked a random WAV I had lying around
(raw from a CD i.e. not converted back from ogg or mp3) - Tom Petty &
The Heartbreakers - She's The One - 03 - Zero From Outer Space.wav

For some reason his binary PHP diff gave me a file 4 bytes shorter but
I'll run with that (haven't bothered to read the source)

My results:

Original filesize    33 203 228
Ogg -q 8 -b 256       5 846 190
Diff (bzip -9)	    6 389 457
Total compress size  12 235 647 
% of orig (bzip)	   36%

i.e. much better than any FLAC I have ever encoded...

I agree though it does sound too good to be true. Looks like I will be
knocking up some scripts and programs to try on a much larger test batch

What would be the best music to try to stress it as much as possible?

Also for some reason oggdec didn't add a RIFF/WAV header. Should it
have? And no I didn't use the -R option...

CH

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