Vorbis dev - Aug 2000 - comparisons

I converted the 128kbps tom.mp3 file into a .wav and then used oggenc -m 2
to
laterally encode it to 128kbps tommy.ogg format. I noticed that it gets very
close to the size of an mp3, great job guys. Then I got to thinking that
maybe it could be compressed further with gzip so I tried it. I also gzipped
the mp3 to compare and it looks like the mp3 gzips better but gzipping the
ogg file will get the size a bit smaller than an ungzipped mp3. I'm not sure
if it's really worth the decompression overhead, although gzip is pretty
fast even though I used -9.

Sorry if I'm a bit naive about compression. ;-)

-rw-r--r--   1 palisade users          4007318 Aug 22 16:31 tommy.ogg
-rw-r--r--   1 palisade users          3989911 Aug 22 16:57 tommy.ogg.gz
-rw-r--r--   1 palisade users          3991638 Aug 22 16:41 tom.mp3
-rw-r--r--   1 palisade users          3959108 Aug 22 16:48 tom.mp3.gz

Sincerely,
Nelson Rush

"<Operandi> well flog me like a misbehaving circus clown"

--- >8 ----
List archives:  http://www.xiph.org/archives/
Ogg project homepage: http://www.xiph.org/ogg/

Nelson,
LZV based compression tools are suitable only for files with a predictable
set of values in them, unlike audio files. So they cannot compress MP3 files
much, which are already "redundancy-removed" through Huffman
algorithm.

----- Original Message -----
From: Nelson Rush <chesterrr@att.net>
To: <vorbis-dev@xiph.org>
Sent: Tuesday, August 22, 2000 5:12 PM
Subject: [vorbis-dev] comparisons
> I converted the 128kbps tom.mp3 file into a .wav and then used oggenc -m 2
> to
> laterally encode it to 128kbps tommy.ogg format. I noticed that it gets
very
> close to the size of an mp3, great job guys. Then I got to thinking that
> maybe it could be compressed further with gzip so I tried it. I also
gzipped
> the mp3 to compare and it looks like the mp3 gzips better but gzipping the
> ogg file will get the size a bit smaller than an ungzipped mp3. I'm not
sure
> if it's really worth the decompression overhead, although gzip is
pretty
> fast even though I used -9.
>
> Sorry if I'm a bit naive about compression. ;-)
>
> -rw-r--r--   1 palisade users          4007318 Aug 22 16:31 tommy.ogg
> -rw-r--r--   1 palisade users          3989911 Aug 22 16:57 tommy.ogg.gz
> -rw-r--r--   1 palisade users          3991638 Aug 22 16:41 tom.mp3
> -rw-r--r--   1 palisade users          3959108 Aug 22 16:48 tom.mp3.gz
>
> Sincerely,
> Nelson Rush
>
> "<Operandi> well flog me like a misbehaving circus clown"
>
>
> --- >8 ----
> List archives:  http://www.xiph.org/archives/
> Ogg project homepage: http://www.xiph.org/ogg/
>
--- >8 ----
List archives:  http://www.xiph.org/archives/
Ogg project homepage: http://www.xiph.org/ogg/

Nelson Rush wrote:
> 
> I converted the 128kbps tom.mp3 file into a .wav and then used oggenc -m 2
> to
> laterally encode it to 128kbps tommy.ogg format. I noticed that it gets
very
> close to the size of an mp3, great job guys.
128 kbps ... 128 kilo bit per second = (128 /8 kbyte = 16 kbyte/s) so
3991638 wil be the size of any 4:09 music (in vorbis, the file isn't
exactly 128 kbps because of his variant bitrate architeture

--- >8 ----
List archives:  http://www.xiph.org/archives/
Ogg project homepage: http://www.xiph.org/ogg/

MoiN

On Tue, Aug 22, 2000 at 07:12:30PM -0500, Nelson Rush
wrote:
> -rw-r--r--   1 palisade users          4007318 Aug 22 16:31 tommy.ogg
> -rw-r--r--   1 palisade users          3989911 Aug 22 16:57 tommy.ogg.gz
> -rw-r--r--   1 palisade users          3991638 Aug 22 16:41 tom.mp3
> -rw-r--r--   1 palisade users          3959108 Aug 22 16:48 tom.mp3.gz
That is about 0.43% gain for the ogg stream, which seems very
doubtable to be useful. You should test with different tracks to
see if the compression gain is really worth.

But compressing the streams you loose the capability to seek to
an (almost) arbitrary position inside the file. The ogg and mp3
files are composed of a numer of small frames, giving you the
ability to start decoding in each frame. If you compress the
whole stream with gzip into a single file you have to decode
almost the whole file using gunzip if you want to play the last
seconds only.

There is an extention to gzip which uses some features to be able
to start decoding in the middle at ftp.dict.org/pub/dict. But the
overhead involved is somewhere around 0.5%.

So you would gain almost nothing compressing audio streams. You
loose the ability to seek and need more memory and cpu-power to
decode them.

    Ingo

-- 
I am the "ILOVEGNU" signature virus. Just copy me to your signature.
This email was infected under the terms of the GNU General Public License.

--- >8 ----
List archives:  http://www.xiph.org/archives/
Ogg project homepage: http://www.xiph.org/ogg/