Hi, I've got some (seven) Ogg Vorbis files with a total size of 18637246 bytes. When I use bzip2 to compress these files, the total size is 16949443. That's 10% less. Is bzip2 supposed to be able to compress Ogg Vorbis files further? If not, are these files encoded with wrong settings? If so, why is there no option to use bzip2 with Ogg Vorbis by default? Olaf van der Spek Almere, Holland http://xccu.sourceforge.net/ --- >8 ---- List archives: http://www.xiph.org/archives/ Ogg project homepage: http://www.xiph.org/ogg/ To unsubscribe from this list, send a message to 'vorbis-request@xiph.org' containing only the word 'unsubscribe' in the body. No subject is needed. Unsubscribe messages sent to the list will be ignored/filtered.
Olaf van der Spek (Olaf@XCC.TMFWeb.NL) wrote:> I've got some (seven) Ogg Vorbis files with a total size of 18637246 bytes. > When I use bzip2 to compress these files, the total size is 16949443. That's > 10% less.How much tag data (vorbiscomment) is there in these files? It doesn't seem likely that the tags would be able to account for so much compressability, but it's the first thing that comes to mind. -- Greg Wooledge | "Truth belongs to everybody." greg@wooledge.org | - The Red Hot Chili Peppers http://wooledge.org/~greg/ | -------------- next part -------------- A non-text attachment was scrubbed... Name: part Type: application/pgp-signature Size: 188 bytes Desc: not available Url : http://lists.xiph.org/pipermail/vorbis/attachments/20021223/0cf491f1/part-0001.pgp
> If so, why is there no option to use bzip2 with Ogg Vorbis by default?Are you saying that you never seek in Ogg? Because I don't believe you can do random seeking in bzip2 files without a full decompress. Not to mention you'd be really adding some extra cpu usage for very little gain. jack. --- >8 ---- List archives: http://www.xiph.org/archives/ Ogg project homepage: http://www.xiph.org/ogg/ To unsubscribe from this list, send a message to 'vorbis-request@xiph.org' containing only the word 'unsubscribe' in the body. No subject is needed. Unsubscribe messages sent to the list will be ignored/filtered.
On Tuesday 24 December 2002 11:30, you wrote:> Hi, > > I've got some (seven) Ogg Vorbis files with a total size of 18637246 > bytes. When I use bzip2 to compress these files, the total size is > 16949443. That's 10% less. > > Is bzip2 supposed to be able to compress Ogg Vorbis files further? > If not, are these files encoded with wrong settings? > If so, why is there no option to use bzip2 with Ogg Vorbis by default?I gather that the story is that the library uses good approximations to the optimal Huffman codes for that phase of compression, so that it can do everything in one pass - obviously a desirable thing for streaming. Someone wrote a rough, hackerware tool to recalculate the optimal codes on an existing file, and I think they got results similar to yours (though maybe bzip2 does a bit better). John --- >8 ---- List archives: http://www.xiph.org/archives/ Ogg project homepage: http://www.xiph.org/ogg/ To unsubscribe from this list, send a message to 'vorbis-request@xiph.org' containing only the word 'unsubscribe' in the body. No subject is needed. Unsubscribe messages sent to the list will be ignored/filtered.
On Mon, Dec 23, 2002 at 11:30:09PM +0100, Olaf van der Spek wrote:> Hi, > > I've got some (seven) Ogg Vorbis files with a total size of 18637246 bytes. > When I use bzip2 to compress these files, the total size is 16949443. That's > 10% less. > > Is bzip2 supposed to be able to compress Ogg Vorbis files further? > If not, are these files encoded with wrong settings? > If so, why is there no option to use bzip2 with Ogg Vorbis by default?Seeking plus pre-set huffman ratios are unlikely to result in losing as much as 10% off optimal, unless there are a few other things at work here. Could you give more information? Monty --- >8 ---- List archives: http://www.xiph.org/archives/ Ogg project homepage: http://www.xiph.org/ogg/ To unsubscribe from this list, send a message to 'vorbis-request@xiph.org' containing only the word 'unsubscribe' in the body. No subject is needed. Unsubscribe messages sent to the list will be ignored/filtered.
On 24 äÅËÁÂÒØ 2002 00:30, Olaf van der Spek wrote:> Hi, > > I've got some (seven) Ogg Vorbis files with a total size of 18637246 > bytes. When I use bzip2 to compress these files, the total size is > 16949443. That's 10% less.Well I can't reproduce that: $ cp 01_Doro_-_Cool_Love.ogg 01_Doro_-_Cool_Love $ bzip2 -9 !$ bzip2 -9 01_Doro_-_Cool_Love $ l 01* -r--r--r-- 1 dan dan 3025510 äÅË 24 18:07 01_Doro_-_Cool_Love.bz2 -r--r--r-- 1 dan dan 3030005 äÅË 24 18:06 01_Doro_-_Cool_Love.ogg $ echo "scale=3; 3025510*100/3030005"|bc 99.851 $ echo "scale=3; 100-3025510*100/3030005"|bc .149 -- [dan@shinestar ~]$ ls -l /dev/brains ls: /dev/brains: No such file or directory --- >8 ---- List archives: http://www.xiph.org/archives/ Ogg project homepage: http://www.xiph.org/ogg/ To unsubscribe from this list, send a message to 'vorbis-request@xiph.org' containing only the word 'unsubscribe' in the body. No subject is needed. Unsubscribe messages sent to the list will be ignored/filtered.