Hi List, I noted that compressing music like Merzbow or other Japanese chaotic noise-bands usually results in very low compression rates. That means, that the resulting .flac-file is nearly as big as the initial .wav-file. Other kinds of music get compressed much better. Any explanation? Regards Thomas -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: application/pgp-signature Size: 189 bytes Desc: not available Url : http://lists.xiph.org/pipermail/flac/attachments/20050220/0f750e69/attachment.pgp
Hi Thomas, The amplitude of the piece has the most to do with the ability of FLAC to compress it. Second to amplitude would be frequency, i.e. higher frequency content would compress less than lower frequency material. FLAC starts by converting the absolute samples to differential samples. Lower amplitude signal have smaller differences between each sample, and thus take less space. Also, lower frequency signals change very slowly, making the difference between each sample smaller. Lots of high frequencies, such as noise, would tend to result in large changes between samples. I do a lot of live recording, and usually the recording level is set low enough to ensure that none of the samples clip. These raw, unprocessed recordings compress very well with FLAC. However, mastering for CD usually involves boosting the average level, followed by compression and/or limited to kill peaks that go over 0 dBFS. The mastered recordings usually produce larger FLAC files, even thought they are "compressed." This is because the amplitude has been raised. I bet that if you look at your Merzbow and Japanese noise in a wave editor, you'll see almost solid black samples! I assume this music is designed to be played loud, and the material is high amplitude and high frequency. Brian Willoughby Sound Consulting Begin forwarded message: Hi List, I noted that compressing music like Merzbow or other Japanese chaotic noise-bands usually results in very low compression rates. That means, that the resulting .flac-file is nearly as big as the initial .wav-file. Other kinds of music get compressed much better. Any explanation?
--- Thomas Bulka <thomas_bulka@gmx.net> wrote:> Hi List, > I noted that compressing music like Merzbow or other Japanese chaotic > noise-bands usually results in very low compression rates. > That means, that the resulting .flac-file is nearly as big as the > initial .wav-file. > Other kinds of music get compressed much better. > Any explanation?noise is by definition random, therefore unpredictable and impossible to losslessly compress. Josh __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com
On Sat, Feb 19, 2005 at 10:32:20PM -0800, Josh Coalson wrote:> noise is by definition random, therefore unpredictable and > impossible to losslessly compress. > > JoshThank you guys. So maybe my only option would be listening to music that has some structure in it ;-) Thomas -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: application/pgp-signature Size: 189 bytes Desc: not available Url : http://lists.xiph.org/pipermail/flac/attachments/20050220/143a7dbb/attachment.pgp