Hello all,
I created today a fake stereo piece of music (the left and right
channels were completely equal), and encoded it with the all the modes
the RC2 encoder supports, and found that:
* * dual * waste * waste * *
mode * joint * stereo * in * in % * *
* stereo * /2 * kbits * of JS * *
***********************************************************************
mode 350K * 232.4 * 138.5 ** 93.9 40.4 *
************************************************** LOSSLESS *
mode 256K * 177.8 * 138.5 ** 39.3 22.1 COUPLING *
***********************************************************************
mode 192K * 147.0 * 102.5 ** 44.5 30.3 *
************************************************** *
mode 160K * 120.7 * 68.5 ** 52.2 43.2 *
************************************************** *
mode 128K * 101.2 * 51.0 ** 50.2 49.6 LOSSY *
************************************************** COUPLING *
mode 96K * 66.1 * 38.0 ** 28.1 42.5 *
************************************************** *
mode 80K * 53.9 * 38.0 ** 15.9 29.5 *
************************************************** *
mode 64K * 44.0 * 29.5 ** 14.5 33.0 *
***********************************************************************
notes:
- In 128K mode joint stereo was almost as bad as dual stereo
- some dual stereo modes gave the same bitrates, i.e. 96K=80K,
350K=256K
- the percentiles represents the approximate size gain which could be
achievable if Vorbis would handle fake stereo files smarter
- I know this experiment may seem silly, since I could preferably
convert the song to mono before encoding, but there could be a
number of CDs of older recordings, which were originally recorded as
mono and burned as fake stereo, right?
Comments?
--
Cheers, _____________________________
SyP (_Szabolcs Péter PGP Key ID:
_____________________)ICQ# 69968772 0x098AEC13
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On Mon, 10 Sep 2001, SyP wrote:> - I know this experiment may seem silly, since I could preferably > convert the song to mono before encoding, but there could be a > number of CDs of older recordings, which were originally recorded as > mono and burned as fake stereo, right?More to the point, any recording containing passages of mono material (e.g. backannounces) would benefit from improving such compression. Geoff. --- >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.
SyP wrote:> - I know this experiment may seem silly, since I could preferably > convert the song to mono before encoding, but there could be a > number of CDs of older recordings, which were originally recorded as > mono and burned as fake stereo, right?I think all audio CDs are two-channel, aren't they? So mono recordings would have to be done as two identical channels (nobody could be so dense as to release it as left-channel-only, with the right channel silent, and surely no one is still promoting "mono reprocessed for stereo", that vile atrocity of the '60s and '70s?). Certainly in my experience, when I rip a mono CD, I get two channels. I experimented a while back (beta 4 or RC1) with taking some of these wavs and throwing away the right channel. Oggenc then quite happily gave me one-channel vorbis files, though the relationship between the command line options and the resulting bit rate was somewhat unintuitive. Craig --- >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, Sep 10, 2001 at 05:34:45PM +0200, SyP wrote:> Hello all, > > I created today a fake stereo piece of music (the left and right > channels were completely equal), and encoded it with the all the modes > the RC2 encoder supports, and found that:Dual stereo is using different internal settings than joint stereo. Joint and Dual modes are not directly comparable. 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.