This mail depends upon the fact that I don't have a couple of good earphones ;-) I read in the site that q=6 is a very high quality, but does it contain perceivable differencies from the original? (for 95% of people, of course). I also found q=6 to produce files slightly bigger (1/10 bigger) than those produced with lame VBR q=2 (about 192 bps on average). I always thought LAME VBR q=2 produced files with very little (if audible) differencies. May OGG obtain better results than mp3 only at low bitrates? (I don't think so, but I don't have enough skills to be sure). I also think that ogg q=6 is the minimum quality level to use with ogg because it has a better way to encode stereo than q=5.x. To summarize, I need an advice about the quality level to set in order to achieve comparable or better results than mp3s (LAME) at about 192 kbps or, as preferred alternative, to produce files with very little perceivable differencies form originals. If this value has a nominal bitrate of more than 256 kbps please give me an idea of the level of distorctions at 192 kbps nominal (OGG of course). That's all! Thank you in advance Olaf <p><olaf@ kjws.com> for every kind of mail, except spam! :-) <p><p>--- >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 Marzocchi wrote:> This mail depends upon the fact that I don't have a couple of good > earphones ;-)Meaning you can't do your own comparisons on reasonable equipment. All right.> I read in the site that q=6 is a very high quality, but does it contain > perceivable differencies from the original? (for 95% of people, of course).I don't know about 95% of people, but I suspect q=5 is adequate for the overwhelming majority of people... for some reasonable value of "overwhelming majority" that I'm not currently prepared to supply.> I also found q=6 to produce files slightly bigger (1/10 bigger) than those > produced with lame VBR q=2 (about 192 bps on average). I always thought > LAME VBR q=2 produced files with very little (if audible) differencies. May > OGG obtain better results than mp3 only at low bitrates? (I don't think so, > but I don't have enough skills to be sure). > I also think that ogg q=6 is the minimum quality level to use with ogg > because it has a better way to encode stereo than q=5.x.It does? 5.0 is where Vorbis transitions from lossy stereo to lossless stereo. I'm not aware of any particular change at 6.0.> To summarize, I need an advice about the quality level to set in order to > achieve comparable or better results than mp3s (LAME) at about 192 kbps or, > as preferred alternative, to produce files with very little perceivable > differencies form originals.In my experience, Vorbis, at any given average bit rate, is _always_ better than any MP3 encoder at the same bit rate. (The differences are more subtle at higher bit rates simply because even MP3 does a fair job at, say, 256k, so the average listener probably can't detect a difference at that rate.) So to equal or surpass the quality of a 192k MP3, go for about 160k average bit rate in Vorbis. q=5 should do nicely. Craig -------------- next part -------------- A non-text attachment was scrubbed... Name: part Type: application/pgp-signature Size: 190 bytes Desc: not available Url : http://lists.xiph.org/pipermail/vorbis/attachments/20020801/44fb4aa3/part-0001.pgp
On Fri, 02 Aug 2002 05:47, Olaf Marzocchi wrote:> This mail depends upon the fact that I don't have a couple of good > earphones ;-) > > I read in the site that q=6 is a very high quality, but does it contain > perceivable differencies from the original? (for 95% of people, of course).I can hear differences between original and encoded applause segments at q6 that go away at q7, but no one else on the list has claimed to hear what I'm hearing, so I expect I'm the 5% minority for that particular kind of artifact. For anything else, something over q4 is fine. What this illustrates is that even if you belive the claim that q6 is good enough for 95% of people (and there's not substantial evidence for this, though intuition would suggest somewhere in the region of q4-5 is more accurate), you still need to find out where in that 95% you are, and for what sort of music.> I also found q=6 to produce files slightly bigger (1/10 bigger) than those > produced with lame VBR q=2 (about 192 bps on average). I always thought > LAME VBR q=2 produced files with very little (if audible) differencies. May > OGG obtain better results than mp3 only at low bitrates? (I don't think so, > but I don't have enough skills to be sure). > I also think that ogg q=6 is the minimum quality level to use with ogg > because it has a better way to encode stereo than q=5.x.I believe lame's VBR mode tends to use joint stereo, while vorbis switchs to a lossless channel coupling method over q5-q6 region - this may account for the difference in size. I haven't heard of anyone claiming that lame vbr 2 is indistinquishable, quality-wise from the original, though that claim might be made for whateve the --r3mix switch sets these days. Certainly fatboy.wav sounds is pretty easy to ABX against lame at any vbr setting, the last time I checked.> To summarize, I need an advice about the quality level to set in order to > achieve comparable or better results than mp3s (LAME) at about 192 kbps or, > as preferred alternative, to produce files with very little perceivable > differencies form originals. > If this value has a nominal bitrate of more than 256 kbps please give me an > idea of the level of distorctions at 192 kbps nominal (OGG of course).I'm going to use q7 for 'hard to encode' stuff, which, for me is just a few live ablums, right now, and q4.99 for everything else - I can't really ABX anything past q4, but I'm adding a bit to account for future improvements in my hearing and equipment, and staying shy of 5.00 as there's still a large bitrate hop between 4.99 and 5.00. I suggest you do some ABX testing against the usual set of difficult to encode samples, and music you're familar with at various different quality levels to find one or two that suit you. If they happen to produce files with a better ABR than lame, use ogg, otherwise stick with lame. John <p>--- >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.