> QUALITY MEASUREMENT IDEA: > I find it difficult to hear 2 voice samples and tell > which is nearer the original, especially if the > background hiss is slightly different. So what if you > actually subtract the post-compression sound from the > original and then listen to the DIFFERENCE. If you > can't hear any voice except background noise and some > hiss from "s"'s and "d"'s and such, that means most of > the actual voice has been maintained. If you can hear > someone speaking, that means there is leftover voice. > If you can actually understand what that someone is > saying, the difference is great. Thoughts?What do you prefer: a codec that sounds good or one for which subtracting the original gives a better signal?> QUESTIONS: > My hearing is not the best I suppose, because I can > barely tell the difference between any of the > encodings and the original for the examples hosted on > the Speex.org website. When I encode, I can barely > tell the difference between quality 3 and quality 10. > Complexity is at 8 or above. SO my questions are: > > 1. What would be a common quality level for 56k modems > to use in voice chat during a game? CPU usage is not > an issue.For 56k, you have ~36kbps upload. If you remove the UDP/RTP overhead, that leaves you about 10 kbps, so I'd suggest the 8 kbps mode. The 11 kbps would probably also work.> 2. Would it be better to have 16khz at quality > 3(complex10) or 8khz at quality 5, they end up roughly > the same size? (let me know if you are refering to VBR > or not or both)Well, what do *you* like better. At this bit-rate, it's mostly a matter of taste, though at higher bit-rate you'll probably want to go with 16 kHz. Jean-Marc -- Jean-Marc Valin, M.Sc.A., ing. jr. LABORIUS (http://www.gel.usherb.ca/laborius) Université de Sherbrooke, Québec, Canada -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 190 bytes Desc: Ceci est une partie de message numériquement signée Url : http://lists.xiph.org/pipermail/speex-dev/attachments/20030820/3a5e84d4/signature-0001.pgp
I think you misunderstood my quality measurement idea. I mean if you subtract the original and the one after, the LESS voice that is less over or the LESS you can tell when someone is speaking, the better the compression. This is still subjective but I think its easier to tell this way because its easier to tell how much voice is remaining than to tell how much the compressed voice is missing from the original. Quick analogy, if you have 3 huge piles of apples (one being the original), of various colors. It is very difficult to tell which of the other 2 piles is closest to having the same proportions of each color BUT, if you subtract them out, it becomes very easy to look at it and see which is closest to the original. Hope that makes some sense, but I fully admit it, until I give it a try some day down the road, I can't be confident in this idea. <p>> What do you prefer: a codec that sounds good or one> for which > subtracting the original gives a better signal?> > QUALITY MEASUREMENT IDEA: > > I find it difficult to hear 2 voice samples and > tell > > which is nearer the original, especially if the > > background hiss is slightly different. So what if > you > > actually subtract the post-compression sound from > the > > original and then listen to the DIFFERENCE. If you > > can't hear any voice except background noise and > some > > hiss from "s"'s and "d"'s and such, that means > most of > > the actual voice has been maintained. If you can > hear > > someone speaking, that means there is leftover > voice. > > If you can actually understand what that someone > is > > saying, the difference is great. Thoughts? ><p>__________________________________ Do you Yahoo!? Yahoo! SiteBuilder - Free, easy-to-use web site design software http://sitebuilder.yahoo.com --- >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 'speex-dev-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.
2 things, first an idea... next a question. QUALITY MEASUREMENT IDEA: I find it difficult to hear 2 voice samples and tell which is nearer the original, especially if the background hiss is slightly different. So what if you actually subtract the post-compression sound from the original and then listen to the DIFFERENCE. If you can't hear any voice except background noise and some hiss from "s"'s and "d"'s and such, that means most of the actual voice has been maintained. If you can hear someone speaking, that means there is leftover voice. If you can actually understand what that someone is saying, the difference is great. Thoughts? QUESTIONS: My hearing is not the best I suppose, because I can barely tell the difference between any of the encodings and the original for the examples hosted on the Speex.org website. When I encode, I can barely tell the difference between quality 3 and quality 10. Complexity is at 8 or above. SO my questions are: 1. What would be a common quality level for 56k modems to use in voice chat during a game? CPU usage is not an issue. 2. Would it be better to have 16khz at quality 3(complex10) or 8khz at quality 5, they end up roughly the same size? (let me know if you are refering to VBR or not or both) Thanks to those who have enough experience to have a general idea of this illusive "quality" stuff I'm asking about. __________________________________ Do you Yahoo!? Yahoo! SiteBuilder - Free, easy-to-use web site design software http://sitebuilder.yahoo.com --- >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 'speex-dev-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.