>> Do you (or the ogg vorbis community) understand how SBR works? There is >> info on http://www.codingtechnologies.de/technology/sbr.htm >> bnut I am guessing this infop is not enough to explain the technology.Robert Voigt:>I haven't heard about SBR before. After reading that webpage I can say the >following: [ . . . ] I don't think SBR will give an improvement >such that 64kbps will sound as >good as 100kbps conventional mp3.This seems to contradict, and with a margin, the current statement of Thomson multimedia. Thomson multimedia says MP3PRO 64 kbps sounds like MP3 at 128 kbps. Thomson is marketing MP3PRO as a technology for doubling the capacity of portable MP-equipment. Thomson: "The new codec, dubbed "mp3PRO", provides 128kbs performance at a 64kbs encoding rate, nearly doubling the digital music capacity of typical flash memory. " -- http://www.thomsonmultimedia.com/vus/04/042/01/090101.htm I am trying here to determine a proper level of skepticism. I've seen double blind results for MP3PRO at 24 kbps vs MP3 at 32 kbps. What I have not seen are results for higher speeds. On the other hand ... I am assuming Thomson has made such tests. Would they really go public with this claim if they had not? Am I perhaps being naive? p.s. I am on the vorbis-dev list now so you don't have to cc me. -- -- Jan Tångring, reporter Datateknik 3.0 (www.datateknik30.se) --- >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-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.
>> Do you (or the ogg vorbis community) understand how SBR works? There is >> info on http://www.codingtechnologies.de/technology/sbr.htm >> bnut I am guessing this infop is not enough to explain the technology.Robert Voigt:>I haven't heard about SBR before. After reading that webpage I can say the >following: [ . . . ] I don't think SBR will give an improvement >such that 64kbps will sound as >good as 100kbps conventional mp3.- Unfortunately your source is wrong in his assumtions, comments Lars Liljeryd on Robert Voigts statement. - We cannot see that there are inherent or future limitations in SBR when in comes to higher sound quality. Lars Liljeryd says he don't want to speculate on where lies the "sweet spot" of SBR. He is not willing to supply further technical details on how SBR works. -- -- Jan Tångring, reporter Datateknik 3.0 (www.datateknik30.se) --- >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-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.
On Monday 14 May 2001 13:51, Jan.Tangring@et.se wrote:> This seems to contradict, and with a margin, the current statement of > Thomson multimedia. Thomson multimedia says MP3PRO 64 kbps sounds like MP3 > at 128 kbps. Thomson is marketing MP3PRO as a technology for doubling the > capacity of portable MP-equipment.I'll tell you how I would obtain to figures like this if I were a greedy inventor wanting to make as much money as possible. I would select some pieces of music where my new audio codec performs very well and do double blind tests with low quality equipment, and claim that this is the kind of equipment most people use for listening to compressed music (computer speakers, headphones that come bundled with mp3 players). Of course my test people won't hear the difference between 128kbps conventional and the shiny new codec at 64kbps. This is not the way to determine the performance of an audio codec, but it's ok for marketing purposes, because most people don't mind being told something that is not exactly true. There have been some improvements in audio codecs since the original mp3 was released, but they are not as great that 64kbps could sound like 128kbps. What's more, mp3pro is supposed to be compatible with mp3. This limits improvements considerably. Not everything can be done like any good engineer would do them if he startet from scratch.> Am I perhaps being naive?No, because you're trying to determine a proper level of skepticism. On Monday 14 May 2001 14:59, Jan.Tangring@et.se wrote:> - Unfortunately your source is wrong in his assumtions, comments Lars > Liljeryd on Robert Voigts statement. > > - We cannot see that there are inherent or future limitations in SBR > when in comes to higher sound quality. > > Lars Liljeryd says he don't want to speculate on where lies the > "sweet spot" of SBR. He is not willing to supply further technical > details on how SBR works.What I said about the figures above applies here too. The only way to claim that 64kbps mp3 with SBR sounds as good as >100kbps mp3 is the above mentioned way. I'm not saying there's no improvement. I'm saying the improvement can't be that great. If that guy was a little more open about the internals of his invention I could estimate the performance better. I wonder why he's trying to keep it a secret. If it's patentet he has nothing to fear. Perhaps I could find out more by searching a patent database, but it's not worth the effort. We can't use it in Vorbis anyway, Vorbis is patent free. --- >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-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.
Hello! I have the following idea about this "spectral band replication": Harmonic frequencies are integer multiples of the fundamental frequency. That means if you take all frequencies in a particular block (say up to 11 KHz for a medium bitrate encoding), double them and add them to the original at a lower volume, then this results in frequencies up to 22 KHz. I suppose that taking anything else but harmonics will rather end up in more noise. And don't know if that's it what mp3pro does, because I didn't find any details, and they probably won't give them out. I already tried this with music that I downsampled to 11 KHz, i.e. frequencies up to 5.5 KHz, and it did sound much better when adding the harmonics x2, x3, x4 or even more. Stefan T. Boettner --- >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-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.