Hi, I wonder if there is specific requirement or restriction for the decoder in order to be consider "Vorbis" compliant (or let's say, to be a "correct" vorbis decoder). I am experimenting with integerized libvorbis and the decoder delivers the audio data as following, (and compare with the floating point version below). $ tail audioout-int.txt 0290670 025e 085c 02cf 0895 0349 08b2 039e 087d 0290680 03ab 07df 03a0 0738 03de 06d6 0458 069f 0290690 04f2 066b 05c3 061a 069d 05cd 0784 057b 02906a0 0865 052e 095d 050e 0a46 04f2 0b0e 04f2 02906b0 0bd0 0505 0c9c 0552 0d48 059f 0dd7 05ec 02906c0 0e88 0675 0f77 0747 1045 07ec 10b0 083f 02906d0 1111 0895 1190 0927 11e4 09a8 1243 0a17 02906e0 12fb 0ab7 1395 0b18 13f6 0b3b 144e 0b22 02906f0 149c 0ab8 14a9 09e6 1509 093d 14a6 07ff 0290700 $ tail audioout-float.txt 0290670 0262 0860 02ee 08a1 0377 08c5 03bc 0884 0290680 03c7 07ea 03be 073c 03d8 06c0 0459 0697 0290690 0506 0664 05bf 0606 06bd 05c6 07b6 0583 02906a0 0883 0528 097d 0505 0a71 04f9 0b23 04dc 02906b0 0beb 0502 0cc6 0564 0d6b 05aa 0df6 05eb 02906c0 0eb4 067a 0fad 0754 1072 07f8 10da 0846 02906d0 114e 08b1 11c8 093f 121c 09b8 128d 0a3d 02906e0 1318 0ac0 1396 0b20 141d 0b5e 1477 0b3c 02906f0 14a0 0aaf 14d1 09f1 14cb 08ed 14a4 07dd 0290700 In theory, must they deliver exactly the same audio output or some errors are tolerable. Thank you very much, Pattara -- Please avoid sending me Word or PowerPoint attachments. See http://www.fsf.org/philosophy/no-word-attachments.html ---------------------------------------------------------------------- Ott Pattara Kiatisevi T L W G M.Sc. INFOTECH Student, Stuttgart, Germany http://linux.thai.net/ ---------------------------------------------------------------------- <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-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.
this is a common problem with Intger decoders. Looking at absolute differences is educational but not very conclusive. There are more complex frequency-domain tests you can do (ie rate/distortion within frequency bands...) How does it sound? <p> ___ Dan Miller (++,) CTO and founder, On2 Technologies On Fri, 5 Apr 2002, Pattara Kiatisevi wrote:> Hi, > > I wonder if there is specific requirement or restriction for the decoder > in order to be consider "Vorbis" compliant (or let's say, to be a > "correct" vorbis decoder). I am experimenting with integerized libvorbis > and the decoder delivers the audio data as following, (and compare with > the floating point version below). > > $ tail audioout-int.txt > 0290670 025e 085c 02cf 0895 0349 08b2 039e 087d > 0290680 03ab 07df 03a0 0738 03de 06d6 0458 069f > 0290690 04f2 066b 05c3 061a 069d 05cd 0784 057b > 02906a0 0865 052e 095d 050e 0a46 04f2 0b0e 04f2 > 02906b0 0bd0 0505 0c9c 0552 0d48 059f 0dd7 05ec > 02906c0 0e88 0675 0f77 0747 1045 07ec 10b0 083f > 02906d0 1111 0895 1190 0927 11e4 09a8 1243 0a17 > 02906e0 12fb 0ab7 1395 0b18 13f6 0b3b 144e 0b22 > 02906f0 149c 0ab8 14a9 09e6 1509 093d 14a6 07ff > 0290700 > > $ tail audioout-float.txt > 0290670 0262 0860 02ee 08a1 0377 08c5 03bc 0884 > 0290680 03c7 07ea 03be 073c 03d8 06c0 0459 0697 > 0290690 0506 0664 05bf 0606 06bd 05c6 07b6 0583 > 02906a0 0883 0528 097d 0505 0a71 04f9 0b23 04dc > 02906b0 0beb 0502 0cc6 0564 0d6b 05aa 0df6 05eb > 02906c0 0eb4 067a 0fad 0754 1072 07f8 10da 0846 > 02906d0 114e 08b1 11c8 093f 121c 09b8 128d 0a3d > 02906e0 1318 0ac0 1396 0b20 141d 0b5e 1477 0b3c > 02906f0 14a0 0aaf 14d1 09f1 14cb 08ed 14a4 07dd > 0290700 > > In theory, must they deliver exactly the same audio output or some > errors are tolerable. > > Thank you very much, > Pattara > > -- > Please avoid sending me Word or PowerPoint attachments. > See http://www.fsf.org/philosophy/no-word-attachments.html > ---------------------------------------------------------------------- > Ott Pattara Kiatisevi T L W G > M.Sc. INFOTECH Student, Stuttgart, Germany http://linux.thai.net/ > ---------------------------------------------------------------------- > > > --- >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. ><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-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.
Pattara Kiatisevi wrote:> > Hi, > > I wonder if there is specific requirement or restriction for the decoder > in order to be consider "Vorbis" compliant (or let's say, to be a > "correct" vorbis decoder). I am experimenting with integerized libvorbis > and the decoder delivers the audio data as following, (and compare with > the floating point version below).First of all, there is no published formal spec yet.> $ tail audioout-int.txt > 0290670 025e 085c 02cf 0895 0349 08b2 039e 087d > 0290680 03ab 07df 03a0 0738 03de 06d6 0458 069f > > $ tail audioout-float.txt > 0290670 0262 0860 02ee 08a1 0377 08c5 03bc 0884 > 0290680 03c7 07ea 03be 073c 03d8 06c0 0459 0697But these differences seem way too big.> In theory, must they deliver exactly the same audio output or some > errors are tolerable.Some slight differences will be unavoidable, I think. But nothing bigger than off-by-one. Again, no formal spec yet. YMMV. Etc. <p>Segher <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-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.
Segher Boessenkool wrote:>> I wonder if there is specific requirement or restriction for the decoder >> in order to be consider "Vorbis" compliant (or let's say, to be a >> "correct" vorbis decoder). I am experimenting with integerized libvorbis >> and the decoder delivers the audio data as following, (and compare with >> the floating point version below). > >First of all, there is no published formal spec yet. > >> $ tail audioout-int.txt >> 0290670 025e 085c 02cf 0895 0349 08b2 039e 087d >> 0290680 03ab 07df 03a0 0738 03de 06d6 0458 069f >> >> $ tail audioout-float.txt >> 0290670 0262 0860 02ee 08a1 0377 08c5 03bc 0884 >> 0290680 03c7 07ea 03be 073c 03d8 06c0 0459 0697 > >But these differences seem way too big. > >> In theory, must they deliver exactly the same audio output or some >> errors are tolerable. > >Some slight differences will be unavoidable, I think. But nothing >bigger than off-by-one.Off by one what? One in the LSB of a 16-bit integer sample? Nonsense. :) Think about it: Take an original piece of PCM data, encode it with Vorbis, and then decode it again using the reference libvorbis. Certainly you would expect the vorbis step to inflict more than an "off-by-one" effect on each sample. Thus perhaps the real question is whether or not a given libvorbis delivers results that are at least as "lossless" as the reference library. And, as another poster noted, you can't really tell just from looking at raw data. It requires a more involved analysis... -Owen --- >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.
Segher Boessenkool wrote:>Adrien Beau wrote: >> >> On Monday 8 April 2002 14:51, Owen Emry wrote: >> > >> > >Some slight differences will be unavoidable, I think. But >> > > nothing bigger than off-by-one. >> > >> > Off by one what? One in the LSB of a 16-bit integer sample? >> > Nonsense. :) Think about it: Take an original piece of PCM >> > data, encode it with Vorbis, and then decode it again using >> > the reference libvorbis. Certainly you would expect the >> > vorbis step to inflict more than an "off-by-one" effect on >> > each sample. >> >> I think Segher perfectly knows this. >> >> > Thus perhaps the real question is whether or not a given >> > libvorbis delivers results that are at least as "lossless" as >> > the reference library. >> >> Thus perhaps Segher meant that he expects nothing bigger >> than off-by-one between the output of a given libvorbis and >> the output of the reference library.Whereas what I meant is that this seems unrealistic, given that the difference introduced by the codec is an order of magnitude greater.>Exactly. Which was exactly what the original post was about. And >errors of more than 1% seem way too big, to me. But the exact >requirements should be set in the formal spec, which doesn't exist yet.I thought you were talking about a difference of 1, not 1%. Anyway, you're correct; there ought to be a spec for tolerable variance, but I still maintain it's a more complicated analysis. -Owen <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-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.