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Vorbis development, status & patent issues, PART 2 - Technical discussion
Gabriel
post Sep 25 2003, 14:37
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Currently the Vorbis patent issue covers these threads:
Vorbis development, status & patent issues PART 1 - NON-technical discussion
Vorbis development, status & patent issues PART 2 - Technical discussion (This thread)
/Moderator comment

By looking at this:
http://www.xiph.org/archives/vorbis-dev/20...2/index.html#83
it seems that Xiph (at least in 2000) was open to the idea of disclosing the patent research.
Is this position changed now, or does it still stand?
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ScorLibran
post Oct 7 2003, 21:20
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QUOTE (sthayashi @ Oct 7 2003, 03:41 PM)
QUOTE (Ivan Dimkovic @ Oct 7 2003, 06:02 AM)
#2 Attacking claim 1 with argument that switching criterion is different from "signal amplitude change"

As for #2, that spells a big oops for Xiph. I've got a question though. Is there any documentation on how the encoder chooses between short and long window sizes? I mean, I believe you, but I have to see it myself, because that's strong evidence of infringement, IMHO.

Here's a page from the Xiph.org developement forum that may shed some light.

Excerpt:
"Vorbis simply normalizes the time-domain envelope before the MDCT.
Each block is scanned for a dynamic range increase over a
predetermined threshhold; the envelope of the time domain signal is
normalized from the point of the change to the end of the block
(current code normalizes to an even =/- 6dB). The envelope is cheap
to compute, easy to encode efficiently (most blocks don't need it, so
we don't encode an envelope in 98% of the blocks) and simple. My
tests with 'castanets.wav' gets better results than with LAME or
Fraunhofer (IMHO ;-) Needless to say, I was a bit surprised."


(Note: This is from August 1999, but the core functionality of the codec has not changed, has it?)

From what I've studied about the architecture of the Vorbis codec over the past week or so, it seems to be using some variant of signal-amplitude changes to determine window size, but the use of "envelope pre-clamping" has to also be considered before determining whether this is ultimately infringing on the patent in question, if it (if I'm reading this right) normalizes the signal before the MDCT step. (Does signal = time/domain envelope?) Also, Monty covers some other points which he believes avoids other MPEG-related patents as well in the linked post.

Everyone's probably already seen this, but it seems relevant right about now.

Edit: Here's a hopefully more relevant reference to the similarity between Vorbis and MPEG codecs concerning how window size determination is done...

"Vorbis is a hybrid transform domain general purpose audio encoder,
like MPEG in some respects (it is rooted in much of the same basic
theory). For the most part, the similarity comes from the fact that
(like nearly all modern audio compressions), Vorbis codes primarily in
the MDCT domain, using nominal 50% overlap with a y=sin(2PI*sin^2(x))
window (the window is a bit unique). The current Vorbis code and
working spec support switching between two block sizes which must
result in power-of-two sized windowed blocks. From here, the details
diverge." ...


This post has been edited by ScorLibran: Oct 7 2003, 22:38
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Posts in this topic
- Gabriel   Vorbis development, status & patent issues   Sep 25 2003, 14:37
- - c_haese   QUOTE (Ivan Dimkovic @ Sep 25 2003, 08:12 AM)...   Sep 25 2003, 14:43
- - Ivan Dimkovic   QUOTE Fair enough, let's start a scientific di...   Sep 25 2003, 14:53
- - Ivan Dimkovic   One more thing - the claims are not related to any...   Sep 25 2003, 14:59
- - menno   Claim 1 from patent US5214742: QUOTE 1. In a metho...   Sep 25 2003, 15:20
- - menno   1.3. High-level Decode Process It seems that the ...   Sep 25 2003, 15:41
- - Ivan Dimkovic   Ok, so we have a pretty clear basis for a serious ...   Sep 25 2003, 15:43
- - c_haese   I've already said everything I'm qualified...   Sep 25 2003, 16:03
- - Ivan Dimkovic   Well, at least there is a nice bunch of factual da...   Sep 25 2003, 16:14
- - petracci   QUOTE (Ivan Dimkovic @ Sep 25 2003, 05:36 PM)...   Sep 25 2003, 16:50
- - Ivan Dimkovic   QUOTE Claim 1 does not claim the "windowing/o...   Sep 25 2003, 16:56
- - petracci   QUOTE (Ivan Dimkovic @ Sep 25 2003, 05:56 PM)...   Sep 25 2003, 17:07
- - Ivan Dimkovic   QUOTE First of all, do you also think that claim 1...   Sep 25 2003, 17:22
- - petracci   Yes, Claim 4 is not easy to avoid. Claim 6 points ...   Sep 25 2003, 17:34
- - c_haese   QUOTE (Ivan Dimkovic @ Sep 25 2003, 11:22 AM)...   Sep 25 2003, 17:36
- - Ivan Dimkovic   QUOTE Wouldn't all claims have to apply to mak...   Sep 25 2003, 18:30
- - jmvalin   QUOTE (petracci @ Sep 25 2003, 11:34 AM)Yes, ...   Sep 25 2003, 23:31
- - JohnV   QUOTE (jmvalin @ Sep 26 2003, 01:31 AM)QUOTE ...   Sep 26 2003, 00:23
- - Ivan Dimkovic   I took a deeper look at the patent - It seems that...   Sep 26 2003, 01:05
- - Ivan Dimkovic   I mean - in my opinion, the purpose of the Claim 1...   Sep 26 2003, 01:13
- - ErikS   QUOTE (Ivan Dimkovic @ Sep 26 2003, 01:13 AM)...   Sep 26 2003, 01:48
- - petracci   QUOTE I took a deeper look at the patent - It seem...   Sep 26 2003, 08:59
- - Ivan Dimkovic   QUOTE E.g. incorporating the rate in the switching...   Sep 26 2003, 09:05
- - petracci   QUOTE I mean - in my opinion, the purpose of the C...   Sep 26 2003, 09:16
- - menno   Doesn't Parseval's Theorem say that freque...   Sep 26 2003, 09:19
- - Ivan Dimkovic   QUOTE I can obviously not say that either of us is...   Sep 26 2003, 09:21
- - petracci   QUOTE (Ivan Dimkovic @ Sep 26 2003, 10:21 AM)...   Sep 26 2003, 09:31
- - Ivan Dimkovic   I think it was: QUOTE 5853 Michael J. Smithers,Br...   Sep 26 2003, 09:48
- - petracci   QUOTE Doesn't Parseval's Theorem say that ...   Sep 26 2003, 09:49
- - petracci   QUOTE (Ivan Dimkovic @ Sep 26 2003, 10:48 AM)...   Sep 26 2003, 09:57
- - Ivan Dimkovic   I think we got into one very serous discussion rig...   Sep 26 2003, 10:04
- - petracci   QUOTE I think we got into one very serous discussi...   Sep 26 2003, 10:12
- - Ivan Dimkovic   http://cvs.sourceforge.net/viewcvs.py/ffmp...=1.18...   Sep 26 2003, 10:38
- - petracci   QUOTE I dunno about the patent - will take some ti...   Sep 26 2003, 10:49
- - Ivan Dimkovic   Actually, I never tried that FFMPEG code, so I am ...   Sep 26 2003, 10:53
- - petracci   QUOTE Actually, I never tried that FFMPEG code, so...   Sep 26 2003, 11:01
- - Ivan Dimkovic   QUOTE If they paid for licensing that patent on wi...   Sep 26 2003, 11:06
- - DSPguru   QUOTE (Ivan Dimkovic @ Sep 26 2003, 16:53 PM)...   Sep 26 2003, 11:15
- - Ivan Dimkovic   QUOTE recently, the official ffmpeg homepage had b...   Sep 26 2003, 11:21
- - Ivan Dimkovic   QUOTE e.g. if the complete technological details w...   Sep 26 2003, 12:01
- - petracci   QUOTE Ivan Dimkovic That is also interesting,...   Sep 26 2003, 12:18
- - Ivan Dimkovic   QUOTE If a respected developer/researcher like Iva...   Sep 26 2003, 12:34
- - petracci   QUOTE You are right - I am not sure,  of cour...   Sep 26 2003, 14:18
- - danchr   QUOTE (DSPguru @ Sep 26 2003, 12:15 PM)QUOTE ...   Sep 27 2003, 11:09
- - c_haese   Okay, let's get back to the scientific problem...   Sep 29 2003, 22:17
- - menno   QUOTE (c_haese @ Sep 29 2003, 10:17 PM)After ...   Sep 30 2003, 14:03
- - Ivan Dimkovic   Ok, for those with lmiited ability to read: Inste...   Sep 30 2003, 23:09
- - JohnV   Thread re-arranged. This thread is now only for te...   Oct 1 2003, 09:00
- - jmvalin   QUOTE (Ivan Dimkovic @ Sep 30 2003, 05:09 PM)...   Oct 1 2003, 23:26
- - Ivan Dimkovic   QUOTE (jmvalin @ Oct 1 2003, 10:26 PM)QUOTE (...   Oct 2 2003, 09:21
- - JohnV   Ok, I asked Xiph's opinion about this specific...   Oct 5 2003, 23:38
- - Ivan Dimkovic   All in all, this is how I perceive the picture... ...   Oct 6 2003, 08:30
- - jmvalin   QUOTE (JohnV @ Oct 5 2003, 05:38 PM)Ok, I ask...   Oct 6 2003, 20:11
- - JohnV   QUOTE (jmvalin @ Oct 6 2003, 10:11 PM)QUOTE (...   Oct 6 2003, 21:25
- - jmvalin   QUOTE (JohnV @ Oct 6 2003, 03:25 PM)Discussio...   Oct 7 2003, 03:17
- - JohnV   QUOTE (jmvalin @ Oct 7 2003, 05:17 AM)I said ...   Oct 7 2003, 04:54
- - jmvalin   QUOTE I was the only one who was talking about tha...   Oct 7 2003, 06:40
- - JohnV   QUOTE (jmvalin @ Oct 7 2003, 08:40 AM)OK, fir...   Oct 7 2003, 07:09
- - Ivan Dimkovic   Like I said - if somebody is so sure he avoided pa...   Oct 7 2003, 08:06
- - PatchWorKs   I don't want to be boring, but i have to say i...   Oct 7 2003, 08:34
- - Dibrom   QUOTE (PatchWorKs @ Oct 7 2003, 12:34 AM)I do...   Oct 7 2003, 08:43
- - sthayashi   JohnV, It seems to me that Monty's unofficial...   Oct 7 2003, 14:22
- - Ivan Dimkovic   QUOTE (PatchWorKs @ Oct 7 2003, 07:34 AM)I do...   Oct 7 2003, 14:36
- - Ivan Dimkovic   QUOTE (sthayashi @ Oct 7 2003, 01:22 PM)JohnV...   Oct 7 2003, 15:02
- - rsilva   Let me try to "preach to the deaf" once ...   Oct 7 2003, 19:17
- - sthayashi   QUOTE (Ivan Dimkovic @ Oct 7 2003, 06:02 AM)W...   Oct 7 2003, 20:41
- - ScorLibran   QUOTE (sthayashi @ Oct 7 2003, 03:41 PM)QUOTE...   Oct 7 2003, 21:20
- - Ivan Dimkovic   QUOTE "Vorbis is a hybrid transform domain ge...   Oct 7 2003, 23:00
- - Ivan Dimkovic   QUOTE (sthayashi @ Oct 7 2003, 07:41 PM) QUOT...   Oct 7 2003, 23:04
- - PatchWorKs   From XviD.org website: QUOTE European parliament ...   Oct 8 2003, 09:39
- - Ivan Dimkovic   I don't know what XVid claims (and for what pa...   Oct 8 2003, 10:07
- - Ivan Dimkovic   QUOTE Sorry to be so boring...  Sorry if I s...   Oct 8 2003, 11:27
- - Garf   QUOTE (ScorLibran @ Oct 7 2003, 10:20 PM)(Not...   Oct 8 2003, 17:07
- - Diocletian   QUOTE (Ivan Dimkovic @ Sep 26 2003, 12:01 PM)...   Oct 9 2003, 18:27
- - ScorLibran   QUOTE (Diocletian @ Oct 9 2003, 01:27 PM)Do y...   Oct 9 2003, 19:09


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