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From: SMITH Linton <Linton.SMITH@Tenix.com>  20040908 23:15:27

David O(...) is mathematical speak for "Order of" meaning that we are talking about a value that is about the size of (...) eg O(10) means a value in the range of ~1099, O(1000) means a value in the range ~1000  9999. So O(Log n) means a value that is in a range around the logarithm of N where N is some value. Original Message From: audacityusersadmin@... [mailto:audacityusersadmin@...]On Behalf Of David R. Sky Sent: Thursday, 9 September 2004 7:07 AM To: audacityusers@... Subject: Re: [Audacityusers] automatic synchronisation of 2 tracks On Wed, 8 Sep 2004, patrick jayet wrote: > Do you know if there exists a solution with audacity (i.e. a plugin) in > order to make an automatic synchronisation (of the bpm) of 2 tracks? > Like what can be made under Win with AcidPro 4.0 and the BeatMapper > plugin. The idea is then to make a mix between these tracks. > > Now I am doing it manually by modifying the sample rate, what is just a > little bit long (about O(log n) steps where n is more or less the > difference between the original sample rate and the target one). Is 'o(log n)' a typo, do you mean '(log n)'? If you explain in detail what you manually do in Audacity (for example, using the (log n) math), I'll give it a go at making such a plugin. Include what variables you want to be able to input, whatever else you want. Does changing the sample rate also change the pitch of the stretched or squeezed track? I haven't used AcidPro or BeatMapper before. David  This SF.Net email is sponsored by BEA Weblogic Workshop FREE Java Enterprise J2EE developer tools! Get your free copy of BEA WebLogic Workshop 8.1 today. http://ads.osdn.com/?ad_id=3D5047&alloc_id=3D10808&op=3Dclick =20 Mailing list: Audacityusers@... To UNSUBSCRIBE, use the form at the bottom of this web page: https://lists.sourceforge.net/lists/listinfo/audacityusers 
From: SMITH Linton <Linton.SMITH@Tenix.com>  20040909 07:54:48

yep that's about right Original Message From: audacityusersadmin@... [mailto:audacityusersadmin@...]On Behalf Of David R. Sky Sent: Thursday, 9 September 2004 1:42 PM To: audacityusers@... Subject: RE: [Audacityusers] automatic synchronisation of 2 tracks On Thu, 9 Sep 2004, SMITH Linton wrote: > O(...) is mathematical speak for "Order of" meaning that we are talking > about a value that is about the size of (...) eg O(10) means a value in > the range of ~1099, O(1000) means a value in the range ~1000  9999. > So O(Log n) means a value that is in a range around the logarithm of N > where N is some value. > What if the value of log n is below 1? o(0.01) is 0.01 to 0.09? Thanks for explaining Linton! David  This SF.Net email is sponsored by BEA Weblogic Workshop FREE Java Enterprise J2EE developer tools! Get your free copy of BEA WebLogic Workshop 8.1 today. http://ads.osdn.com/?ad_id=3D5047&alloc_id=3D10808&op=3Dclick =20 Mailing list: Audacityusers@... To UNSUBSCRIBE, use the form at the bottom of this web page: https://lists.sourceforge.net/lists/listinfo/audacityusers 
From: David R. Sky <sky@wa...>  20040909 04:11:42

On Thu, 9 Sep 2004, SMITH Linton wrote: > O(...) is mathematical speak for "Order of" meaning that we are talking > about a value that is about the size of (...) eg O(10) means a value in > the range of ~1099, O(1000) means a value in the range ~1000  9999. > So O(Log n) means a value that is in a range around the logarithm of N > where N is some value. > What if the value of log n is below 1? o(0.01) is 0.01 to 0.09? Thanks for explaining Linton! David 
From: John Haxby <jch@th...>  20040909 09:03:01

The original poster was referring to algortihmic complexity rather than=20 anything else. In that O(1) (generally pronounced "bigoh one" but=20 sometimes "order one") means constant regardless of the size of the=20 dataset. One of the triumphs of the Linux 2.6 kernel scheduler is that = it is O(1). O(log n) means that that the execution time for the=20 algorithm depends on the logarithm of the data set. Usually we're=20 speaking about log base 2 here and I think the original poster was using = binary chop to find the right value. O(n) is sometimes pronounced=20 linear; O(n=B2) (n squared) is quadratic and moderately unpleasant; O(e^n= )=20 (I don't have an n superscript) is expoential and fairly horrible;=20 O(n^n) is a total disaster for an algorithm. For maths, I take O(n) to mean, roughly, n/10 to n*10 so order(10) is=20 somewhere between 1 and 100  they're all the same order of=20 magnitude. In astrophysics, being to within a couple of orders of=20 magnitude is often regarded as dead spot on accurate :) jch David R. Sky wrote: >On Thu, 9 Sep 2004, SMITH Linton wrote: > =20 > >>O(...) is mathematical speak for "Order of" meaning that we are talking= >>about a value that is about the size of (...) eg O(10) means a value i= n >>the range of ~1099, O(1000) means a value in the range ~1000  9999. >>So O(Log n) means a value that is in a range around the logarithm of N >>where N is some value. >> =20 >> >What if the value of log n is below 1? o(0.01) is 0.01 to 0.09? > >Thanks for explaining Linton! > >David > =20 > 
From: David R. Sky <sky@wa...>  20040909 09:11:06

John, Thanks for your explanation, at the moment it's above my head. So I'll let the original poster explain what exactly he does to fix his problem, and then I'll try to build a plugin from there. Cheers David On Thu, 9 Sep 2004, John Haxby wrote: > The original poster was referring to algortihmic complexity rather than > anything else. In that O(1) (generally pronounced "bigoh one" but > sometimes "order one") means constant regardless of the size of the > dataset. One of the triumphs of the Linux 2.6 kernel scheduler is that > it is O(1). O(log n) means that that the execution time for the > algorithm depends on the logarithm of the data set. Usually we're > speaking about log base 2 here and I think the original poster was using > binary chop to find the right value. O(n) is sometimes pronounced > linear; O(n=B2) (n squared) is quadratic and moderately unpleasant; O(e^n= ) > (I don't have an n superscript) is expoential and fairly horrible; > O(n^n) is a total disaster for an algorithm. > > For maths, I take O(n) to mean, roughly, n/10 to n*10 so order(10) is > somewhere between 1 and 100  they're all the same order of > magnitude. In astrophysics, being to within a couple of orders of > magnitude is often regarded as dead spot on accurate :) > > jch > > > David R. Sky wrote: > > >On Thu, 9 Sep 2004, SMITH Linton wrote: > > > > > >>O(...) is mathematical speak for "Order of" meaning that we are talking > >>about a value that is about the size of (...) eg O(10) means a value i= n > >>the range of ~1099, O(1000) means a value in the range ~1000  9999. > >>So O(Log n) means a value that is in a range around the logarithm of N > >>where N is some value. > >> > >> > >What if the value of log n is below 1? o(0.01) is 0.01 to 0.09? > > > >Thanks for explaining Linton! > > > >David > > > > > > > > >  > This SF.Net email is sponsored by BEA Weblogic Workshop > FREE Java Enterprise J2EE developer tools! > Get your free copy of BEA WebLogic Workshop 8.1 today. > http://ads.osdn.com/?ad_idP47&alloc_id=10808&op=CCk > =20 
From: patrick jayet <jayetp@st...>  20040909 19:27:51

BEGIN PGP SIGNED MESSAGE Hash: SHA1 Hi David, Sorry for using the bigoh notation without explaining it. It is effectively, like explained by John Haxby, used in algorithmic complexity and has the meaning of the "the order of". However what I wanted to say is quite simple: I am using audacity to synchronize the beat of two tracks by changing gradually the sample rate (that means the speed and tone together) of one track. That is doable by hand[1], but I am wondering if there exist a plugin that could determine automatically the bpm of a track (with some precision) in order to calculate the sample rate to set to one of the 2 tracks. I haven't used BeatMapper neither AcidPro 4.0. I could possibly ask a few question to a friend, who uses it, to know more precisely how it works. Have a nice (dayevening). ;) Regards. Patrick [1] A facultative information about de binary search: Like explained in my first post, i am using by hand an algorithm to find the exact sample rate called binary search. The idea is quite simple: if i am searching a number in an array of 1000 ordered numbers, i pick the number in the middle, according to the fact that the number I search is greater or smaller, I know that I must search in the first half or the second half of the array (it is ordered). So I take the corresponding half and repeat the process until the end (when I get an array of size 1, I have found the number or not if it wasn't present in the array). The number of steps of the process is given by log_2(n) where n is the size of the original array. For my search of the right sample rate, if I am starting at 44'100 Hz and I have a difference of about +/2000 Hz, n=4000 so I need about 12 steps in order to find my exact sample rate. BEGIN PGP SIGNATURE Version: GnuPG v1.2.4 (GNU/Linux) Comment: Using GnuPG with Mozilla  http://enigmail.mozdev.org iD8DBQFBQK7sDdcPKzlCXVMRAh6BAJ9yYxyVfc1iM5uesRjrpRilpxyg/QCguYBB lfvCeSrrxu2O3QPf5rnEC8U= =wSJk END PGP SIGNATURE 
From: David R. Sky <sky@wa...>  20040910 01:25:07

On Thu, 9 Sep 2004, patrick jayet wrote: > Sorry for using the bigoh notation without explaining it. It is > effectively, like explained by John Haxby, used in algorithmic > complexity and has the meaning of the "the order of". > > However what I wanted to say is quite simple: I am using audacity to > synchronize the beat of two tracks by changing gradually the sample rate > (that means the speed and tone together) of one track. That is doable by > hand[1], but I am wondering if there exist a plugin that could determine > automatically the bpm of a track (with some precision) in order to > calculate the sample rate to set to one of the 2 tracks. > Hi Patrick There is something called 'Beat Finder' under the analyze menu  alta if you're using Windows. I have no idea how to use it though, I have not worked with any of the analyze plugins. If you're interested, I think you'll find the plugin Nyquist code for it in beat.ny in the Audacity plugins folder. Good luck! David 
From: Ishwar Rattan <ishwar@pa...>  20040910 02:05:34

System is Win2K with audacity1.2.2 I recorded some music from tape and there are some scratchy patches in it. Is there a some bulitin filter (in effects) or any other plug in that might improve the quality a little?? Thanks in advance, ishwar 
From: David R. Sky <sky@wa...>  20040910 02:33:12

On Thu, 9 Sep 2004, Ishwar Rattan wrote: > System is Win2K with audacity1.2.2 > > I recorded some music from tape and there are some scratchy > patches in it. Is there a some bulitin filter (in effects) > or any other plug in that might improve the quality a little?? > Try noise removal under the effects menu. I've tried using but didn't have success, probably because I don't understand it. Many others on this list have used it successfully. David 
From: Ishwar Rattan <ishwar@pa...>  20040910 12:37:16

I tried noise removal effect but had no success. ishwar On Thu, 9 Sep 2004, David R. Sky wrote: > On Thu, 9 Sep 2004, Ishwar Rattan wrote: > > > System is Win2K with audacity1.2.2 > > > > I recorded some music from tape and there are some scratchy > > patches in it. Is there a some bulitin filter (in effects) > > or any other plug in that might improve the quality a little?? > > > Try noise removal under the effects menu. I've tried using but didn't have > success, probably because I don't understand it. Many others on this list > have used it successfully. > > David > > > >  > This SF.Net email is sponsored by: YOU BE THE JUDGE. Be one of 170 > Project Admins to receive an Apple iPod Mini FREE for your judgement on > who ports your project to Linux PPC the best. Sponsored by IBM. > Deadline: Sept. 13. Go here: http://sf.net/ppc_contest.php >  > Mailing list: Audacityusers@... > To UNSUBSCRIBE, use the form at the bottom of this web page: > https://lists.sourceforge.net/lists/listinfo/audacityusers > 
From: Phil Nelson <pdn@PhilNelson.DNSalias.net>  20040911 02:14:46

Ishwar Rattan wrote: > On Thu, 9 Sep 2004, David R. Sky wrote: > > >>On Thu, 9 Sep 2004, Ishwar Rattan wrote: >> >> >> >>>System is Win2K with audacity1.2.2 >>> >>>I recorded some music from tape and there are some scratchy >>>patches in it. Is there a some bulitin filter (in effects) >>>or any other plug in that might improve the quality a little?? >>> >>> >>> >>Try noise removal under the effects menu. I've tried using but didn't have >>success, probably because I don't understand it. Many others on this list >>have used it successfully. >> >>David >> >> >> >> >I tried noise removal effect but had no success. > >ishwar > > > Maybe you had the volume set a little too high and the "scratchy patches" are clipping? Did you try rerecording with lower volume?  Phil Nelson 
From: patrick jayet <jayetp@st...>  20040910 17:56:10

BEGIN PGP SIGNED MESSAGE Hash: SHA1 Hi David,  There is something called 'Beat Finder' under the analyze menu  alta if  you're using Windows. I have no idea how to use it though, I have not worked  with any of the analyze plugins. If you're interested, I think you'll find  the plugin Nyquist code for it in beat.ny in the Audacity plugins folder. Unfortunately Beat Finder doesn't seem to be what I am looking for. When I run it, it simply asks for a threshold value and then try to identify on the track the locations of the beats, that are then marked on a separated label track. The result is not very precise (because the algorithm seems not very accurate and that we need to enter a threshold) and it doesn't give the value of the BPM, the information that I am looking for. I have no idea if it is hard to write a plugin for something like that. I must say I have almost no experience in the sound processing domain. My opinion is that the plugin should not need a threshold. On a track, the beat is regular (for electronic music), is situated in a welldefined frequency range and is quite powerful in amplitude. I suppose these informations would suffice a plugin to determine the exact bpm. What do you think David? Would it be hard to write something like that or is it something existing for audacity? Regards! Patrick BEGIN PGP SIGNATURE Version: GnuPG v1.2.4 (GNU/Linux) Comment: Using GnuPG with Mozilla  http://enigmail.mozdev.org iD8DBQFBQeryDdcPKzlCXVMRAiK6AJ9AOoUD9GgTDMoWmx+fMoPrL/HkFwCgutTC L/6eL2QNV0bqmSAyR6an6m4= =Sgk5 END PGP SIGNATURE 
From: David R. Sky <sky@wa...>  20040910 19:06:42

patrick: Unfortunately Beat Finder doesn't seem to be what I am looking for. When I run it, it simply asks for a threshold value and then try to identify on the track the locations of the beats, that are then marked on a separated label track. The result is not very precise (because the algorithm seems not very accurate and that we need to enter a threshold) and it doesn't give the value of the BPM, the information that I am looking for. I have no idea if it is hard to write a plugin for something like that. I must say I have almost no experience in the sound processing domain. My opinion is that the plugin should not need a threshold. David: Different music will have different volumes relative to each other, so I assume that's why that edit field is there. Otherwise the plugin would be trying to find a beat for both a soft piece as well as a loud rockin' thumpin' thing. Try a couple different threshold values, a low and then a relatively high value and see what difference that makes. If one of those works, then what's needed next in the plugin itself is to determine the length of the audio and do a bit of math. Patrick: On a track, the beat is regular (for electronic music), is situated in a welldefined frequency range and is quite powerful in amplitude. I suppose these informations would suffice a plugin to determine the exact bpm. What do you think David? Would it be hard to write something like that or is it something existing for audacity? David: It sounds simple enough, but I have no experience writing analyze plugins, just effect and generate so far. I'll forward your post to someone who could probably help. Cheers David  
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