beat detection?

Discussion in 'TRAKTOR PRO / TRAKTOR SCRATCH PRO' started by djprince, Aug 20, 2009.

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  1. djprince

    djprince Forum Member

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    My ? is why when you delete the beatmarker traktor detects every beat precise.

    Obiously it detects it good enough so why after entering the right bpm why cant

    traktor base a grid on these beats?
  2. djreff

    djreff NI Product Owner

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    111
    now that is a solid point

    N.I why
  3. djprince

    djprince Forum Member

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    73
    lets keep this goin. it really bothers me.
  4. DiscoNova

    DiscoNova NI Product Owner

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    1,198
    Programmatically, detecting when a beat occurs is not the hard part, but indeed quite easy. What is harder is to determine how those beats map to a grid in a best possible way. The reason is that there are easily both false positives (an identified "beat" that is not actually a beat) as well as false negatives (a beat that was not identified for some reason). This means that in the sequence of identified beats, there are both caps as well as extra stuff that doesn't belong there.

    The grid mapping is usually done by a combination of statistical analysis (which of the detected beats do not appear to be part of the series) and bruteforce (generating an oscillator that matches most of the detected beats) to find the tempo the beats represent. Because of this, finding the individual beats only gets you half way up to knowing the tempo.

    A fine example of hard to determine beat (for programs that is; humans can do it quite easily) is Culture Beat's Mr. Vain ... between the actual "beats" that should be taken into account when determining the tempo, the bass has three 1/16th notes that the detector must disregard or the resulting bpm is nowhere near correct.
  5. RunningManDJ

    RunningManDJ NI Product Owner

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    But all your doing (in the original ?) is giving Traktor a better idea of how to do it. The vast majority of songs are going to have pretty tight bpms. It's not like we're asking traktor to figure tempo changes for a jam band. Most all of it is made on a computer anyways. Other programs have been doing something similar to what to what Prince said for years now.
  6. JohnnyH

    JohnnyH NI Product Owner

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    176
    Trakor beat mach problems

    Hi

    I don't why NI (Traktor) don't purchase the beat grid technology from Mixmeister ?

    I have yet to see Mixmeister fall over when detecting bpm of any dance tune I have, it seem spot on all the time, and if beat grid does need a tweak it always seems easy to do

    To get each track spot on in traktor manually is time consuming and a real pain !

    even more so when you have 1000's of dance tracks.

    Traktor seems to auto bpm better with digital music rather than record or analogue

    Lets hope version 1.2 has cracked the poor bpm detection
  7. goonzy

    goonzy Modérateur

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    2,885
    Poor? I barely have 1% of the tracks with a real wrong tempo.. moreover Mixmeister technology analyses tempo OK, but will not provide a beatgrid.
  8. djprince

    djprince Forum Member

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    try setting grids for spannish music like salsa its imposible. Their really loosing alot of

    business cause certain genre just cant be gridded and i dont get why it cant be fixed if

    it detects every bet perfect when you deleat the beatmarker.
  9. DiscoNova

    DiscoNova NI Product Owner

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    Removing the beatmarker does not make Traktor work better; without it, Traktor has no idea of the tempo - it only knows where there appear to be beats. And as I wrote in my earlier response, this is only the first stage of tempo detection ... and it really is the easiest part of it. But you need to keep in mind that there is more to be done with the "raw beats" than just detecting them...
  10. djprince

    djprince Forum Member

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    73
    i know it doesnt work correct without a beatmarker. Im saying that say you type in

    the correct tempo say using mixmeister and without the beatmarker it sees all the

    beats perfect why cant traktor use these beats to make the grid according to the

    tempo entered?
  11. DiscoNova

    DiscoNova NI Product Owner

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    1,198
    Because it needs a beatmarker for the grid. A beatmarker tells the application where there is the "first" beat of a bar. And you can indeed enter the tempo manually. The problem arises if that tempo is not consistent (ie. try to beatgrid a live band with a bad timing where the tempo fluctuates greatly).

    As for "why cant traktor use these beats to make the grid according to the tempo entered", the difference with beats and beatgrid is that the beatgrid is constant; it starts from the beatmarker and is evenly spaced from that point on (based on the detected overall tempo of the track). This means that the grid does not definetely fall onto where the detected "beats" are, because on some types of music the beats are not where they're "supposed to be". On Mixmeister and the kinds this poses a problem, because it thinks that a beat should occur where the grid is...

    I know that sounds a bit stupid, but I can't express the thoughts in my head too coherently at this point :(

    Personally, I don't usually have problems setting up the grids - even on latin or caribean music. Of course, there are some tracks that you simply can not beatgrid in a way that makes sense - but those tracks are a minority. Furthermore, it doesn't come as a surprise that some genres of music it is very hard to automatically set the grid for.
  12. JohnnyH

    JohnnyH NI Product Owner

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    176
    Whats Goonzy Secret

    I would like to know what is Goonzy BPM DETECTION secret in Traktor is ?

    quote Poor? I barely have 1% of the tracks with a real wrong tempo ?


    Everyone seems to have a different percentage of success !


    Me including, more like 60% success and 40% wrong tempo (Dance Music)

    You know its out by using the ticking metrome, every track you seem to have to finite tune & tweak !

    I do use flacs instead of crappy mp3's but I can not see this should affect the BMP detection ?


    I would be intrested to know why Goonzy has such a high success rate ?
    ---
    More Importantly

    Is Traktor Ver 1.2 going to address these BPM problems ? and be any better at BPM detection / Beat Grid ?

    As this is what I am waiting for.....


    There seems to be a few problems with Traktor at the moment (BPM Detection Mainly & Poor Sound Quality)

    If these can be rectified in version 1.2 Im sure they will then have a serious product that DJ's will warm to.

    At the moment the thought of manualy BPMing / checking / tweaking all 10,000 od track I have has put me right off


    I hope someone has addressed these problems in forthcoming verion1.2
  13. goonzy

    goonzy Modérateur

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    2,885
    Well I'm playing mostly straight 4x4 techno and tech housey stuff... My tracks only come from digital stores or digital sources (studios from friends, DAT or CD masters). The only problems I've had were with very oldskool acid house tracks which probably were recorded originally on analogue equipment withouta digital timecode (like good old Fostex or Tascam 4 trackers). Problems arise when using vinyl rips... and non electronic music of course :))

    I do get the 1/2 tempo recognition on breakbeat stuff.. but I don't consider this as bad tempo recognition (as only on click is required to get the right tempo) but I reckon I've had some 130 bpm tracks recognised as 100 or 150 on really "broken beats" and on tracks lacking dynamics.
  14. JohnnyH

    JohnnyH NI Product Owner

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    176
    Thanks for you reply

    Most of my problems in Traktor are from vinyl rips...

    This where most of my music comes from, (analogue, non precise Locked time code)

    and at the moment seems to be a problem in Traktor, I hope there are major imporovements in version 1.2

    It would now make sense as to why your success rate is so high


    Thanks anyway
  15. Rasmuffin

    Rasmuffin NI Product Owner

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    1,584
    The problem you are having JohnnyH will not be addressed by Traktor unless they decide to make a warp function that will bring the track to a consistant tempo. A grid is rigid and spaced like rungs on a ladder. If your track cannot line up to those "rungs" it will never match a beatgrid. The solution for you is to A) Warp the tracks in Ableton or similar software (time consuming but possible.) B) Use two beatgrids. One at the beginning and one at the end for mixing in and out. C) Delete the grid and use your ear and/or the phase meter to mix with the pitch fader. The problem is within the tracks. The wow and flutter of the turntable used to record them is the source of the tempo changes. Traktor can't change your tracks. There was some talk of introducing a "warp" like feature, but it may be way out and is not in the next update.
  16. JohnnyH

    JohnnyH NI Product Owner

    Messages:
    176
    Thanks will look into Ableton

    Lets hope they consider to put the warp feature in Traktor Soon

    Cos there are still a lot of DJ's with Record Mixes and still a lot of DJ's having this problem

    I still don't understand why mixmister deal's with record rips better, the metrome is spot on mixmister ?

    Regards
    Last edited: Aug 23, 2009
  17. goonzy

    goonzy Modérateur

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    2,885
    It's not a problem with traktor... the software is trying to provide an average value of a tempo changing constantly (and you'll see how much it varies when Warping in Ableton Live.

    Also depending on the kind of stuff you're playing, try to find the tracks from CD compilations instead of vinyls. In most cases, you'll get a much more stable tempo.
  18. DiscoNova

    DiscoNova NI Product Owner

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    1,198
    Mixmeister's "grid" is actually a "warper" like the one in Ableton. Also, Mixmeister has its own problems; it is unable to handle a track that has an intentional tempo change (something like M's "Razzia 2" is what I have in mind) because it attempts to force the track into single tempo and tracks with intentional tempo changes don't really work when single uniform tempo is applied to them.
  19. neoyoung

    neoyoung Forum Member

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    24
    I read something about using two beat grids. I'm not sure if this could solve my problems with tracks who start ok, but after a break the beat grid is completely wrong. I'm not talking very good English, so maybe I'm stupid and asking the same question again.

    Is there a way to solve this problem. For example have a beat grid section of 16 or 32 beats in the beginning of the track so I can loop this part, and a beat grid section at the end of the track for mixing out? If yes, can someone explain to me how this works?
    Last edited: Aug 28, 2009
  20. Rasmuffin

    Rasmuffin NI Product Owner

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    1,584
    This will work if the tempo doesn't change but the phase shifts after a break. Set a cue and save it as a grid marker near the point you want to mix out or after the break where the phase shifts. It will also work for vinyl rips if you are going to use a 4 bar loop to mix in and out.
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