[aubio-user] Informations about aubio beat detection setting

[Paul Brossier]

Hello Patrice,

On 05/15/2014 09:25 AM, Patrice Péau wrote:
> Hello, I am looking for some informations about the beat tracking 
> fonction of aubio. I am looking for something to make a simple beat 
> grid of music and especially electronic music like we can see on 
> every dj application.
> 
> but I think, I am doing something wrong because I made a lot of tests
> and the result is definitely not that I was expected.
> 
> I've got just a average of 35% of beats detected correctly on 
> electronic music so just rhythm. In fact 1 song on 5 is not so bad 
> and some of them are even less of 15%.

indeed, something might be wrong, you should be able to get better
results, especially on electronic music. what values are you using for
samplerate, win_s, and hop_s? can you reproduce those result with
python/demos/demo_bpm_extract.py?

> So at first,  what means confidence on the beat tracking system 
> because I have 0 for nothing that one is good , but sometimes I have 
> for example : 0.40 to 1.80 during 1 minutes then 80.0 for 4 beats and
> then 0.12 to 1.80 during still 3 minutes and 20.0. so what means this
> value ? is a percent ? or how can I use it for example to fix the
> others beats.

the confidence is an indicator of how much trust the algorithm has in
this event. the higher it is, the more confidence the algorithm has.
(but it still could be wrong).

it should be bound between 0 and 1, so a value of 80.0 is surprising,
but you might have found a bug.

> And maybe there are some tricks to customize the detection to expect
>  something with more sense.

for now, the algorithm needs a good 6 seconds to start tracking. so if
you run it on short files, it is unlikely to give good results.

let us know how it goes,

Best, Paul

> 
> Thanks for your help
> 
> Patrice
> 
> 
> 
> 
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