Re: [Banshee-List] Crossfading and BPM detection

[Neil Loknath <neil loknath gmail com>]

Cool.  Thanks.  I'm thinking the GStreamer BPM plugin is probably not based on an optimal algorithm then.  I tried to find the BPM of maybe 10 songs.  Of the 10, 1 or 2 were close to perfect.  Another 1 or 2 were double the correct BPM (sometimes humans can even make this mistake).  And, the rest were just way off...usually around 30 beats too low.  Of course, that is a small sample and my bad results may have been just bad song choices on my part.  However, I tried other software with the same songs that were way off and got much better results.  Anyway, it will be worth a look at some point.

On Thu, Feb 19, 2009 at 3:07 PM, Gabriel Burt <gabriel burt gmail com> wrote:

2009/2/19 Neil Loknath <neil loknath gmail com>:

> Bertrand,
>
> I built from SVN trunk last night and played around with the new BPM
> feature.  Unfortunately, my results were disappointing.  I think there could
> be 2 reasons for this:
>
> 1. The GStreamer implementation of BPM detection is not an optimal
> algorithm.
> 2. The sample of music passed to the algorithm is not from the most optimal
> time.  For example, the beginnings of some songs can be very different from
> their middles.

Just fyi, I currently have bpmdetect processing the whole file, and it
spits out bpm values at various points - usually many per file - and I
take the mode of those as the one-true-BPM.

Gabriel

Justin, 

That approach could be taken.  But, beat detection at the start and end of songs would probably have a rather high error rate.  A lot of the time, drums don't kick in for a few seconds and sometimes the last few seconds of songs can have no percussion at all.  Without percussion present, beat detection would be more difficult. 

Just a thought:  would it not be best for the purposes of more seamless transitions to sample at the beginning and end of the song in order to match the preceding and following songs, respectively?  I would think that this would be an easier route to reliable matches than trying to define a single value for each song.

Raphael,

Banshee already has manual BPM help.  It's on the Extra tab of the Edit Track dialog.

I would like to see a BPM recording help. Like you could start a BPM recording
mode and then press the Space-bar or any other key according to the beat while
the song is playing and banshee calculates the BPM from your keystrokes.