To begin, something that would let user manually shift beat mark grid phase would be nice. Such feature could be also retained when Mixxx will be able to find correctly first beat in most cases, to fine adjust marks. In any case, please note that marks drift after a while if BPM detection it not perfect. The best thing, I think, would be to let user not only manually set phase but also correct beat length in arbitrary way, even beat per beat.
Russell Ryan ha scritto: > I looked into it once and I think that when the BPM is roughly > correct, except offset by a constant time-distance, that that is > actually a bug of ours. There used to be code for getting the offset > of the 'first beat' in the song. Currently when the BPM is detected, > the beat marks are rendered as if the first beat started at the first > sample of the song. This is most definitely wrong, we just don't have > more accurate information. There is definitely an opportunity to add > the first-beat thing back in. I haven't looked long enough at the BPM > code to see how though. > > RJ > > > Nick Guenther wrote: >> I don't think any algorithm is ever going to solve that problem. It's >> not always possible for a human even to tell where to place beats, and >> sometimes there's multiple ways you could reasonably interpret the >> beats. And if you have an algorithm that works perfectly for gabber it >> probably won't work for folk, or ambient, or punk rock. And what if >> the time signature is not 4/4?. That's one of the reasons why you need >> a human to DJ well. >> >> Traktor has beat grids for this purpose, perhaps we should think about >> doing those? >> >> On Wed, Jan 14, 2009 at 12:39 PM, <[email protected]> wrote: >> >>> I have noticed that often peaks do not coincide with real beat >>> starts: peaks >>> are detected "right shifted", that is some time after beat really >>> starts. >>> This could be due to two reasons: 1) the LP filter cuts too low: >>> typically >>> kick drums peaks at about 100 Hz, but if kick drum is not present at >>> the >>> begin of a track also higher frequency range should be considered. >>> 2) the >>> envelope of a typical kickdrum waveform: there is a short raise time >>> before >>> peak is reached. This raise time (some tens ms) could be subtracted >>> to peak >>> positions. >>> >> >> ------------------------------------------------------------------------------ >> >> >> This SF.net email is sponsored by: >> SourcForge Community >> SourceForge wants to tell your story. >> http://p.sf.net/sfu/sf-spreadtheword >> _______________________________________________ >> Mixxx-devel mailing list >> [email protected] >> https://lists.sourceforge.net/lists/listinfo/mixxx-devel >> > > > ------------------------------------------------------------------------------ This SF.net email is sponsored by: SourcForge Community SourceForge wants to tell your story. http://p.sf.net/sfu/sf-spreadtheword _______________________________________________ Mixxx-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/mixxx-devel
