Re: [Audacity-devel] Find Zero Crossing bug
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From: Martyn S. <mar...@go...> - 2009-08-30 22:56:18
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Hi Al I don't know what the thinking was behind this code when Dominic put it in back in May 2003, maybe he can remember and could contribute? But I know he's moved on to other things mostly. Audacity was certainly much less sophisticated then than it is now, and so it may have been an easier problem to solve. I think the idea was to find a location where a cut would create the minimal amount of audible click (or maybe that's just what I would have done?). So finding upwards (an arbitrary choice) zerocrossings with minimal difference from zero seemed like a good idea. I think that searching over a number of tracks for matching zerocrossings is going to be a fruitless task. They may well be unrelated. I'm tempted to say that this 'feature' should be abandoned, at least in a multi-track situation, but kept (and improved) when just one track is selected / active. I think that we should consider what we are trying to achieve here. What should we press to do what in what situation? And what should it do? TTFN Martyn Al Dimond wrote: > Just yesterday I wrote: >> Or maybe we should simply find the nearest ascending zero-crossing that >> makes the selection size smaller. >> >> I have been working under the assumption that the existing code is as it is >> for a good reason. > > After some messing around it looks like one of the reasons the existing code > is as it is is because in that algorithm there's a very intuitive way to deal > with stereo/multiple tracks: just sum the scores for each sample (basically). > There's nothing that obvious if we're just scanning in one direction for zero- > crossings. Maybe check for zero-crossings in any track, then score them based > on how close they are to the starting point, how close to zero the other > tracks are, and whether they're ascending (using similar logic to the existing > code, so the results may not be much less weird than what we have). Does > anyone have other ideas? > > ------------------------------------------------------------------------------ > Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day > trial. Simplify your report design, integration and deployment - and focus on > what you do best, core application coding. Discover what's new with > Crystal Reports now. http://p.sf.net/sfu/bobj-july > _______________________________________________ > audacity-devel mailing list > aud...@li... > https://lists.sourceforge.net/lists/listinfo/audacity-devel > |