BufNoveltySlice: new help file with filtersize

release-packaging/HelpSource/Classes/FluidBufNoveltySlice.schelp

@@ -40,7 +40,10 @@ ARGUMENT:: kernelSize
 	The granularity of the window in which the algorithm looks for change, in samples. A small number will be sensitive to short term changes, and a large number should look for long term changes.
 
 ARGUMENT:: thresh
-	The normalised threshold, between 0 an 1, to consider a peak as a sinusoidal component from the in the novelty curve.
+	The normalised threshold, between 0 an 1, on the novelty curve to consider it a segmentation point.
+
+ARGUMENT:: filterSize
+	The size of a smoothing filter that is applied on the novelty curve. A larger filter filter size allows for cleaner cuts on very sharp changes.
 
 ARGUMENT:: winSize
 	The window size. As novelty estimation relies on spectral frames, we need to decide what precision we give it spectrally and temporally, in line with Gabor Uncertainty principles. http://www.subsurfwiki.org/wiki/Gabor_uncertainty
@@ -91,3 +94,39 @@ c.query;
 		}.play;
 )
 	::
+
+STRONG::Examples of the impact of the filterSize::
+
+	CODE::
+// load some buffers
+(
+b = Buffer.read(s,File.realpath(FluidBufNoveltySlice.class.filenameSymbol).dirname.withTrailingSlash ++ "../AudioFiles/Tremblay-AaS-AcousticStrums-M.wav");
+c = Buffer.new(s);
+)
+
+// process with a given filterSize
+FluidBufNoveltySlice.process(s,b.bufnum, transBufNum: c.bufnum, kernelSize:31, thresh:0.35, filterSize:0)
+
+//check the number of slices: it is the number of frames in the transBuf minus the boundary index.
+c.query;
+
+//play slice number 2
+(
+{
+	BufRd.ar(1, b.bufnum,
+		Line.ar(
+			BufRd.kr(1, c.bufnum, DC.kr(2), 0, 1),
+			BufRd.kr(1, c.bufnum, DC.kr(3), 0, 1),
+			(BufRd.kr(1, c.bufnum, DC.kr(3)) - BufRd.kr(1, c.bufnum, DC.kr(2), 0, 1) + 1) / s.sampleRate),
+		0,1);
+}.play;
+)
+
+// change the filterSize in the code above to 4. Then to 8. Listen in between to the differences.
+
+// What's happening? In the first instance (filterSize = 0), the novelty line is jittery and therefore overtriggers on the arpegiated guitar. We also can hear attacks at the end of the segment. Setting the threshold higher (like in the 'Basic Example' pane) misses some more subtle variations.
+
+// So in the second settings (filterSize = 4), we smooth the novelty line a little, which allows us to catch small differences that are not jittery. It also corrects the ending cutting by the same trick: the averaging of the sharp pick is sliding up, crossing the threshold slightly earlier.
+
+// If we smooth too much, like the third settings (filterSize = 8), we start to loose precision. Have fun with different values of theshold then will allow you to find the perfect segment for your signal.
+::