wolffd@0: function varargout = mirlowenergy(x,varargin)
wolffd@0: %   p = mirlowenergy(f) computes the percentage of frames showing a RMS 
wolffd@0: %       energy that is lower than a given threshold. 
wolffd@0: %   For instance, for a musical excerpt with some very loud frames and 
wolffd@0: %       lots of silent frames, we would get a high low-energy rate.
wolffd@0: %   Optional argument:
wolffd@0: %       mirlowenergy(...,'Threshold',t) expressed as a ratio to the average
wolffd@0: %           energy over the frames.
wolffd@0: %           Default value: t = 1
wolffd@0: %       mirlowenergy(...,'Frame',l,h) specifies the use of frames of
wolffd@0: %           length l seconds and a hop rate h.
wolffd@0: %           Default values: l = .05 s, h = .5
wolffd@0: %       mirlowenergy(...,'Root',0) uses mean square instead of root mean
wolffd@0: %           square
wolffd@0: %       mirlowenergy(...,'ASR') computes the Average Silence Ratio, which
wolffd@0: %           corresponds in fact to mirlowenergy(...,'Root',0,'Threshold',t)
wolffd@0: %           where t is fixed here by default to t = .5
wolffd@0: %   [p,e] = mirlowenergy(...) also returns the RMS energy curve.
wolffd@0:     
wolffd@0:         asr.key = 'ASR';
wolffd@0:         asr.type = 'Boolean';
wolffd@0:         asr.default = 0;
wolffd@0:     option.asr = asr;
wolffd@0:     
wolffd@0:         root.key = 'Root';
wolffd@0:         root.type = 'Boolean';
wolffd@0:         root.default = 1;
wolffd@0:     option.root = root;
wolffd@0:     
wolffd@0:         thr.key = 'Threshold';
wolffd@0:         thr.type = 'Integer';
wolffd@0:         thr.default = NaN;
wolffd@0:     option.thr = thr;
wolffd@0: 
wolffd@0:         frame.key = 'Frame';
wolffd@0:         frame.type = 'Integer';
wolffd@0:         frame.number = 2;
wolffd@0:         frame.default = [.05 .5];
wolffd@0:     option.frame = frame;
wolffd@0: 
wolffd@0: specif.option = option;
wolffd@0: 
wolffd@0: specif.combinechunk = {'Average',@nothing};
wolffd@0: specif.extensive = 1;
wolffd@0: 
wolffd@0: varargout = mirfunction(@mirlowenergy,x,varargin,nargout,specif,@init,@main);
wolffd@0: 
wolffd@0: 
wolffd@0: function [x type] = init(x,option)
wolffd@0: if option.asr
wolffd@0:     option.root = 0;
wolffd@0: end
wolffd@0: if isamir(x,'miraudio')
wolffd@0:     if isframed(x)
wolffd@0:         x = mirrms(x,'Root',option.root);
wolffd@0:     else
wolffd@0:         x = mirrms(x,'Frame',option.frame.length.val,option.frame.length.unit,...
wolffd@0:                              option.frame.hop.val,option.frame.hop.unit,...
wolffd@0:                              'Root',option.root);
wolffd@0:     end
wolffd@0: end
wolffd@0: type = 'mirscalar';
wolffd@0: 
wolffd@0: 
wolffd@0: function e = main(r,option,postoption)
wolffd@0: if iscell(r)
wolffd@0:     r = r{1};
wolffd@0: end
wolffd@0: if isnan(option.thr)
wolffd@0:     if option.asr
wolffd@0:         option.thr = .5;
wolffd@0:     else
wolffd@0:         option.thr = 1;
wolffd@0:     end
wolffd@0: end
wolffd@0: v = mircompute(@algo,get(r,'Data'),option.thr);
wolffd@0: fp = mircompute(@noframe,get(r,'FramePos'));
wolffd@0: e = mirscalar(r,'Data',v,'Title','Low energy','Unit','/1','FramePos',fp);
wolffd@0: e = {e,r};
wolffd@0: 
wolffd@0: 
wolffd@0: function v = algo(d,thr)
wolffd@0: v = sum(d < repmat(thr*mean(d,2),[1 size(d,2) 1]));
wolffd@0: v = v / size(d,2);
wolffd@0: 
wolffd@0: 
wolffd@0: function fp = noframe(fp)
wolffd@0: fp = [fp(1);fp(end)];
wolffd@0: 
wolffd@0: 
wolffd@0: function y = nothing(old,new)
wolffd@0: y = old;