comparison Code/Descriptors/Matlab/MPEG7/FromWeb/mpeg7init.m @ 4:92ca03a8fa99 tip

Update to ICASSP 2013 benchmark

+function standvar = mpeg7init(fs,hopsize,windowsize,window,FFTsize)
+
+% This function creates a structure of the default values
+% to be used throughout the descriptors
+
+% Written by Melanie Jackson
+
+% Version 1 15th March 2001
+% Modified 30/04/2002 by Thorsten Kastner - changed standard hopsize to 30ms
+%                                         - set hopsize = windowsize (no overlap for ASF)
+  
+if nargin == 0
+    Error = 'need to specify the sampling frequency: standvar = mpeg7init(fs)'
+    standvar = [];
+    return 
+end
+
+try	% variable defined
+    if isempty(hopsize)			% variable defined but no value
+      hopsize = [fs*30 1000]; % Changed hopsize: 30ms recommend
+    else
+        hopsize = [fs*hopsize(1) hopsize(2)];
+    end   
+catch
+    hopsize = [fs*30 1000] ;
+end
+[q, n, d] = h_fraction(hopsize(1),hopsize(2));
+% This next section of code is to ensure minimal stray from the sampling period
+% This is done by interleaving minor hopsize with major
+% e.g if  10 10 10 10 10 11 11 are the hops then the pattern should be
+% 10 10 10 11 10 10 11
+if n==0
+    hopsize = q;
+elseif d-n>=n
+    k = ceil((d-n)/n); % ratio of q to q+1 occurence
+    fr = floor((d-n)/(k)); % number of sub sequences required
+    frr = [q*ones(1,k) q+1]; % subsequence - length k+1
+    hopsize = reshape(frr'*ones(1,fr),1,(k+1)*fr); % append subsequences to each other
+    hopsize = [hopsize q*ones(1,d-n-k*fr) (q+1)*ones(1,n-fr)]; % attach extra values
+else  
+    k = ceil(n/(d-n));
+    fr = floor(n/k);
+    frr = [(q+1)*ones(1,k) q];
+    hopsize = reshape(frr'*ones(1,fr),1,(k+1)*fr);
+    hopsize = [hopsize (q+1)*ones(1,n-k*fr) q*ones(1,d-n-fr)];
+end
+
+
+try
+  if isempty(windowsize) 	% variable defined but no value
+      windowsize = ceil(fs*30/1000); % Changed:Windowsize fixed at 30ms
+    end
+catch
+  windowsize = ceil(fs*30/1000); % Changed: Windowsize fixed at 30ms
+end
+
+try
+  if isempty(FFTsize)			% variable defined but no value
+    FFTsize = 2^nextpow2(windowsize);
+  end
+catch
+  FFTsize = 2^nextpow2(windowsize);
+end
+
+try
+  if isempty(window)			% variable defined but no value
+    window = [hamming(windowsize)];
+  end
+catch
+  window = [hamming(windowsize)];
+end
+
+standvar = struct('fs',fs,'hopsize',hopsize,'windowsize',windowsize,'window',window,'FFTsize',FFTsize);
+return