diff yetilab/stream/framer.yeti @ 290:21ec05237c1a

Revise overlap-add

--- a/yetilab/stream/framer.yeti	Thu May 30 22:33:16 2013 +0100
+++ b/yetilab/stream/framer.yeti	Fri May 31 10:58:00 2013 +0100
@@ -94,17 +94,24 @@
         close = \(),
     });
 
-overlapAdd channels framesize hop frames =
+overlapAdd channels overlap frames =
    (ola fr acc =
         if empty? fr then
            [acc]
         else
+            pre = mat.columnSlice acc 0 (mat.width acc - overlap);
+            added = mat.sum (head fr) 
+               (mat.resizedTo { columns = mat.width (head fr), rows = channels }
+                   (mat.columnSlice acc (mat.width acc - overlap) (mat.width acc)));
+    /*               
             frameSized = mat.resizedTo
                { columns = framesize, rows = channels };
             extended = frameSized
                (mat.columnSlice acc hop (mat.width acc));
             added = mat.sum (frameSized (head fr)) extended;
            (mat.columnSlice acc 0 hop) :: ola (tail fr) added;
+*/
+            pre :: ola (tail fr) added;
         fi;
     mat.concat (Horizontal ()) (ola frames (mat.zeroSizeMatrix ())));
 
@@ -113,7 +120,8 @@
     var buffered = mat.zeroSizeMatrix ();
     var position = 0;
     factor = hop / (framesize/2);
-    w = bf.scaled factor (win.hann framesize);
+    w = bf.scaled factor (win.hann framesize); // periodic window, not symmetric
+    println "window is \(vec.list w)";
     channels = mat.height (head frames); // so we don't need to keep a head ptr
     filt.delayedBy (- framesize)
         {
@@ -127,16 +135,22 @@
                     if samples <= 0 or empty? remaining then
                         acc
                     else
-                        this = mat.newMatrix (RowMajor ())
-                           (map (bf.multiply w) (mat.asRows (head remaining)));
+                        println "multiplying \(head remaining) by window";
+                        this = mat.resizedTo
+                            { columns = framesize, rows = channels }
+                            (mat.newMatrix (RowMajor ())
+                                (map (bf.multiply w)
+                                    (mat.asRows (head remaining))));
                         remaining := tail remaining;
                         framesFor (samples - hop) (acc ++ [this])
                     fi;
-                source = overlapAdd channels framesize hop
+                source = overlapAdd channels (framesize - hop)
                    (framesFor count [buffered]);
                 toReturn = mat.columnSlice source 0 count;
                 position := position + mat.width toReturn;
                 buffered := mat.columnSlice source count (mat.width source);
+                println "count = \(count), framesize = \(framesize), hop = \(hop)";
+                println "leaving position = \(position), buffered = \(buffered), returning \(toReturn)";
                 toReturn),
             close = \(),
         });