optimize copyMacroblock by keeping partial sums and reusing them. Also cleanup.

jsmpg.js

 	dest = (this.mbRow * width + this.mbCol) << 2;
 	last = dest + (width << 2);
 
-	var y11, y21, y12, y22, y;
+	var y1, y2, y;
 	if( oddH ) {
 		if( oddV ) {
 			while( dest < last ) {
-				y21 = sY[src]; y22 = sY[src+width]; src++;
+				y1 = sY[src] + sY[src+width]; src++;
 				for( var x = 0; x < 4; x++ ) {
-					//y11 = y21; y12 = y22; y21 = sY[src]; y22 = sY[src+width]; src++;
-					y11 = sY[src]; y12 = sY[src+width]; src++;
-					y = (((y11 + y21 + y12 + y22 + 2) >> 2) & 0xff);
+					y2 = sY[src] + sY[src+width]; src++;
+					y = (((y1 + y2 + 2) >> 2) & 0xff);
 
-					//y11 = y21; y12 = y22; y21 = sY[src]; y22 = sY[src+width]; src++;
-					y21 = sY[src]; y22 = sY[src+width]; src++;
-					y |= (((y11 + y21 + y12 + y22 + 2) << 6) & 0xff00);
+					y1 = sY[src] + sY[src+width]; src++;
+					y |= (((y1 + y2 + 2) << 6) & 0xff00);
 					
-					//y11 = y21; y12 = y22; y21 = sY[src]; y22 = sY[src+width]; src++;
-					y11 = sY[src]; y12 = sY[src+width]; src++;
-					y |= (((y11 + y21 + y12 + y22 + 2) << 14) & 0xff0000);
+					y2 = sY[src] + sY[src+width]; src++;
+					y |= (((y1 + y2 + 2) << 14) & 0xff0000);
 
-					//y11 = y21; y12 = y22; y21 = sY[src]; y22 = sY[src+width]; src++;
-					y21 = sY[src]; y22 = sY[src+width]; src++;
-					y |= (((y11 + y21 + y12 + y22 + 2) << 22) & 0xff000000);
+					y1 = sY[src] + sY[src+width]; src++;
+					y |= (((y1 + y2 + 2) << 22) & 0xff000000);
 
 					dY[dest++] = y;
 				}
 		}
 		else {
 			while( dest < last ) {
-				//y21 = sY[src]; src++;
-				y11 = sY[src++];
+				y1 = sY[src++];
 				for( var x = 0; x < 4; x++ ) {
-					//y11 = y21; y21 = sY[src]; src++;
-					y21 = sY[src++];
-					y = (((y11 + y21 + 1) >> 1) & 0xff);
+					y2 = sY[src++];
+					y = (((y1 + y2 + 1) >> 1) & 0xff);
 					
-					//y11 = y21; y21 = sY[src]; src++;
-					y11 = sY[src++];
-					y |= (((y11 + y21 + 1) << 7) & 0xff00);
+					y1 = sY[src++];
+					y |= (((y1 + y2 + 1) << 7) & 0xff00);
 					
-					//y11 = y21; y21 = sY[src]; src++;
-					y21 = sY[src++];
-					y |= (((y11 + y21 + 1) << 15) & 0xff0000);
+					y2 = sY[src++];
+					y |= (((y1 + y2 + 1) << 15) & 0xff0000);
 					
-					//y11 = y21; y21 = sY[src]; src++;
-					y11 = sY[src++];
-					y |= (((y11 + y21 + 1) << 23) & 0xff000000);
+					y1 = sY[src++];
+					y |= (((y1 + y2 + 1) << 23) & 0xff000000);
 
 					dY[dest++] = y;
 				}
 	dest = (this.mbRow * width + this.mbCol) << 1;
 	last = dest + (width << 1);
 	
-	var cr11, cr21, cr12, cr22, cr;
-	var cb11, cb21, cb12, cb22, cb;
+	var cr1, cr2, cr;
+	var cb1, cb2, cb;
 	if( oddH ) {
 		if( oddV ) {
 			while( dest < last ) {
-				cr21 = sCr[src]; cr22 = sCr[src+width];
-				cb21 = sCb[src]; cb22 = sCb[src+width];
+				cr1 = sCr[src] + sCr[src+width];
+				cb1 = sCb[src] + sCb[src+width];
 				src++;
 				for( var x = 0; x < 2; x++ ) {
-					//cr11 = cr21; cr12 = cr22; cr21 = sCr[src]; cr22 = sCr[src+width];
-					cr11 = sCr[src]; cr12 = sCr[src+width];
-					//cb11 = cb21; cb12 = cb22; cb21 = sCb[src]; cb22 = sCb[src+width]; src++;
-					cb11 = sCb[src]; cb12 = sCb[src+width]; src++;
-					cr = (((cr11 + cr21 + cr12 + cr22 + 2) >> 2) & 0xff);
-					cb = (((cb11 + cb21 + cb12 + cb22 + 2) >> 2) & 0xff);
-
-					//cr11 = cr21; cr12 = cr22; cr21 = sCr[src]; cr22 = sCr[src+width];
-					cr21 = sCr[src]; cr22 = sCr[src+width];
-					//cb11 = cb21; cb12 = cb22; cb21 = sCb[src]; cb22 = sCb[src+width]; src++;
-					cb21 = sCb[src]; cb22 = sCb[src+width]; src++;
-					cr |= (((cr11 + cr21 + cr12 + cr22 + 2) << 6) & 0xff00);
-					cb |= (((cb11 + cb21 + cb12 + cb22 + 2) << 6) & 0xff00);
-
-					//cr11 = cr21; cr12 = cr22; cr21 = sCr[src]; cr22 = sCr[src+width];
-					cr11 = sCr[src]; cr12 = sCr[src+width];
-					//cb11 = cb21; cb12 = cb22; cb21 = sCb[src]; cb22 = sCb[src+width]; src++;
-					cb11 = sCb[src]; cb12 = sCb[src+width]; src++;
-					cr |= (((cr11 + cr21 + cr12 + cr22 + 2) << 14) & 0xff0000);
-					cb |= (((cb11 + cb21 + cb12 + cb22 + 2) << 14) & 0xff0000);
-
-					//cr11 = cr21; cr12 = cr22; cr21 = sCr[src]; cr22 = sCr[src+width];
-					cr21 = sCr[src]; cr22 = sCr[src+width];
-					//cb11 = cb21; cb12 = cb22; cb21 = sCb[src]; cb22 = sCb[src+width]; src++;
-					cb21 = sCb[src]; cb22 = sCb[src+width]; src++;
-					cr |= (((cr11 + cr21 + cr12 + cr22 + 2) << 22) & 0xff000000);
-					cb |= (((cb11 + cb21 + cb12 + cb22 + 2) << 22) & 0xff000000);
+					cr2 = sCr[src] + sCr[src+width];
+					cb2 = sCb[src] + sCb[src+width]; src++;
+					cr = (((cr1 + cr2 + 2) >> 2) & 0xff);
+					cb = (((cb1 + cb2 + 2) >> 2) & 0xff);
+
+					cr1 = sCr[src] + sCr[src+width];
+					cb1 = sCb[src] + sCb[src+width]; src++;
+					cr |= (((cr1 + cr2 + 2) << 6) & 0xff00);
+					cb |= (((cb1 + cb2 + 2) << 6) & 0xff00);
+
+					cr2 = sCr[src] + sCr[src+width];
+					cb2 = sCb[src] + sCb[src+width]; src++;
+					cr |= (((cr1 + cr2 + 2) << 14) & 0xff0000);
+					cb |= (((cb1 + cb2 + 2) << 14) & 0xff0000);
+
+					cr1 = sCr[src] + sCr[src+width];
+					cb1 = sCb[src] + sCb[src+width]; src++;
+					cr |= (((cr1 + cr2 + 2) << 22) & 0xff000000);
+					cb |= (((cb1 + cb2 + 2) << 22) & 0xff000000);
 
 					dCr[dest] = cr;
 					dCb[dest] = cb;
 		}
 		else {
 			while( dest < last ) {
-				cr21 = sCr[src];
-				cb21 = sCb[src];
+				cr1 = sCr[src];
+				cb1 = sCb[src];
 				src++;
 				for( var x = 0; x < 2; x++ ) {
-					//cr11 = cr21; cr21 = sCr[src];
-					cr11 = sCr[src];
-					//cb11 = cb21; cb21 = sCb[src]; src++;
-					cb11 = sCb[src++];
-					cr = (((cr11 + cr21 + 1) >> 1) & 0xff);
-					cb = (((cb11 + cb21 + 1) >> 1) & 0xff);
-
-					//cr11 = cr21; cr21 = sCr[src];
-					cr21 = sCr[src];
-					//cb11 = cb21; cb21 = sCb[src]; src++;
-					cb21 = sCb[src++];
-					cr |= (((cr11 + cr21 + 1) << 7) & 0xff00);
-					cb |= (((cb11 + cb21 + 1) << 7) & 0xff00);
-
-					//cr11 = cr21; cr21 = sCr[src];
-					cr11 = sCr[src];
-					//cb11 = cb21; cb21 = sCb[src]; src++;
-					cb11 = sCb[src++];
-					cr |= (((cr11 + cr21 + 1) << 15) & 0xff0000);
-					cb |= (((cb11 + cb21 + 1) << 15) & 0xff0000);
-
-					//cr11 = cr21; cr21 = sCr[src];
-					cr21 = sCr[src];
-					//cb11 = cb21; cb21 = sCb[src]; src++;
-					cb21 = sCb[src++];
-					cr |= (((cr11 + cr21 + 1) << 23) & 0xff000000);
-					cb |= (((cb11 + cb21 + 1) << 23) & 0xff000000);
+					cr2 = sCr[src];
+					cb2 = sCb[src++];
+					cr = (((cr1 + cr2 + 1) >> 1) & 0xff);
+					cb = (((cb1 + cb2 + 1) >> 1) & 0xff);
+
+					cr1 = sCr[src];
+					cb1 = sCb[src++];
+					cr |= (((cr1 + cr2 + 1) << 7) & 0xff00);
+					cb |= (((cb1 + cb2 + 1) << 7) & 0xff00);
+
+					cr2 = sCr[src];
+					cb2 = sCb[src++];
+					cr |= (((cr1 + cr2 + 1) << 15) & 0xff0000);
+					cb |= (((cb1 + cb2 + 1) << 15) & 0xff0000);
+
+					cr1 = sCr[src];
+					cb1 = sCb[src++];
+					cr |= (((cr1 + cr2 + 1) << 23) & 0xff000000);
+					cb |= (((cb1 + cb2 + 1) << 23) & 0xff000000);
 
 					dCr[dest] = cr;
 					dCb[dest] = cb;