floating point AAN DCT

Originally committed as revision 2415 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 156 insertions, 0 deletions

diff --git a/libavcodec/faandct.c b/libavcodec/faandct.c
new file mode 100644
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+++ b/libavcodec/faandct.c
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+/*
+ * Floating point AAN DCT
+ * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ */
+
+/**
+ * @file faandct.c
+ * @brief 
+ *     Floating point AAN DCT
+ * @author Michael Niedermayer <michaelni@gmx.at>
+ */
+
+#include <math.h>
+
+#include "dsputil.h"
+#include "faandct.h"
+
+#define FLOAT float
+
+//numbers generated by simple c code (not as accurate as they could be)
+/*
+for(i=0; i<8; i++){
+    printf("#define B%d %1.20llf\n", i, (long double)1.0/(cosl(i*acosl(-1.0)/(long double)16.0)*sqrtl(2)));
+}
+*/
+#define B0 1.00000000000000000000
+#define B1 0.72095982200694791383 // (cos(pi*1/16)sqrt(2))^-1
+#define B2 0.76536686473017954350 // (cos(pi*2/16)sqrt(2))^-1
+#define B3 0.85043009476725644878 // (cos(pi*3/16)sqrt(2))^-1
+#define B4 1.00000000000000000000 // (cos(pi*4/16)sqrt(2))^-1
+#define B5 1.27275858057283393842 // (cos(pi*5/16)sqrt(2))^-1
+#define B6 1.84775906502257351242 // (cos(pi*6/16)sqrt(2))^-1
+#define B7 3.62450978541155137218 // (cos(pi*7/16)sqrt(2))^-1
+
+
+#define A1 0.70710678118654752438 // cos(pi*4/16)
+#define A2 0.54119610014619698435 // cos(pi*6/16)sqrt(2)
+#define A5 0.38268343236508977170 // cos(pi*6/16)
+#define A4 1.30656296487637652774 // cos(pi*2/16)sqrt(2)
+
+static FLOAT postscale[64]={
+B0*B0, B0*B1, B0*B2, B0*B3, B0*B4, B0*B5, B0*B6, B0*B7,
+B1*B0, B1*B1, B1*B2, B1*B3, B1*B4, B1*B5, B1*B6, B1*B7,
+B2*B0, B2*B1, B2*B2, B2*B3, B2*B4, B2*B5, B2*B6, B2*B7,
+B3*B0, B3*B1, B3*B2, B3*B3, B3*B4, B3*B5, B3*B6, B3*B7,
+B4*B0, B4*B1, B4*B2, B4*B3, B4*B4, B4*B5, B4*B6, B4*B7,
+B5*B0, B5*B1, B5*B2, B5*B3, B5*B4, B5*B5, B5*B6, B5*B7,
+B6*B0, B6*B1, B6*B2, B6*B3, B6*B4, B6*B5, B6*B6, B6*B7,
+B7*B0, B7*B1, B7*B2, B7*B3, B7*B4, B7*B5, B7*B6, B7*B7,
+};
+
+void ff_faandct(DCTELEM * data)
+{
+    FLOAT tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7;
+    FLOAT tmp10, tmp11, tmp12, tmp13;
+    FLOAT z1, z2, z3, z4, z5, z11, z13;
+    FLOAT temp[64];
+    int i;
+
+    emms();
+
+    for (i=0; i<8*8; i+=8) {
+        tmp0= data[0 + i] + data[7 + i];
+        tmp7= data[0 + i] - data[7 + i];
+        tmp1= data[1 + i] + data[6 + i];
+        tmp6= data[1 + i] - data[6 + i];
+        tmp2= data[2 + i] + data[5 + i];
+        tmp5= data[2 + i] - data[5 + i];
+        tmp3= data[3 + i] + data[4 + i];
+        tmp4= data[3 + i] - data[4 + i];
+        
+        tmp10= tmp0 + tmp3;
+        tmp13= tmp0 - tmp3;
+        tmp11= tmp1 + tmp2;
+        tmp12= tmp1 - tmp2;
+        
+        temp[0 + i]= tmp10 + tmp11;
+        temp[4 + i]= tmp10 - tmp11;
+        
+        z1= (tmp12 + tmp13)*A1;
+        temp[2 + i]= tmp13 + z1;
+        temp[6 + i]= tmp13 - z1;
+        
+        tmp10= tmp4 + tmp5;
+        tmp11= tmp5 + tmp6;
+        tmp12= tmp6 + tmp7;
+
+        z5= (tmp10 - tmp12) * A5;
+        z2= tmp10*A2 + z5;
+        z4= tmp12*A4 + z5;
+        z3= tmp11*A1;
+
+        z11= tmp7 + z3;
+        z13= tmp7 - z3;
+
+        temp[5 + i]= z13 + z2;
+        temp[3 + i]= z13 - z2;
+        temp[1 + i]= z11 + z4;
+        temp[7 + i]= z11 - z4;
+    }
+
+    for (i=0; i<8; i++) {
+        tmp0= temp[8*0 + i] + temp[8*7 + i];
+        tmp7= temp[8*0 + i] - temp[8*7 + i];
+        tmp1= temp[8*1 + i] + temp[8*6 + i];
+        tmp6= temp[8*1 + i] - temp[8*6 + i];
+        tmp2= temp[8*2 + i] + temp[8*5 + i];
+        tmp5= temp[8*2 + i] - temp[8*5 + i];
+        tmp3= temp[8*3 + i] + temp[8*4 + i];
+        tmp4= temp[8*3 + i] - temp[8*4 + i];
+        
+        tmp10= tmp0 + tmp3;
+        tmp13= tmp0 - tmp3;
+        tmp11= tmp1 + tmp2;
+        tmp12= tmp1 - tmp2;
+        
+        data[8*0 + i]= lrint(postscale[8*0 + i] * (tmp10 + tmp11));
+        data[8*4 + i]= lrint(postscale[8*4 + i] * (tmp10 - tmp11));
+        
+        z1= (tmp12 + tmp13)* A1;
+        data[8*2 + i]= lrint(postscale[8*2 + i] * (tmp13 + z1));
+        data[8*6 + i]= lrint(postscale[8*6 + i] * (tmp13 - z1));
+        
+        tmp10= tmp4 + tmp5;
+        tmp11= tmp5 + tmp6;
+        tmp12= tmp6 + tmp7;
+
+        z5= (tmp10 - tmp12) * A5;
+        z2= tmp10*A2 + z5;
+        z4= tmp12*A4 + z5;
+        z3= tmp11*A1;
+
+        z11= tmp7 + z3;
+        z13= tmp7 - z3;
+
+        data[8*5 + i]= lrint(postscale[8*5 + i] * (z13 + z2));
+        data[8*3 + i]= lrint(postscale[8*3 + i] * (z13 - z2));
+        data[8*1 + i]= lrint(postscale[8*1 + i] * (z11 + z4));
+        data[8*7 + i]= lrint(postscale[8*7 + i] * (z11 - z4));
+    }
+}