From 6f08c541b4b0f96c193e4b761f1947841c07abc3 Mon Sep 17 00:00:00 2001
From: Michael Niedermayer <michaelni@gmx.at>
Date: Tue, 26 Feb 2008 14:59:11 +0000
Subject: floating point AAN IDCT

Originally committed as revision 12233 to svn://svn.ffmpeg.org/ffmpeg/trunk
---
 libavcodec/faanidct.c | 166 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 166 insertions(+)
 create mode 100644 libavcodec/faanidct.c

(limited to 'libavcodec/faanidct.c')

diff --git a/libavcodec/faanidct.c b/libavcodec/faanidct.c
new file mode 100644
index 0000000000..75c09cda86
--- /dev/null
+++ b/libavcodec/faanidct.c
@@ -0,0 +1,166 @@
+/*
+ * Floating point AAN IDCT
+ * Copyright (c) 2008 Michael Niedermayer <michaelni@gmx.at>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg 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 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg 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 FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+#include "mpegvideo.h"
+
+#define FLOAT float
+
+#define B0 1.0000000000000000000000
+#define B1 1.3870398453221474618216 // cos(pi*1/16)sqrt(2)
+#define B2 1.3065629648763765278566 // cos(pi*2/16)sqrt(2)
+#define B3 1.1758756024193587169745 // cos(pi*3/16)sqrt(2)
+#define B4 1.0000000000000000000000 // cos(pi*4/16)sqrt(2)
+#define B5 0.7856949583871021812779 // cos(pi*5/16)sqrt(2)
+#define B6 0.5411961001461969843997 // cos(pi*6/16)sqrt(2)
+#define B7 0.2758993792829430123360 // cos(pi*7/16)sqrt(2)
+
+#define A4 0.70710678118654752438 // cos(pi*4/16)
+#define A2 0.92387953251128675613 // cos(pi*2/16)
+
+static const FLOAT prescale[64]={
+B0*B0/8, B0*B1/8, B0*B2/8, B0*B3/8, B0*B4/8, B0*B5/8, B0*B6/8, B0*B7/8,
+B1*B0/8, B1*B1/8, B1*B2/8, B1*B3/8, B1*B4/8, B1*B5/8, B1*B6/8, B1*B7/8,
+B2*B0/8, B2*B1/8, B2*B2/8, B2*B3/8, B2*B4/8, B2*B5/8, B2*B6/8, B2*B7/8,
+B3*B0/8, B3*B1/8, B3*B2/8, B3*B3/8, B3*B4/8, B3*B5/8, B3*B6/8, B3*B7/8,
+B4*B0/8, B4*B1/8, B4*B2/8, B4*B3/8, B4*B4/8, B4*B5/8, B4*B6/8, B4*B7/8,
+B5*B0/8, B5*B1/8, B5*B2/8, B5*B3/8, B5*B4/8, B5*B5/8, B5*B6/8, B5*B7/8,
+B6*B0/8, B6*B1/8, B6*B2/8, B6*B3/8, B6*B4/8, B6*B5/8, B6*B6/8, B6*B7/8,
+B7*B0/8, B7*B1/8, B7*B2/8, B7*B3/8, B7*B4/8, B7*B5/8, B7*B6/8, B7*B7/8,
+};
+
+static inline void p8idct(DCTELEM data[64], FLOAT temp[64], uint8_t *dest, int stride, int x, int y, int type){
+    int i;
+    FLOAT tmp0, tmp1;
+    FLOAT s04, d04, s17, d17, s26, d26, s53, d53;
+    FLOAT os07, os16, os25, os34;
+    FLOAT od07, od16, od25, od34;
+
+    for(i=0; i<y*8; i+=y){
+        s17= temp[1*x + i] + temp[7*x + i];
+        d17= temp[1*x + i] - temp[7*x + i];
+        s53= temp[5*x + i] + temp[3*x + i];
+        d53= temp[5*x + i] - temp[3*x + i];
+
+        od07=  s17 + s53;
+        od25= (s17 - s53)*(2*A4);
+
+#if 0 //these 2 are equivalent
+        tmp0= (d17 + d53)*(2*A2);
+        od34=  d17*( 2*B6) - tmp0;
+        od16=  d53*(-2*B2) + tmp0;
+#else
+        od34=  d17*(2*(B6-A2)) - d53*(2*A2);
+        od16=  d53*(2*(A2-B2)) + d17*(2*A2);
+#endif
+
+        od16 -= od07;
+        od25 -= od16;
+        od34 += od25;
+
+        s26 = temp[2*x + i] + temp[6*x + i];
+        d26 = temp[2*x + i] - temp[6*x + i];
+        tmp1= d26*(2*A4) - s26;
+
+        s04= temp[0*x + i] + temp[4*x + i];
+        d04= temp[0*x + i] - temp[4*x + i];
+
+        os07= s04 + s26;
+        os34= s04 - s26;
+        os16= d04 + tmp1;
+        os25= d04 - tmp1;
+
+        if(type==0){
+            temp[0*x + i]= os07 + od07;
+            temp[7*x + i]= os07 - od07;
+            temp[1*x + i]= os16 + od16;
+            temp[6*x + i]= os16 - od16;
+            temp[2*x + i]= os25 + od25;
+            temp[5*x + i]= os25 - od25;
+            temp[3*x + i]= os34 - od34;
+            temp[4*x + i]= os34 + od34;
+        }else if(type==1){
+            data[0*x + i]= lrintf(os07 + od07);
+            data[7*x + i]= lrintf(os07 - od07);
+            data[1*x + i]= lrintf(os16 + od16);
+            data[6*x + i]= lrintf(os16 - od16);
+            data[2*x + i]= lrintf(os25 + od25);
+            data[5*x + i]= lrintf(os25 - od25);
+            data[3*x + i]= lrintf(os34 - od34);
+            data[4*x + i]= lrintf(os34 + od34);
+        }else if(type==2){
+            dest[0*stride + i]= av_clip_uint8(((int)dest[0*stride + i]) + lrintf(os07 + od07));
+            dest[7*stride + i]= av_clip_uint8(((int)dest[7*stride + i]) + lrintf(os07 - od07));
+            dest[1*stride + i]= av_clip_uint8(((int)dest[1*stride + i]) + lrintf(os16 + od16));
+            dest[6*stride + i]= av_clip_uint8(((int)dest[6*stride + i]) + lrintf(os16 - od16));
+            dest[2*stride + i]= av_clip_uint8(((int)dest[2*stride + i]) + lrintf(os25 + od25));
+            dest[5*stride + i]= av_clip_uint8(((int)dest[5*stride + i]) + lrintf(os25 - od25));
+            dest[3*stride + i]= av_clip_uint8(((int)dest[3*stride + i]) + lrintf(os34 - od34));
+            dest[4*stride + i]= av_clip_uint8(((int)dest[4*stride + i]) + lrintf(os34 + od34));
+        }else{
+            dest[0*stride + i]= av_clip_uint8(lrintf(os07 + od07));
+            dest[7*stride + i]= av_clip_uint8(lrintf(os07 - od07));
+            dest[1*stride + i]= av_clip_uint8(lrintf(os16 + od16));
+            dest[6*stride + i]= av_clip_uint8(lrintf(os16 - od16));
+            dest[2*stride + i]= av_clip_uint8(lrintf(os25 + od25));
+            dest[5*stride + i]= av_clip_uint8(lrintf(os25 - od25));
+            dest[3*stride + i]= av_clip_uint8(lrintf(os34 - od34));
+            dest[4*stride + i]= av_clip_uint8(lrintf(os34 + od34));
+        }
+    }
+}
+
+void ff_faanidct(DCTELEM block[64]){
+    FLOAT temp[64];
+    int i;
+
+    emms_c();
+
+    for(i=0; i<64; i++)
+        temp[i] = block[i] * prescale[i];
+
+    p8idct(block, temp, NULL, 0, 1, 8, 0);
+    p8idct(block, temp, NULL, 0, 8, 1, 1);
+}
+
+void ff_faanidct_add(uint8_t *dest, int line_size, DCTELEM block[64]){
+    FLOAT temp[64];
+    int i;
+
+    emms_c();
+
+    for(i=0; i<64; i++)
+        temp[i] = block[i] * prescale[i];
+
+    p8idct(block, temp, NULL,         0, 1, 8, 0);
+    p8idct(NULL , temp, dest, line_size, 8, 1, 2);
+}
+
+void ff_faanidct_put(uint8_t *dest, int line_size, DCTELEM block[64]){
+    FLOAT temp[64];
+    int i;
+
+    emms_c();
+
+    for(i=0; i<64; i++)
+        temp[i] = block[i] * prescale[i];
+
+    p8idct(block, temp, NULL,         0, 1, 8, 0);
+    p8idct(NULL , temp, dest, line_size, 8, 1, 3);
+}
-- 
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