From 15318cad33835e4e2dc620d033e43cd930676cdd Mon Sep 17 00:00:00 2001
From: kergoth <kergoth>
Date: Fri, 25 Jan 2002 22:14:26 +0000
Subject: Initial revision

---
(limited to 'core/multimedia/opieplayer/libmpeg3/video/idct.c')

diff --git a/core/multimedia/opieplayer/libmpeg3/video/idct.c b/core/multimedia/opieplayer/libmpeg3/video/idct.c
new file mode 100644
index 0000000..c79f90a
--- a/dev/null
+++ b/core/multimedia/opieplayer/libmpeg3/video/idct.c
@@ -0,0 +1,160 @@
+#include "idct.h"
+#include <stdlib.h>
+
+/**********************************************************/
+/* inverse two dimensional DCT, Chen-Wang algorithm       */
+/* (cf. IEEE ASSP-32, pp. 803-816, Aug. 1984)             */
+/* 32-bit integer arithmetic (8 bit coefficients)         */
+/* 11 mults, 29 adds per DCT                              */
+/*                                      sE, 18.8.91       */
+/**********************************************************/
+/* coefficients extended to 12 bit for IEEE1180-1990      */
+/* compliance                           sE,  2.1.94       */
+/**********************************************************/
+
+/* this code assumes >> to be a two's-complement arithmetic */
+/* right shift: (-2)>>1 == -1 , (-3)>>1 == -2               */
+
+#define W1 2841 /* 2048*sqrt(2)*cos(1*pi/16) */
+#define W2 2676 /* 2048*sqrt(2)*cos(2*pi/16) */
+#define W3 2408 /* 2048*sqrt(2)*cos(3*pi/16) */
+#define W5 1609 /* 2048*sqrt(2)*cos(5*pi/16) */
+#define W6 1108 /* 2048*sqrt(2)*cos(6*pi/16) */
+#define W7 565  /* 2048*sqrt(2)*cos(7*pi/16) */
+
+/* row (horizontal) IDCT
+ *
+ *           7                       pi         1
+ * dst[k] = sum c[l] * src[l] * cos( -- * ( k + - ) * l )
+ *          l=0                      8          2
+ *
+ * where: c[0]    = 128
+ *        c[1..7] = 128*sqrt(2)
+ */
+
+int mpeg3video_idctrow(short *blk)
+{
+	int x0, x1, x2, x3, x4, x5, x6, x7, x8;
+
+	/* shortcut */
+	if (!((x1 = blk[4]<<11) | (x2 = blk[6]) | (x3 = blk[2]) |
+          (x4 = blk[1]) | (x5 = blk[7]) | (x6 = blk[5]) | (x7 = blk[3])))
+	{
+      blk[0]=blk[1]=blk[2]=blk[3]=blk[4]=blk[5]=blk[6]=blk[7]=blk[0]<<3;
+      return 0;
+	}
+
+	x0 = (blk[0]<<11) + 128; /* for proper rounding in the fourth stage */
+
+	/* first stage */
+	x8 = W7*(x4+x5);
+	x4 = x8 + (W1-W7)*x4;
+	x5 = x8 - (W1+W7)*x5;
+	x8 = W3*(x6+x7);
+	x6 = x8 - (W3-W5)*x6;
+	x7 = x8 - (W3+W5)*x7;
+
+	/* second stage */
+	x8 = x0 + x1;
+	x0 -= x1;
+	x1 = W6*(x3+x2);
+	x2 = x1 - (W2+W6)*x2;
+	x3 = x1 + (W2-W6)*x3;
+	x1 = x4 + x6;
+	x4 -= x6;
+	x6 = x5 + x7;
+	x5 -= x7;
+
+	/* third stage */
+	x7 = x8 + x3;
+	x8 -= x3;
+	x3 = x0 + x2;
+	x0 -= x2;
+	x2 = (181*(x4+x5)+128)>>8;
+	x4 = (181*(x4-x5)+128)>>8;
+
+	/* fourth stage */
+	blk[0] = (x7+x1)>>8;
+	blk[1] = (x3+x2)>>8;
+	blk[2] = (x0+x4)>>8;
+	blk[3] = (x8+x6)>>8;
+	blk[4] = (x8-x6)>>8;
+	blk[5] = (x0-x4)>>8;
+	blk[6] = (x3-x2)>>8;
+	blk[7] = (x7-x1)>>8;
+
+	return 1;
+}
+
+/* column (vertical) IDCT
+ *
+ *             7                         pi         1
+ * dst[8*k] = sum c[l] * src[8*l] * cos( -- * ( k + - ) * l )
+ *            l=0                        8          2
+ *
+ * where: c[0]    = 1/1024
+ *        c[1..7] = (1/1024)*sqrt(2)
+ */
+
+int mpeg3video_idctcol(short *blk)
+{
+  int x0, x1, x2, x3, x4, x5, x6, x7, x8;
+
+  /* shortcut */
+  if (!((x1 = (blk[8 * 4]<<8)) | (x2 = blk[8 * 6]) | (x3 = blk[8 * 2]) |
+        (x4 = blk[8*1]) | (x5 = blk[8 * 7]) | (x6 = blk[8 * 5]) | (x7 = blk[8 * 3]))){
+    blk[8*0]=blk[8*1]=blk[8 * 2]=blk[8 * 3]=blk[8 * 4]=blk[8 * 5]=blk[8 * 6]=blk[8 * 7]=
+      (blk[8*0]+32)>>6;
+    return 0;
+  }
+
+  x0 = (blk[8*0]<<8) + 8192;
+
+  /* first stage */
+  x8 = W7*(x4+x5) + 4;
+  x4 = (x8+(W1-W7)*x4)>>3;
+  x5 = (x8-(W1+W7)*x5)>>3;
+  x8 = W3*(x6+x7) + 4;
+  x6 = (x8-(W3-W5)*x6)>>3;
+  x7 = (x8-(W3+W5)*x7)>>3;
+  
+  /* second stage */
+  x8 = x0 + x1;
+  x0 -= x1;
+  x1 = W6*(x3+x2) + 4;
+  x2 = (x1-(W2+W6)*x2)>>3;
+  x3 = (x1+(W2-W6)*x3)>>3;
+  x1 = x4 + x6;
+  x4 -= x6;
+  x6 = x5 + x7;
+  x5 -= x7;
+  
+  /* third stage */
+  x7 = x8 + x3;
+  x8 -= x3;
+  x3 = x0 + x2;
+  x0 -= x2;
+  x2 = (181 * (x4 + x5) + 128) >> 8;
+  x4 = (181 * (x4 - x5) + 128) >> 8;
+  
+  /* fourth stage */
+  blk[8 * 0] = (x7 + x1) >> 14;
+  blk[8 * 1] = (x3 + x2) >> 14;
+  blk[8 * 2] = (x0 + x4) >> 14;
+  blk[8 * 3] = (x8 + x6) >> 14;
+  blk[8 * 4] = (x8 - x6) >> 14;
+  blk[8 * 5] = (x0 - x4) >> 14;
+  blk[8 * 6] = (x3 - x2) >> 14;
+  blk[8 * 7] = (x7 - x1) >> 14;
+
+  return 1;
+}
+
+
+/* two dimensional inverse discrete cosine transform */
+void mpeg3video_idct_conversion(short* block)
+{
+	int i;
+	for(i = 0; i < 8; i++) mpeg3video_idctrow(block + 8 * i);
+	for(i = 0; i < 8; i++) mpeg3video_idctcol(block + i);
+}
--
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