1 files changed, 102 insertions, 0 deletions
diff --git a/gst-libs/gst/idct/floatidct.c b/gst-libs/gst/idct/floatidct.c
new file mode 100644
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+++ b/gst-libs/gst/idct/floatidct.c
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+/* Reference_IDCT.c, Inverse Discrete Fourier Transform, double precision          */
+
+/* Copyright (C) 1996, MPEG Software Simulation Group. All Rights Reserved. */
+
+/*
+ * Disclaimer of Warranty
+ *
+ * These software programs are available to the user without any license fee or
+ * royalty on an "as is" basis.  The MPEG Software Simulation Group disclaims
+ * any and all warranties, whether express, implied, or statuary, including any
+ * implied warranties or merchantability or of fitness for a particular
+ * purpose.  In no event shall the copyright-holder be liable for any
+ * incidental, punitive, or consequential damages of any kind whatsoever
+ * arising from the use of these programs.
+ *
+ * This disclaimer of warranty extends to the user of these programs and user's
+ * customers, employees, agents, transferees, successors, and assigns.
+ *
+ * The MPEG Software Simulation Group does not represent or warrant that the
+ * programs furnished hereunder are free of infringement of any third-party
+ * patents.
+ *
+ * Commercial implementations of MPEG-1 and MPEG-2 video, including shareware,
+ * are subject to royalty fees to patent holders.  Many of these patents are
+ * general enough such that they are unavoidable regardless of implementation
+ * design.
+ *
+ */
+
+/*  Perform IEEE 1180 reference (64-bit floating point, separable 8x1
+ *  direct matrix multiply) Inverse Discrete Cosine Transform
+*/
+
+
+/* Here we use math.h to generate constants.  Compiler results may
+   vary a little */
+
+#include <math.h>
+
+#ifndef PI
+# ifdef M_PI
+#  define PI M_PI
+# else
+#  define PI 3.14159265358979323846
+# endif
+#endif
+
+/* private data */
+
+/* cosine transform matrix for 8x1 IDCT */
+static double gst_idct_float_c[8][8];
+
+/* initialize DCT coefficient matrix */
+
+void gst_idct_init_float_idct()
+{
+  int freq, time;
+  double scale;
+
+  for (freq=0; freq < 8; freq++)
+  {
+    scale = (freq == 0) ? sqrt(0.125) : 0.5;
+    for (time=0; time<8; time++)
+      gst_idct_float_c[freq][time] = scale*cos((PI/8.0)*freq*(time + 0.5));
+  }
+}
+
+/* perform IDCT matrix multiply for 8x8 coefficient block */
+
+void gst_idct_float_idct(block)
+short *block;
+{
+  int i, j, k, v;
+  double partial_product;
+  double tmp[64];
+
+  for (i=0; i<8; i++)
+    for (j=0; j<8; j++)
+    {
+      partial_product = 0.0;
+
+      for (k=0; k<8; k++)
+        partial_product+= gst_idct_float_c[k][j]*block[8*i+k];
+
+      tmp[8*i+j] = partial_product;
+    }
+
+  /* Transpose operation is integrated into address mapping by switching 
+     loop order of i and j */
+
+  for (j=0; j<8; j++)
+    for (i=0; i<8; i++)
+    {
+      partial_product = 0.0;
+
+      for (k=0; k<8; k++)
+        partial_product+= gst_idct_float_c[k][i]*tmp[8*k+j];
+
+      v = (int) floor(partial_product+0.5);
+      block[8*i+j] = (v<-256) ? -256 : ((v>255) ? 255 : v);
+    }
+}