OpenCores
URL https://opencores.org/ocsvn/mpeg2fpga/mpeg2fpga/trunk

Subversion Repositories mpeg2fpga

[/] [mpeg2fpga/] [trunk/] [tools/] [mpeg2dec/] [idctref.c] - Rev 2

Compare with Previous | Blame | View Log

#ifdef HAVE_MMX
#include <string.h>
 
void Initialize_Reference_IDCT() { /* nothing */ }
 
/* perform intel mmx IDCT matrix multiply for 8x8 coefficient block */
 
void Reference_IDCT(block, i)
short *block;
int i;	/* is intra */
{
   if (0)
	block[0] += 8;	/* add 0.5 to [0][0] for I-frames */
   IDCT_mmx(block);
}
 
#else
/* 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>
 
#include "config.h"
 
#ifndef PI
# ifdef M_PI
#  define PI M_PI
# else
#  define PI 3.14159265358979323846
# endif
#endif
 
/* global declarations */
void Initialize_Fast_IDCTref _ANSI_ARGS_((void));
void Reference_IDCT _ANSI_ARGS_((short *block));
 
/* private data */
 
/* cosine transform matrix for 8x1 IDCT */
static double c[8][8];
 
/* initialize DCT coefficient matrix */
 
void Initialize_Reference_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++)
      c[freq][time] = scale*cos((PI/8.0)*freq*(time + 0.5));
  }
}
 
/* perform IDCT matrix multiply for 8x8 coefficient block */
 
void Reference_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+= 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+= 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);
    }
}
#endif
 

Compare with Previous | Blame | View Log

powered by: WebSVN 2.1.0

© copyright 1999-2019 OpenCores.org, equivalent to Oliscience, all rights reserved. OpenCores®, registered trademark.