Diff of /branches/release-1_0-branch/xvidcore/src/dct/idct.c

-trunk/xvidcore/src/dct/idct.c
revision 461, Tue Sep 10 20:38:24 2002 UTC
+branches/release-1_0-branch/xvidcore/src/dct/idct.c
revision 1537, Sun Aug 22 13:16:12 2004 UTC
 Line 1
  /*****************************************************************************
   *
   *  XVID MPEG-4 VIDEO CODEC
-  *  - inverse fast disrete cosine transformation - integer C version
+  *  - Inverse DCT  -
   *
   *  These routines are from Independent JPEG Group's free JPEG software
   *  Copyright (C) 1991-1998, Thomas G. Lane (see the file README.IJG)
   *
-  *  This program is an implementation of a part of one or more MPEG-4
-  *  Video tools as specified in ISO/IEC 14496-2 standard.  Those intending
-  *  to use this software module in hardware or software products are
-  *  advised that its use may infringe existing patents or copyrights, and
-  *  any such use would be at such party's own risk.  The original
-  *  developer of this software module and his/her company, and subsequent
-  *  editors and their companies, will have no liability for use of this
-  *  software or modifications or derivatives thereof.
-  *
   *  This program is free software; you can redistribute it and/or modify
   *  it under the terms of the GNU General Public License as published by
   *  the Free Software Foundation; either version 2 of the License, or
-Line 29
+Line 20
   *  along with this program; if not, write to the Free Software
   *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
   *
-  *************************************************************************/
+  * $Id: idct.c,v 1.7.2.1 2004-08-22 13:15:15 edgomez Exp $
+  *
+  ****************************************************************************/
+ /* 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.
+  *
+  * MPEG2AVI
+  * --------
+  * v0.16B33 renamed the initialization function to init_idct_int32()
+  * v0.16B32 removed the unused idct_row() and idct_col() functions
+  * v0.16B3  changed var declarations to static, to enforce data align
+  * v0.16B22  idct_FAST() renamed to idct_int32()
+  *        also merged idct_FAST() into a single function, to help VC++
+  *        optimize it.
+  *
+  * v0.14  changed int to long, to avoid confusion when compiling on x86
+  *        platform ( in VC++ "int" -> 32bits )
+  */
  /**********************************************************/
  /* inverse two dimensional DCT, Chen-Wang algorithm       */
-Line 54
+Line 85
  #define W6 1108                                 /* 2048*sqrt(2)*cos(6*pi/16) */
  #define W7 565                                  /* 2048*sqrt(2)*cos(7*pi/16) */
+ /* private data
- /* global declarations */
+  * Initialized by idct_int32_init so it's mostly RO data,
- //void init_idct_int32 (void);
+  * doesn't hurt thread safety */
- //void idct_int32 (short *block);
- /* private data */
  static short iclip[1024];               /* clipping table */
  static short *iclp;
  /* private prototypes */
- //static void idctrow _ANSI_ARGS_((short *blk));
- //static void idctcol _ANSI_ARGS_((short *blk));
  /* row (horizontal) IDCT
   *
-Line 77
+Line 103
   *        c[1..7] = 128*sqrt(2)
   */
- /*
+ #if 0
  static void idctrow(blk)
  short *blk;
  {
    int X0, X1, X2, X3, X4, X5, X6, X7, X8;
-   // shortcut
+   /* shortcut  */
    if (!((X1 = blk[4]<<11) | (X2 = blk[6]) | (X3 = blk[2]) |
          (X4 = blk[1]) | (X5 = blk[7]) | (X6 = blk[5]) | (X7 = blk[3])))
    {
-Line 91
+Line 117
      return;
    }
-   X0 = (blk[0]<<11) + 128; // for proper rounding in the fourth stage
+   X0 = (blk[0]<<11) + 128; /* for proper rounding in the fourth stage  */
-   // first stage
+   /* first stage  */
    X8 = W7*(X4+X5);
    X4 = X8 + (W1-W7)*X4;
    X5 = X8 - (W1+W7)*X5;
-Line 101
+Line 127
    X6 = X8 - (W3-W5)*X6;
    X7 = X8 - (W3+W5)*X7;
-   // second stage
+   /* second stage  */
    X8 = X0 + X1;
    X0 -= X1;
    X1 = W6*(X3+X2);
-Line 112
+Line 138
    X6 = X5 + X7;
    X5 -= X7;
-   // third stage
+   /* third stage  */
    X7 = X8 + X3;
    X8 -= X3;
    X3 = X0 + X2;
-Line 120
+Line 146
    X2 = (181*(X4+X5)+128)>>8;
    X4 = (181*(X4-X5)+128)>>8;
-   // fourth stage
+   /* fourth stage  */
    blk[0] = (X7+X1)>>8;
    blk[1] = (X3+X2)>>8;
    blk[2] = (X0+X4)>>8;
-Line 129
+Line 155
    blk[5] = (X0-X4)>>8;
    blk[6] = (X3-X2)>>8;
    blk[7] = (X7-X1)>>8;
- }*/
+ }
+ #endif
  /* column (vertical) IDCT
   *
-Line 140
+Line 167
   * where: c[0]    = 1/1024
   *        c[1..7] = (1/1024)*sqrt(2)
   */
- /*
+ #if 0
  static void idctcol(blk)
  short *blk;
  {
    int X0, X1, X2, X3, X4, X5, X6, X7, X8;
-   // shortcut
+   /* 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])))
    {
-Line 157
+Line 185
    X0 = (blk[8*0]<<8) + 8192;
-   // first stage
+   /* first stage  */
    X8 = W7*(X4+X5) + 4;
    X4 = (X8+(W1-W7)*X4)>>3;
    X5 = (X8-(W1+W7)*X5)>>3;
-Line 165
+Line 193
    X6 = (X8-(W3-W5)*X6)>>3;
    X7 = (X8-(W3+W5)*X7)>>3;
-   // second stage
+   /* second stage */
    X8 = X0 + X1;
    X0 -= X1;
    X1 = W6*(X3+X2) + 4;
-Line 176
+Line 204
    X6 = X5 + X7;
    X5 -= X7;
-   // third stage
+   /* third stage  */
    X7 = X8 + X3;
    X8 -= X3;
    X3 = X0 + X2;
-Line 184
+Line 212
    X2 = (181*(X4+X5)+128)>>8;
    X4 = (181*(X4-X5)+128)>>8;
-   // fourth stage
+   /* fourth stage */
    blk[8*0] = iclp[(X7+X1)>>14];
    blk[8*1] = iclp[(X3+X2)>>14];
    blk[8*2] = iclp[(X0+X4)>>14];
-Line 193
+Line 221
    blk[8*5] = iclp[(X0-X4)>>14];
    blk[8*6] = iclp[(X3-X2)>>14];
    blk[8*7] = iclp[(X7-X1)>>14];
- }*/
+ }
+ #endif
- // function pointer
+ /* function pointer */
  idctFuncPtr idct;
  /* two dimensional inverse discrete cosine transform */
- //void j_rev_dct(block)
- //short *block;
  void
  idct_int32(short *const block)
  {
-         // idct_int32_init() must be called before the first call to this function!
+         /*
+          * idct_int32_init() must be called before the first call to this
+          * function!
+          */
-         /*int i;
+ #if 0
+         int i;
             long i;
             for (i=0; i<8; i++)
             idctrow(block+8*i);
             for (i=0; i<8; i++)
-            idctcol(block+i); */
+                 idctcol(block+i);
-         static short *blk;
+ #endif
-         static long i;
-         static long X0, X1, X2, X3, X4, X5, X6, X7, X8;
+         short *blk;
+         long i;
+         long X0, X1, X2, X3, X4, X5, X6, X7, X8;
-         for (i = 0; i < 8; i++)         // idct rows
+         for (i = 0; i < 8; i++)         /* idct rows */
          {
                  blk = block + (i << 3);
                  if (!
-Line 233
+Line 266
                          continue;
                  }
-                 X0 = (blk[0] << 11) + 128;      // for proper rounding in the fourth stage
+                 X0 = (blk[0] << 11) + 128;      /* for proper rounding in the fourth stage  */
-                 // first stage
+                 /* first stage  */
                  X8 = W7 * (X4 + X5);
                  X4 = X8 + (W1 - W7) * X4;
                  X5 = X8 - (W1 + W7) * X5;
-Line 243
+Line 276
                  X6 = X8 - (W3 - W5) * X6;
                  X7 = X8 - (W3 + W5) * X7;
-                 // second stage
+                 /* second stage  */
                  X8 = X0 + X1;
                  X0 -= X1;
                  X1 = W6 * (X3 + X2);
-Line 254
+Line 287
                  X6 = X5 + X7;
                  X5 -= X7;
-                 // third stage
+                 /* third stage  */
                  X7 = X8 + X3;
                  X8 -= X3;
                  X3 = X0 + X2;
-Line 262
+Line 295
                  X2 = (181 * (X4 + X5) + 128) >> 8;
                  X4 = (181 * (X4 - X5) + 128) >> 8;
-                 // fourth stage
+                 /* fourth stage  */
                  blk[0] = (short) ((X7 + X1) >> 8);
                  blk[1] = (short) ((X3 + X2) >> 8);
-Line 273
+Line 306
                  blk[6] = (short) ((X3 - X2) >> 8);
                  blk[7] = (short) ((X7 - X1) >> 8);
-         }                                                       // end for ( i = 0; i < 8; ++i ) IDCT-rows
+         }                                                       /* end for ( i = 0; i < 8; ++i ) IDCT-rows */
-         for (i = 0; i < 8; i++)         // idct columns
+         for (i = 0; i < 8; i++)         /* idct columns */
          {
                  blk = block + i;
-                 // shortcut
+                 /* shortcut  */
                  if (!
                          ((X1 = (blk[8 * 4] << 8)) | (X2 = blk[8 * 6]) | (X3 =
                                                                                                                           blk[8 *
-Line 296
+Line 329
                  X0 = (blk[8 * 0] << 8) + 8192;
-                 // first stage
+                 /* first stage  */
                  X8 = W7 * (X4 + X5) + 4;
                  X4 = (X8 + (W1 - W7) * X4) >> 3;
                  X5 = (X8 - (W1 + W7) * X5) >> 3;
-Line 304
+Line 337
                  X6 = (X8 - (W3 - W5) * X6) >> 3;
                  X7 = (X8 - (W3 + W5) * X7) >> 3;
-                 // second stage
+                 /* second stage  */
                  X8 = X0 + X1;
                  X0 -= X1;
                  X1 = W6 * (X3 + X2) + 4;
-Line 315
+Line 348
                  X6 = X5 + X7;
                  X5 -= X7;
-                 // third stage
+                 /* third stage  */
                  X7 = X8 + X3;
                  X8 -= X3;
                  X3 = X0 + X2;
-Line 323
+Line 356
                  X2 = (181 * (X4 + X5) + 128) >> 8;
                  X4 = (181 * (X4 - X5) + 128) >> 8;
-                 // fourth stage
+                 /* fourth stage  */
                  blk[8 * 0] = iclp[(X7 + X1) >> 14];
                  blk[8 * 1] = iclp[(X3 + X2) >> 14];
                  blk[8 * 2] = iclp[(X0 + X4) >> 14];
-Line 334
+Line 367
                  blk[8 * 7] = iclp[(X7 - X1) >> 14];
          }
- }                                                               // end function idct_int32(block)
+ }                                                               /* end function idct_int32(block) */
- //void
- //idct_int32_init()
  void
  idct_int32_init()
  {

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