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revision 3, Fri Mar 8 02:46:11 2002 UTC revision 1382, Mon Mar 22 22:36:25 2004 UTC
# Line 1  Line 1 
1  /* idct.c, inverse fast discrete cosine transform                           */  /*****************************************************************************
2     *
3     *  XVID MPEG-4 VIDEO CODEC
4     *  - Inverse DCT  -
5     *
6     *  These routines are from Independent JPEG Group's free JPEG software
7     *  Copyright (C) 1991-1998, Thomas G. Lane (see the file README.IJG)
8     *
9     *  This program is free software ; you can redistribute it and/or modify
10     *  it under the terms of the GNU General Public License as published by
11     *  the Free Software Foundation ; either version 2 of the License, or
12     *  (at your option) any later version.
13     *
14     *  This program is distributed in the hope that it will be useful,
15     *  but WITHOUT ANY WARRANTY ; without even the implied warranty of
16     *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17     *  GNU General Public License for more details.
18     *
19     *  You should have received a copy of the GNU General Public License
20     *  along with this program ; if not, write to the Free Software
21     *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
22     *
23     * $Id: idct.c,v 1.7 2004-03-22 22:36:23 edgomez Exp $
24     *
25     ****************************************************************************/
26    
27  /* Copyright (C) 1996, MPEG Software Simulation Group. All Rights Reserved. */  /* Copyright (C) 1996, MPEG Software Simulation Group. All Rights Reserved. */
28    
# Line 52  Line 76 
76  /* this code assumes >> to be a two's-complement arithmetic */  /* this code assumes >> to be a two's-complement arithmetic */
77  /* right shift: (-2)>>1 == -1 , (-3)>>1 == -2               */  /* right shift: (-2)>>1 == -1 , (-3)>>1 == -2               */
78    
 //#include <windows.h>  
79  #include "idct.h"  #include "idct.h"
80    
81  #define W1 2841 /* 2048*sqrt(2)*cos(1*pi/16) */  #define W1 2841 /* 2048*sqrt(2)*cos(1*pi/16) */
# Line 62  Line 85 
85  #define W6 1108 /* 2048*sqrt(2)*cos(6*pi/16) */  #define W6 1108 /* 2048*sqrt(2)*cos(6*pi/16) */
86  #define W7 565  /* 2048*sqrt(2)*cos(7*pi/16) */  #define W7 565  /* 2048*sqrt(2)*cos(7*pi/16) */
87    
   
 /* global declarations */  
 //void init_idct_int32 (void);  
 //void idct_int32 (short *block);  
   
88  /* private data */  /* private data */
89  static short iclip[1024]; /* clipping table */  static short iclip[1024]; /* clipping table */
90  static short *iclp;  static short *iclp;
91    
92  /* private prototypes */  /* private prototypes */
 //static void idctrow _ANSI_ARGS_((short *blk));  
 //static void idctcol _ANSI_ARGS_((short *blk));  
93    
94  /* row (horizontal) IDCT  /* row (horizontal) IDCT
95   *   *
# Line 85  Line 101 
101   *        c[1..7] = 128*sqrt(2)   *        c[1..7] = 128*sqrt(2)
102   */   */
103    
104  /*  #if 0
105  static void idctrow(blk)  static void idctrow(blk)
106  short *blk;  short *blk;
107  {  {
108    int X0, X1, X2, X3, X4, X5, X6, X7, X8;    int X0, X1, X2, X3, X4, X5, X6, X7, X8;
109    
110    // shortcut    /* shortcut  */
111    if (!((X1 = blk[4]<<11) | (X2 = blk[6]) | (X3 = blk[2]) |    if (!((X1 = blk[4]<<11) | (X2 = blk[6]) | (X3 = blk[2]) |
112          (X4 = blk[1]) | (X5 = blk[7]) | (X6 = blk[5]) | (X7 = blk[3])))          (X4 = blk[1]) | (X5 = blk[7]) | (X6 = blk[5]) | (X7 = blk[3])))
113    {    {
# Line 99  Line 115 
115      return;      return;
116    }    }
117    
118    X0 = (blk[0]<<11) + 128; // for proper rounding in the fourth stage    X0 = (blk[0]<<11) + 128; /* for proper rounding in the fourth stage  */
119    
120    // first stage    /* first stage  */
121    X8 = W7*(X4+X5);    X8 = W7*(X4+X5);
122    X4 = X8 + (W1-W7)*X4;    X4 = X8 + (W1-W7)*X4;
123    X5 = X8 - (W1+W7)*X5;    X5 = X8 - (W1+W7)*X5;
# Line 109  Line 125 
125    X6 = X8 - (W3-W5)*X6;    X6 = X8 - (W3-W5)*X6;
126    X7 = X8 - (W3+W5)*X7;    X7 = X8 - (W3+W5)*X7;
127    
128    // second stage    /* second stage  */
129    X8 = X0 + X1;    X8 = X0 + X1;
130    X0 -= X1;    X0 -= X1;
131    X1 = W6*(X3+X2);    X1 = W6*(X3+X2);
# Line 120  Line 136 
136    X6 = X5 + X7;    X6 = X5 + X7;
137    X5 -= X7;    X5 -= X7;
138    
139    // third stage    /* third stage  */
140    X7 = X8 + X3;    X7 = X8 + X3;
141    X8 -= X3;    X8 -= X3;
142    X3 = X0 + X2;    X3 = X0 + X2;
# Line 128  Line 144 
144    X2 = (181*(X4+X5)+128)>>8;    X2 = (181*(X4+X5)+128)>>8;
145    X4 = (181*(X4-X5)+128)>>8;    X4 = (181*(X4-X5)+128)>>8;
146    
147    // fourth stage    /* fourth stage  */
148    blk[0] = (X7+X1)>>8;    blk[0] = (X7+X1)>>8;
149    blk[1] = (X3+X2)>>8;    blk[1] = (X3+X2)>>8;
150    blk[2] = (X0+X4)>>8;    blk[2] = (X0+X4)>>8;
# Line 137  Line 153 
153    blk[5] = (X0-X4)>>8;    blk[5] = (X0-X4)>>8;
154    blk[6] = (X3-X2)>>8;    blk[6] = (X3-X2)>>8;
155    blk[7] = (X7-X1)>>8;    blk[7] = (X7-X1)>>8;
156  }*/  }
157    #endif
158    
159  /* column (vertical) IDCT  /* column (vertical) IDCT
160   *   *
# Line 148  Line 165 
165   * where: c[0]    = 1/1024   * where: c[0]    = 1/1024
166   *        c[1..7] = (1/1024)*sqrt(2)   *        c[1..7] = (1/1024)*sqrt(2)
167   */   */
168  /*  
169    #if 0
170  static void idctcol(blk)  static void idctcol(blk)
171  short *blk;  short *blk;
172  {  {
173    int X0, X1, X2, X3, X4, X5, X6, X7, X8;    int X0, X1, X2, X3, X4, X5, X6, X7, X8;
174    
175    // shortcut    /* shortcut  */
176    if (!((X1 = (blk[8*4]<<8)) | (X2 = blk[8*6]) | (X3 = blk[8*2]) |    if (!((X1 = (blk[8*4]<<8)) | (X2 = blk[8*6]) | (X3 = blk[8*2]) |
177          (X4 = blk[8*1]) | (X5 = blk[8*7]) | (X6 = blk[8*5]) | (X7 = blk[8*3])))          (X4 = blk[8*1]) | (X5 = blk[8*7]) | (X6 = blk[8*5]) | (X7 = blk[8*3])))
178    {    {
# Line 165  Line 183 
183    
184    X0 = (blk[8*0]<<8) + 8192;    X0 = (blk[8*0]<<8) + 8192;
185    
186    // first stage    /* first stage  */
187    X8 = W7*(X4+X5) + 4;    X8 = W7*(X4+X5) + 4;
188    X4 = (X8+(W1-W7)*X4)>>3;    X4 = (X8+(W1-W7)*X4)>>3;
189    X5 = (X8-(W1+W7)*X5)>>3;    X5 = (X8-(W1+W7)*X5)>>3;
# Line 173  Line 191 
191    X6 = (X8-(W3-W5)*X6)>>3;    X6 = (X8-(W3-W5)*X6)>>3;
192    X7 = (X8-(W3+W5)*X7)>>3;    X7 = (X8-(W3+W5)*X7)>>3;
193    
194    // second stage    /* second stage */
195    X8 = X0 + X1;    X8 = X0 + X1;
196    X0 -= X1;    X0 -= X1;
197    X1 = W6*(X3+X2) + 4;    X1 = W6*(X3+X2) + 4;
# Line 184  Line 202 
202    X6 = X5 + X7;    X6 = X5 + X7;
203    X5 -= X7;    X5 -= X7;
204    
205    // third stage    /* third stage  */
206    X7 = X8 + X3;    X7 = X8 + X3;
207    X8 -= X3;    X8 -= X3;
208    X3 = X0 + X2;    X3 = X0 + X2;
# Line 192  Line 210 
210    X2 = (181*(X4+X5)+128)>>8;    X2 = (181*(X4+X5)+128)>>8;
211    X4 = (181*(X4-X5)+128)>>8;    X4 = (181*(X4-X5)+128)>>8;
212    
213    // fourth stage    /* fourth stage */
214    blk[8*0] = iclp[(X7+X1)>>14];    blk[8*0] = iclp[(X7+X1)>>14];
215    blk[8*1] = iclp[(X3+X2)>>14];    blk[8*1] = iclp[(X3+X2)>>14];
216    blk[8*2] = iclp[(X0+X4)>>14];    blk[8*2] = iclp[(X0+X4)>>14];
# Line 201  Line 219 
219    blk[8*5] = iclp[(X0-X4)>>14];    blk[8*5] = iclp[(X0-X4)>>14];
220    blk[8*6] = iclp[(X3-X2)>>14];    blk[8*6] = iclp[(X3-X2)>>14];
221    blk[8*7] = iclp[(X7-X1)>>14];    blk[8*7] = iclp[(X7-X1)>>14];
222  }*/  }
223    #endif
224    
225  // function pointer  /* function pointer */
226  idctFuncPtr idct;  idctFuncPtr idct;
227    
228  /* two dimensional inverse discrete cosine transform */  /* two dimensional inverse discrete cosine transform */
229  //void j_rev_dct(block)  void
230  //short *block;  idct_int32(short *const block)
 void idct_int32(short * const block)  
231  {  {
232    
233    // idct_int32_init() must be called before the first call to this function!          /*
234             * idct_int32_init() must be called before the first call to this
235             * function!
236             */
237    
238    
239    /*int i;  #if 0
240            int i;
241    long i;    long i;
242    
243    for (i=0; i<8; i++)    for (i=0; i<8; i++)
244      idctrow(block+8*i);      idctrow(block+8*i);
245    
246    for (i=0; i<8; i++)    for (i=0; i<8; i++)
247      idctcol(block+i);*/                  idctcol(block+i);
248    #endif
249    
250    static short *blk;    static short *blk;
251    static long i;    static long i;
252    static long X0, X1, X2, X3, X4, X5, X6, X7, X8;    static long X0, X1, X2, X3, X4, X5, X6, X7, X8;
253    
254    
255    for (i=0; i<8; i++)   // idct rows          for (i = 0; i < 8; i++)         /* idct rows */
256    {    {
257          blk = block+(i<<3);          blk = block+(i<<3);
258          if (!((X1 = blk[4]<<11) | (X2 = blk[6]) | (X3 = blk[2]) |                  if (!
259          (X4 = blk[1]) | (X5 = blk[7]) | (X6 = blk[5]) | (X7 = blk[3])))                          ((X1 = blk[4] << 11) | (X2 = blk[6]) | (X3 = blk[2]) | (X4 =
260          {                                                                                                                                          blk[1]) |
261                  blk[0]=blk[1]=blk[2]=blk[3]=blk[4]=blk[5]=blk[6]=blk[7]=blk[0]<<3;                           (X5 = blk[7]) | (X6 = blk[5]) | (X7 = blk[3]))) {
262                            blk[0] = blk[1] = blk[2] = blk[3] = blk[4] = blk[5] = blk[6] =
263                                    blk[7] = blk[0] << 3;
264                  continue;                  continue;
265          }          }
266    
267          X0 = (blk[0]<<11) + 128; // for proper rounding in the fourth stage                  X0 = (blk[0] << 11) + 128;      /* for proper rounding in the fourth stage  */
268    
269          // first stage                  /* first stage  */
270          X8 = W7*(X4+X5);          X8 = W7*(X4+X5);
271          X4 = X8 + (W1-W7)*X4;          X4 = X8 + (W1-W7)*X4;
272          X5 = X8 - (W1+W7)*X5;          X5 = X8 - (W1+W7)*X5;
# Line 248  Line 274 
274          X6 = X8 - (W3-W5)*X6;          X6 = X8 - (W3-W5)*X6;
275          X7 = X8 - (W3+W5)*X7;          X7 = X8 - (W3+W5)*X7;
276    
277          // second stage                  /* second stage  */
278          X8 = X0 + X1;          X8 = X0 + X1;
279          X0 -= X1;          X0 -= X1;
280          X1 = W6*(X3+X2);          X1 = W6*(X3+X2);
# Line 259  Line 285 
285          X6 = X5 + X7;          X6 = X5 + X7;
286          X5 -= X7;          X5 -= X7;
287    
288          // third stage                  /* third stage  */
289          X7 = X8 + X3;          X7 = X8 + X3;
290          X8 -= X3;          X8 -= X3;
291          X3 = X0 + X2;          X3 = X0 + X2;
# Line 267  Line 293 
293          X2 = (181*(X4+X5)+128)>>8;          X2 = (181*(X4+X5)+128)>>8;
294          X4 = (181*(X4-X5)+128)>>8;          X4 = (181*(X4-X5)+128)>>8;
295    
296          // fourth stage                  /* fourth stage  */
297    
298          blk[0] = (short)((X7+X1)>>8);          blk[0] = (short)((X7+X1)>>8);
299          blk[1] = (short)((X3+X2)>>8);          blk[1] = (short)((X3+X2)>>8);
# Line 278  Line 304 
304          blk[6] = (short)((X3-X2)>>8);          blk[6] = (short)((X3-X2)>>8);
305          blk[7] = (short)((X7-X1)>>8);          blk[7] = (short)((X7-X1)>>8);
306    
307    } // end for ( i = 0; i < 8; ++i ) IDCT-rows          }                                                       /* end for ( i = 0; i < 8; ++i ) IDCT-rows */
308    
309    
310    
311    for (i=0; i<8; i++)   // idct columns          for (i = 0; i < 8; i++)         /* idct columns */
312    {    {
313          blk = block + i;          blk = block + i;
314      // shortcut                  /* shortcut  */
315          if (!((X1 = (blk[8*4]<<8)) | (X2 = blk[8*6]) | (X3 = blk[8*2]) |                  if (!
316          (X4 = blk[8*1]) | (X5 = blk[8*7]) | (X6 = blk[8*5]) | (X7 = blk[8*3])))                          ((X1 = (blk[8 * 4] << 8)) | (X2 = blk[8 * 6]) | (X3 =
317          {                                                                                                                           blk[8 *
318                                                                                                                                     2]) | (X4 =
319                                                                                                                                                    blk[8 *
320                                                                                                                                                            1])
321                             | (X5 = blk[8 * 7]) | (X6 = blk[8 * 5]) | (X7 = blk[8 * 3]))) {
322                  blk[8*0]=blk[8*1]=blk[8*2]=blk[8*3]=blk[8*4]=                  blk[8*0]=blk[8*1]=blk[8*2]=blk[8*3]=blk[8*4]=
323                          blk[8*5]=blk[8*6]=blk[8*7]=iclp[(blk[8*0]+32)>>6];                                  blk[8 * 5] = blk[8 * 6] = blk[8 * 7] =
324                                    iclp[(blk[8 * 0] + 32) >> 6];
325                  continue;                  continue;
326          }          }
327    
328          X0 = (blk[8*0]<<8) + 8192;          X0 = (blk[8*0]<<8) + 8192;
329    
330          // first stage                  /* first stage  */
331          X8 = W7*(X4+X5) + 4;          X8 = W7*(X4+X5) + 4;
332          X4 = (X8+(W1-W7)*X4)>>3;          X4 = (X8+(W1-W7)*X4)>>3;
333          X5 = (X8-(W1+W7)*X5)>>3;          X5 = (X8-(W1+W7)*X5)>>3;
# Line 304  Line 335 
335          X6 = (X8-(W3-W5)*X6)>>3;          X6 = (X8-(W3-W5)*X6)>>3;
336          X7 = (X8-(W3+W5)*X7)>>3;          X7 = (X8-(W3+W5)*X7)>>3;
337    
338          // second stage                  /* second stage  */
339          X8 = X0 + X1;          X8 = X0 + X1;
340          X0 -= X1;          X0 -= X1;
341          X1 = W6*(X3+X2) + 4;          X1 = W6*(X3+X2) + 4;
# Line 315  Line 346 
346          X6 = X5 + X7;          X6 = X5 + X7;
347          X5 -= X7;          X5 -= X7;
348    
349          // third stage                  /* third stage  */
350          X7 = X8 + X3;          X7 = X8 + X3;
351          X8 -= X3;          X8 -= X3;
352          X3 = X0 + X2;          X3 = X0 + X2;
# Line 323  Line 354 
354          X2 = (181*(X4+X5)+128)>>8;          X2 = (181*(X4+X5)+128)>>8;
355          X4 = (181*(X4-X5)+128)>>8;          X4 = (181*(X4-X5)+128)>>8;
356    
357          // fourth stage                  /* fourth stage  */
358          blk[8*0] = iclp[(X7+X1)>>14];          blk[8*0] = iclp[(X7+X1)>>14];
359          blk[8*1] = iclp[(X3+X2)>>14];          blk[8*1] = iclp[(X3+X2)>>14];
360          blk[8*2] = iclp[(X0+X4)>>14];          blk[8*2] = iclp[(X0+X4)>>14];
# Line 334  Line 365 
365          blk[8*7] = iclp[(X7-X1)>>14];          blk[8*7] = iclp[(X7-X1)>>14];
366    }    }
367    
368  } // end function idct_int32(block)  }                                                               /* end function idct_int32(block) */
369    
370    
371  //void  void
372  //idct_int32_init()  idct_int32_init()
 void idct_int32_init()  
373  {  {
374    int i;    int i;
375    
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