51 |
* exception also makes it possible to release a modified version which |
* exception also makes it possible to release a modified version which |
52 |
* carries forward this exception. |
* carries forward this exception. |
53 |
* |
* |
54 |
* $Id: idct.c,v 1.4 2002-11-16 23:51:58 edgomez Exp $ |
* $Id: idct.c,v 1.5 2002-11-26 23:44:10 edgomez Exp $ |
55 |
* |
* |
56 |
*************************************************************************/ |
*************************************************************************/ |
57 |
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80 |
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81 |
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82 |
/* global declarations */ |
/* global declarations */ |
83 |
//void init_idct_int32 (void); |
/*void init_idct_int32 (void); */ |
84 |
//void idct_int32 (short *block); |
/*void idct_int32 (short *block); */ |
85 |
|
|
86 |
/* private data */ |
/* private data */ |
87 |
static short iclip[1024]; /* clipping table */ |
static short iclip[1024]; /* clipping table */ |
88 |
static short *iclp; |
static short *iclp; |
89 |
|
|
90 |
/* private prototypes */ |
/* private prototypes */ |
91 |
//static void idctrow _ANSI_ARGS_((short *blk)); |
/*static void idctrow _ANSI_ARGS_((short *blk)); */ |
92 |
//static void idctcol _ANSI_ARGS_((short *blk)); |
/*static void idctcol _ANSI_ARGS_((short *blk)); */ |
93 |
|
|
94 |
/* row (horizontal) IDCT |
/* row (horizontal) IDCT |
95 |
* |
* |
101 |
* c[1..7] = 128*sqrt(2) |
* c[1..7] = 128*sqrt(2) |
102 |
*/ |
*/ |
103 |
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|
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 |
{ |
{ |
115 |
return; |
return; |
116 |
} |
} |
117 |
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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; |
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); |
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; |
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; |
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 |
* |
* |
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 |
/* |
#if 0 |
169 |
static void idctcol(blk) |
static void idctcol(blk) |
170 |
short *blk; |
short *blk; |
171 |
{ |
{ |
172 |
int X0, X1, X2, X3, X4, X5, X6, X7, X8; |
int X0, X1, X2, X3, X4, X5, X6, X7, X8; |
173 |
|
|
174 |
// shortcut |
/* shortcut */ |
175 |
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]) | |
176 |
(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]))) |
177 |
{ |
{ |
182 |
|
|
183 |
X0 = (blk[8*0]<<8) + 8192; |
X0 = (blk[8*0]<<8) + 8192; |
184 |
|
|
185 |
// first stage |
/* first stage */ |
186 |
X8 = W7*(X4+X5) + 4; |
X8 = W7*(X4+X5) + 4; |
187 |
X4 = (X8+(W1-W7)*X4)>>3; |
X4 = (X8+(W1-W7)*X4)>>3; |
188 |
X5 = (X8-(W1+W7)*X5)>>3; |
X5 = (X8-(W1+W7)*X5)>>3; |
190 |
X6 = (X8-(W3-W5)*X6)>>3; |
X6 = (X8-(W3-W5)*X6)>>3; |
191 |
X7 = (X8-(W3+W5)*X7)>>3; |
X7 = (X8-(W3+W5)*X7)>>3; |
192 |
|
|
193 |
// second stage |
/* second stage */ |
194 |
X8 = X0 + X1; |
X8 = X0 + X1; |
195 |
X0 -= X1; |
X0 -= X1; |
196 |
X1 = W6*(X3+X2) + 4; |
X1 = W6*(X3+X2) + 4; |
201 |
X6 = X5 + X7; |
X6 = X5 + X7; |
202 |
X5 -= X7; |
X5 -= X7; |
203 |
|
|
204 |
// third stage |
/* third stage */ |
205 |
X7 = X8 + X3; |
X7 = X8 + X3; |
206 |
X8 -= X3; |
X8 -= X3; |
207 |
X3 = X0 + X2; |
X3 = X0 + X2; |
209 |
X2 = (181*(X4+X5)+128)>>8; |
X2 = (181*(X4+X5)+128)>>8; |
210 |
X4 = (181*(X4-X5)+128)>>8; |
X4 = (181*(X4-X5)+128)>>8; |
211 |
|
|
212 |
// fourth stage |
/* fourth stage */ |
213 |
blk[8*0] = iclp[(X7+X1)>>14]; |
blk[8*0] = iclp[(X7+X1)>>14]; |
214 |
blk[8*1] = iclp[(X3+X2)>>14]; |
blk[8*1] = iclp[(X3+X2)>>14]; |
215 |
blk[8*2] = iclp[(X0+X4)>>14]; |
blk[8*2] = iclp[(X0+X4)>>14]; |
218 |
blk[8*5] = iclp[(X0-X4)>>14]; |
blk[8*5] = iclp[(X0-X4)>>14]; |
219 |
blk[8*6] = iclp[(X3-X2)>>14]; |
blk[8*6] = iclp[(X3-X2)>>14]; |
220 |
blk[8*7] = iclp[(X7-X1)>>14]; |
blk[8*7] = iclp[(X7-X1)>>14]; |
221 |
}*/ |
} |
222 |
|
#endif |
223 |
|
|
224 |
// function pointer |
/* function pointer */ |
225 |
idctFuncPtr idct; |
idctFuncPtr idct; |
226 |
|
|
227 |
/* two dimensional inverse discrete cosine transform */ |
/* two dimensional inverse discrete cosine transform */ |
228 |
//void j_rev_dct(block) |
/*void j_rev_dct(block) */ |
229 |
//short *block; |
/*short *block; */ |
230 |
void |
void |
231 |
idct_int32(short *const block) |
idct_int32(short *const block) |
232 |
{ |
{ |
233 |
|
|
234 |
// 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! */ |
235 |
|
|
236 |
|
|
237 |
/*int i; |
/*int i; |
247 |
static long X0, X1, X2, X3, X4, X5, X6, X7, X8; |
static long X0, X1, X2, X3, X4, X5, X6, X7, X8; |
248 |
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|
249 |
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|
250 |
for (i = 0; i < 8; i++) // idct rows |
for (i = 0; i < 8; i++) /* idct rows */ |
251 |
{ |
{ |
252 |
blk = block + (i << 3); |
blk = block + (i << 3); |
253 |
if (! |
if (! |
259 |
continue; |
continue; |
260 |
} |
} |
261 |
|
|
262 |
X0 = (blk[0] << 11) + 128; // for proper rounding in the fourth stage |
X0 = (blk[0] << 11) + 128; /* for proper rounding in the fourth stage */ |
263 |
|
|
264 |
// first stage |
/* first stage */ |
265 |
X8 = W7 * (X4 + X5); |
X8 = W7 * (X4 + X5); |
266 |
X4 = X8 + (W1 - W7) * X4; |
X4 = X8 + (W1 - W7) * X4; |
267 |
X5 = X8 - (W1 + W7) * X5; |
X5 = X8 - (W1 + W7) * X5; |
269 |
X6 = X8 - (W3 - W5) * X6; |
X6 = X8 - (W3 - W5) * X6; |
270 |
X7 = X8 - (W3 + W5) * X7; |
X7 = X8 - (W3 + W5) * X7; |
271 |
|
|
272 |
// second stage |
/* second stage */ |
273 |
X8 = X0 + X1; |
X8 = X0 + X1; |
274 |
X0 -= X1; |
X0 -= X1; |
275 |
X1 = W6 * (X3 + X2); |
X1 = W6 * (X3 + X2); |
280 |
X6 = X5 + X7; |
X6 = X5 + X7; |
281 |
X5 -= X7; |
X5 -= X7; |
282 |
|
|
283 |
// third stage |
/* third stage */ |
284 |
X7 = X8 + X3; |
X7 = X8 + X3; |
285 |
X8 -= X3; |
X8 -= X3; |
286 |
X3 = X0 + X2; |
X3 = X0 + X2; |
288 |
X2 = (181 * (X4 + X5) + 128) >> 8; |
X2 = (181 * (X4 + X5) + 128) >> 8; |
289 |
X4 = (181 * (X4 - X5) + 128) >> 8; |
X4 = (181 * (X4 - X5) + 128) >> 8; |
290 |
|
|
291 |
// fourth stage |
/* fourth stage */ |
292 |
|
|
293 |
blk[0] = (short) ((X7 + X1) >> 8); |
blk[0] = (short) ((X7 + X1) >> 8); |
294 |
blk[1] = (short) ((X3 + X2) >> 8); |
blk[1] = (short) ((X3 + X2) >> 8); |
299 |
blk[6] = (short) ((X3 - X2) >> 8); |
blk[6] = (short) ((X3 - X2) >> 8); |
300 |
blk[7] = (short) ((X7 - X1) >> 8); |
blk[7] = (short) ((X7 - X1) >> 8); |
301 |
|
|
302 |
} // end for ( i = 0; i < 8; ++i ) IDCT-rows |
} /* end for ( i = 0; i < 8; ++i ) IDCT-rows */ |
303 |
|
|
304 |
|
|
305 |
|
|
306 |
for (i = 0; i < 8; i++) // idct columns |
for (i = 0; i < 8; i++) /* idct columns */ |
307 |
{ |
{ |
308 |
blk = block + i; |
blk = block + i; |
309 |
// shortcut |
/* shortcut */ |
310 |
if (! |
if (! |
311 |
((X1 = (blk[8 * 4] << 8)) | (X2 = blk[8 * 6]) | (X3 = |
((X1 = (blk[8 * 4] << 8)) | (X2 = blk[8 * 6]) | (X3 = |
312 |
blk[8 * |
blk[8 * |
322 |
|
|
323 |
X0 = (blk[8 * 0] << 8) + 8192; |
X0 = (blk[8 * 0] << 8) + 8192; |
324 |
|
|
325 |
// first stage |
/* first stage */ |
326 |
X8 = W7 * (X4 + X5) + 4; |
X8 = W7 * (X4 + X5) + 4; |
327 |
X4 = (X8 + (W1 - W7) * X4) >> 3; |
X4 = (X8 + (W1 - W7) * X4) >> 3; |
328 |
X5 = (X8 - (W1 + W7) * X5) >> 3; |
X5 = (X8 - (W1 + W7) * X5) >> 3; |
330 |
X6 = (X8 - (W3 - W5) * X6) >> 3; |
X6 = (X8 - (W3 - W5) * X6) >> 3; |
331 |
X7 = (X8 - (W3 + W5) * X7) >> 3; |
X7 = (X8 - (W3 + W5) * X7) >> 3; |
332 |
|
|
333 |
// second stage |
/* second stage */ |
334 |
X8 = X0 + X1; |
X8 = X0 + X1; |
335 |
X0 -= X1; |
X0 -= X1; |
336 |
X1 = W6 * (X3 + X2) + 4; |
X1 = W6 * (X3 + X2) + 4; |
341 |
X6 = X5 + X7; |
X6 = X5 + X7; |
342 |
X5 -= X7; |
X5 -= X7; |
343 |
|
|
344 |
// third stage |
/* third stage */ |
345 |
X7 = X8 + X3; |
X7 = X8 + X3; |
346 |
X8 -= X3; |
X8 -= X3; |
347 |
X3 = X0 + X2; |
X3 = X0 + X2; |
349 |
X2 = (181 * (X4 + X5) + 128) >> 8; |
X2 = (181 * (X4 + X5) + 128) >> 8; |
350 |
X4 = (181 * (X4 - X5) + 128) >> 8; |
X4 = (181 * (X4 - X5) + 128) >> 8; |
351 |
|
|
352 |
// fourth stage |
/* fourth stage */ |
353 |
blk[8 * 0] = iclp[(X7 + X1) >> 14]; |
blk[8 * 0] = iclp[(X7 + X1) >> 14]; |
354 |
blk[8 * 1] = iclp[(X3 + X2) >> 14]; |
blk[8 * 1] = iclp[(X3 + X2) >> 14]; |
355 |
blk[8 * 2] = iclp[(X0 + X4) >> 14]; |
blk[8 * 2] = iclp[(X0 + X4) >> 14]; |
360 |
blk[8 * 7] = iclp[(X7 - X1) >> 14]; |
blk[8 * 7] = iclp[(X7 - X1) >> 14]; |
361 |
} |
} |
362 |
|
|
363 |
} // end function idct_int32(block) |
} /* end function idct_int32(block) */ |
364 |
|
|
365 |
|
|
366 |
//void |
/*void */ |
367 |
//idct_int32_init() |
/*idct_int32_init() */ |
368 |
void |
void |
369 |
idct_int32_init() |
idct_int32_init(void) |
370 |
{ |
{ |
371 |
int i; |
int i; |
372 |
|
|