1 /*****************************************************************************
2 * idctclassic.c : Classic IDCT module
3 *****************************************************************************
4 * Copyright (C) 1999, 2000 VideoLAN
5 * $Id: idctclassic.c,v 1.4 2001/01/16 05:04:25 sam Exp $
7 * Authors: Gaƫl Hendryckx <jimmy@via.ecp.fr>
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.
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.
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, USA.
22 *****************************************************************************/
24 #define MODULE_NAME idctclassic
26 /*****************************************************************************
28 *****************************************************************************/
40 #include "video_output.h"
42 #include "video_decoder.h"
45 #include "modules_inner.h"
49 /*****************************************************************************
50 * Local and extern prototypes.
51 *****************************************************************************/
52 static void idct_getfunctions( function_list_t * p_function_list );
54 static int idct_Probe ( probedata_t *p_data );
55 static void vdec_InitIDCT ( vdec_thread_t * p_vdec);
56 void vdec_SparseIDCT ( vdec_thread_t * p_vdec, dctelem_t * p_block,
58 static void vdec_IDCT ( vdec_thread_t * p_vdec, dctelem_t * p_block,
62 /*****************************************************************************
63 * Build configuration tree.
64 *****************************************************************************/
66 ADD_WINDOW( "Configuration for classic IDCT module" )
67 ADD_COMMENT( "Ha, ha -- nothing to configure yet" )
70 /*****************************************************************************
71 * InitModule: get the module structure and configuration.
72 *****************************************************************************
73 * We have to fill psz_name, psz_longname and psz_version. These variables
74 * will be strdup()ed later by the main application because the module can
75 * be unloaded later to save memory, and we want to be able to access this
76 * data even after the module has been unloaded.
77 *****************************************************************************/
78 int InitModule( module_t * p_module )
80 p_module->psz_name = MODULE_STRING;
81 p_module->psz_longname = "classic C IDCT module";
82 p_module->psz_version = VERSION;
84 p_module->i_capabilities = MODULE_CAPABILITY_NULL
85 | MODULE_CAPABILITY_IDCT;
90 /*****************************************************************************
91 * ActivateModule: set the module to an usable state.
92 *****************************************************************************
93 * This function fills the capability functions and the configuration
94 * structure. Once ActivateModule() has been called, the i_usage can
95 * be set to 0 and calls to NeedModule() be made to increment it. To unload
96 * the module, one has to wait until i_usage == 0 and call DeactivateModule().
97 *****************************************************************************/
98 int ActivateModule( module_t * p_module )
100 p_module->p_functions = malloc( sizeof( module_functions_t ) );
101 if( p_module->p_functions == NULL )
106 idct_getfunctions( &p_module->p_functions->idct );
108 p_module->p_config = p_config;
113 /*****************************************************************************
114 * DeactivateModule: make sure the module can be unloaded.
115 *****************************************************************************
116 * This function must only be called when i_usage == 0. If it successfully
117 * returns, i_usage can be set to -1 and the module unloaded. Be careful to
118 * lock usage_lock during the whole process.
119 *****************************************************************************/
120 int DeactivateModule( module_t * p_module )
122 free( p_module->p_functions );
127 /* Following functions are local */
129 /*****************************************************************************
130 * Functions exported as capabilities. They are declared as static so that
131 * we don't pollute the namespace too much.
132 *****************************************************************************/
133 static void idct_getfunctions( function_list_t * p_function_list )
135 p_function_list->pf_probe = idct_Probe;
136 p_function_list->functions.idct.pf_init = vdec_InitIDCT;
137 p_function_list->functions.idct.pf_sparse_idct = vdec_SparseIDCT;
138 p_function_list->functions.idct.pf_idct = vdec_IDCT;
141 /*****************************************************************************
142 * idct_Probe: returns a preference score
143 *****************************************************************************/
144 static int idct_Probe( probedata_t *p_data )
146 if( TestMethod( IDCT_METHOD_VAR, "idctclassic" ) )
151 /* This plugin always works */
155 /*****************************************************************************
156 * vdec_InitIDCT : initialize datas for vdec_SparseIDCT
157 *****************************************************************************/
158 static void vdec_InitIDCT (vdec_thread_t * p_vdec)
162 dctelem_t * p_pre = p_vdec->p_pre_idct;
163 memset( p_pre, 0, 64*64*sizeof(dctelem_t) );
165 for( i=0 ; i < 64 ; i++ )
167 p_pre[i*64+i] = 1 << SPARSE_SCALE_FACTOR;
168 vdec_IDCT( p_vdec, &p_pre[i*64], 0) ;
173 /*****************************************************************************
174 * vdec_IDCT : IDCT function for normal matrices
175 *****************************************************************************/
176 static void vdec_IDCT( vdec_thread_t * p_vdec, dctelem_t * p_block,
179 /* dct classique: pour tester la meilleure entre la classique et la */
181 s32 tmp0, tmp1, tmp2, tmp3;
182 s32 tmp10, tmp11, tmp12, tmp13;
183 s32 z1, z2, z3, z4, z5;
188 /* Pass 1: process rows. */
189 /* Note results are scaled up by sqrt(8) compared to a true IDCT; */
190 /* furthermore, we scale the results by 2**PASS1_BITS. */
193 for (rowctr = DCTSIZE-1; rowctr >= 0; rowctr--)
195 /* Due to quantization, we will usually find that many of the input
196 * coefficients are zero, especially the AC terms. We can exploit this
197 * by short-circuiting the IDCT calculation for any row in which all
198 * the AC terms are zero. In that case each output is equal to the
199 * DC coefficient (with scale factor as needed).
200 * With typical images and quantization tables, half or more of the
201 * row DCT calculations can be simplified this way.
204 if ((dataptr[1] | dataptr[2] | dataptr[3] | dataptr[4] |
205 dataptr[5] | dataptr[6] | dataptr[7]) == 0)
207 /* AC terms all zero */
208 dctelem_t dcval = (dctelem_t) (dataptr[0] << PASS1_BITS);
219 dataptr += DCTSIZE; /* advance pointer to next row */
223 /* Even part: reverse the even part of the forward DCT. */
224 /* The rotator is sqrt(2)*c(-6). */
226 z2 = (s32) dataptr[2];
227 z3 = (s32) dataptr[6];
229 z1 = MULTIPLY(z2 + z3, FIX(0.541196100));
230 tmp2 = z1 + MULTIPLY(z3, - FIX(1.847759065));
231 tmp3 = z1 + MULTIPLY(z2, FIX(0.765366865));
233 tmp0 = ((s32) dataptr[0] + (s32) dataptr[4]) << CONST_BITS;
234 tmp1 = ((s32) dataptr[0] - (s32) dataptr[4]) << CONST_BITS;
241 /* Odd part per figure 8; the matrix is unitary and hence its
242 * transpose is its inverse. i0..i3 are y7,y5,y3,y1 respectively.
245 tmp0 = (s32) dataptr[7];
246 tmp1 = (s32) dataptr[5];
247 tmp2 = (s32) dataptr[3];
248 tmp3 = (s32) dataptr[1];
254 z5 = MULTIPLY(z3 + z4, FIX(1.175875602)); /* sqrt(2) * c3 */
256 tmp0 = MULTIPLY(tmp0, FIX(0.298631336)); /* sqrt(2) * (-c1+c3+c5-c7) */
257 tmp1 = MULTIPLY(tmp1, FIX(2.053119869)); /* sqrt(2) * ( c1+c3-c5+c7) */
258 tmp2 = MULTIPLY(tmp2, FIX(3.072711026)); /* sqrt(2) * ( c1+c3+c5-c7) */
259 tmp3 = MULTIPLY(tmp3, FIX(1.501321110)); /* sqrt(2) * ( c1+c3-c5-c7) */
260 z1 = MULTIPLY(z1, - FIX(0.899976223)); /* sqrt(2) * (c7-c3) */
261 z2 = MULTIPLY(z2, - FIX(2.562915447)); /* sqrt(2) * (-c1-c3) */
262 z3 = MULTIPLY(z3, - FIX(1.961570560)); /* sqrt(2) * (-c3-c5) */
263 z4 = MULTIPLY(z4, - FIX(0.390180644)); /* sqrt(2) * (c5-c3) */
273 /* Final output stage: inputs are tmp10..tmp13, tmp0..tmp3 */
275 dataptr[0] = (dctelem_t) DESCALE(tmp10 + tmp3, CONST_BITS-PASS1_BITS);
276 dataptr[7] = (dctelem_t) DESCALE(tmp10 - tmp3, CONST_BITS-PASS1_BITS);
277 dataptr[1] = (dctelem_t) DESCALE(tmp11 + tmp2, CONST_BITS-PASS1_BITS);
278 dataptr[6] = (dctelem_t) DESCALE(tmp11 - tmp2, CONST_BITS-PASS1_BITS);
279 dataptr[2] = (dctelem_t) DESCALE(tmp12 + tmp1, CONST_BITS-PASS1_BITS);
280 dataptr[5] = (dctelem_t) DESCALE(tmp12 - tmp1, CONST_BITS-PASS1_BITS);
281 dataptr[3] = (dctelem_t) DESCALE(tmp13 + tmp0, CONST_BITS-PASS1_BITS);
282 dataptr[4] = (dctelem_t) DESCALE(tmp13 - tmp0, CONST_BITS-PASS1_BITS);
284 dataptr += DCTSIZE; /* advance pointer to next row */
287 /* Pass 2: process columns. */
288 /* Note that we must descale the results by a factor of 8 == 2**3, */
289 /* and also undo the PASS1_BITS scaling. */
292 for (rowctr = DCTSIZE-1; rowctr >= 0; rowctr--)
294 /* Columns of zeroes can be exploited in the same way as we did with rows.
295 * However, the row calculation has created many nonzero AC terms, so the
296 * simplification applies less often (typically 5% to 10% of the time).
297 * On machines with very fast multiplication, it's possible that the
298 * test takes more time than it's worth. In that case this section
299 * may be commented out.
302 #ifndef NO_ZERO_COLUMN_TEST /*ajoute un test mais evite des calculs */
303 if ((dataptr[DCTSIZE*1] | dataptr[DCTSIZE*2] | dataptr[DCTSIZE*3] |
304 dataptr[DCTSIZE*4] | dataptr[DCTSIZE*5] | dataptr[DCTSIZE*6] |
305 dataptr[DCTSIZE*7]) == 0)
307 /* AC terms all zero */
308 dctelem_t dcval = (dctelem_t) DESCALE((s32) dataptr[0], PASS1_BITS+3);
310 dataptr[DCTSIZE*0] = dcval;
311 dataptr[DCTSIZE*1] = dcval;
312 dataptr[DCTSIZE*2] = dcval;
313 dataptr[DCTSIZE*3] = dcval;
314 dataptr[DCTSIZE*4] = dcval;
315 dataptr[DCTSIZE*5] = dcval;
316 dataptr[DCTSIZE*6] = dcval;
317 dataptr[DCTSIZE*7] = dcval;
319 dataptr++; /* advance pointer to next column */
324 /* Even part: reverse the even part of the forward DCT. */
325 /* The rotator is sqrt(2)*c(-6). */
327 z2 = (s32) dataptr[DCTSIZE*2];
328 z3 = (s32) dataptr[DCTSIZE*6];
330 z1 = MULTIPLY(z2 + z3, FIX(0.541196100));
331 tmp2 = z1 + MULTIPLY(z3, - FIX(1.847759065));
332 tmp3 = z1 + MULTIPLY(z2, FIX(0.765366865));
334 tmp0 = ((s32) dataptr[DCTSIZE*0] + (s32) dataptr[DCTSIZE*4]) << CONST_BITS;
335 tmp1 = ((s32) dataptr[DCTSIZE*0] - (s32) dataptr[DCTSIZE*4]) << CONST_BITS;
342 /* Odd part per figure 8; the matrix is unitary and hence its
343 * transpose is its inverse. i0..i3 are y7,y5,y3,y1 respectively.
346 tmp0 = (s32) dataptr[DCTSIZE*7];
347 tmp1 = (s32) dataptr[DCTSIZE*5];
348 tmp2 = (s32) dataptr[DCTSIZE*3];
349 tmp3 = (s32) dataptr[DCTSIZE*1];
355 z5 = MULTIPLY(z3 + z4, FIX(1.175875602)); /* sqrt(2) * c3 */
357 tmp0 = MULTIPLY(tmp0, FIX(0.298631336)); /* sqrt(2) * (-c1+c3+c5-c7) */
358 tmp1 = MULTIPLY(tmp1, FIX(2.053119869)); /* sqrt(2) * ( c1+c3-c5+c7) */
359 tmp2 = MULTIPLY(tmp2, FIX(3.072711026)); /* sqrt(2) * ( c1+c3+c5-c7) */
360 tmp3 = MULTIPLY(tmp3, FIX(1.501321110)); /* sqrt(2) * ( c1+c3-c5-c7) */
361 z1 = MULTIPLY(z1, - FIX(0.899976223)); /* sqrt(2) * (c7-c3) */
362 z2 = MULTIPLY(z2, - FIX(2.562915447)); /* sqrt(2) * (-c1-c3) */
363 z3 = MULTIPLY(z3, - FIX(1.961570560)); /* sqrt(2) * (-c3-c5) */
364 z4 = MULTIPLY(z4, - FIX(0.390180644)); /* sqrt(2) * (c5-c3) */
374 /* Final output stage: inputs are tmp10..tmp13, tmp0..tmp3 */
376 dataptr[DCTSIZE*0] = (dctelem_t) DESCALE(tmp10 + tmp3,
377 CONST_BITS+PASS1_BITS+3);
378 dataptr[DCTSIZE*7] = (dctelem_t) DESCALE(tmp10 - tmp3,
379 CONST_BITS+PASS1_BITS+3);
380 dataptr[DCTSIZE*1] = (dctelem_t) DESCALE(tmp11 + tmp2,
381 CONST_BITS+PASS1_BITS+3);
382 dataptr[DCTSIZE*6] = (dctelem_t) DESCALE(tmp11 - tmp2,
383 CONST_BITS+PASS1_BITS+3);
384 dataptr[DCTSIZE*2] = (dctelem_t) DESCALE(tmp12 + tmp1,
385 CONST_BITS+PASS1_BITS+3);
386 dataptr[DCTSIZE*5] = (dctelem_t) DESCALE(tmp12 - tmp1,
387 CONST_BITS+PASS1_BITS+3);
388 dataptr[DCTSIZE*3] = (dctelem_t) DESCALE(tmp13 + tmp0,
389 CONST_BITS+PASS1_BITS+3);
390 dataptr[DCTSIZE*4] = (dctelem_t) DESCALE(tmp13 - tmp0,
391 CONST_BITS+PASS1_BITS+3);
393 dataptr++; /* advance pointer to next column */