1 /*****************************************************************************
2 * idctclassic.c : Classic IDCT module
3 *****************************************************************************
4 * Copyright (C) 1999, 2000 VideoLAN
5 * $Id: idctclassic.c,v 1.3 2001/01/16 02:16:38 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 *****************************************************************************/
39 #include "video_output.h"
41 #include "video_decoder.h"
44 #include "modules_inner.h"
48 /*****************************************************************************
49 * Local and extern prototypes.
50 *****************************************************************************/
51 static void idct_getfunctions( function_list_t * p_function_list );
53 static int idct_Probe ( probedata_t *p_data );
54 static void vdec_InitIDCT ( vdec_thread_t * p_vdec);
55 void vdec_SparseIDCT ( vdec_thread_t * p_vdec, dctelem_t * p_block,
57 static void vdec_IDCT ( vdec_thread_t * p_vdec, dctelem_t * p_block,
61 /*****************************************************************************
62 * Build configuration tree.
63 *****************************************************************************/
65 ADD_WINDOW( "Configuration for classic IDCT module" )
66 ADD_COMMENT( "Ha, ha -- nothing to configure yet" )
69 /*****************************************************************************
70 * InitModule: get the module structure and configuration.
71 *****************************************************************************
72 * We have to fill psz_name, psz_longname and psz_version. These variables
73 * will be strdup()ed later by the main application because the module can
74 * be unloaded later to save memory, and we want to be able to access this
75 * data even after the module has been unloaded.
76 *****************************************************************************/
77 int InitModule( module_t * p_module )
79 p_module->psz_name = MODULE_STRING;
80 p_module->psz_longname = "classic C IDCT module";
81 p_module->psz_version = VERSION;
83 p_module->i_capabilities = MODULE_CAPABILITY_NULL
84 | MODULE_CAPABILITY_IDCT;
89 /*****************************************************************************
90 * ActivateModule: set the module to an usable state.
91 *****************************************************************************
92 * This function fills the capability functions and the configuration
93 * structure. Once ActivateModule() has been called, the i_usage can
94 * be set to 0 and calls to NeedModule() be made to increment it. To unload
95 * the module, one has to wait until i_usage == 0 and call DeactivateModule().
96 *****************************************************************************/
97 int ActivateModule( module_t * p_module )
99 p_module->p_functions = malloc( sizeof( module_functions_t ) );
100 if( p_module->p_functions == NULL )
105 idct_getfunctions( &p_module->p_functions->idct );
107 p_module->p_config = p_config;
112 /*****************************************************************************
113 * DeactivateModule: make sure the module can be unloaded.
114 *****************************************************************************
115 * This function must only be called when i_usage == 0. If it successfully
116 * returns, i_usage can be set to -1 and the module unloaded. Be careful to
117 * lock usage_lock during the whole process.
118 *****************************************************************************/
119 int DeactivateModule( module_t * p_module )
121 free( p_module->p_functions );
126 /* Following functions are local */
128 /*****************************************************************************
129 * Functions exported as capabilities. They are declared as static so that
130 * we don't pollute the namespace too much.
131 *****************************************************************************/
132 static void idct_getfunctions( function_list_t * p_function_list )
134 p_function_list->pf_probe = idct_Probe;
135 p_function_list->functions.idct.pf_init = vdec_InitIDCT;
136 p_function_list->functions.idct.pf_sparse_idct = vdec_SparseIDCT;
137 p_function_list->functions.idct.pf_idct = vdec_IDCT;
140 /*****************************************************************************
141 * idct_Probe: returns a preference score
142 *****************************************************************************/
143 static int idct_Probe( probedata_t *p_data )
145 /* This plugin always works */
149 /*****************************************************************************
150 * vdec_InitIDCT : initialize datas for vdec_SparseIDCT
151 *****************************************************************************/
152 static void vdec_InitIDCT (vdec_thread_t * p_vdec)
156 dctelem_t * p_pre = p_vdec->p_pre_idct;
157 memset( p_pre, 0, 64*64*sizeof(dctelem_t) );
159 for( i=0 ; i < 64 ; i++ )
161 p_pre[i*64+i] = 1 << SPARSE_SCALE_FACTOR;
162 vdec_IDCT( p_vdec, &p_pre[i*64], 0) ;
167 /*****************************************************************************
168 * vdec_IDCT : IDCT function for normal matrices
169 *****************************************************************************/
170 static void vdec_IDCT( vdec_thread_t * p_vdec, dctelem_t * p_block,
173 /* dct classique: pour tester la meilleure entre la classique et la */
175 s32 tmp0, tmp1, tmp2, tmp3;
176 s32 tmp10, tmp11, tmp12, tmp13;
177 s32 z1, z2, z3, z4, z5;
182 /* Pass 1: process rows. */
183 /* Note results are scaled up by sqrt(8) compared to a true IDCT; */
184 /* furthermore, we scale the results by 2**PASS1_BITS. */
187 for (rowctr = DCTSIZE-1; rowctr >= 0; rowctr--)
189 /* Due to quantization, we will usually find that many of the input
190 * coefficients are zero, especially the AC terms. We can exploit this
191 * by short-circuiting the IDCT calculation for any row in which all
192 * the AC terms are zero. In that case each output is equal to the
193 * DC coefficient (with scale factor as needed).
194 * With typical images and quantization tables, half or more of the
195 * row DCT calculations can be simplified this way.
198 if ((dataptr[1] | dataptr[2] | dataptr[3] | dataptr[4] |
199 dataptr[5] | dataptr[6] | dataptr[7]) == 0)
201 /* AC terms all zero */
202 dctelem_t dcval = (dctelem_t) (dataptr[0] << PASS1_BITS);
213 dataptr += DCTSIZE; /* advance pointer to next row */
217 /* Even part: reverse the even part of the forward DCT. */
218 /* The rotator is sqrt(2)*c(-6). */
220 z2 = (s32) dataptr[2];
221 z3 = (s32) dataptr[6];
223 z1 = MULTIPLY(z2 + z3, FIX(0.541196100));
224 tmp2 = z1 + MULTIPLY(z3, - FIX(1.847759065));
225 tmp3 = z1 + MULTIPLY(z2, FIX(0.765366865));
227 tmp0 = ((s32) dataptr[0] + (s32) dataptr[4]) << CONST_BITS;
228 tmp1 = ((s32) dataptr[0] - (s32) dataptr[4]) << CONST_BITS;
235 /* Odd part per figure 8; the matrix is unitary and hence its
236 * transpose is its inverse. i0..i3 are y7,y5,y3,y1 respectively.
239 tmp0 = (s32) dataptr[7];
240 tmp1 = (s32) dataptr[5];
241 tmp2 = (s32) dataptr[3];
242 tmp3 = (s32) dataptr[1];
248 z5 = MULTIPLY(z3 + z4, FIX(1.175875602)); /* sqrt(2) * c3 */
250 tmp0 = MULTIPLY(tmp0, FIX(0.298631336)); /* sqrt(2) * (-c1+c3+c5-c7) */
251 tmp1 = MULTIPLY(tmp1, FIX(2.053119869)); /* sqrt(2) * ( c1+c3-c5+c7) */
252 tmp2 = MULTIPLY(tmp2, FIX(3.072711026)); /* sqrt(2) * ( c1+c3+c5-c7) */
253 tmp3 = MULTIPLY(tmp3, FIX(1.501321110)); /* sqrt(2) * ( c1+c3-c5-c7) */
254 z1 = MULTIPLY(z1, - FIX(0.899976223)); /* sqrt(2) * (c7-c3) */
255 z2 = MULTIPLY(z2, - FIX(2.562915447)); /* sqrt(2) * (-c1-c3) */
256 z3 = MULTIPLY(z3, - FIX(1.961570560)); /* sqrt(2) * (-c3-c5) */
257 z4 = MULTIPLY(z4, - FIX(0.390180644)); /* sqrt(2) * (c5-c3) */
267 /* Final output stage: inputs are tmp10..tmp13, tmp0..tmp3 */
269 dataptr[0] = (dctelem_t) DESCALE(tmp10 + tmp3, CONST_BITS-PASS1_BITS);
270 dataptr[7] = (dctelem_t) DESCALE(tmp10 - tmp3, CONST_BITS-PASS1_BITS);
271 dataptr[1] = (dctelem_t) DESCALE(tmp11 + tmp2, CONST_BITS-PASS1_BITS);
272 dataptr[6] = (dctelem_t) DESCALE(tmp11 - tmp2, CONST_BITS-PASS1_BITS);
273 dataptr[2] = (dctelem_t) DESCALE(tmp12 + tmp1, CONST_BITS-PASS1_BITS);
274 dataptr[5] = (dctelem_t) DESCALE(tmp12 - tmp1, CONST_BITS-PASS1_BITS);
275 dataptr[3] = (dctelem_t) DESCALE(tmp13 + tmp0, CONST_BITS-PASS1_BITS);
276 dataptr[4] = (dctelem_t) DESCALE(tmp13 - tmp0, CONST_BITS-PASS1_BITS);
278 dataptr += DCTSIZE; /* advance pointer to next row */
281 /* Pass 2: process columns. */
282 /* Note that we must descale the results by a factor of 8 == 2**3, */
283 /* and also undo the PASS1_BITS scaling. */
286 for (rowctr = DCTSIZE-1; rowctr >= 0; rowctr--)
288 /* Columns of zeroes can be exploited in the same way as we did with rows.
289 * However, the row calculation has created many nonzero AC terms, so the
290 * simplification applies less often (typically 5% to 10% of the time).
291 * On machines with very fast multiplication, it's possible that the
292 * test takes more time than it's worth. In that case this section
293 * may be commented out.
296 #ifndef NO_ZERO_COLUMN_TEST /*ajoute un test mais evite des calculs */
297 if ((dataptr[DCTSIZE*1] | dataptr[DCTSIZE*2] | dataptr[DCTSIZE*3] |
298 dataptr[DCTSIZE*4] | dataptr[DCTSIZE*5] | dataptr[DCTSIZE*6] |
299 dataptr[DCTSIZE*7]) == 0)
301 /* AC terms all zero */
302 dctelem_t dcval = (dctelem_t) DESCALE((s32) dataptr[0], PASS1_BITS+3);
304 dataptr[DCTSIZE*0] = dcval;
305 dataptr[DCTSIZE*1] = dcval;
306 dataptr[DCTSIZE*2] = dcval;
307 dataptr[DCTSIZE*3] = dcval;
308 dataptr[DCTSIZE*4] = dcval;
309 dataptr[DCTSIZE*5] = dcval;
310 dataptr[DCTSIZE*6] = dcval;
311 dataptr[DCTSIZE*7] = dcval;
313 dataptr++; /* advance pointer to next column */
318 /* Even part: reverse the even part of the forward DCT. */
319 /* The rotator is sqrt(2)*c(-6). */
321 z2 = (s32) dataptr[DCTSIZE*2];
322 z3 = (s32) dataptr[DCTSIZE*6];
324 z1 = MULTIPLY(z2 + z3, FIX(0.541196100));
325 tmp2 = z1 + MULTIPLY(z3, - FIX(1.847759065));
326 tmp3 = z1 + MULTIPLY(z2, FIX(0.765366865));
328 tmp0 = ((s32) dataptr[DCTSIZE*0] + (s32) dataptr[DCTSIZE*4]) << CONST_BITS;
329 tmp1 = ((s32) dataptr[DCTSIZE*0] - (s32) dataptr[DCTSIZE*4]) << CONST_BITS;
336 /* Odd part per figure 8; the matrix is unitary and hence its
337 * transpose is its inverse. i0..i3 are y7,y5,y3,y1 respectively.
340 tmp0 = (s32) dataptr[DCTSIZE*7];
341 tmp1 = (s32) dataptr[DCTSIZE*5];
342 tmp2 = (s32) dataptr[DCTSIZE*3];
343 tmp3 = (s32) dataptr[DCTSIZE*1];
349 z5 = MULTIPLY(z3 + z4, FIX(1.175875602)); /* sqrt(2) * c3 */
351 tmp0 = MULTIPLY(tmp0, FIX(0.298631336)); /* sqrt(2) * (-c1+c3+c5-c7) */
352 tmp1 = MULTIPLY(tmp1, FIX(2.053119869)); /* sqrt(2) * ( c1+c3-c5+c7) */
353 tmp2 = MULTIPLY(tmp2, FIX(3.072711026)); /* sqrt(2) * ( c1+c3+c5-c7) */
354 tmp3 = MULTIPLY(tmp3, FIX(1.501321110)); /* sqrt(2) * ( c1+c3-c5-c7) */
355 z1 = MULTIPLY(z1, - FIX(0.899976223)); /* sqrt(2) * (c7-c3) */
356 z2 = MULTIPLY(z2, - FIX(2.562915447)); /* sqrt(2) * (-c1-c3) */
357 z3 = MULTIPLY(z3, - FIX(1.961570560)); /* sqrt(2) * (-c3-c5) */
358 z4 = MULTIPLY(z4, - FIX(0.390180644)); /* sqrt(2) * (c5-c3) */
368 /* Final output stage: inputs are tmp10..tmp13, tmp0..tmp3 */
370 dataptr[DCTSIZE*0] = (dctelem_t) DESCALE(tmp10 + tmp3,
371 CONST_BITS+PASS1_BITS+3);
372 dataptr[DCTSIZE*7] = (dctelem_t) DESCALE(tmp10 - tmp3,
373 CONST_BITS+PASS1_BITS+3);
374 dataptr[DCTSIZE*1] = (dctelem_t) DESCALE(tmp11 + tmp2,
375 CONST_BITS+PASS1_BITS+3);
376 dataptr[DCTSIZE*6] = (dctelem_t) DESCALE(tmp11 - tmp2,
377 CONST_BITS+PASS1_BITS+3);
378 dataptr[DCTSIZE*2] = (dctelem_t) DESCALE(tmp12 + tmp1,
379 CONST_BITS+PASS1_BITS+3);
380 dataptr[DCTSIZE*5] = (dctelem_t) DESCALE(tmp12 - tmp1,
381 CONST_BITS+PASS1_BITS+3);
382 dataptr[DCTSIZE*3] = (dctelem_t) DESCALE(tmp13 + tmp0,
383 CONST_BITS+PASS1_BITS+3);
384 dataptr[DCTSIZE*4] = (dctelem_t) DESCALE(tmp13 - tmp0,
385 CONST_BITS+PASS1_BITS+3);
387 dataptr++; /* advance pointer to next column */