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Annotation of /xvidcore/src/bitstream/cbp.c

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Revision 1.10.2.2 - (view) (download)

1 : edgomez 1.10.2.2 /*****************************************************************************
2 :     *
3 :     * XVID MPEG-4 VIDEO CODEC
4 :     * - CBP related function -
5 :     *
6 :     * Copyright(C) 2002-2003 Edouard Gomez <ed.gomez@free.fr>
7 :     * 2003 Christoph Lampert <gruel@web.de>
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 :     * $Id$
24 :     *
25 :     ****************************************************************************/
26 :    
27 : Isibaar 1.1 #include "../portab.h"
28 :     #include "cbp.h"
29 :    
30 :     cbpFuncPtr calc_cbp;
31 :    
32 : edgomez 1.2 /*
33 :     * Returns a field of bits that indicates non zero ac blocks
34 :     * for this macro block
35 :     */
36 : edgomez 1.10.2.1
37 :     /* naive C */
38 : edgomez 1.5 uint32_t
39 : edgomez 1.10.2.1 calc_cbp_plain(const int16_t codes[6 * 64])
40 : Isibaar 1.1 {
41 : edgomez 1.10.2.1 int i, j;
42 : edgomez 1.2 uint32_t cbp = 0;
43 : Isibaar 1.1
44 : edgomez 1.5 for (i = 0; i < 6; i++) {
45 : edgomez 1.10.2.1 for (j=1; j<64;j++) {
46 :     if (codes[64*i+j]) {
47 :     cbp |= 1 << (5-i);
48 : Isibaar 1.1 break;
49 :     }
50 :     }
51 : edgomez 1.10.2.1 }
52 :     return cbp;
53 :     }
54 :    
55 :     /* optimized C */
56 :     uint32_t
57 :     calc_cbp_c(const int16_t codes[6 * 64])
58 :     {
59 :     unsigned int i=6;
60 :     uint32_t cbp = 0;
61 : edgomez 1.2
62 : edgomez 1.10.2.1 /* uses fixed relation: 4*codes = 1*codes64 */
63 :     /* if prototype is changed (e.g. from int16_t to something like int32) this routine
64 :     has to be changed! */
65 : edgomez 1.2
66 : edgomez 1.10.2.1 do {
67 :     uint64_t *codes64 = (uint64_t*)codes; /* the compiler doesn't really make this */
68 :     uint32_t *codes32 = (uint32_t*)codes; /* variables, just "addressing modes" */
69 : edgomez 1.2
70 : edgomez 1.10.2.1 cbp += cbp;
71 :     if (codes[1] || codes32[1]) {
72 :     cbp++;
73 :     }
74 :     else if (codes64[1] | codes64[2] | codes64[3]) {
75 :     cbp++;
76 :     }
77 :     else if (codes64[4] | codes64[5] | codes64[6] | codes64[7]) {
78 :     cbp++;
79 :     }
80 :     else if (codes64[8] | codes64[9] | codes64[10] | codes64[11]) {
81 :     cbp++;
82 :     }
83 :     else if (codes64[12] | codes64[13] | codes64[14] | codes64[15]) {
84 :     cbp++;
85 :     }
86 :     codes += 64;
87 :     i--;
88 :     } while (i != 0);
89 : edgomez 1.2
90 : edgomez 1.10.2.1 return cbp;
91 : Isibaar 1.1 }
92 : edgomez 1.10.2.1
93 :    
94 :    
95 :    
96 :     /* older code maybe better on some plattforms? */
97 :     #if 0
98 :     for (i = 5; i >= 0; i--) {
99 :     if (codes[1] | codes[2] | codes[3])
100 :     cbp |= 1 << i;
101 :     else {
102 :     for (j = 4; j <= 56; j+=4) /* [60],[61],[62],[63] are last */
103 :     if (codes[j] | codes[j+1] | codes[j+2] | codes[j+3]) {
104 :     cbp |= 1 << i;
105 :     break;
106 :     }
107 :     }
108 :     codes += 64;
109 :     }
110 :    
111 :     return cbp;
112 :     #endif

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