fbui | Framebuffer-based graphical environment |
| download: https://git.y1.nz/archives/fbui.tar.gz | |
| README | Files | Log | Refs |
libfbui/MPEG/motion.c
1 /* motion.c, motion vector decoding */
2
3 /* Copyright (C) 1996, MPEG Software Simulation Group. All Rights Reserved. */
4
5 /*
6 * Disclaimer of Warranty
7 *
8 * These software programs are available to the user without any license fee or
9 * royalty on an "as is" basis. The MPEG Software Simulation Group disclaims
10 * any and all warranties, whether express, implied, or statuary, including any
11 * implied warranties or merchantability or of fitness for a particular
12 * purpose. In no event shall the copyright-holder be liable for any
13 * incidental, punitive, or consequential damages of any kind whatsoever
14 * arising from the use of these programs.
15 *
16 * This disclaimer of warranty extends to the user of these programs and user's
17 * customers, employees, agents, transferees, successors, and assigns.
18 *
19 * The MPEG Software Simulation Group does not represent or warrant that the
20 * programs furnished hereunder are free of infringement of any third-party
21 * patents.
22 *
23 * Commercial implementations of MPEG-1 and MPEG-2 video, including shareware,
24 * are subject to royalty fees to patent holders. Many of these patents are
25 * general enough such that they are unavoidable regardless of implementation
26 * design.
27 *
28 */
29
30 #include <stdio.h>
31
32 #include "config.h"
33 #include "global.h"
34
35 /* private prototypes */
36 static void decode_motion_vector _ANSI_ARGS_((int *pred, int r_size, int motion_code,
37 int motion_residualesidual, int full_pel_vector));
38
39 /* ISO/IEC 13818-2 sections 6.2.5.2, 6.3.17.2, and 7.6.3: Motion vectors */
40 void motion_vectors(PMV,dmvector,
41 motion_vertical_field_select,s,motion_vector_count,mv_format,h_r_size,v_r_size,dmv,mvscale)
42 int PMV[2][2][2];
43 int dmvector[2];
44 int motion_vertical_field_select[2][2];
45 int s, motion_vector_count, mv_format, h_r_size, v_r_size, dmv, mvscale;
46 {
47 if (motion_vector_count==1)
48 {
49 if (mv_format==MV_FIELD && !dmv)
50 {
51 motion_vertical_field_select[1][s] = motion_vertical_field_select[0][s] = Get_Bits(1);
52 #ifdef TRACE
53 if (Trace_Flag)
54 {
55 printf("motion_vertical_field_select[][%d] (%d): %d\n",s,
56 motion_vertical_field_select[0][s],motion_vertical_field_select[0][s]);
57 }
58 #endif /* TRACE */
59 }
60
61 motion_vector(PMV[0][s],dmvector,h_r_size,v_r_size,dmv,mvscale,0);
62
63 /* update other motion vector predictors */
64 PMV[1][s][0] = PMV[0][s][0];
65 PMV[1][s][1] = PMV[0][s][1];
66 }
67 else
68 {
69 motion_vertical_field_select[0][s] = Get_Bits(1);
70 #ifdef TRACE
71 if (Trace_Flag)
72 {
73 printf("motion_vertical_field_select[0][%d] (%d): %d\n",s,
74 motion_vertical_field_select[0][s],motion_vertical_field_select[0][s]);
75 }
76 #endif /* TRACE */
77 motion_vector(PMV[0][s],dmvector,h_r_size,v_r_size,dmv,mvscale,0);
78
79 motion_vertical_field_select[1][s] = Get_Bits(1);
80 #ifdef TRACE
81 if (Trace_Flag)
82 {
83 printf("motion_vertical_field_select[1][%d] (%d): %d\n",s,
84 motion_vertical_field_select[1][s],motion_vertical_field_select[1][s]);
85 }
86 #endif /* TRACE */
87 motion_vector(PMV[1][s],dmvector,h_r_size,v_r_size,dmv,mvscale,0);
88 }
89 }
90
91 /* get and decode motion vector and differential motion vector
92 for one prediction */
93 void motion_vector(PMV,dmvector,
94 h_r_size,v_r_size,dmv,mvscale,full_pel_vector)
95 int *PMV;
96 int *dmvector;
97 int h_r_size;
98 int v_r_size;
99 int dmv; /* MPEG-2 only: get differential motion vectors */
100 int mvscale; /* MPEG-2 only: field vector in frame pic */
101 int full_pel_vector; /* MPEG-1 only */
102 {
103 int motion_code, motion_residual;
104
105 /* horizontal component */
106 /* ISO/IEC 13818-2 Table B-10 */
107 motion_code = Get_motion_code();
108
109 motion_residual = (h_r_size!=0 && motion_code!=0) ? Get_Bits(h_r_size) : 0;
110
111 #ifdef TRACE
112 if (Trace_Flag)
113 {
114 if (h_r_size!=0 && motion_code!=0)
115 {
116 printf("motion_residual (");
117 Print_Bits(motion_residual,h_r_size,h_r_size);
118 printf("): %d\n",motion_residual);
119 }
120 }
121 #endif /* TRACE */
122
123
124 decode_motion_vector(&PMV[0],h_r_size,motion_code,motion_residual,full_pel_vector);
125
126 if (dmv)
127 dmvector[0] = Get_dmvector();
128
129
130 /* vertical component */
131 motion_code = Get_motion_code();
132 motion_residual = (v_r_size!=0 && motion_code!=0) ? Get_Bits(v_r_size) : 0;
133
134 #ifdef TRACE
135 if (Trace_Flag)
136 {
137 if (v_r_size!=0 && motion_code!=0)
138 {
139 printf("motion_residual (");
140 Print_Bits(motion_residual,v_r_size,v_r_size);
141 printf("): %d\n",motion_residual);
142 }
143 }
144 #endif /* TRACE */
145
146 if (mvscale)
147 PMV[1] >>= 1; /* DIV 2 */
148
149 decode_motion_vector(&PMV[1],v_r_size,motion_code,motion_residual,full_pel_vector);
150
151 if (mvscale)
152 PMV[1] <<= 1;
153
154 if (dmv)
155 dmvector[1] = Get_dmvector();
156
157 #ifdef TRACE
158 if (Trace_Flag)
159 printf("PMV = %d,%d\n",PMV[0],PMV[1]);
160 #endif /* TRACE */
161 }
162
163 /* calculate motion vector component */
164 /* ISO/IEC 13818-2 section 7.6.3.1: Decoding the motion vectors */
165 /* Note: the arithmetic here is more elegant than that which is shown
166 in 7.6.3.1. The end results (PMV[][][]) should, however, be the same. */
167
168 static void decode_motion_vector(pred,r_size,motion_code,motion_residual,full_pel_vector)
169 int *pred;
170 int r_size, motion_code, motion_residual;
171 int full_pel_vector; /* MPEG-1 (ISO/IEC 11172-1) support */
172 {
173 int lim, vec;
174
175 lim = 16<<r_size;
176 vec = full_pel_vector ? (*pred >> 1) : (*pred);
177
178 if (motion_code>0)
179 {
180 vec+= ((motion_code-1)<<r_size) + motion_residual + 1;
181 if (vec>=lim)
182 vec-= lim + lim;
183 }
184 else if (motion_code<0)
185 {
186 vec-= ((-motion_code-1)<<r_size) + motion_residual + 1;
187 if (vec<-lim)
188 vec+= lim + lim;
189 }
190 *pred = full_pel_vector ? (vec<<1) : vec;
191 }
192
193
194 /* ISO/IEC 13818-2 section 7.6.3.6: Dual prime additional arithmetic */
195 void Dual_Prime_Arithmetic(DMV,dmvector,mvx,mvy)
196 int DMV[][2];
197 int *dmvector; /* differential motion vector */
198 int mvx, mvy; /* decoded mv components (always in field format) */
199 {
200 if (picture_structure==FRAME_PICTURE)
201 {
202 if (top_field_first)
203 {
204 /* vector for prediction of top field from bottom field */
205 DMV[0][0] = ((mvx +(mvx>0))>>1) + dmvector[0];
206 DMV[0][1] = ((mvy +(mvy>0))>>1) + dmvector[1] - 1;
207
208 /* vector for prediction of bottom field from top field */
209 DMV[1][0] = ((3*mvx+(mvx>0))>>1) + dmvector[0];
210 DMV[1][1] = ((3*mvy+(mvy>0))>>1) + dmvector[1] + 1;
211 }
212 else
213 {
214 /* vector for prediction of top field from bottom field */
215 DMV[0][0] = ((3*mvx+(mvx>0))>>1) + dmvector[0];
216 DMV[0][1] = ((3*mvy+(mvy>0))>>1) + dmvector[1] - 1;
217
218 /* vector for prediction of bottom field from top field */
219 DMV[1][0] = ((mvx +(mvx>0))>>1) + dmvector[0];
220 DMV[1][1] = ((mvy +(mvy>0))>>1) + dmvector[1] + 1;
221 }
222 }
223 else
224 {
225 /* vector for prediction from field of opposite 'parity' */
226 DMV[0][0] = ((mvx+(mvx>0))>>1) + dmvector[0];
227 DMV[0][1] = ((mvy+(mvy>0))>>1) + dmvector[1];
228
229 /* correct for vertical field shift */
230 if (picture_structure==TOP_FIELD)
231 DMV[0][1]--;
232 else
233 DMV[0][1]++;
234 }
235 }
236
This webpage is intended to be an accessible preview of this repository. To get a fuller picture, clone it and use the git CLI.