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mpeg4video.c
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1 /*
2  * MPEG4 decoder / encoder common code.
3  * Copyright (c) 2000,2001 Fabrice Bellard
4  * Copyright (c) 2002-2010 Michael Niedermayer <michaelni@gmx.at>
5  *
6  * This file is part of FFmpeg.
7  *
8  * FFmpeg is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU Lesser General Public
10  * License as published by the Free Software Foundation; either
11  * version 2.1 of the License, or (at your option) any later version.
12  *
13  * FFmpeg is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16  * Lesser General Public License for more details.
17  *
18  * You should have received a copy of the GNU Lesser General Public
19  * License along with FFmpeg; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21  */
22 
23 #include "mpegutils.h"
24 #include "mpegvideo.h"
25 #include "mpeg4video.h"
26 #include "mpeg4data.h"
27 
29 
31 {
32  switch (s->pict_type) {
33  case AV_PICTURE_TYPE_I:
34  return 16;
35  case AV_PICTURE_TYPE_P:
36  case AV_PICTURE_TYPE_S:
37  return s->f_code + 15;
38  case AV_PICTURE_TYPE_B:
39  return FFMAX3(s->f_code, s->b_code, 2) + 15;
40  default:
41  return -1;
42  }
43 }
44 
46 {
47  int c_wrap, c_xy, l_wrap, l_xy;
48 
49  l_wrap = s->b8_stride;
50  l_xy = (2 * s->mb_y - 1) * l_wrap + s->mb_x * 2 - 1;
51  c_wrap = s->mb_stride;
52  c_xy = (s->mb_y - 1) * c_wrap + s->mb_x - 1;
53 
54 #if 0
55  /* clean DC */
56  memsetw(s->dc_val[0] + l_xy, 1024, l_wrap * 2 + 1);
57  memsetw(s->dc_val[1] + c_xy, 1024, c_wrap + 1);
58  memsetw(s->dc_val[2] + c_xy, 1024, c_wrap + 1);
59 #endif
60 
61  /* clean AC */
62  memset(s->ac_val[0] + l_xy, 0, (l_wrap * 2 + 1) * 16 * sizeof(int16_t));
63  memset(s->ac_val[1] + c_xy, 0, (c_wrap + 1) * 16 * sizeof(int16_t));
64  memset(s->ac_val[2] + c_xy, 0, (c_wrap + 1) * 16 * sizeof(int16_t));
65 
66  /* clean MV */
67  // we can't clear the MVs as they might be needed by a b frame
68 // memset(s->motion_val + l_xy, 0, (l_wrap * 2 + 1) * 2 * sizeof(int16_t));
69 // memset(s->motion_val, 0, 2 * sizeof(int16_t) * (2 + s->mb_width * 2) *
70 // (2 + s->mb_height * 2));
71  s->last_mv[0][0][0] =
72  s->last_mv[0][0][1] =
73  s->last_mv[1][0][0] =
74  s->last_mv[1][0][1] = 0;
75 }
76 
77 #define tab_size ((signed)FF_ARRAY_ELEMS(s->direct_scale_mv[0]))
78 #define tab_bias (tab_size / 2)
79 
80 // used by mpeg4 and rv10 decoder
82 {
83  int i;
84  for (i = 0; i < tab_size; i++) {
85  s->direct_scale_mv[0][i] = (i - tab_bias) * s->pb_time / s->pp_time;
86  s->direct_scale_mv[1][i] = (i - tab_bias) * (s->pb_time - s->pp_time) /
87  s->pp_time;
88  }
89 }
90 
91 static inline void ff_mpeg4_set_one_direct_mv(MpegEncContext *s, int mx,
92  int my, int i)
93 {
94  int xy = s->block_index[i];
95  uint16_t time_pp = s->pp_time;
96  uint16_t time_pb = s->pb_time;
97  int p_mx, p_my;
98 
99  p_mx = s->next_picture.motion_val[0][xy][0];
100  if ((unsigned)(p_mx + tab_bias) < tab_size) {
101  s->mv[0][i][0] = s->direct_scale_mv[0][p_mx + tab_bias] + mx;
102  s->mv[1][i][0] = mx ? s->mv[0][i][0] - p_mx
103  : s->direct_scale_mv[1][p_mx + tab_bias];
104  } else {
105  s->mv[0][i][0] = p_mx * time_pb / time_pp + mx;
106  s->mv[1][i][0] = mx ? s->mv[0][i][0] - p_mx
107  : p_mx * (time_pb - time_pp) / time_pp;
108  }
109  p_my = s->next_picture.motion_val[0][xy][1];
110  if ((unsigned)(p_my + tab_bias) < tab_size) {
111  s->mv[0][i][1] = s->direct_scale_mv[0][p_my + tab_bias] + my;
112  s->mv[1][i][1] = my ? s->mv[0][i][1] - p_my
113  : s->direct_scale_mv[1][p_my + tab_bias];
114  } else {
115  s->mv[0][i][1] = p_my * time_pb / time_pp + my;
116  s->mv[1][i][1] = my ? s->mv[0][i][1] - p_my
117  : p_my * (time_pb - time_pp) / time_pp;
118  }
119 }
120 
121 #undef tab_size
122 #undef tab_bias
123 
124 /**
125  * @return the mb_type
126  */
128 {
129  const int mb_index = s->mb_x + s->mb_y * s->mb_stride;
130  const int colocated_mb_type = s->next_picture.mb_type[mb_index];
131  uint16_t time_pp;
132  uint16_t time_pb;
133  int i;
134 
135  // FIXME avoid divides
136  // try special case with shifts for 1 and 3 B-frames?
137 
138  if (IS_8X8(colocated_mb_type)) {
139  s->mv_type = MV_TYPE_8X8;
140  for (i = 0; i < 4; i++)
141  ff_mpeg4_set_one_direct_mv(s, mx, my, i);
143  } else if (IS_INTERLACED(colocated_mb_type)) {
144  s->mv_type = MV_TYPE_FIELD;
145  for (i = 0; i < 2; i++) {
146  int field_select = s->next_picture.ref_index[0][4 * mb_index + 2 * i];
147  s->field_select[0][i] = field_select;
148  s->field_select[1][i] = i;
149  if (s->top_field_first) {
150  time_pp = s->pp_field_time - field_select + i;
151  time_pb = s->pb_field_time - field_select + i;
152  } else {
153  time_pp = s->pp_field_time + field_select - i;
154  time_pb = s->pb_field_time + field_select - i;
155  }
156  s->mv[0][i][0] = s->p_field_mv_table[i][0][mb_index][0] *
157  time_pb / time_pp + mx;
158  s->mv[0][i][1] = s->p_field_mv_table[i][0][mb_index][1] *
159  time_pb / time_pp + my;
160  s->mv[1][i][0] = mx ? s->mv[0][i][0] -
161  s->p_field_mv_table[i][0][mb_index][0]
162  : s->p_field_mv_table[i][0][mb_index][0] *
163  (time_pb - time_pp) / time_pp;
164  s->mv[1][i][1] = my ? s->mv[0][i][1] -
165  s->p_field_mv_table[i][0][mb_index][1]
166  : s->p_field_mv_table[i][0][mb_index][1] *
167  (time_pb - time_pp) / time_pp;
168  }
169  return MB_TYPE_DIRECT2 | MB_TYPE_16x8 |
171  } else {
172  ff_mpeg4_set_one_direct_mv(s, mx, my, 0);
173  s->mv[0][1][0] =
174  s->mv[0][2][0] =
175  s->mv[0][3][0] = s->mv[0][0][0];
176  s->mv[0][1][1] =
177  s->mv[0][2][1] =
178  s->mv[0][3][1] = s->mv[0][0][1];
179  s->mv[1][1][0] =
180  s->mv[1][2][0] =
181  s->mv[1][3][0] = s->mv[1][0][0];
182  s->mv[1][1][1] =
183  s->mv[1][2][1] =
184  s->mv[1][3][1] = s->mv[1][0][1];
186  !s->quarter_sample)
187  s->mv_type = MV_TYPE_16X16;
188  else
189  s->mv_type = MV_TYPE_8X8;
190  // Note see prev line
192  }
193 }