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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 "mpegvideo.h"
24 #include "mpeg4video.h"
25 #include "mpeg4data.h"
26 
28 
30 {
31  switch (s->pict_type) {
32  case AV_PICTURE_TYPE_I:
33  return 16;
34  case AV_PICTURE_TYPE_P:
35  case AV_PICTURE_TYPE_S:
36  return s->f_code + 15;
37  case AV_PICTURE_TYPE_B:
38  return FFMAX3(s->f_code, s->b_code, 2) + 15;
39  default:
40  return -1;
41  }
42 }
43 
45 {
46  int c_wrap, c_xy, l_wrap, l_xy;
47 
48  l_wrap = s->b8_stride;
49  l_xy = (2 * s->mb_y - 1) * l_wrap + s->mb_x * 2 - 1;
50  c_wrap = s->mb_stride;
51  c_xy = (s->mb_y - 1) * c_wrap + s->mb_x - 1;
52 
53 #if 0
54  /* clean DC */
55  memsetw(s->dc_val[0] + l_xy, 1024, l_wrap * 2 + 1);
56  memsetw(s->dc_val[1] + c_xy, 1024, c_wrap + 1);
57  memsetw(s->dc_val[2] + c_xy, 1024, c_wrap + 1);
58 #endif
59 
60  /* clean AC */
61  memset(s->ac_val[0] + l_xy, 0, (l_wrap * 2 + 1) * 16 * sizeof(int16_t));
62  memset(s->ac_val[1] + c_xy, 0, (c_wrap + 1) * 16 * sizeof(int16_t));
63  memset(s->ac_val[2] + c_xy, 0, (c_wrap + 1) * 16 * sizeof(int16_t));
64 
65  /* clean MV */
66  // we can't clear the MVs as they might be needed by a b frame
67 // memset(s->motion_val + l_xy, 0, (l_wrap * 2 + 1) * 2 * sizeof(int16_t));
68 // memset(s->motion_val, 0, 2 * sizeof(int16_t) * (2 + s->mb_width * 2) *
69 // (2 + s->mb_height * 2));
70  s->last_mv[0][0][0] =
71  s->last_mv[0][0][1] =
72  s->last_mv[1][0][0] =
73  s->last_mv[1][0][1] = 0;
74 }
75 
76 #define tab_size ((signed)FF_ARRAY_ELEMS(s->direct_scale_mv[0]))
77 #define tab_bias (tab_size / 2)
78 
79 // used by mpeg4 and rv10 decoder
81 {
82  int i;
83  for (i = 0; i < tab_size; i++) {
84  s->direct_scale_mv[0][i] = (i - tab_bias) * s->pb_time / s->pp_time;
85  s->direct_scale_mv[1][i] = (i - tab_bias) * (s->pb_time - s->pp_time) /
86  s->pp_time;
87  }
88 }
89 
90 static inline void ff_mpeg4_set_one_direct_mv(MpegEncContext *s, int mx,
91  int my, int i)
92 {
93  int xy = s->block_index[i];
94  uint16_t time_pp = s->pp_time;
95  uint16_t time_pb = s->pb_time;
96  int p_mx, p_my;
97 
98  p_mx = s->next_picture.motion_val[0][xy][0];
99  if ((unsigned)(p_mx + tab_bias) < tab_size) {
100  s->mv[0][i][0] = s->direct_scale_mv[0][p_mx + tab_bias] + mx;
101  s->mv[1][i][0] = mx ? s->mv[0][i][0] - p_mx
102  : s->direct_scale_mv[1][p_mx + tab_bias];
103  } else {
104  s->mv[0][i][0] = p_mx * time_pb / time_pp + mx;
105  s->mv[1][i][0] = mx ? s->mv[0][i][0] - p_mx
106  : p_mx * (time_pb - time_pp) / time_pp;
107  }
108  p_my = s->next_picture.motion_val[0][xy][1];
109  if ((unsigned)(p_my + tab_bias) < tab_size) {
110  s->mv[0][i][1] = s->direct_scale_mv[0][p_my + tab_bias] + my;
111  s->mv[1][i][1] = my ? s->mv[0][i][1] - p_my
112  : s->direct_scale_mv[1][p_my + tab_bias];
113  } else {
114  s->mv[0][i][1] = p_my * time_pb / time_pp + my;
115  s->mv[1][i][1] = my ? s->mv[0][i][1] - p_my
116  : p_my * (time_pb - time_pp) / time_pp;
117  }
118 }
119 
120 #undef tab_size
121 #undef tab_bias
122 
123 /**
124  * @return the mb_type
125  */
127 {
128  const int mb_index = s->mb_x + s->mb_y * s->mb_stride;
129  const int colocated_mb_type = s->next_picture.mb_type[mb_index];
130  uint16_t time_pp;
131  uint16_t time_pb;
132  int i;
133 
134  // FIXME avoid divides
135  // try special case with shifts for 1 and 3 B-frames?
136 
137  if (IS_8X8(colocated_mb_type)) {
138  s->mv_type = MV_TYPE_8X8;
139  for (i = 0; i < 4; i++)
140  ff_mpeg4_set_one_direct_mv(s, mx, my, i);
142  } else if (IS_INTERLACED(colocated_mb_type)) {
143  s->mv_type = MV_TYPE_FIELD;
144  for (i = 0; i < 2; i++) {
145  int field_select = s->next_picture.ref_index[0][4 * mb_index + 2 * i];
146  s->field_select[0][i] = field_select;
147  s->field_select[1][i] = i;
148  if (s->top_field_first) {
149  time_pp = s->pp_field_time - field_select + i;
150  time_pb = s->pb_field_time - field_select + i;
151  } else {
152  time_pp = s->pp_field_time + field_select - i;
153  time_pb = s->pb_field_time + field_select - i;
154  }
155  s->mv[0][i][0] = s->p_field_mv_table[i][0][mb_index][0] *
156  time_pb / time_pp + mx;
157  s->mv[0][i][1] = s->p_field_mv_table[i][0][mb_index][1] *
158  time_pb / time_pp + my;
159  s->mv[1][i][0] = mx ? s->mv[0][i][0] -
160  s->p_field_mv_table[i][0][mb_index][0]
161  : s->p_field_mv_table[i][0][mb_index][0] *
162  (time_pb - time_pp) / time_pp;
163  s->mv[1][i][1] = my ? s->mv[0][i][1] -
164  s->p_field_mv_table[i][0][mb_index][1]
165  : s->p_field_mv_table[i][0][mb_index][1] *
166  (time_pb - time_pp) / time_pp;
167  }
168  return MB_TYPE_DIRECT2 | MB_TYPE_16x8 |
170  } else {
171  ff_mpeg4_set_one_direct_mv(s, mx, my, 0);
172  s->mv[0][1][0] =
173  s->mv[0][2][0] =
174  s->mv[0][3][0] = s->mv[0][0][0];
175  s->mv[0][1][1] =
176  s->mv[0][2][1] =
177  s->mv[0][3][1] = s->mv[0][0][1];
178  s->mv[1][1][0] =
179  s->mv[1][2][0] =
180  s->mv[1][3][0] = s->mv[1][0][0];
181  s->mv[1][1][1] =
182  s->mv[1][2][1] =
183  s->mv[1][3][1] = s->mv[1][0][1];
185  !s->quarter_sample)
186  s->mv_type = MV_TYPE_16X16;
187  else
188  s->mv_type = MV_TYPE_8X8;
189  // Note see prev line
191  }
192 }