FFmpeg: libavcodec/mpeg4video.c Source File

FFmpeg
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 
27  uint8_t ff_mpeg4_static_rl_table_store[3][2][2*MAX_RUN + MAX_LEVEL + 3];
28 
29  int ff_mpeg4_get_video_packet_prefix_length(MpegEncContext *s){
30  switch(s->pict_type){
31  case AV_PICTURE_TYPE_I:
32  return 16;
33  case AV_PICTURE_TYPE_P:
34  case AV_PICTURE_TYPE_S:
35  return s->f_code+15;
36  case AV_PICTURE_TYPE_B:
37  return FFMAX3(s->f_code, s->b_code, 2) + 15;
38  default:
39  return -1;
40  }
41 }
42 
43  void ff_mpeg4_clean_buffers(MpegEncContext *s)
44 {
45  int c_wrap, c_xy, l_wrap, l_xy;
46 
47  l_wrap= s->b8_stride;
48  l_xy= (2*s->mb_y-1)*l_wrap + s->mb_x*2 - 1;
49  c_wrap= s->mb_stride;
50  c_xy= (s->mb_y-1)*c_wrap + s->mb_x - 1;
51 
52 #if 0
53  /* clean DC */
54  memsetw(s->dc_val[0] + l_xy, 1024, l_wrap*2+1);
55  memsetw(s->dc_val[1] + c_xy, 1024, c_wrap+1);
56  memsetw(s->dc_val[2] + c_xy, 1024, c_wrap+1);
57 #endif
58 
59  /* clean AC */
60  memset(s->ac_val[0] + l_xy, 0, (l_wrap*2+1)*16*sizeof(int16_t));
61  memset(s->ac_val[1] + c_xy, 0, (c_wrap +1)*16*sizeof(int16_t));
62  memset(s->ac_val[2] + c_xy, 0, (c_wrap +1)*16*sizeof(int16_t));
63 
64  /* clean MV */
65  // we can't clear the MVs as they might be needed by a b frame
66 // memset(s->motion_val + l_xy, 0, (l_wrap*2+1)*2*sizeof(int16_t));
67 // memset(s->motion_val, 0, 2*sizeof(int16_t)*(2 + s->mb_width*2)*(2 + s->mb_height*2));
68  s->last_mv[0][0][0]=
69  s->last_mv[0][0][1]=
70  s->last_mv[1][0][0]=
71  s->last_mv[1][0][1]= 0;
72 }
73 
74  #define tab_size ((signed)FF_ARRAY_ELEMS(s->direct_scale_mv[0]))
75  #define tab_bias (tab_size/2)
76 
77 //used by mpeg4 and rv10 decoder
78  void ff_mpeg4_init_direct_mv(MpegEncContext *s){
79  int i;
80  for(i=0; i<tab_size; i++){
81  s->direct_scale_mv[0][i] = (i-tab_bias)*s->pb_time/s->pp_time;
82  s->direct_scale_mv[1][i] = (i-tab_bias)*(s->pb_time-s->pp_time)/s->pp_time;
83  }
84 }
85 
86  static inline void ff_mpeg4_set_one_direct_mv(MpegEncContext *s, int mx, int my, int i){
87  int xy= s->block_index[i];
88  uint16_t time_pp= s->pp_time;
89  uint16_t time_pb= s->pb_time;
90  int p_mx, p_my;
91 
92  p_mx = s->next_picture.f.motion_val[0][xy][0];
93  if((unsigned)(p_mx + tab_bias) < tab_size){
94  s->mv[0][i][0] = s->direct_scale_mv[0][p_mx + tab_bias] + mx;
95  s->mv[1][i][0] = mx ? s->mv[0][i][0] - p_mx
96  : s->direct_scale_mv[1][p_mx + tab_bias];
97  }else{
98  s->mv[0][i][0] = p_mx*time_pb/time_pp + mx;
99  s->mv[1][i][0] = mx ? s->mv[0][i][0] - p_mx
100  : p_mx*(time_pb - time_pp)/time_pp;
101  }
102  p_my = s->next_picture.f.motion_val[0][xy][1];
103  if((unsigned)(p_my + tab_bias) < tab_size){
104  s->mv[0][i][1] = s->direct_scale_mv[0][p_my + tab_bias] + my;
105  s->mv[1][i][1] = my ? s->mv[0][i][1] - p_my
106  : s->direct_scale_mv[1][p_my + tab_bias];
107  }else{
108  s->mv[0][i][1] = p_my*time_pb/time_pp + my;
109  s->mv[1][i][1] = my ? s->mv[0][i][1] - p_my
110  : p_my*(time_pb - time_pp)/time_pp;
111  }
112 }
113 
114 #undef tab_size
115 #undef tab_bias
116 
117 /**
118  *
119  * @return the mb_type
120  */
121  int ff_mpeg4_set_direct_mv(MpegEncContext *s, int mx, int my){
122  const int mb_index= s->mb_x + s->mb_y*s->mb_stride;
123  const int colocated_mb_type = s->next_picture.f.mb_type[mb_index];
124  uint16_t time_pp;
125  uint16_t time_pb;
126  int i;
127 
128  //FIXME avoid divides
129  // try special case with shifts for 1 and 3 B-frames?
130 
131  if(IS_8X8(colocated_mb_type)){
132  s->mv_type = MV_TYPE_8X8;
133  for(i=0; i<4; i++){
134  ff_mpeg4_set_one_direct_mv(s, mx, my, i);
135  }
136  return MB_TYPE_DIRECT2 | MB_TYPE_8x8 | MB_TYPE_L0L1;
137  } else if(IS_INTERLACED(colocated_mb_type)){
138  s->mv_type = MV_TYPE_FIELD;
139  for(i=0; i<2; i++){
140  int field_select = s->next_picture.f.ref_index[0][4 * mb_index + 2 * i];
141  s->field_select[0][i]= field_select;
142  s->field_select[1][i]= i;
143  if(s->top_field_first){
144  time_pp= s->pp_field_time - field_select + i;
145  time_pb= s->pb_field_time - field_select + i;
146  }else{
147  time_pp= s->pp_field_time + field_select - i;
148  time_pb= s->pb_field_time + field_select - i;
149  }
150  s->mv[0][i][0] = s->p_field_mv_table[i][0][mb_index][0]*time_pb/time_pp + mx;
151  s->mv[0][i][1] = s->p_field_mv_table[i][0][mb_index][1]*time_pb/time_pp + my;
152  s->mv[1][i][0] = mx ? s->mv[0][i][0] - s->p_field_mv_table[i][0][mb_index][0]
153  : s->p_field_mv_table[i][0][mb_index][0]*(time_pb - time_pp)/time_pp;
154  s->mv[1][i][1] = my ? s->mv[0][i][1] - s->p_field_mv_table[i][0][mb_index][1]
155  : s->p_field_mv_table[i][0][mb_index][1]*(time_pb - time_pp)/time_pp;
156  }
157  return MB_TYPE_DIRECT2 | MB_TYPE_16x8 | MB_TYPE_L0L1 | MB_TYPE_INTERLACED;
158  }else{
159  ff_mpeg4_set_one_direct_mv(s, mx, my, 0);
160  s->mv[0][1][0] = s->mv[0][2][0] = s->mv[0][3][0] = s->mv[0][0][0];
161  s->mv[0][1][1] = s->mv[0][2][1] = s->mv[0][3][1] = s->mv[0][0][1];
162  s->mv[1][1][0] = s->mv[1][2][0] = s->mv[1][3][0] = s->mv[1][0][0];
163  s->mv[1][1][1] = s->mv[1][2][1] = s->mv[1][3][1] = s->mv[1][0][1];
164  if((s->avctx->workaround_bugs & FF_BUG_DIRECT_BLOCKSIZE) || !s->quarter_sample)
165  s->mv_type= MV_TYPE_16X16;
166  else
167  s->mv_type= MV_TYPE_8X8;
168  return MB_TYPE_DIRECT2 | MB_TYPE_16x16 | MB_TYPE_L0L1; //Note see prev line
169  }
170 }
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