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mpeg4video.h
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1 /*
2  * MPEG4 encoder/decoder internal header.
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 #ifndef AVCODEC_MPEG4VIDEO_H
24 #define AVCODEC_MPEG4VIDEO_H
25 
26 #include <stdint.h>
27 
28 #include "get_bits.h"
29 #include "mpegvideo.h"
30 #include "rl.h"
31 
32 // shapes
33 #define RECT_SHAPE 0
34 #define BIN_SHAPE 1
35 #define BIN_ONLY_SHAPE 2
36 #define GRAY_SHAPE 3
37 
38 #define SIMPLE_VO_TYPE 1
39 #define CORE_VO_TYPE 3
40 #define MAIN_VO_TYPE 4
41 #define NBIT_VO_TYPE 5
42 #define ARTS_VO_TYPE 10
43 #define ACE_VO_TYPE 12
44 #define ADV_SIMPLE_VO_TYPE 17
45 
46 // aspect_ratio_info
47 #define EXTENDED_PAR 15
48 
49 //vol_sprite_usage / sprite_enable
50 #define STATIC_SPRITE 1
51 #define GMC_SPRITE 2
52 
53 #define MOTION_MARKER 0x1F001
54 #define DC_MARKER 0x6B001
55 
56 #define VOS_STARTCODE 0x1B0
57 #define USER_DATA_STARTCODE 0x1B2
58 #define GOP_STARTCODE 0x1B3
59 #define VISUAL_OBJ_STARTCODE 0x1B5
60 #define VOP_STARTCODE 0x1B6
61 
62 /* smaller packets likely don't contain a real frame */
63 #define MAX_NVOP_SIZE 19
64 
65 typedef struct Mpeg4DecContext {
67 
68  /// number of bits to represent the fractional part of time
70  int shape;
74  /// sprite trajectory points
75  uint16_t sprite_traj[4][2];
76  /// sprite shift [isChroma]
77  int sprite_shift[2];
78 
79  // reversible vlc
80  int rvlc;
81  /// could this stream contain resync markers
83  /// time distance of first I -> B, used for interlaced B-frames
84  int t_frame;
85 
86  int new_pred;
90 
91  /// QP above which the ac VLC should be used for intra dc
93 
94  /* bug workarounds */
99 
100  /// flag for having shown the warning about invalid Divx B-frames
102  /** does the stream contain the low_delay flag,
103  * used to work around buggy encoders. */
109 
110 /* dc encoding for mpeg4 */
111 extern const uint8_t ff_mpeg4_DCtab_lum[13][2];
112 extern const uint8_t ff_mpeg4_DCtab_chrom[13][2];
113 
114 extern const uint16_t ff_mpeg4_intra_vlc[103][2];
115 extern const int8_t ff_mpeg4_intra_level[102];
116 extern const int8_t ff_mpeg4_intra_run[102];
117 
119 
120 /* Note this is identical to the intra rvlc except that it is reordered. */
123 
124 extern const uint16_t ff_sprite_trajectory_tab[15][2];
125 extern const uint8_t ff_mb_type_b_tab[4][2];
126 
127 /* these matrixes will be permuted for the idct */
128 extern const int16_t ff_mpeg4_default_intra_matrix[64];
129 extern const int16_t ff_mpeg4_default_non_intra_matrix[64];
130 
131 extern const uint8_t ff_mpeg4_y_dc_scale_table[32];
132 extern const uint8_t ff_mpeg4_c_dc_scale_table[32];
133 extern const uint16_t ff_mpeg4_resync_prefix[8];
134 
135 extern const uint8_t ff_mpeg4_dc_threshold[8];
136 
138  int16_t block[6][64],
139  int motion_x, int motion_y);
140 void ff_mpeg4_pred_ac(MpegEncContext *s, int16_t *block, int n,
141  int dir);
143 void ff_mpeg4_encode_picture_header(MpegEncContext *s, int picture_number);
144 
158 int ff_mpeg4_frame_end(AVCodecContext *avctx, const uint8_t *buf, int buf_size);
159 
160 /**
161  *
162  * @return the mb_type
163  */
164 int ff_mpeg4_set_direct_mv(MpegEncContext *s, int mx, int my);
165 
167 
168 #if 0 //3IV1 is quite rare and it slows things down a tiny bit
169 #define IS_3IV1 s->codec_tag == AV_RL32("3IV1")
170 #else
171 #define IS_3IV1 0
172 #endif
173 
174 /**
175  * Predict the dc.
176  * encoding quantized level -> quantized diff
177  * decoding quantized diff -> quantized level
178  * @param n block index (0-3 are luma, 4-5 are chroma)
179  * @param dir_ptr pointer to an integer where the prediction direction will be stored
180  */
181 static inline int ff_mpeg4_pred_dc(MpegEncContext *s, int n, int level,
182  int *dir_ptr, int encoding)
183 {
184  int a, b, c, wrap, pred, scale, ret;
185  int16_t *dc_val;
186 
187  /* find prediction */
188  if (n < 4)
189  scale = s->y_dc_scale;
190  else
191  scale = s->c_dc_scale;
192  if (IS_3IV1)
193  scale = 8;
194 
195  wrap = s->block_wrap[n];
196  dc_val = s->dc_val[0] + s->block_index[n];
197 
198  /* B C
199  * A X
200  */
201  a = dc_val[-1];
202  b = dc_val[-1 - wrap];
203  c = dc_val[-wrap];
204 
205  /* outside slice handling (we can't do that by memset as we need the
206  * dc for error resilience) */
207  if (s->first_slice_line && n != 3) {
208  if (n != 2)
209  b = c = 1024;
210  if (n != 1 && s->mb_x == s->resync_mb_x)
211  b = a = 1024;
212  }
213  if (s->mb_x == s->resync_mb_x && s->mb_y == s->resync_mb_y + 1) {
214  if (n == 0 || n == 4 || n == 5)
215  b = 1024;
216  }
217 
218  if (abs(a - b) < abs(b - c)) {
219  pred = c;
220  *dir_ptr = 1; /* top */
221  } else {
222  pred = a;
223  *dir_ptr = 0; /* left */
224  }
225  /* we assume pred is positive */
226  pred = FASTDIV((pred + (scale >> 1)), scale);
227 
228  if (encoding) {
229  ret = level - pred;
230  } else {
231  level += pred;
232  ret = level;
234  if (level < 0) {
236  "dc<0 at %dx%d\n", s->mb_x, s->mb_y);
237  return -1;
238  }
239  if (level * scale > 2048 + scale) {
241  "dc overflow at %dx%d\n", s->mb_x, s->mb_y);
242  return -1;
243  }
244  }
245  }
246  level *= scale;
247  if (level & (~2047)) {
248  if (level < 0)
249  level = 0;
250  else if (!(s->workaround_bugs & FF_BUG_DC_CLIP))
251  level = 2047;
252  }
253  dc_val[0] = level;
254 
255  return ret;
256 }
257 
258 #endif /* AVCODEC_MPEG4VIDEO_H */