FFmpeg
mpeg4video.h
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1 /*
2  * MPEG-4 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 "mpegvideo.h"
29 
30 // shapes
31 #define RECT_SHAPE 0
32 #define BIN_SHAPE 1
33 #define BIN_ONLY_SHAPE 2
34 #define GRAY_SHAPE 3
35 
36 #define SIMPLE_VO_TYPE 1
37 #define CORE_VO_TYPE 3
38 #define MAIN_VO_TYPE 4
39 #define NBIT_VO_TYPE 5
40 #define ARTS_VO_TYPE 10
41 #define ACE_VO_TYPE 12
42 #define SIMPLE_STUDIO_VO_TYPE 14
43 #define CORE_STUDIO_VO_TYPE 15
44 #define ADV_SIMPLE_VO_TYPE 17
45 
46 #define VOT_VIDEO_ID 1
47 #define VOT_STILL_TEXTURE_ID 2
48 
49 // aspect_ratio_info
50 #define EXTENDED_PAR 15
51 
52 //vol_sprite_usage / sprite_enable
53 #define STATIC_SPRITE 1
54 #define GMC_SPRITE 2
55 
56 #define MOTION_MARKER 0x1F001
57 #define DC_MARKER 0x6B001
58 
59 #define VOS_STARTCODE 0x1B0
60 #define USER_DATA_STARTCODE 0x1B2
61 #define GOP_STARTCODE 0x1B3
62 #define VISUAL_OBJ_STARTCODE 0x1B5
63 #define VOP_STARTCODE 0x1B6
64 #define SLICE_STARTCODE 0x1B7
65 #define EXT_STARTCODE 0x1B8
66 
67 #define QUANT_MATRIX_EXT_ID 0x3
68 
69 /* smaller packets likely don't contain a real frame */
70 #define MAX_NVOP_SIZE 19
71 
75 
76 /**
77  * @return the mb_type
78  */
79 int ff_mpeg4_set_direct_mv(MpegEncContext *s, int mx, int my);
80 
81 #if 0 //3IV1 is quite rare and it slows things down a tiny bit
82 #define IS_3IV1 s->codec_tag == AV_RL32("3IV1")
83 #else
84 #define IS_3IV1 0
85 #endif
86 
87 /**
88  * Predict the dc.
89  * encoding quantized level -> quantized diff
90  * decoding quantized diff -> quantized level
91  * @param n block index (0-3 are luma, 4-5 are chroma)
92  * @param dir_ptr pointer to an integer where the prediction direction will be stored
93  */
94 static inline int ff_mpeg4_pred_dc(MpegEncContext *s, int n, int level,
95  int *dir_ptr, int encoding)
96 {
97  int a, b, c, wrap, pred, scale, ret;
98  int16_t *dc_val;
99 
100  /* find prediction */
101  if (n < 4)
102  scale = s->y_dc_scale;
103  else
104  scale = s->c_dc_scale;
105  if (IS_3IV1)
106  scale = 8;
107 
108  wrap = s->block_wrap[n];
109  dc_val = s->dc_val[0] + s->block_index[n];
110 
111  /* B C
112  * A X
113  */
114  a = dc_val[-1];
115  b = dc_val[-1 - wrap];
116  c = dc_val[-wrap];
117 
118  /* outside slice handling (we can't do that by memset as we need the
119  * dc for error resilience) */
120  if (s->first_slice_line && n != 3) {
121  if (n != 2)
122  b = c = 1024;
123  if (n != 1 && s->mb_x == s->resync_mb_x)
124  b = a = 1024;
125  }
126  if (s->mb_x == s->resync_mb_x && s->mb_y == s->resync_mb_y + 1) {
127  if (n == 0 || n == 4 || n == 5)
128  b = 1024;
129  }
130 
131  if (abs(a - b) < abs(b - c)) {
132  pred = c;
133  *dir_ptr = 1; /* top */
134  } else {
135  pred = a;
136  *dir_ptr = 0; /* left */
137  }
138  /* we assume pred is positive */
139  pred = FASTDIV((pred + (scale >> 1)), scale);
140 
141  if (encoding) {
142  ret = level - pred;
143  } else {
144  level += pred;
145  ret = level;
146  }
147  level *= scale;
148  if (level & (~2047)) {
149  if (!s->encoding && (s->avctx->err_recognition & (AV_EF_BITSTREAM | AV_EF_AGGRESSIVE))) {
150  if (level < 0) {
151  av_log(s->avctx, AV_LOG_ERROR,
152  "dc<0 at %dx%d\n", s->mb_x, s->mb_y);
153  return AVERROR_INVALIDDATA;
154  }
155  if (level > 2048 + scale) {
156  av_log(s->avctx, AV_LOG_ERROR,
157  "dc overflow at %dx%d\n", s->mb_x, s->mb_y);
158  return AVERROR_INVALIDDATA;
159  }
160  }
161  if (level < 0)
162  level = 0;
163  else if (!(s->workaround_bugs & FF_BUG_DC_CLIP))
164  level = 2047;
165  }
166  dc_val[0] = level;
167 
168  return ret;
169 }
170 
171 #endif /* AVCODEC_MPEG4VIDEO_H */
FF_BUG_DC_CLIP
#define FF_BUG_DC_CLIP
Definition: avcodec.h:1292
level
uint8_t level
Definition: svq3.c:206
b
#define b
Definition: input.c:34
mpegvideo.h
ff_mpeg4_init_direct_mv
void ff_mpeg4_init_direct_mv(MpegEncContext *s)
Definition: mpeg4video.c:83
wrap
#define wrap(func)
Definition: neontest.h:65
scale
static av_always_inline float scale(float x, float s)
Definition: vf_v360.c:1389
AV_EF_BITSTREAM
#define AV_EF_BITSTREAM
detect bitstream specification deviations
Definition: avcodec.h:1362
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:180
s
#define s(width, name)
Definition: cbs_vp9.c:256
abs
#define abs(x)
Definition: cuda_runtime.h:35
FASTDIV
#define FASTDIV(a, b)
Definition: mathops.h:204
c
Undefined Behavior In the C some operations are like signed integer dereferencing freed accessing outside allocated Undefined Behavior must not occur in a C it is not safe even if the output of undefined operations is unused The unsafety may seem nit picking but Optimizing compilers have in fact optimized code on the assumption that no undefined Behavior occurs Optimizing code based on wrong assumptions can and has in some cases lead to effects beyond the output of computations The signed integer overflow problem in speed critical code Code which is highly optimized and works with signed integers sometimes has the problem that often the output of the computation does not c
Definition: undefined.txt:32
ff_mpeg4_set_direct_mv
int ff_mpeg4_set_direct_mv(MpegEncContext *s, int mx, int my)
Definition: mpeg4video.c:129
ff_mpeg4_pred_dc
static int ff_mpeg4_pred_dc(MpegEncContext *s, int n, int level, int *dir_ptr, int encoding)
Predict the dc.
Definition: mpeg4video.h:94
a
The reader does not expect b to be semantically here and if the code is changed by maybe adding a a division or other the signedness will almost certainly be mistaken To avoid this confusion a new type was SUINT is the C unsigned type but it holds a signed int to use the same example SUINT a
Definition: undefined.txt:41
ff_mpeg4_get_video_packet_prefix_length
int ff_mpeg4_get_video_packet_prefix_length(MpegEncContext *s)
Definition: mpeg4video.c:42
ret
ret
Definition: filter_design.txt:187
pred
static const float pred[4]
Definition: siprdata.h:259
ff_mpeg4_clean_buffers
void ff_mpeg4_clean_buffers(MpegEncContext *s)
Definition: mpeg4video.c:57
AV_EF_AGGRESSIVE
#define AV_EF_AGGRESSIVE
consider things that a sane encoder should not do as an error
Definition: avcodec.h:1369
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:27
AVERROR_INVALIDDATA
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:61
MpegEncContext
MpegEncContext.
Definition: mpegvideo.h:62
IS_3IV1
#define IS_3IV1
Definition: mpeg4video.h:84