Libav
mpeg12.c
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1 /*
2  * MPEG-1/2 decoder
3  * Copyright (c) 2000, 2001 Fabrice Bellard
4  * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
5  *
6  * This file is part of Libav.
7  *
8  * Libav 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  * Libav 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 Libav; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21  */
22 
28 #include "libavutil/attributes.h"
29 #include "internal.h"
30 #include "avcodec.h"
31 #include "mpegvideo.h"
32 #include "error_resilience.h"
33 #include "mpeg12.h"
34 #include "mpeg12data.h"
35 #include "bytestream.h"
36 #include "thread.h"
37 
39 
40 static const uint8_t table_mb_ptype[7][2] = {
41  { 3, 5 }, // 0x01 MB_INTRA
42  { 1, 2 }, // 0x02 MB_PAT
43  { 1, 3 }, // 0x08 MB_FOR
44  { 1, 1 }, // 0x0A MB_FOR|MB_PAT
45  { 1, 6 }, // 0x11 MB_QUANT|MB_INTRA
46  { 1, 5 }, // 0x12 MB_QUANT|MB_PAT
47  { 2, 5 }, // 0x1A MB_QUANT|MB_FOR|MB_PAT
48 };
49 
50 static const uint8_t table_mb_btype[11][2] = {
51  { 3, 5 }, // 0x01 MB_INTRA
52  { 2, 3 }, // 0x04 MB_BACK
53  { 3, 3 }, // 0x06 MB_BACK|MB_PAT
54  { 2, 4 }, // 0x08 MB_FOR
55  { 3, 4 }, // 0x0A MB_FOR|MB_PAT
56  { 2, 2 }, // 0x0C MB_FOR|MB_BACK
57  { 3, 2 }, // 0x0E MB_FOR|MB_BACK|MB_PAT
58  { 1, 6 }, // 0x11 MB_QUANT|MB_INTRA
59  { 2, 6 }, // 0x16 MB_QUANT|MB_BACK|MB_PAT
60  { 3, 6 }, // 0x1A MB_QUANT|MB_FOR|MB_PAT
61  { 2, 5 }, // 0x1E MB_QUANT|MB_FOR|MB_BACK|MB_PAT
62 };
63 
64 #define INIT_2D_VLC_RL(rl, static_size)\
65 {\
66  static RL_VLC_ELEM rl_vlc_table[static_size];\
67  INIT_VLC_STATIC(&rl.vlc, TEX_VLC_BITS, rl.n + 2,\
68  &rl.table_vlc[0][1], 4, 2,\
69  &rl.table_vlc[0][0], 4, 2, static_size);\
70 \
71  rl.rl_vlc[0] = rl_vlc_table;\
72  init_2d_vlc_rl(&rl);\
73 }
74 
75 static av_cold void init_2d_vlc_rl(RLTable *rl)
76 {
77  int i;
78 
79  for (i = 0; i < rl->vlc.table_size; i++) {
80  int code = rl->vlc.table[i][0];
81  int len = rl->vlc.table[i][1];
82  int level, run;
83 
84  if (len == 0) { // illegal code
85  run = 65;
86  level = MAX_LEVEL;
87  } else if (len<0) { //more bits needed
88  run = 0;
89  level = code;
90  } else {
91  if (code == rl->n) { //esc
92  run = 65;
93  level = 0;
94  } else if (code == rl->n+1) { //eob
95  run = 0;
96  level = 127;
97  } else {
98  run = rl->table_run [code] + 1;
99  level = rl->table_level[code];
100  }
101  }
102  rl->rl_vlc[0][i].len = len;
103  rl->rl_vlc[0][i].level = level;
104  rl->rl_vlc[0][i].run = run;
105  }
106 }
107 
109 {
110 
111  s->y_dc_scale_table =
113 
114 }
115 
117 {
118  s->last_dc[0] = 1 << (7 + s->intra_dc_precision);
119  s->last_dc[1] = s->last_dc[0];
120  s->last_dc[2] = s->last_dc[0];
121  memset(s->last_mv, 0, sizeof(s->last_mv));
122 }
123 
124 
125 /******************************************/
126 /* decoding */
127 
129 
132 
137 
139 {
140  static int done = 0;
141 
142  if (!done) {
143  done = 1;
144 
145  INIT_VLC_STATIC(&ff_dc_lum_vlc, DC_VLC_BITS, 12,
147  ff_mpeg12_vlc_dc_lum_code, 2, 2, 512);
148  INIT_VLC_STATIC(&ff_dc_chroma_vlc, DC_VLC_BITS, 12,
150  ff_mpeg12_vlc_dc_chroma_code, 2, 2, 514);
151  INIT_VLC_STATIC(&ff_mv_vlc, MV_VLC_BITS, 17,
152  &ff_mpeg12_mbMotionVectorTable[0][1], 2, 1,
153  &ff_mpeg12_mbMotionVectorTable[0][0], 2, 1, 518);
154  INIT_VLC_STATIC(&ff_mbincr_vlc, MBINCR_VLC_BITS, 36,
155  &ff_mpeg12_mbAddrIncrTable[0][1], 2, 1,
156  &ff_mpeg12_mbAddrIncrTable[0][0], 2, 1, 538);
157  INIT_VLC_STATIC(&ff_mb_pat_vlc, MB_PAT_VLC_BITS, 64,
158  &ff_mpeg12_mbPatTable[0][1], 2, 1,
159  &ff_mpeg12_mbPatTable[0][0], 2, 1, 512);
160 
161  INIT_VLC_STATIC(&ff_mb_ptype_vlc, MB_PTYPE_VLC_BITS, 7,
162  &table_mb_ptype[0][1], 2, 1,
163  &table_mb_ptype[0][0], 2, 1, 64);
164  INIT_VLC_STATIC(&ff_mb_btype_vlc, MB_BTYPE_VLC_BITS, 11,
165  &table_mb_btype[0][1], 2, 1,
166  &table_mb_btype[0][0], 2, 1, 64);
169 
172  }
173 }
174 
179 int ff_mpeg1_find_frame_end(ParseContext *pc, const uint8_t *buf, int buf_size, AVCodecParserContext *s)
180 {
181  int i;
182  uint32_t state = pc->state;
183 
184  /* EOF considered as end of frame */
185  if (buf_size == 0)
186  return 0;
187 
188 /*
189  0 frame start -> 1/4
190  1 first_SEQEXT -> 0/2
191  2 first field start -> 3/0
192  3 second_SEQEXT -> 2/0
193  4 searching end
194 */
195 
196  for (i = 0; i < buf_size; i++) {
197  assert(pc->frame_start_found >= 0 && pc->frame_start_found <= 4);
198  if (pc->frame_start_found & 1) {
199  if (state == EXT_START_CODE && (buf[i] & 0xF0) != 0x80)
200  pc->frame_start_found--;
201  else if (state == EXT_START_CODE + 2) {
202  if ((buf[i] & 3) == 3)
203  pc->frame_start_found = 0;
204  else
205  pc->frame_start_found = (pc->frame_start_found + 1) & 3;
206  }
207  state++;
208  } else {
209  i = avpriv_find_start_code(buf + i, buf + buf_size, &state) - buf - 1;
210  if (pc->frame_start_found == 0 && state >= SLICE_MIN_START_CODE && state <= SLICE_MAX_START_CODE) {
211  i++;
212  pc->frame_start_found = 4;
213  }
214  if (state == SEQ_END_CODE) {
215  pc->frame_start_found = 0;
216  pc->state=-1;
217  return i+1;
218  }
219  if (pc->frame_start_found == 2 && state == SEQ_START_CODE)
220  pc->frame_start_found = 0;
221  if (pc->frame_start_found < 4 && state == EXT_START_CODE)
222  pc->frame_start_found++;
223  if (pc->frame_start_found == 4 && (state & 0xFFFFFF00) == 0x100) {
224  if (state < SLICE_MIN_START_CODE || state > SLICE_MAX_START_CODE) {
225  pc->frame_start_found = 0;
226  pc->state = -1;
227  return i - 3;
228  }
229  }
230  if (pc->frame_start_found == 0 && s && state == PICTURE_START_CODE) {
231  ff_fetch_timestamp(s, i - 3, 1);
232  }
233  }
234  }
235  pc->state = state;
236  return END_NOT_FOUND;
237 }
#define MBINCR_VLC_BITS
Definition: mpeg12.h:31
int table_size
Definition: get_bits.h:67
#define SLICE_MAX_START_CODE
Definition: cavs.h:32
VLC ff_dc_lum_vlc
Definition: mpeg12.c:130
const uint8_t * y_dc_scale_table
qscale -> y_dc_scale table
Definition: mpegvideo.h:314
int last_mv[2][2][2]
last MV, used for MV prediction in MPEG1 & B-frame MPEG4
Definition: mpegvideo.h:400
av_cold void ff_mpeg12_init_vlcs(void)
Definition: mpeg12.c:138
const unsigned char ff_mpeg12_vlc_dc_lum_bits[12]
Definition: mpeg12data.c:55
void ff_mpeg1_clean_buffers(MpegEncContext *s)
Definition: mpeg12.c:116
mpegvideo header.
const uint16_t ff_mpeg12_vlc_dc_lum_code[12]
Definition: mpeg12data.c:52
const int8_t * table_level
Definition: rl.h:43
uint8_t run
Definition: svq3.c:146
#define SLICE_MIN_START_CODE
Definition: mpegvideo.h:85
int frame_start_found
Definition: parser.h:34
RLTable.
Definition: rl.h:38
Macro definitions for various function/variable attributes.
#define MB_PAT_VLC_BITS
Definition: mpeg12.h:32
#define INIT_2D_VLC_RL(rl, static_size)
Definition: mpeg12.c:64
uint8_t
#define av_cold
Definition: attributes.h:66
RLTable ff_rl_mpeg2
Definition: mpeg12data.c:174
#define INIT_VLC_STATIC(vlc, bits, a, b, c, d, e, f, g, static_size)
Definition: get_bits.h:443
Multithreading support functions.
int intra_dc_precision
Definition: mpegvideo.h:572
static const uint8_t table_mb_ptype[7][2]
Definition: mpeg12.c:40
VLC ff_mv_vlc
Definition: mpeg12.c:128
#define MAX_LEVEL
Definition: rl.h:35
void ff_fetch_timestamp(AVCodecParserContext *s, int off, int remove)
Fetch timestamps for a specific byte within the current access unit.
Definition: parser.c:95
int last_dc[3]
last DC values for MPEG1
Definition: mpegvideo.h:311
const uint16_t ff_mpeg12_vlc_dc_chroma_code[12]
Definition: mpeg12data.c:59
#define SEQ_END_CODE
Definition: mpegvideo.h:81
VLC vlc
decoding only deprecated FIXME remove
Definition: rl.h:47
VLC ff_mb_pat_vlc
Definition: mpeg12.c:136
int8_t len
Definition: get_bits.h:72
Definition: get_bits.h:64
static const uint8_t table_mb_btype[11][2]
Definition: mpeg12.c:50
#define MB_PTYPE_VLC_BITS
Definition: mpeg12.h:33
int n
number of entries of table_vlc minus 1
Definition: rl.h:39
static av_cold void init_2d_vlc_rl(RLTable *rl)
Definition: mpeg12.c:75
#define MB_BTYPE_VLC_BITS
Definition: mpeg12.h:34
const unsigned char ff_mpeg12_vlc_dc_chroma_bits[12]
Definition: mpeg12data.c:62
RLTable ff_rl_mpeg1
Definition: mpeg12data.c:166
const int8_t * table_run
Definition: rl.h:42
#define EXT_START_CODE
Definition: cavs.h:33
RL_VLC_ELEM * rl_vlc[32]
decoding only
Definition: rl.h:48
#define MV_VLC_BITS
Definition: ituh263dec.c:49
const uint8_t *const ff_mpeg2_dc_scale_table[4]
Definition: mpegvideo.c:103
VLC ff_dc_chroma_vlc
Definition: mpeg12.c:131
Libavcodec external API header.
MPEG1/2 tables.
uint32_t state
contains the last few bytes in MSB order
Definition: parser.h:33
VLC ff_mb_ptype_vlc
Definition: mpeg12.c:134
int ff_mpeg1_find_frame_end(ParseContext *pc, const uint8_t *buf, int buf_size, AVCodecParserContext *s)
Find the end of the current frame in the bitstream.
Definition: mpeg12.c:179
#define END_NOT_FOUND
Definition: parser.h:40
av_cold void ff_mpeg12_common_init(MpegEncContext *s)
Definition: mpeg12.c:108
static uint32_t state
Definition: trasher.c:27
const uint8_t * c_dc_scale_table
qscale -> c_dc_scale table
Definition: mpegvideo.h:315
uint8_t level
Definition: svq3.c:147
#define DC_VLC_BITS
Definition: intrax8.c:36
const uint8_t * avpriv_find_start_code(const uint8_t *restrict p, const uint8_t *end, uint32_t *restrict state)
Definition: utils.c:2394
MpegEncContext.
Definition: mpegvideo.h:204
uint8_t run
Definition: get_bits.h:73
#define MAX_RUN
Definition: rl.h:34
common internal api header.
uint8_t ff_mpeg12_static_rl_table_store[2][2][2 *MAX_RUN+MAX_LEVEL+3]
Definition: mpeg12.c:38
VLC ff_mbincr_vlc
Definition: mpeg12.c:133
const uint8_t ff_mpeg12_mbPatTable[64][2]
Definition: mpeg12data.c:221
int len
#define SEQ_START_CODE
Definition: mpegvideo.h:82
av_cold void ff_init_rl(RLTable *rl, uint8_t static_store[2][2 *MAX_RUN+MAX_LEVEL+3])
Definition: mpegvideo.c:1528
const uint8_t ff_mpeg12_mbAddrIncrTable[36][2]
Definition: mpeg12data.c:182
VLC_TYPE(* table)[2]
code, bits
Definition: get_bits.h:66
int16_t level
Definition: get_bits.h:71
const uint8_t ff_mpeg12_mbMotionVectorTable[17][2]
Definition: mpeg12data.c:288
#define PICTURE_START_CODE
Definition: mpegvideo.h:84
VLC ff_mb_btype_vlc
Definition: mpeg12.c:135