be5227f058ccc368ed216f10b7fb7afed860454c
[libav.git] / libavcodec / mpeg12.c
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
23 /**
24 * @file
25 * MPEG-1/2 decoder
26 */
27
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
38 uint8_t ff_mpeg12_static_rl_table_store[2][2][2*MAX_RUN + MAX_LEVEL + 3];
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
108 av_cold void ff_mpeg12_common_init(MpegEncContext *s)
109 {
110
111 s->y_dc_scale_table =
112 s->c_dc_scale_table = ff_mpeg2_dc_scale_table[s->intra_dc_precision];
113
114 }
115
116 void ff_mpeg1_clean_buffers(MpegEncContext *s)
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
128 VLC ff_mv_vlc;
129
130 VLC ff_dc_lum_vlc;
131 VLC ff_dc_chroma_vlc;
132
133 VLC ff_mbincr_vlc;
134 VLC ff_mb_ptype_vlc;
135 VLC ff_mb_btype_vlc;
136 VLC ff_mb_pat_vlc;
137
138 av_cold void ff_mpeg12_init_vlcs(void)
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,
146 ff_mpeg12_vlc_dc_lum_bits, 1, 1,
147 ff_mpeg12_vlc_dc_lum_code, 2, 2, 512);
148 INIT_VLC_STATIC(&ff_dc_chroma_vlc, DC_VLC_BITS, 12,
149 ff_mpeg12_vlc_dc_chroma_bits, 1, 1,
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);
167 ff_init_rl(&ff_rl_mpeg1, ff_mpeg12_static_rl_table_store[0]);
168 ff_init_rl(&ff_rl_mpeg2, ff_mpeg12_static_rl_table_store[1]);
169
170 INIT_2D_VLC_RL(ff_rl_mpeg1, 680);
171 INIT_2D_VLC_RL(ff_rl_mpeg2, 674);
172 }
173 }
174
175 /**
176 * Find the end of the current frame in the bitstream.
177 * @return the position of the first byte of the next frame, or -1
178 */
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 }