528e676059cdfc6133a871abdcef835d6df6b4b4
[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 "dsputil.h"
32 #include "mpegvideo.h"
33 #include "error_resilience.h"
34 #include "mpeg12.h"
35 #include "mpeg12data.h"
36 #include "mpeg12decdata.h"
37 #include "bytestream.h"
38 #include "vdpau_internal.h"
39 #include "xvmc_internal.h"
40 #include "thread.h"
41
42 uint8_t ff_mpeg12_static_rl_table_store[2][2][2*MAX_RUN + MAX_LEVEL + 3];
43
44 #define INIT_2D_VLC_RL(rl, static_size)\
45 {\
46 static RL_VLC_ELEM rl_vlc_table[static_size];\
47 INIT_VLC_STATIC(&rl.vlc, TEX_VLC_BITS, rl.n + 2,\
48 &rl.table_vlc[0][1], 4, 2,\
49 &rl.table_vlc[0][0], 4, 2, static_size);\
50 \
51 rl.rl_vlc[0] = rl_vlc_table;\
52 init_2d_vlc_rl(&rl);\
53 }
54
55 static av_cold void init_2d_vlc_rl(RLTable *rl)
56 {
57 int i;
58
59 for (i = 0; i < rl->vlc.table_size; i++) {
60 int code = rl->vlc.table[i][0];
61 int len = rl->vlc.table[i][1];
62 int level, run;
63
64 if (len == 0) { // illegal code
65 run = 65;
66 level = MAX_LEVEL;
67 } else if (len<0) { //more bits needed
68 run = 0;
69 level = code;
70 } else {
71 if (code == rl->n) { //esc
72 run = 65;
73 level = 0;
74 } else if (code == rl->n+1) { //eob
75 run = 0;
76 level = 127;
77 } else {
78 run = rl->table_run [code] + 1;
79 level = rl->table_level[code];
80 }
81 }
82 rl->rl_vlc[0][i].len = len;
83 rl->rl_vlc[0][i].level = level;
84 rl->rl_vlc[0][i].run = run;
85 }
86 }
87
88 av_cold void ff_mpeg12_common_init(MpegEncContext *s)
89 {
90
91 s->y_dc_scale_table =
92 s->c_dc_scale_table = ff_mpeg2_dc_scale_table[s->intra_dc_precision];
93
94 }
95
96 void ff_mpeg1_clean_buffers(MpegEncContext *s)
97 {
98 s->last_dc[0] = 1 << (7 + s->intra_dc_precision);
99 s->last_dc[1] = s->last_dc[0];
100 s->last_dc[2] = s->last_dc[0];
101 memset(s->last_mv, 0, sizeof(s->last_mv));
102 }
103
104
105 /******************************************/
106 /* decoding */
107
108 VLC ff_mv_vlc;
109
110 VLC ff_dc_lum_vlc;
111 VLC ff_dc_chroma_vlc;
112
113 VLC ff_mbincr_vlc;
114 VLC ff_mb_ptype_vlc;
115 VLC ff_mb_btype_vlc;
116 VLC ff_mb_pat_vlc;
117
118 av_cold void ff_mpeg12_init_vlcs(void)
119 {
120 static int done = 0;
121
122 if (!done) {
123 done = 1;
124
125 INIT_VLC_STATIC(&ff_dc_lum_vlc, DC_VLC_BITS, 12,
126 ff_mpeg12_vlc_dc_lum_bits, 1, 1,
127 ff_mpeg12_vlc_dc_lum_code, 2, 2, 512);
128 INIT_VLC_STATIC(&ff_dc_chroma_vlc, DC_VLC_BITS, 12,
129 ff_mpeg12_vlc_dc_chroma_bits, 1, 1,
130 ff_mpeg12_vlc_dc_chroma_code, 2, 2, 514);
131 INIT_VLC_STATIC(&ff_mv_vlc, MV_VLC_BITS, 17,
132 &ff_mpeg12_mbMotionVectorTable[0][1], 2, 1,
133 &ff_mpeg12_mbMotionVectorTable[0][0], 2, 1, 518);
134 INIT_VLC_STATIC(&ff_mbincr_vlc, MBINCR_VLC_BITS, 36,
135 &ff_mpeg12_mbAddrIncrTable[0][1], 2, 1,
136 &ff_mpeg12_mbAddrIncrTable[0][0], 2, 1, 538);
137 INIT_VLC_STATIC(&ff_mb_pat_vlc, MB_PAT_VLC_BITS, 64,
138 &ff_mpeg12_mbPatTable[0][1], 2, 1,
139 &ff_mpeg12_mbPatTable[0][0], 2, 1, 512);
140
141 INIT_VLC_STATIC(&ff_mb_ptype_vlc, MB_PTYPE_VLC_BITS, 7,
142 &table_mb_ptype[0][1], 2, 1,
143 &table_mb_ptype[0][0], 2, 1, 64);
144 INIT_VLC_STATIC(&ff_mb_btype_vlc, MB_BTYPE_VLC_BITS, 11,
145 &table_mb_btype[0][1], 2, 1,
146 &table_mb_btype[0][0], 2, 1, 64);
147 ff_init_rl(&ff_rl_mpeg1, ff_mpeg12_static_rl_table_store[0]);
148 ff_init_rl(&ff_rl_mpeg2, ff_mpeg12_static_rl_table_store[1]);
149
150 INIT_2D_VLC_RL(ff_rl_mpeg1, 680);
151 INIT_2D_VLC_RL(ff_rl_mpeg2, 674);
152 }
153 }
154
155 /**
156 * Find the end of the current frame in the bitstream.
157 * @return the position of the first byte of the next frame, or -1
158 */
159 int ff_mpeg1_find_frame_end(ParseContext *pc, const uint8_t *buf, int buf_size, AVCodecParserContext *s)
160 {
161 int i;
162 uint32_t state = pc->state;
163
164 /* EOF considered as end of frame */
165 if (buf_size == 0)
166 return 0;
167
168 /*
169 0 frame start -> 1/4
170 1 first_SEQEXT -> 0/2
171 2 first field start -> 3/0
172 3 second_SEQEXT -> 2/0
173 4 searching end
174 */
175
176 for (i = 0; i < buf_size; i++) {
177 assert(pc->frame_start_found >= 0 && pc->frame_start_found <= 4);
178 if (pc->frame_start_found & 1) {
179 if (state == EXT_START_CODE && (buf[i] & 0xF0) != 0x80)
180 pc->frame_start_found--;
181 else if (state == EXT_START_CODE + 2) {
182 if ((buf[i] & 3) == 3)
183 pc->frame_start_found = 0;
184 else
185 pc->frame_start_found = (pc->frame_start_found + 1) & 3;
186 }
187 state++;
188 } else {
189 i = avpriv_find_start_code(buf + i, buf + buf_size, &state) - buf - 1;
190 if (pc->frame_start_found == 0 && state >= SLICE_MIN_START_CODE && state <= SLICE_MAX_START_CODE) {
191 i++;
192 pc->frame_start_found = 4;
193 }
194 if (state == SEQ_END_CODE) {
195 pc->frame_start_found = 0;
196 pc->state=-1;
197 return i+1;
198 }
199 if (pc->frame_start_found == 2 && state == SEQ_START_CODE)
200 pc->frame_start_found = 0;
201 if (pc->frame_start_found < 4 && state == EXT_START_CODE)
202 pc->frame_start_found++;
203 if (pc->frame_start_found == 4 && (state & 0xFFFFFF00) == 0x100) {
204 if (state < SLICE_MIN_START_CODE || state > SLICE_MAX_START_CODE) {
205 pc->frame_start_found = 0;
206 pc->state = -1;
207 return i - 3;
208 }
209 }
210 if (pc->frame_start_found == 0 && s && state == PICTURE_START_CODE) {
211 ff_fetch_timestamp(s, i - 3, 1);
212 }
213 }
214 }
215 pc->state = state;
216 return END_NOT_FOUND;
217 }