Split MPEG-1/2 decoder code off from MPEG-1/2 common code
[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 //#define DEBUG
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 //#undef NDEBUG
43 //#include <assert.h>
44
45 uint8_t ff_mpeg12_static_rl_table_store[2][2][2*MAX_RUN + MAX_LEVEL + 3];
46
47 #define INIT_2D_VLC_RL(rl, static_size)\
48 {\
49 static RL_VLC_ELEM rl_vlc_table[static_size];\
50 INIT_VLC_STATIC(&rl.vlc, TEX_VLC_BITS, rl.n + 2,\
51 &rl.table_vlc[0][1], 4, 2,\
52 &rl.table_vlc[0][0], 4, 2, static_size);\
53 \
54 rl.rl_vlc[0] = rl_vlc_table;\
55 init_2d_vlc_rl(&rl);\
56 }
57
58 static void init_2d_vlc_rl(RLTable *rl)
59 {
60 int i;
61
62 for (i = 0; i < rl->vlc.table_size; i++) {
63 int code = rl->vlc.table[i][0];
64 int len = rl->vlc.table[i][1];
65 int level, run;
66
67 if (len == 0) { // illegal code
68 run = 65;
69 level = MAX_LEVEL;
70 } else if (len<0) { //more bits needed
71 run = 0;
72 level = code;
73 } else {
74 if (code == rl->n) { //esc
75 run = 65;
76 level = 0;
77 } else if (code == rl->n+1) { //eob
78 run = 0;
79 level = 127;
80 } else {
81 run = rl->table_run [code] + 1;
82 level = rl->table_level[code];
83 }
84 }
85 rl->rl_vlc[0][i].len = len;
86 rl->rl_vlc[0][i].level = level;
87 rl->rl_vlc[0][i].run = run;
88 }
89 }
90
91 void ff_mpeg12_common_init(MpegEncContext *s)
92 {
93
94 s->y_dc_scale_table =
95 s->c_dc_scale_table = ff_mpeg2_dc_scale_table[s->intra_dc_precision];
96
97 }
98
99 void ff_mpeg1_clean_buffers(MpegEncContext *s)
100 {
101 s->last_dc[0] = 1 << (7 + s->intra_dc_precision);
102 s->last_dc[1] = s->last_dc[0];
103 s->last_dc[2] = s->last_dc[0];
104 memset(s->last_mv, 0, sizeof(s->last_mv));
105 }
106
107
108 /******************************************/
109 /* decoding */
110
111 VLC ff_mv_vlc;
112
113 VLC ff_dc_lum_vlc;
114 VLC ff_dc_chroma_vlc;
115
116 VLC ff_mbincr_vlc;
117 VLC ff_mb_ptype_vlc;
118 VLC ff_mb_btype_vlc;
119 VLC ff_mb_pat_vlc;
120
121 av_cold void ff_mpeg12_init_vlcs(void)
122 {
123 static int done = 0;
124
125 if (!done) {
126 done = 1;
127
128 INIT_VLC_STATIC(&ff_dc_lum_vlc, DC_VLC_BITS, 12,
129 ff_mpeg12_vlc_dc_lum_bits, 1, 1,
130 ff_mpeg12_vlc_dc_lum_code, 2, 2, 512);
131 INIT_VLC_STATIC(&ff_dc_chroma_vlc, DC_VLC_BITS, 12,
132 ff_mpeg12_vlc_dc_chroma_bits, 1, 1,
133 ff_mpeg12_vlc_dc_chroma_code, 2, 2, 514);
134 INIT_VLC_STATIC(&ff_mv_vlc, MV_VLC_BITS, 17,
135 &ff_mpeg12_mbMotionVectorTable[0][1], 2, 1,
136 &ff_mpeg12_mbMotionVectorTable[0][0], 2, 1, 518);
137 INIT_VLC_STATIC(&ff_mbincr_vlc, MBINCR_VLC_BITS, 36,
138 &ff_mpeg12_mbAddrIncrTable[0][1], 2, 1,
139 &ff_mpeg12_mbAddrIncrTable[0][0], 2, 1, 538);
140 INIT_VLC_STATIC(&ff_mb_pat_vlc, MB_PAT_VLC_BITS, 64,
141 &ff_mpeg12_mbPatTable[0][1], 2, 1,
142 &ff_mpeg12_mbPatTable[0][0], 2, 1, 512);
143
144 INIT_VLC_STATIC(&ff_mb_ptype_vlc, MB_PTYPE_VLC_BITS, 7,
145 &table_mb_ptype[0][1], 2, 1,
146 &table_mb_ptype[0][0], 2, 1, 64);
147 INIT_VLC_STATIC(&ff_mb_btype_vlc, MB_BTYPE_VLC_BITS, 11,
148 &table_mb_btype[0][1], 2, 1,
149 &table_mb_btype[0][0], 2, 1, 64);
150 ff_init_rl(&ff_rl_mpeg1, ff_mpeg12_static_rl_table_store[0]);
151 ff_init_rl(&ff_rl_mpeg2, ff_mpeg12_static_rl_table_store[1]);
152
153 INIT_2D_VLC_RL(ff_rl_mpeg1, 680);
154 INIT_2D_VLC_RL(ff_rl_mpeg2, 674);
155 }
156 }
157
158 /**
159 * Find the end of the current frame in the bitstream.
160 * @return the position of the first byte of the next frame, or -1
161 */
162 int ff_mpeg1_find_frame_end(ParseContext *pc, const uint8_t *buf, int buf_size, AVCodecParserContext *s)
163 {
164 int i;
165 uint32_t state = pc->state;
166
167 /* EOF considered as end of frame */
168 if (buf_size == 0)
169 return 0;
170
171 /*
172 0 frame start -> 1/4
173 1 first_SEQEXT -> 0/2
174 2 first field start -> 3/0
175 3 second_SEQEXT -> 2/0
176 4 searching end
177 */
178
179 for (i = 0; i < buf_size; i++) {
180 assert(pc->frame_start_found >= 0 && pc->frame_start_found <= 4);
181 if (pc->frame_start_found & 1) {
182 if (state == EXT_START_CODE && (buf[i] & 0xF0) != 0x80)
183 pc->frame_start_found--;
184 else if (state == EXT_START_CODE + 2) {
185 if ((buf[i] & 3) == 3)
186 pc->frame_start_found = 0;
187 else
188 pc->frame_start_found = (pc->frame_start_found + 1) & 3;
189 }
190 state++;
191 } else {
192 i = avpriv_find_start_code(buf + i, buf + buf_size, &state) - buf - 1;
193 if (pc->frame_start_found == 0 && state >= SLICE_MIN_START_CODE && state <= SLICE_MAX_START_CODE) {
194 i++;
195 pc->frame_start_found = 4;
196 }
197 if (state == SEQ_END_CODE) {
198 pc->frame_start_found = 0;
199 pc->state=-1;
200 return i+1;
201 }
202 if (pc->frame_start_found == 2 && state == SEQ_START_CODE)
203 pc->frame_start_found = 0;
204 if (pc->frame_start_found < 4 && state == EXT_START_CODE)
205 pc->frame_start_found++;
206 if (pc->frame_start_found == 4 && (state & 0xFFFFFF00) == 0x100) {
207 if (state < SLICE_MIN_START_CODE || state > SLICE_MAX_START_CODE) {
208 pc->frame_start_found = 0;
209 pc->state = -1;
210 return i - 3;
211 }
212 }
213 if (pc->frame_start_found == 0 && s && state == PICTURE_START_CODE) {
214 ff_fetch_timestamp(s, i - 3, 1);
215 }
216 }
217 }
218 pc->state = state;
219 return END_NOT_FOUND;
220 }