| 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 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 | /** |
| 24 | * @file |
| 25 | * MPEG-1/2 decoder |
| 26 | */ |
| 27 | |
| 28 | #define UNCHECKED_BITSTREAM_READER 1 |
| 29 | |
| 30 | #include "libavutil/attributes.h" |
| 31 | #include "libavutil/avassert.h" |
| 32 | #include "libavutil/timecode.h" |
| 33 | |
| 34 | #include "internal.h" |
| 35 | #include "avcodec.h" |
| 36 | #include "mpegvideo.h" |
| 37 | #include "error_resilience.h" |
| 38 | #include "mpeg12.h" |
| 39 | #include "mpeg12data.h" |
| 40 | #include "bytestream.h" |
| 41 | #include "vdpau_internal.h" |
| 42 | #include "thread.h" |
| 43 | |
| 44 | uint8_t ff_mpeg12_static_rl_table_store[2][2][2*MAX_RUN + MAX_LEVEL + 3]; |
| 45 | |
| 46 | static const uint8_t table_mb_ptype[7][2] = { |
| 47 | { 3, 5 }, // 0x01 MB_INTRA |
| 48 | { 1, 2 }, // 0x02 MB_PAT |
| 49 | { 1, 3 }, // 0x08 MB_FOR |
| 50 | { 1, 1 }, // 0x0A MB_FOR|MB_PAT |
| 51 | { 1, 6 }, // 0x11 MB_QUANT|MB_INTRA |
| 52 | { 1, 5 }, // 0x12 MB_QUANT|MB_PAT |
| 53 | { 2, 5 }, // 0x1A MB_QUANT|MB_FOR|MB_PAT |
| 54 | }; |
| 55 | |
| 56 | static const uint8_t table_mb_btype[11][2] = { |
| 57 | { 3, 5 }, // 0x01 MB_INTRA |
| 58 | { 2, 3 }, // 0x04 MB_BACK |
| 59 | { 3, 3 }, // 0x06 MB_BACK|MB_PAT |
| 60 | { 2, 4 }, // 0x08 MB_FOR |
| 61 | { 3, 4 }, // 0x0A MB_FOR|MB_PAT |
| 62 | { 2, 2 }, // 0x0C MB_FOR|MB_BACK |
| 63 | { 3, 2 }, // 0x0E MB_FOR|MB_BACK|MB_PAT |
| 64 | { 1, 6 }, // 0x11 MB_QUANT|MB_INTRA |
| 65 | { 2, 6 }, // 0x16 MB_QUANT|MB_BACK|MB_PAT |
| 66 | { 3, 6 }, // 0x1A MB_QUANT|MB_FOR|MB_PAT |
| 67 | { 2, 5 }, // 0x1E MB_QUANT|MB_FOR|MB_BACK|MB_PAT |
| 68 | }; |
| 69 | |
| 70 | #define INIT_2D_VLC_RL(rl, static_size)\ |
| 71 | {\ |
| 72 | static RL_VLC_ELEM rl_vlc_table[static_size];\ |
| 73 | rl.rl_vlc[0] = rl_vlc_table;\ |
| 74 | init_2d_vlc_rl(&rl, static_size);\ |
| 75 | } |
| 76 | |
| 77 | static av_cold void init_2d_vlc_rl(RLTable *rl, unsigned static_size) |
| 78 | { |
| 79 | int i; |
| 80 | VLC_TYPE table[680][2] = {{0}}; |
| 81 | VLC vlc = { .table = table, .table_allocated = static_size }; |
| 82 | av_assert0(static_size <= FF_ARRAY_ELEMS(table)); |
| 83 | init_vlc(&vlc, TEX_VLC_BITS, rl->n + 2, &rl->table_vlc[0][1], 4, 2, &rl->table_vlc[0][0], 4, 2, INIT_VLC_USE_NEW_STATIC); |
| 84 | |
| 85 | for (i = 0; i < vlc.table_size; i++) { |
| 86 | int code = vlc.table[i][0]; |
| 87 | int len = vlc.table[i][1]; |
| 88 | int level, run; |
| 89 | |
| 90 | if (len == 0) { // illegal code |
| 91 | run = 65; |
| 92 | level = MAX_LEVEL; |
| 93 | } else if (len<0) { //more bits needed |
| 94 | run = 0; |
| 95 | level = code; |
| 96 | } else { |
| 97 | if (code == rl->n) { //esc |
| 98 | run = 65; |
| 99 | level = 0; |
| 100 | } else if (code == rl->n+1) { //eob |
| 101 | run = 0; |
| 102 | level = 127; |
| 103 | } else { |
| 104 | run = rl->table_run [code] + 1; |
| 105 | level = rl->table_level[code]; |
| 106 | } |
| 107 | } |
| 108 | rl->rl_vlc[0][i].len = len; |
| 109 | rl->rl_vlc[0][i].level = level; |
| 110 | rl->rl_vlc[0][i].run = run; |
| 111 | } |
| 112 | } |
| 113 | |
| 114 | av_cold void ff_mpeg12_common_init(MpegEncContext *s) |
| 115 | { |
| 116 | |
| 117 | s->y_dc_scale_table = |
| 118 | s->c_dc_scale_table = ff_mpeg2_dc_scale_table[s->intra_dc_precision]; |
| 119 | |
| 120 | } |
| 121 | |
| 122 | void ff_mpeg1_clean_buffers(MpegEncContext *s) |
| 123 | { |
| 124 | s->last_dc[0] = 1 << (7 + s->intra_dc_precision); |
| 125 | s->last_dc[1] = s->last_dc[0]; |
| 126 | s->last_dc[2] = s->last_dc[0]; |
| 127 | memset(s->last_mv, 0, sizeof(s->last_mv)); |
| 128 | } |
| 129 | |
| 130 | |
| 131 | /******************************************/ |
| 132 | /* decoding */ |
| 133 | |
| 134 | VLC ff_mv_vlc; |
| 135 | |
| 136 | VLC ff_dc_lum_vlc; |
| 137 | VLC ff_dc_chroma_vlc; |
| 138 | |
| 139 | VLC ff_mbincr_vlc; |
| 140 | VLC ff_mb_ptype_vlc; |
| 141 | VLC ff_mb_btype_vlc; |
| 142 | VLC ff_mb_pat_vlc; |
| 143 | |
| 144 | av_cold void ff_mpeg12_init_vlcs(void) |
| 145 | { |
| 146 | static int done = 0; |
| 147 | |
| 148 | if (!done) { |
| 149 | done = 1; |
| 150 | |
| 151 | INIT_VLC_STATIC(&ff_dc_lum_vlc, DC_VLC_BITS, 12, |
| 152 | ff_mpeg12_vlc_dc_lum_bits, 1, 1, |
| 153 | ff_mpeg12_vlc_dc_lum_code, 2, 2, 512); |
| 154 | INIT_VLC_STATIC(&ff_dc_chroma_vlc, DC_VLC_BITS, 12, |
| 155 | ff_mpeg12_vlc_dc_chroma_bits, 1, 1, |
| 156 | ff_mpeg12_vlc_dc_chroma_code, 2, 2, 514); |
| 157 | INIT_VLC_STATIC(&ff_mv_vlc, MV_VLC_BITS, 17, |
| 158 | &ff_mpeg12_mbMotionVectorTable[0][1], 2, 1, |
| 159 | &ff_mpeg12_mbMotionVectorTable[0][0], 2, 1, 518); |
| 160 | INIT_VLC_STATIC(&ff_mbincr_vlc, MBINCR_VLC_BITS, 36, |
| 161 | &ff_mpeg12_mbAddrIncrTable[0][1], 2, 1, |
| 162 | &ff_mpeg12_mbAddrIncrTable[0][0], 2, 1, 538); |
| 163 | INIT_VLC_STATIC(&ff_mb_pat_vlc, MB_PAT_VLC_BITS, 64, |
| 164 | &ff_mpeg12_mbPatTable[0][1], 2, 1, |
| 165 | &ff_mpeg12_mbPatTable[0][0], 2, 1, 512); |
| 166 | |
| 167 | INIT_VLC_STATIC(&ff_mb_ptype_vlc, MB_PTYPE_VLC_BITS, 7, |
| 168 | &table_mb_ptype[0][1], 2, 1, |
| 169 | &table_mb_ptype[0][0], 2, 1, 64); |
| 170 | INIT_VLC_STATIC(&ff_mb_btype_vlc, MB_BTYPE_VLC_BITS, 11, |
| 171 | &table_mb_btype[0][1], 2, 1, |
| 172 | &table_mb_btype[0][0], 2, 1, 64); |
| 173 | ff_init_rl(&ff_rl_mpeg1, ff_mpeg12_static_rl_table_store[0]); |
| 174 | ff_init_rl(&ff_rl_mpeg2, ff_mpeg12_static_rl_table_store[1]); |
| 175 | |
| 176 | INIT_2D_VLC_RL(ff_rl_mpeg1, 680); |
| 177 | INIT_2D_VLC_RL(ff_rl_mpeg2, 674); |
| 178 | } |
| 179 | } |
| 180 | |
| 181 | /** |
| 182 | * Find the end of the current frame in the bitstream. |
| 183 | * @return the position of the first byte of the next frame, or -1 |
| 184 | */ |
| 185 | int ff_mpeg1_find_frame_end(ParseContext *pc, const uint8_t *buf, int buf_size, AVCodecParserContext *s) |
| 186 | { |
| 187 | int i; |
| 188 | uint32_t state = pc->state; |
| 189 | |
| 190 | /* EOF considered as end of frame */ |
| 191 | if (buf_size == 0) |
| 192 | return 0; |
| 193 | |
| 194 | /* |
| 195 | 0 frame start -> 1/4 |
| 196 | 1 first_SEQEXT -> 0/2 |
| 197 | 2 first field start -> 3/0 |
| 198 | 3 second_SEQEXT -> 2/0 |
| 199 | 4 searching end |
| 200 | */ |
| 201 | |
| 202 | for (i = 0; i < buf_size; i++) { |
| 203 | av_assert1(pc->frame_start_found >= 0 && pc->frame_start_found <= 4); |
| 204 | if (pc->frame_start_found & 1) { |
| 205 | if (state == EXT_START_CODE && (buf[i] & 0xF0) != 0x80) |
| 206 | pc->frame_start_found--; |
| 207 | else if (state == EXT_START_CODE + 2) { |
| 208 | if ((buf[i] & 3) == 3) |
| 209 | pc->frame_start_found = 0; |
| 210 | else |
| 211 | pc->frame_start_found = (pc->frame_start_found + 1) & 3; |
| 212 | } |
| 213 | state++; |
| 214 | } else { |
| 215 | i = avpriv_find_start_code(buf + i, buf + buf_size, &state) - buf - 1; |
| 216 | if (pc->frame_start_found == 0 && state >= SLICE_MIN_START_CODE && state <= SLICE_MAX_START_CODE) { |
| 217 | i++; |
| 218 | pc->frame_start_found = 4; |
| 219 | } |
| 220 | if (state == SEQ_END_CODE) { |
| 221 | pc->frame_start_found = 0; |
| 222 | pc->state=-1; |
| 223 | return i+1; |
| 224 | } |
| 225 | if (pc->frame_start_found == 2 && state == SEQ_START_CODE) |
| 226 | pc->frame_start_found = 0; |
| 227 | if (pc->frame_start_found < 4 && state == EXT_START_CODE) |
| 228 | pc->frame_start_found++; |
| 229 | if (pc->frame_start_found == 4 && (state & 0xFFFFFF00) == 0x100) { |
| 230 | if (state < SLICE_MIN_START_CODE || state > SLICE_MAX_START_CODE) { |
| 231 | pc->frame_start_found = 0; |
| 232 | pc->state = -1; |
| 233 | return i - 3; |
| 234 | } |
| 235 | } |
| 236 | if (pc->frame_start_found == 0 && s && state == PICTURE_START_CODE) { |
| 237 | ff_fetch_timestamp(s, i - 3, 1); |
| 238 | } |
| 239 | } |
| 240 | } |
| 241 | pc->state = state; |
| 242 | return END_NOT_FOUND; |
| 243 | } |
| 244 | |