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 44uint8_t ff_mpeg12_static_rl_table_store[2][2][2*MAX_RUN + MAX_LEVEL + 3]; 45 46static 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 56static 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 INIT_VLC_STATIC(&rl.vlc, TEX_VLC_BITS, rl.n + 2,\ 74 &rl.table_vlc[0][1], 4, 2,\ 75 &rl.table_vlc[0][0], 4, 2, static_size);\ 76\ 77 rl.rl_vlc[0] = rl_vlc_table;\ 78 init_2d_vlc_rl(&rl);\ 79} 80 81static av_cold void init_2d_vlc_rl(RLTable *rl) 82{ 83 int i; 84 85 for (i = 0; i < rl->vlc.table_size; i++) { 86 int code = rl->vlc.table[i][0]; 87 int len = rl->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 114av_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 122void 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 134VLC ff_mv_vlc; 135 136VLC ff_dc_lum_vlc; 137VLC ff_dc_chroma_vlc; 138 139VLC ff_mbincr_vlc; 140VLC ff_mb_ptype_vlc; 141VLC ff_mb_btype_vlc; 142VLC ff_mb_pat_vlc; 143 144av_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 */ 185int 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} 244 245