/* * MPEG-1/2 decoder * Copyright (c) 2000, 2001 Fabrice Bellard * Copyright (c) 2002-2004 Michael Niedermayer * * This file is part of FFmpeg. * * FFmpeg is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * FFmpeg is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ /** * @file * MPEG-1/2 decoder */ #define UNCHECKED_BITSTREAM_READER 1 #include "libavutil/attributes.h" #include "libavutil/avassert.h" #include "libavutil/thread.h" #include "avcodec.h" #include "mpegvideo.h" #include "mpeg12.h" #include "mpeg12codecs.h" #include "mpeg12data.h" #include "mpeg12dec.h" #include "rl.h" #include "startcode.h" static const uint8_t table_mb_ptype[7][2] = { { 3, 5 }, // 0x01 MB_INTRA { 1, 2 }, // 0x02 MB_PAT { 1, 3 }, // 0x08 MB_FOR { 1, 1 }, // 0x0A MB_FOR|MB_PAT { 1, 6 }, // 0x11 MB_QUANT|MB_INTRA { 1, 5 }, // 0x12 MB_QUANT|MB_PAT { 2, 5 }, // 0x1A MB_QUANT|MB_FOR|MB_PAT }; static const uint8_t table_mb_btype[11][2] = { { 3, 5 }, // 0x01 MB_INTRA { 2, 3 }, // 0x04 MB_BACK { 3, 3 }, // 0x06 MB_BACK|MB_PAT { 2, 4 }, // 0x08 MB_FOR { 3, 4 }, // 0x0A MB_FOR|MB_PAT { 2, 2 }, // 0x0C MB_FOR|MB_BACK { 3, 2 }, // 0x0E MB_FOR|MB_BACK|MB_PAT { 1, 6 }, // 0x11 MB_QUANT|MB_INTRA { 2, 6 }, // 0x16 MB_QUANT|MB_BACK|MB_PAT { 3, 6 }, // 0x1A MB_QUANT|MB_FOR|MB_PAT { 2, 5 }, // 0x1E MB_QUANT|MB_FOR|MB_BACK|MB_PAT }; av_cold void ff_init_2d_vlc_rl(const uint16_t table_vlc[][2], RL_VLC_ELEM rl_vlc[], const int8_t table_run[], const uint8_t table_level[], int n, unsigned static_size, int flags) { int i; VLCElem table[680] = { 0 }; VLC vlc = { .table = table, .table_allocated = static_size }; av_assert0(static_size <= FF_ARRAY_ELEMS(table)); init_vlc(&vlc, TEX_VLC_BITS, n + 2, &table_vlc[0][1], 4, 2, &table_vlc[0][0], 4, 2, INIT_VLC_USE_NEW_STATIC | flags); for (i = 0; i < vlc.table_size; i++) { int code = vlc.table[i].sym; int len = vlc.table[i].len; int level, run; if (len == 0) { // illegal code run = 65; level = MAX_LEVEL; } else if (len<0) { //more bits needed run = 0; level = code; } else { if (code == n) { //esc run = 65; level = 0; } else if (code == n + 1) { //eob run = 0; level = 127; } else { run = table_run [code] + 1; level = table_level[code]; } } rl_vlc[i].len = len; rl_vlc[i].level = level; rl_vlc[i].run = run; } } void ff_mpeg1_clean_buffers(MpegEncContext *s) { s->last_dc[0] = 1 << (7 + s->intra_dc_precision); s->last_dc[1] = s->last_dc[0]; s->last_dc[2] = s->last_dc[0]; memset(s->last_mv, 0, sizeof(s->last_mv)); } /******************************************/ /* decoding */ VLC ff_mv_vlc; VLC ff_dc_lum_vlc; VLC ff_dc_chroma_vlc; VLC ff_mbincr_vlc; VLC ff_mb_ptype_vlc; VLC ff_mb_btype_vlc; VLC ff_mb_pat_vlc; RL_VLC_ELEM ff_mpeg1_rl_vlc[680]; RL_VLC_ELEM ff_mpeg2_rl_vlc[674]; static av_cold void mpeg12_init_vlcs(void) { INIT_VLC_STATIC(&ff_dc_lum_vlc, DC_VLC_BITS, 12, ff_mpeg12_vlc_dc_lum_bits, 1, 1, ff_mpeg12_vlc_dc_lum_code, 2, 2, 512); INIT_VLC_STATIC(&ff_dc_chroma_vlc, DC_VLC_BITS, 12, ff_mpeg12_vlc_dc_chroma_bits, 1, 1, ff_mpeg12_vlc_dc_chroma_code, 2, 2, 514); INIT_VLC_STATIC(&ff_mv_vlc, MV_VLC_BITS, 17, &ff_mpeg12_mbMotionVectorTable[0][1], 2, 1, &ff_mpeg12_mbMotionVectorTable[0][0], 2, 1, 266); INIT_VLC_STATIC(&ff_mbincr_vlc, MBINCR_VLC_BITS, 36, &ff_mpeg12_mbAddrIncrTable[0][1], 2, 1, &ff_mpeg12_mbAddrIncrTable[0][0], 2, 1, 538); INIT_VLC_STATIC(&ff_mb_pat_vlc, MB_PAT_VLC_BITS, 64, &ff_mpeg12_mbPatTable[0][1], 2, 1, &ff_mpeg12_mbPatTable[0][0], 2, 1, 512); INIT_VLC_STATIC(&ff_mb_ptype_vlc, MB_PTYPE_VLC_BITS, 7, &table_mb_ptype[0][1], 2, 1, &table_mb_ptype[0][0], 2, 1, 64); INIT_VLC_STATIC(&ff_mb_btype_vlc, MB_BTYPE_VLC_BITS, 11, &table_mb_btype[0][1], 2, 1, &table_mb_btype[0][0], 2, 1, 64); ff_init_2d_vlc_rl(ff_mpeg1_vlc_table, ff_mpeg1_rl_vlc, ff_mpeg12_run, ff_mpeg12_level, MPEG12_RL_NB_ELEMS, FF_ARRAY_ELEMS(ff_mpeg1_rl_vlc), 0); ff_init_2d_vlc_rl(ff_mpeg2_vlc_table, ff_mpeg2_rl_vlc, ff_mpeg12_run, ff_mpeg12_level, MPEG12_RL_NB_ELEMS, FF_ARRAY_ELEMS(ff_mpeg2_rl_vlc), 0); } av_cold void ff_mpeg12_init_vlcs(void) { static AVOnce init_static_once = AV_ONCE_INIT; ff_thread_once(&init_static_once, mpeg12_init_vlcs); } #define MAX_INDEX (64 - 1) int ff_mpeg1_decode_block_intra(GetBitContext *gb, const uint16_t *quant_matrix, const uint8_t *scantable, int last_dc[3], int16_t *block, int index, int qscale) { int dc, diff, i = 0, component; /* DC coefficient */ component = index <= 3 ? 0 : index - 4 + 1; diff = decode_dc(gb, component); if (diff >= 0xffff) return AVERROR_INVALIDDATA; dc = last_dc[component]; dc += diff; last_dc[component] = dc; block[0] = dc * quant_matrix[0]; { OPEN_READER(re, gb); UPDATE_CACHE(re, gb); if (((int32_t)GET_CACHE(re, gb)) <= (int32_t)0xBFFFFFFF) goto end; /* now quantify & encode AC coefficients */ while (1) { int level, run, j; GET_RL_VLC(level, run, re, gb, ff_mpeg1_rl_vlc, TEX_VLC_BITS, 2, 0); if (level != 0) { i += run; if (i > MAX_INDEX) break; j = scantable[i]; level = (level * qscale * quant_matrix[j]) >> 4; level = (level - 1) | 1; level = (level ^ SHOW_SBITS(re, gb, 1)) - SHOW_SBITS(re, gb, 1); SKIP_BITS(re, gb, 1); } else { /* escape */ run = SHOW_UBITS(re, gb, 6) + 1; LAST_SKIP_BITS(re, gb, 6); UPDATE_CACHE(re, gb); level = SHOW_SBITS(re, gb, 8); SKIP_BITS(re, gb, 8); if (level == -128) { level = SHOW_UBITS(re, gb, 8) - 256; SKIP_BITS(re, gb, 8); } else if (level == 0) { level = SHOW_UBITS(re, gb, 8); SKIP_BITS(re, gb, 8); } i += run; if (i > MAX_INDEX) break; j = scantable[i]; if (level < 0) { level = -level; level = (level * qscale * quant_matrix[j]) >> 4; level = (level - 1) | 1; level = -level; } else { level = (level * qscale * quant_matrix[j]) >> 4; level = (level - 1) | 1; } } block[j] = level; if (((int32_t)GET_CACHE(re, gb)) <= (int32_t)0xBFFFFFFF) break; UPDATE_CACHE(re, gb); } end: LAST_SKIP_BITS(re, gb, 2); CLOSE_READER(re, gb); } if (i > MAX_INDEX) i = AVERROR_INVALIDDATA; return i; }