/* * 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/timecode.h" #include "internal.h" #include "avcodec.h" #include "mpegvideo.h" #include "error_resilience.h" #include "mpeg12.h" #include "mpeg12data.h" #include "mpegvideodata.h" #include "bytestream.h" #include "thread.h" uint8_t ff_mpeg12_static_rl_table_store[2][2][2*MAX_RUN + MAX_LEVEL + 3]; 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(RLTable *rl, unsigned static_size, int flags) { int i; VLC_TYPE table[680][2] = {{0}}; VLC vlc = { .table = table, .table_allocated = static_size }; av_assert0(static_size <= FF_ARRAY_ELEMS(table)); 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 | flags); for (i = 0; i < vlc.table_size; i++) { int code = vlc.table[i][0]; int len = vlc.table[i][1]; 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 == rl->n) { //esc run = 65; level = 0; } else if (code == rl->n+1) { //eob run = 0; level = 127; } else { run = rl->table_run [code] + 1; level = rl->table_level[code]; } } rl->rl_vlc[0][i].len = len; rl->rl_vlc[0][i].level = level; rl->rl_vlc[0][i].run = run; } } av_cold void ff_mpeg12_common_init(MpegEncContext *s) { s->y_dc_scale_table = s->c_dc_scale_table = ff_mpeg2_dc_scale_table[s->intra_dc_precision]; } 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; av_cold void ff_mpeg12_init_vlcs(void) { static int done = 0; if (!done) { done = 1; 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, 518); 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_rl_init(&ff_rl_mpeg1, ff_mpeg12_static_rl_table_store[0]); ff_rl_init(&ff_rl_mpeg2, ff_mpeg12_static_rl_table_store[1]); INIT_2D_VLC_RL(ff_rl_mpeg1, 680, 0); INIT_2D_VLC_RL(ff_rl_mpeg2, 674, 0); } } /** * Find the end of the current frame in the bitstream. * @return the position of the first byte of the next frame, or -1 */ int ff_mpeg1_find_frame_end(ParseContext *pc, const uint8_t *buf, int buf_size, AVCodecParserContext *s) { int i; uint32_t state = pc->state; /* EOF considered as end of frame */ if (buf_size == 0) return 0; /* 0 frame start -> 1/4 1 first_SEQEXT -> 0/2 2 first field start -> 3/0 3 second_SEQEXT -> 2/0 4 searching end */ for (i = 0; i < buf_size; i++) { av_assert1(pc->frame_start_found >= 0 && pc->frame_start_found <= 4); if (pc->frame_start_found & 1) { if (state == EXT_START_CODE && (buf[i] & 0xF0) != 0x80) pc->frame_start_found--; else if (state == EXT_START_CODE + 2) { if ((buf[i] & 3) == 3) pc->frame_start_found = 0; else pc->frame_start_found = (pc->frame_start_found + 1) & 3; } state++; } else { i = avpriv_find_start_code(buf + i, buf + buf_size, &state) - buf - 1; if (pc->frame_start_found == 0 && state >= SLICE_MIN_START_CODE && state <= SLICE_MAX_START_CODE) { i++; pc->frame_start_found = 4; } if (state == SEQ_END_CODE) { pc->frame_start_found = 0; pc->state=-1; return i+1; } if (pc->frame_start_found == 2 && state == SEQ_START_CODE) pc->frame_start_found = 0; if (pc->frame_start_found < 4 && state == EXT_START_CODE) pc->frame_start_found++; if (pc->frame_start_found == 4 && (state & 0xFFFFFF00) == 0x100) { if (state < SLICE_MIN_START_CODE || state > SLICE_MAX_START_CODE) { pc->frame_start_found = 0; pc->state = -1; return i - 3; } } if (pc->frame_start_found == 0 && s && state == PICTURE_START_CODE) { ff_fetch_timestamp(s, i - 3, 1, i > 3); } } } pc->state = state; return END_NOT_FOUND; } #define MAX_INDEX (64 - 1) int ff_mpeg1_decode_block_intra(GetBitContext *gb, const uint16_t *quant_matrix, uint8_t *const scantable, int last_dc[3], int16_t *block, int index, int qscale) { int dc, diff, i = 0, component; RLTable *rl = &ff_rl_mpeg1; /* 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, rl->rl_vlc[0], 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; }