/* * 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 "dsputil.h" #include "mpegvideo.h" #include "error_resilience.h" #include "mpeg12.h" #include "mpeg12data.h" #include "mpeg12decdata.h" #include "bytestream.h" #include "vdpau_internal.h" #include "xvmc_internal.h" #include "thread.h" uint8_t ff_mpeg12_static_rl_table_store[2][2][2*MAX_RUN + MAX_LEVEL + 3]; #define INIT_2D_VLC_RL(rl, static_size)\ {\ static RL_VLC_ELEM rl_vlc_table[static_size];\ INIT_VLC_STATIC(&rl.vlc, TEX_VLC_BITS, rl.n + 2,\ &rl.table_vlc[0][1], 4, 2,\ &rl.table_vlc[0][0], 4, 2, static_size);\ \ rl.rl_vlc[0] = rl_vlc_table;\ init_2d_vlc_rl(&rl);\ } static av_cold void init_2d_vlc_rl(RLTable *rl) { int i; for (i = 0; i < rl->vlc.table_size; i++) { int code = rl->vlc.table[i][0]; int len = rl->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_init_rl(&ff_rl_mpeg1, ff_mpeg12_static_rl_table_store[0]); ff_init_rl(&ff_rl_mpeg2, ff_mpeg12_static_rl_table_store[1]); INIT_2D_VLC_RL(ff_rl_mpeg1, 680); INIT_2D_VLC_RL(ff_rl_mpeg2, 674); } } /** * 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); } } } pc->state = state; return END_NOT_FOUND; }