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223 lines
7.0 KiB
223 lines
7.0 KiB
/* |
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* MPEG-1/2 decoder |
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* Copyright (c) 2000, 2001 Fabrice Bellard |
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* Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at> |
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* |
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* This file is part of FFmpeg. |
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* |
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* FFmpeg is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public |
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* License as published by the Free Software Foundation; either |
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* version 2.1 of the License, or (at your option) any later version. |
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* |
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* FFmpeg is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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* Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public |
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* License along with FFmpeg; if not, write to the Free Software |
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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*/ |
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/** |
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* @file |
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* MPEG-1/2 decoder |
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*/ |
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#define UNCHECKED_BITSTREAM_READER 1 |
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#include "libavutil/attributes.h" |
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#include "libavutil/avassert.h" |
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#include "libavutil/timecode.h" |
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#include "internal.h" |
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#include "avcodec.h" |
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#include "dsputil.h" |
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#include "mpegvideo.h" |
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#include "error_resilience.h" |
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#include "mpeg12.h" |
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#include "mpeg12data.h" |
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#include "mpeg12decdata.h" |
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#include "bytestream.h" |
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#include "vdpau_internal.h" |
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#include "xvmc_internal.h" |
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#include "thread.h" |
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uint8_t ff_mpeg12_static_rl_table_store[2][2][2*MAX_RUN + MAX_LEVEL + 3]; |
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#define INIT_2D_VLC_RL(rl, static_size)\ |
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{\ |
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static RL_VLC_ELEM rl_vlc_table[static_size];\ |
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INIT_VLC_STATIC(&rl.vlc, TEX_VLC_BITS, rl.n + 2,\ |
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&rl.table_vlc[0][1], 4, 2,\ |
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&rl.table_vlc[0][0], 4, 2, static_size);\ |
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\ |
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rl.rl_vlc[0] = rl_vlc_table;\ |
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init_2d_vlc_rl(&rl);\ |
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} |
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static av_cold void init_2d_vlc_rl(RLTable *rl) |
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{ |
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int i; |
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for (i = 0; i < rl->vlc.table_size; i++) { |
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int code = rl->vlc.table[i][0]; |
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int len = rl->vlc.table[i][1]; |
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int level, run; |
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if (len == 0) { // illegal code |
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run = 65; |
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level = MAX_LEVEL; |
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} else if (len<0) { //more bits needed |
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run = 0; |
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level = code; |
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} else { |
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if (code == rl->n) { //esc |
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run = 65; |
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level = 0; |
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} else if (code == rl->n+1) { //eob |
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run = 0; |
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level = 127; |
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} else { |
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run = rl->table_run [code] + 1; |
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level = rl->table_level[code]; |
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} |
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} |
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rl->rl_vlc[0][i].len = len; |
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rl->rl_vlc[0][i].level = level; |
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rl->rl_vlc[0][i].run = run; |
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} |
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} |
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av_cold void ff_mpeg12_common_init(MpegEncContext *s) |
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{ |
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s->y_dc_scale_table = |
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s->c_dc_scale_table = ff_mpeg2_dc_scale_table[s->intra_dc_precision]; |
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} |
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void ff_mpeg1_clean_buffers(MpegEncContext *s) |
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{ |
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s->last_dc[0] = 1 << (7 + s->intra_dc_precision); |
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s->last_dc[1] = s->last_dc[0]; |
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s->last_dc[2] = s->last_dc[0]; |
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memset(s->last_mv, 0, sizeof(s->last_mv)); |
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} |
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/******************************************/ |
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/* decoding */ |
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VLC ff_mv_vlc; |
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VLC ff_dc_lum_vlc; |
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VLC ff_dc_chroma_vlc; |
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VLC ff_mbincr_vlc; |
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VLC ff_mb_ptype_vlc; |
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VLC ff_mb_btype_vlc; |
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VLC ff_mb_pat_vlc; |
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av_cold void ff_mpeg12_init_vlcs(void) |
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{ |
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static int done = 0; |
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if (!done) { |
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done = 1; |
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INIT_VLC_STATIC(&ff_dc_lum_vlc, DC_VLC_BITS, 12, |
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ff_mpeg12_vlc_dc_lum_bits, 1, 1, |
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ff_mpeg12_vlc_dc_lum_code, 2, 2, 512); |
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INIT_VLC_STATIC(&ff_dc_chroma_vlc, DC_VLC_BITS, 12, |
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ff_mpeg12_vlc_dc_chroma_bits, 1, 1, |
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ff_mpeg12_vlc_dc_chroma_code, 2, 2, 514); |
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INIT_VLC_STATIC(&ff_mv_vlc, MV_VLC_BITS, 17, |
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&ff_mpeg12_mbMotionVectorTable[0][1], 2, 1, |
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&ff_mpeg12_mbMotionVectorTable[0][0], 2, 1, 518); |
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INIT_VLC_STATIC(&ff_mbincr_vlc, MBINCR_VLC_BITS, 36, |
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&ff_mpeg12_mbAddrIncrTable[0][1], 2, 1, |
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&ff_mpeg12_mbAddrIncrTable[0][0], 2, 1, 538); |
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INIT_VLC_STATIC(&ff_mb_pat_vlc, MB_PAT_VLC_BITS, 64, |
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&ff_mpeg12_mbPatTable[0][1], 2, 1, |
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&ff_mpeg12_mbPatTable[0][0], 2, 1, 512); |
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INIT_VLC_STATIC(&ff_mb_ptype_vlc, MB_PTYPE_VLC_BITS, 7, |
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&table_mb_ptype[0][1], 2, 1, |
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&table_mb_ptype[0][0], 2, 1, 64); |
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INIT_VLC_STATIC(&ff_mb_btype_vlc, MB_BTYPE_VLC_BITS, 11, |
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&table_mb_btype[0][1], 2, 1, |
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&table_mb_btype[0][0], 2, 1, 64); |
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ff_init_rl(&ff_rl_mpeg1, ff_mpeg12_static_rl_table_store[0]); |
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ff_init_rl(&ff_rl_mpeg2, ff_mpeg12_static_rl_table_store[1]); |
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INIT_2D_VLC_RL(ff_rl_mpeg1, 680); |
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INIT_2D_VLC_RL(ff_rl_mpeg2, 674); |
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} |
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} |
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/** |
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* Find the end of the current frame in the bitstream. |
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* @return the position of the first byte of the next frame, or -1 |
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*/ |
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int ff_mpeg1_find_frame_end(ParseContext *pc, const uint8_t *buf, int buf_size, AVCodecParserContext *s) |
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{ |
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int i; |
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uint32_t state = pc->state; |
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/* EOF considered as end of frame */ |
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if (buf_size == 0) |
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return 0; |
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/* |
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0 frame start -> 1/4 |
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1 first_SEQEXT -> 0/2 |
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2 first field start -> 3/0 |
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3 second_SEQEXT -> 2/0 |
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4 searching end |
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*/ |
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for (i = 0; i < buf_size; i++) { |
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av_assert1(pc->frame_start_found >= 0 && pc->frame_start_found <= 4); |
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if (pc->frame_start_found & 1) { |
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if (state == EXT_START_CODE && (buf[i] & 0xF0) != 0x80) |
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pc->frame_start_found--; |
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else if (state == EXT_START_CODE + 2) { |
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if ((buf[i] & 3) == 3) |
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pc->frame_start_found = 0; |
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else |
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pc->frame_start_found = (pc->frame_start_found + 1) & 3; |
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} |
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state++; |
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} else { |
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i = avpriv_find_start_code(buf + i, buf + buf_size, &state) - buf - 1; |
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if (pc->frame_start_found == 0 && state >= SLICE_MIN_START_CODE && state <= SLICE_MAX_START_CODE) { |
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i++; |
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pc->frame_start_found = 4; |
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} |
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if (state == SEQ_END_CODE) { |
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pc->frame_start_found = 0; |
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pc->state=-1; |
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return i+1; |
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} |
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if (pc->frame_start_found == 2 && state == SEQ_START_CODE) |
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pc->frame_start_found = 0; |
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if (pc->frame_start_found < 4 && state == EXT_START_CODE) |
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pc->frame_start_found++; |
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if (pc->frame_start_found == 4 && (state & 0xFFFFFF00) == 0x100) { |
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if (state < SLICE_MIN_START_CODE || state > SLICE_MAX_START_CODE) { |
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pc->frame_start_found = 0; |
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pc->state = -1; |
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return i - 3; |
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} |
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} |
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if (pc->frame_start_found == 0 && s && state == PICTURE_START_CODE) { |
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ff_fetch_timestamp(s, i - 3, 1); |
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} |
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} |
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} |
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pc->state = state; |
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return END_NOT_FOUND; |
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} |
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