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https://github.com/FFmpeg/FFmpeg.git
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19e30a58fc
XvMC has long ago been superseded by newer acceleration APIs, such as VDPAU, and few downstreams still support it. Furthermore XvMC is not implemented within the hwaccel framework, but requires its own specific code in the MPEG-1/2 decoder, which is a maintenance burden.
239 lines
7.5 KiB
C
239 lines
7.5 KiB
C
/*
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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 Libav.
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*
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* Libav 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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* Libav 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 Libav; 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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#include "libavutil/attributes.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 "bytestream.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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static const uint8_t table_mb_ptype[7][2] = {
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{ 3, 5 }, // 0x01 MB_INTRA
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{ 1, 2 }, // 0x02 MB_PAT
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{ 1, 3 }, // 0x08 MB_FOR
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{ 1, 1 }, // 0x0A MB_FOR|MB_PAT
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{ 1, 6 }, // 0x11 MB_QUANT|MB_INTRA
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{ 1, 5 }, // 0x12 MB_QUANT|MB_PAT
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{ 2, 5 }, // 0x1A MB_QUANT|MB_FOR|MB_PAT
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};
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static const uint8_t table_mb_btype[11][2] = {
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{ 3, 5 }, // 0x01 MB_INTRA
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{ 2, 3 }, // 0x04 MB_BACK
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{ 3, 3 }, // 0x06 MB_BACK|MB_PAT
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{ 2, 4 }, // 0x08 MB_FOR
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{ 3, 4 }, // 0x0A MB_FOR|MB_PAT
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{ 2, 2 }, // 0x0C MB_FOR|MB_BACK
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{ 3, 2 }, // 0x0E MB_FOR|MB_BACK|MB_PAT
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{ 1, 6 }, // 0x11 MB_QUANT|MB_INTRA
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{ 2, 6 }, // 0x16 MB_QUANT|MB_BACK|MB_PAT
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{ 3, 6 }, // 0x1A MB_QUANT|MB_FOR|MB_PAT
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{ 2, 5 }, // 0x1E MB_QUANT|MB_FOR|MB_BACK|MB_PAT
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};
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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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assert(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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