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ffmpeg / libavcodec / h264_parser.c @ 346db3ef

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/*
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 * H.26L/H.264/AVC/JVT/14496-10/... parser
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 * Copyright (c) 2003 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 libavcodec/h264_parser.c
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 * H.264 / AVC / MPEG4 part10 parser.
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 * @author Michael Niedermayer <michaelni@gmx.at>
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 */
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#include "parser.h"
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#include "h264_parser.h"
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#include "h264data.h"
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#include "golomb.h"
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#include <assert.h>
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int ff_h264_find_frame_end(H264Context *h, const uint8_t *buf, int buf_size)
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{
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    int i;
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    uint32_t state;
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    ParseContext *pc = &(h->s.parse_context);
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//printf("first %02X%02X%02X%02X\n", buf[0], buf[1],buf[2],buf[3]);
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//    mb_addr= pc->mb_addr - 1;
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    state= pc->state;
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    if(state>13)
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        state= 7;
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    for(i=0; i<buf_size; i++){
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        if(state==7){
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#if HAVE_FAST_UNALIGNED
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        /* we check i<buf_size instead of i+3/7 because its simpler
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         * and there should be FF_INPUT_BUFFER_PADDING_SIZE bytes at the end
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         */
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#    if HAVE_FAST_64BIT
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            while(i<buf_size && !((~*(const uint64_t*)(buf+i) & (*(const uint64_t*)(buf+i) - 0x0101010101010101ULL)) & 0x8080808080808080ULL))
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                i+=8;
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#    else
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            while(i<buf_size && !((~*(const uint32_t*)(buf+i) & (*(const uint32_t*)(buf+i) - 0x01010101U)) & 0x80808080U))
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                i+=4;
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#    endif
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#endif
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            for(; i<buf_size; i++){
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                if(!buf[i]){
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                    state=2;
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                    break;
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                }
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            }
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        }else if(state<=2){
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            if(buf[i]==1)   state^= 5; //2->7, 1->4, 0->5
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            else if(buf[i]) state = 7;
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            else            state>>=1; //2->1, 1->0, 0->0
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        }else if(state<=5){
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            int v= buf[i] & 0x1F;
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            if(v==7 || v==8 || v==9){
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                if(pc->frame_start_found){
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                    i++;
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                    goto found;
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                }
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            }else if(v==1 || v==2 || v==5){
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                if(pc->frame_start_found){
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                    state+=8;
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                    continue;
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                }else
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                    pc->frame_start_found = 1;
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            }
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            state= 7;
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        }else{
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            if(buf[i] & 0x80)
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                goto found;
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            state= 7;
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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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found:
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    pc->state=7;
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    pc->frame_start_found= 0;
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    return i-(state&5);
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}
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/*!
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 * Parse NAL units of found picture and decode some basic information.
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 *
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 * @param s parser context.
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 * @param avctx codec context.
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 * @param buf buffer with field/frame data.
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 * @param buf_size size of the buffer.
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 */
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static inline int parse_nal_units(AVCodecParserContext *s,
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                                  AVCodecContext *avctx,
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                                  const uint8_t *buf, int buf_size)
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{
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    H264Context *h = s->priv_data;
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    const uint8_t *buf_end = buf + buf_size;
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    unsigned int pps_id;
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    unsigned int slice_type;
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    int state;
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    const uint8_t *ptr;
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    /* set some sane default values */
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    s->pict_type = FF_I_TYPE;
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    s->key_frame = 0;
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    h->s.avctx= avctx;
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    h->sei_recovery_frame_cnt = -1;
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    for(;;) {
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        int src_length, dst_length, consumed;
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        buf = ff_find_start_code(buf, buf_end, &state);
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        if(buf >= buf_end)
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            break;
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        --buf;
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        src_length = buf_end - buf;
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        switch (state & 0x1f) {
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        case NAL_SLICE:
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        case NAL_IDR_SLICE:
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            // Do not walk the whole buffer just to decode slice header
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            if (src_length > 20)
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                src_length = 20;
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            break;
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        }
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        ptr= ff_h264_decode_nal(h, buf, &dst_length, &consumed, src_length);
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        if (ptr==NULL || dst_length < 0)
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            break;
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        init_get_bits(&h->s.gb, ptr, 8*dst_length);
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        switch(h->nal_unit_type) {
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        case NAL_SPS:
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            ff_h264_decode_seq_parameter_set(h);
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            break;
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        case NAL_PPS:
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            ff_h264_decode_picture_parameter_set(h, h->s.gb.size_in_bits);
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            break;
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        case NAL_SEI:
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            ff_h264_decode_sei(h);
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            break;
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        case NAL_IDR_SLICE:
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            s->key_frame = 1;
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            /* fall through */
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        case NAL_SLICE:
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            get_ue_golomb(&h->s.gb);  // skip first_mb_in_slice
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            slice_type = get_ue_golomb_31(&h->s.gb);
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            s->pict_type = golomb_to_pict_type[slice_type % 5];
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            if (h->sei_recovery_frame_cnt >= 0) {
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                /* key frame, since recovery_frame_cnt is set */
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                s->key_frame = 1;
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            }
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            pps_id= get_ue_golomb(&h->s.gb);
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            if(pps_id>=MAX_PPS_COUNT) {
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                av_log(h->s.avctx, AV_LOG_ERROR, "pps_id out of range\n");
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                return -1;
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            }
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            if(!h->pps_buffers[pps_id]) {
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                av_log(h->s.avctx, AV_LOG_ERROR, "non-existing PPS referenced\n");
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                return -1;
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            }
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            h->pps= *h->pps_buffers[pps_id];
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            if(!h->sps_buffers[h->pps.sps_id]) {
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                av_log(h->s.avctx, AV_LOG_ERROR, "non-existing SPS referenced\n");
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                return -1;
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            }
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            h->sps = *h->sps_buffers[h->pps.sps_id];
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            h->frame_num = get_bits(&h->s.gb, h->sps.log2_max_frame_num);
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            if(h->sps.frame_mbs_only_flag){
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                h->s.picture_structure= PICT_FRAME;
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            }else{
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                if(get_bits1(&h->s.gb)) { //field_pic_flag
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                    h->s.picture_structure= PICT_TOP_FIELD + get_bits1(&h->s.gb); //bottom_field_flag
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                } else {
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                    h->s.picture_structure= PICT_FRAME;
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                }
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            }
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            if(h->sps.pic_struct_present_flag) {
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                switch (h->sei_pic_struct) {
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                    case SEI_PIC_STRUCT_TOP_FIELD:
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                    case SEI_PIC_STRUCT_BOTTOM_FIELD:
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                        s->repeat_pict = -1;
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                        break;
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                    case SEI_PIC_STRUCT_FRAME:
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                    case SEI_PIC_STRUCT_TOP_BOTTOM:
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                    case SEI_PIC_STRUCT_BOTTOM_TOP:
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                        s->repeat_pict = 0;
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                        break;
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                    case SEI_PIC_STRUCT_TOP_BOTTOM_TOP:
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                    case SEI_PIC_STRUCT_BOTTOM_TOP_BOTTOM:
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                        s->repeat_pict = 1;
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                        break;
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                    case SEI_PIC_STRUCT_FRAME_DOUBLING:
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                        s->repeat_pict = 2;
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                        break;
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                    case SEI_PIC_STRUCT_FRAME_TRIPLING:
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                        s->repeat_pict = 4;
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                        break;
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                    default:
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                        s->repeat_pict = h->s.picture_structure == PICT_FRAME ? 0 : -1;
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                        break;
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                }
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            } else {
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                s->repeat_pict = h->s.picture_structure == PICT_FRAME ? 0 : -1;
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            }
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            return 0; /* no need to evaluate the rest */
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        }
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        buf += consumed;
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    }
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    /* didn't find a picture! */
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    av_log(h->s.avctx, AV_LOG_ERROR, "missing picture in access unit\n");
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    return -1;
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}
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static int h264_parse(AVCodecParserContext *s,
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                      AVCodecContext *avctx,
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                      const uint8_t **poutbuf, int *poutbuf_size,
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                      const uint8_t *buf, int buf_size)
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{
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    H264Context *h = s->priv_data;
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    ParseContext *pc = &h->s.parse_context;
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    int next;
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    if(s->flags & PARSER_FLAG_COMPLETE_FRAMES){
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        next= buf_size;
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    }else{
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        next= ff_h264_find_frame_end(h, buf, buf_size);
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        if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
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            *poutbuf = NULL;
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            *poutbuf_size = 0;
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            return buf_size;
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        }
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        if(next<0 && next != END_NOT_FOUND){
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            assert(pc->last_index + next >= 0 );
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            ff_h264_find_frame_end(h, &pc->buffer[pc->last_index + next], -next); //update state
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        }
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        parse_nal_units(s, avctx, buf, buf_size);
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    }
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    *poutbuf = buf;
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    *poutbuf_size = buf_size;
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    return next;
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}
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static int h264_split(AVCodecContext *avctx,
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                      const uint8_t *buf, int buf_size)
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{
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    int i;
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    uint32_t state = -1;
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    int has_sps= 0;
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    for(i=0; i<=buf_size; i++){
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        if((state&0xFFFFFF1F) == 0x107)
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            has_sps=1;
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/*        if((state&0xFFFFFF1F) == 0x101 || (state&0xFFFFFF1F) == 0x102 || (state&0xFFFFFF1F) == 0x105){
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        }*/
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        if((state&0xFFFFFF00) == 0x100 && (state&0xFFFFFF1F) != 0x107 && (state&0xFFFFFF1F) != 0x108 && (state&0xFFFFFF1F) != 0x109){
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            if(has_sps){
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                while(i>4 && buf[i-5]==0) i--;
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                return i-4;
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            }
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        }
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        if (i<buf_size)
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            state= (state<<8) | buf[i];
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    }
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    return 0;
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}
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static void close(AVCodecParserContext *s)
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{
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    H264Context *h = s->priv_data;
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    ParseContext *pc = &h->s.parse_context;
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    av_free(pc->buffer);
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}
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AVCodecParser h264_parser = {
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    { CODEC_ID_H264 },
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    sizeof(H264Context),
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    NULL,
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    h264_parse,
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    close,
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    h264_split,
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};