351 lines
11 KiB
C
351 lines
11 KiB
C
/*
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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 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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* 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 "h264data.h"
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#include "golomb.h"
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#include <assert.h>
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static 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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// 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==6 || 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 = -1;
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const uint8_t *ptr;
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/* set some sane default values */
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s->pict_type = AV_PICTURE_TYPE_I;
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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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h->sei_dpb_output_delay = 0;
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h->sei_cpb_removal_delay = -1;
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h->sei_buffering_period_present = 0;
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if (!buf_size)
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return 0;
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for(;;) {
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int src_length, dst_length, consumed;
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buf = avpriv_mpv_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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avctx->profile = ff_h264_get_profile(&h->sps);
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avctx->level = h->sps.level_idc;
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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 = 0;
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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 = 1;
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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 = 2;
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break;
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case SEI_PIC_STRUCT_FRAME_DOUBLING:
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s->repeat_pict = 3;
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break;
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case SEI_PIC_STRUCT_FRAME_TRIPLING:
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s->repeat_pict = 5;
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break;
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default:
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s->repeat_pict = h->s.picture_structure == PICT_FRAME ? 1 : 0;
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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 ? 1 : 0;
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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 (!h->got_first) {
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h->got_first = 1;
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if (avctx->extradata_size) {
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h->s.avctx = avctx;
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// must be done like in the decoder.
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// otherwise opening the parser, creating extradata,
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// and then closing and opening again
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// will cause has_b_frames to be always set.
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// NB: estimate_timings_from_pts behaves exactly like this.
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if (!avctx->has_b_frames)
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h->s.low_delay = 1;
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ff_h264_decode_extradata(h);
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}
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}
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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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}
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parse_nal_units(s, avctx, buf, buf_size);
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if (h->sei_cpb_removal_delay >= 0) {
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s->dts_sync_point = h->sei_buffering_period_present;
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s->dts_ref_dts_delta = h->sei_cpb_removal_delay;
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s->pts_dts_delta = h->sei_dpb_output_delay;
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} else {
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s->dts_sync_point = INT_MIN;
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s->dts_ref_dts_delta = INT_MIN;
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s->pts_dts_delta = INT_MIN;
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}
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if (s->flags & PARSER_FLAG_ONCE) {
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s->flags &= PARSER_FLAG_COMPLETE_FRAMES;
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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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ff_h264_free_context(h);
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}
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static int init(AVCodecParserContext *s)
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{
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H264Context *h = s->priv_data;
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h->thread_context[0] = h;
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h->s.slice_context_count = 1;
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return 0;
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}
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AVCodecParser ff_h264_parser = {
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.codec_ids = { AV_CODEC_ID_H264 },
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.priv_data_size = sizeof(H264Context),
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.parser_init = init,
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.parser_parse = h264_parse,
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.parser_close = close,
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.split = h264_split,
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};
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