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ffmpeg / libavcodec / h264_parser.c @ 26b4fe82

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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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/**
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 * @file 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 <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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            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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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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            }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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}
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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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    }
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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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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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    ff_parse_close,
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    h264_split,
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};