libavcodec/h264_parser.c

   1 /*
   2  * H.26L/H.264/AVC/JVT/14496-10/... parser
   3  * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
   4  *
   5  * This file is part of FFmpeg.
   6  *
   7  * FFmpeg is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * FFmpeg is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with FFmpeg; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 /**
  23  * @file h264_parser.c
  24  * H.264 / AVC / MPEG4 part10 parser.
  25  * @author Michael Niedermayer <michaelni@gmx.at>
  26  */
  27
  28 #include "parser.h"
  29 #include "h264_parser.h"
  30
  31 #include <assert.h>
  32
  33
  34 int ff_h264_find_frame_end(H264Context *h, const uint8_t *buf, int buf_size)
  35 {
  36     int i;
  37     uint32_t state;
  38     ParseContext *pc = &(h->s.parse_context);
  39 //printf("first %02X%02X%02X%02X\n", buf[0], buf[1],buf[2],buf[3]);
  40 //    mb_addr= pc->mb_addr - 1;
  41     state= pc->state;
  42     if(state>13)
  43         state= 7;
  44
  45     for(i=0; i<buf_size; i++){
  46         if(state==7){
  47             for(; i<buf_size; i++){
  48                 if(!buf[i]){
  49                     state=2;
  50                     break;
  51                 }
  52             }
  53         }else if(state<=2){
  54             if(buf[i]==1)   state^= 5; //2->7, 1->4, 0->5
  55             else if(buf[i]) state = 7;
  56             else            state>>=1; //2->1, 1->0, 0->0
  57         }else if(state<=5){
  58             int v= buf[i] & 0x1F;
  59             if(v==7 || v==8 || v==9){
  60                 if(pc->frame_start_found){
  61                     i++;
  62 found:
  63                     pc->state=7;
  64                     pc->frame_start_found= 0;
  65                     return i-(state&5);
  66                 }
  67             }else if(v==1 || v==2 || v==5){
  68                 if(pc->frame_start_found){
  69                     state+=8;
  70                     continue;
  71                 }else
  72                     pc->frame_start_found = 1;
  73             }
  74             state= 7;
  75         }else{
  76             if(buf[i] & 0x80)
  77                 goto found;
  78             state= 7;
  79         }
  80     }
  81     pc->state= state;
  82     return END_NOT_FOUND;
  83 }
  84
  85 static int h264_parse(AVCodecParserContext *s,
  86                       AVCodecContext *avctx,
  87                       const uint8_t **poutbuf, int *poutbuf_size,
  88                       const uint8_t *buf, int buf_size)
  89 {
  90     H264Context *h = s->priv_data;
  91     ParseContext *pc = &h->s.parse_context;
  92     int next;
  93
  94     if(s->flags & PARSER_FLAG_COMPLETE_FRAMES){
  95         next= buf_size;
  96     }else{
  97         next= ff_h264_find_frame_end(h, buf, buf_size);
  98
  99         if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
 100             *poutbuf = NULL;
 101             *poutbuf_size = 0;
 102             return buf_size;
 103         }
 104
 105         if(next<0 && next != END_NOT_FOUND){
 106             assert(pc->last_index + next >= 0 );
 107             ff_h264_find_frame_end(h, &pc->buffer[pc->last_index + next], -next); //update state
 108         }
 109     }
 110
 111     *poutbuf = buf;
 112     *poutbuf_size = buf_size;
 113     return next;
 114 }
 115
 116 static int h264_split(AVCodecContext *avctx,
 117                       const uint8_t *buf, int buf_size)
 118 {
 119     int i;
 120     uint32_t state = -1;
 121     int has_sps= 0;
 122
 123     for(i=0; i<=buf_size; i++){
 124         if((state&0xFFFFFF1F) == 0x107)
 125             has_sps=1;
 126 /*        if((state&0xFFFFFF1F) == 0x101 || (state&0xFFFFFF1F) == 0x102 || (state&0xFFFFFF1F) == 0x105){
 127         }*/
 128         if((state&0xFFFFFF00) == 0x100 && (state&0xFFFFFF1F) != 0x107 && (state&0xFFFFFF1F) != 0x108 && (state&0xFFFFFF1F) != 0x109){
 129             if(has_sps){
 130                 while(i>4 && buf[i-5]==0) i--;
 131                 return i-4;
 132             }
 133         }
 134         if (i<buf_size)
 135             state= (state<<8) | buf[i];
 136     }
 137     return 0;
 138 }
 139
 140
 141 AVCodecParser h264_parser = {
 142     { CODEC_ID_H264 },
 143     sizeof(H264Context),
 144     NULL,
 145     h264_parse,
 146     ff_parse_close,
 147     h264_split,
 148 };