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 #ifdef HAVE_FAST_UNALIGNED
  48 #    ifdef HAVE_FAST_64BIT
  49             while(i<buf_size && !((~*(uint64_t*)(buf+i) & (*(uint64_t*)(buf+i) - 0x0101010101010101ULL)) & 0x8080808080808080ULL))
  50                 i+=8;
  51 #    else
  52             while(i<buf_size && !((~*(uint32_t*)(buf+i) & (*(uint32_t*)(buf+i) - 0x01010101U)) & 0x80808080U))
  53                 i+=4;
  54 #    endif
  55 #endif
  56             for(; i<buf_size; i++){
  57                 if(!buf[i]){
  58                     state=2;
  59                     break;
  60                 }
  61             }
  62         }else if(state<=2){
  63             if(buf[i]==1)   state^= 5; //2->7, 1->4, 0->5
  64             else if(buf[i]) state = 7;
  65             else            state>>=1; //2->1, 1->0, 0->0
  66         }else if(state<=5){
  67             int v= buf[i] & 0x1F;
  68             if(v==7 || v==8 || v==9){
  69                 if(pc->frame_start_found){
  70                     i++;
  71                     goto found;
  72                 }
  73             }else if(v==1 || v==2 || v==5){
  74                 if(pc->frame_start_found){
  75                     state+=8;
  76                     continue;
  77                 }else
  78                     pc->frame_start_found = 1;
  79             }
  80             state= 7;
  81         }else{
  82             if(buf[i] & 0x80)
  83                 goto found;
  84             state= 7;
  85         }
  86     }
  87     pc->state= state;
  88     return END_NOT_FOUND;
  89
  90 found:
  91     pc->state=7;
  92     pc->frame_start_found= 0;
  93     return i-(state&5);
  94 }
  95
  96 static int h264_parse(AVCodecParserContext *s,
  97                       AVCodecContext *avctx,
  98                       const uint8_t **poutbuf, int *poutbuf_size,
  99                       const uint8_t *buf, int buf_size)
 100 {
 101     H264Context *h = s->priv_data;
 102     ParseContext *pc = &h->s.parse_context;
 103     int next;
 104
 105     if(s->flags & PARSER_FLAG_COMPLETE_FRAMES){
 106         next= buf_size;
 107     }else{
 108         next= ff_h264_find_frame_end(h, buf, buf_size);
 109
 110         if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
 111             *poutbuf = NULL;
 112             *poutbuf_size = 0;
 113             return buf_size;
 114         }
 115
 116         if(next<0 && next != END_NOT_FOUND){
 117             assert(pc->last_index + next >= 0 );
 118             ff_h264_find_frame_end(h, &pc->buffer[pc->last_index + next], -next); //update state
 119         }
 120     }
 121
 122     *poutbuf = buf;
 123     *poutbuf_size = buf_size;
 124     return next;
 125 }
 126
 127 static int h264_split(AVCodecContext *avctx,
 128                       const uint8_t *buf, int buf_size)
 129 {
 130     int i;
 131     uint32_t state = -1;
 132     int has_sps= 0;
 133
 134     for(i=0; i<=buf_size; i++){
 135         if((state&0xFFFFFF1F) == 0x107)
 136             has_sps=1;
 137 /*        if((state&0xFFFFFF1F) == 0x101 || (state&0xFFFFFF1F) == 0x102 || (state&0xFFFFFF1F) == 0x105){
 138         }*/
 139         if((state&0xFFFFFF00) == 0x100 && (state&0xFFFFFF1F) != 0x107 && (state&0xFFFFFF1F) != 0x108 && (state&0xFFFFFF1F) != 0x109){
 140             if(has_sps){
 141                 while(i>4 && buf[i-5]==0) i--;
 142                 return i-4;
 143             }
 144         }
 145         if (i<buf_size)
 146             state= (state<<8) | buf[i];
 147     }
 148     return 0;
 149 }
 150
 151 static void close(AVCodecParserContext *s)
 152 {
 153     H264Context *h = s->priv_data;
 154     ParseContext *pc = &h->s.parse_context;
 155
 156     av_free(pc->buffer);
 157 }
 158
 159
 160 AVCodecParser h264_parser = {
 161     { CODEC_ID_H264 },
 162     sizeof(H264Context),
 163     NULL,
 164     h264_parse,
 165     close,
 166     h264_split,
 167 };