libavcodec/parser.c

   1 /*
   2  * Audio and Video frame extraction
   3  * Copyright (c) 2003 Fabrice Bellard
   4  * Copyright (c) 2003 Michael Niedermayer
   5  *
   6  * This file is part of Libav.
   7  *
   8  * Libav is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; either
  11  * version 2.1 of the License, or (at your option) any later version.
  12  *
  13  * Libav is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with Libav; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  21  */
  22
  23 #include <string.h>
  24
  25 #include "parser.h"
  26 #include "libavutil/mem.h"
  27
  28 static AVCodecParser *av_first_parser = NULL;
  29
  30 AVCodecParser* av_parser_next(AVCodecParser *p){
  31     if(p) return p->next;
  32     else  return av_first_parser;
  33 }
  34
  35 void av_register_codec_parser(AVCodecParser *parser)
  36 {
  37     parser->next = av_first_parser;
  38     av_first_parser = parser;
  39 }
  40
  41 AVCodecParserContext *av_parser_init(int codec_id)
  42 {
  43     AVCodecParserContext *s;
  44     AVCodecParser *parser;
  45     int ret;
  46
  47     if(codec_id == AV_CODEC_ID_NONE)
  48         return NULL;
  49
  50     for(parser = av_first_parser; parser != NULL; parser = parser->next) {
  51         if (parser->codec_ids[0] == codec_id ||
  52             parser->codec_ids[1] == codec_id ||
  53             parser->codec_ids[2] == codec_id ||
  54             parser->codec_ids[3] == codec_id ||
  55             parser->codec_ids[4] == codec_id)
  56             goto found;
  57     }
  58     return NULL;
  59  found:
  60     s = av_mallocz(sizeof(AVCodecParserContext));
  61     if (!s)
  62         return NULL;
  63     s->parser = parser;
  64     if (parser->priv_data_size) {
  65         s->priv_data = av_mallocz(parser->priv_data_size);
  66         if (!s->priv_data) {
  67             av_free(s);
  68             return NULL;
  69         }
  70     }
  71     if (parser->parser_init) {
  72         ret = parser->parser_init(s);
  73         if (ret != 0) {
  74             av_free(s->priv_data);
  75             av_free(s);
  76             return NULL;
  77         }
  78     }
  79     s->fetch_timestamp=1;
  80     s->pict_type = AV_PICTURE_TYPE_I;
  81     s->key_frame = -1;
  82     s->convergence_duration = 0;
  83     s->dts_sync_point       = INT_MIN;
  84     s->dts_ref_dts_delta    = INT_MIN;
  85     s->pts_dts_delta        = INT_MIN;
  86     return s;
  87 }
  88
  89 void ff_fetch_timestamp(AVCodecParserContext *s, int off, int remove){
  90     int i;
  91
  92     s->dts= s->pts= AV_NOPTS_VALUE;
  93     s->pos= -1;
  94     s->offset= 0;
  95     for(i = 0; i < AV_PARSER_PTS_NB; i++) {
  96         if (   s->cur_offset + off >= s->cur_frame_offset[i]
  97             && (s->frame_offset < s->cur_frame_offset[i] ||
  98               (!s->frame_offset && !s->next_frame_offset)) // first field/frame
  99             // check disabled since MPEG-TS does not send complete PES packets
 100             && /*s->next_frame_offset + off <*/  s->cur_frame_end[i]){
 101             s->dts= s->cur_frame_dts[i];
 102             s->pts= s->cur_frame_pts[i];
 103             s->pos= s->cur_frame_pos[i];
 104             s->offset = s->next_frame_offset - s->cur_frame_offset[i];
 105             if(remove)
 106                 s->cur_frame_offset[i]= INT64_MAX;
 107             if(s->cur_offset + off < s->cur_frame_end[i])
 108                 break;
 109         }
 110     }
 111 }
 112
 113 int av_parser_parse2(AVCodecParserContext *s,
 114                      AVCodecContext *avctx,
 115                      uint8_t **poutbuf, int *poutbuf_size,
 116                      const uint8_t *buf, int buf_size,
 117                      int64_t pts, int64_t dts,
 118                      int64_t pos)
 119 {
 120     int index, i;
 121     uint8_t dummy_buf[FF_INPUT_BUFFER_PADDING_SIZE];
 122
 123     if(!(s->flags & PARSER_FLAG_FETCHED_OFFSET)) {
 124         s->next_frame_offset =
 125         s->cur_offset        = pos;
 126         s->flags |= PARSER_FLAG_FETCHED_OFFSET;
 127     }
 128
 129     if (buf_size == 0) {
 130         /* padding is always necessary even if EOF, so we add it here */
 131         memset(dummy_buf, 0, sizeof(dummy_buf));
 132         buf = dummy_buf;
 133     } else if (s->cur_offset + buf_size !=
 134                s->cur_frame_end[s->cur_frame_start_index]) { /* skip remainder packets */
 135         /* add a new packet descriptor */
 136             i = (s->cur_frame_start_index + 1) & (AV_PARSER_PTS_NB - 1);
 137             s->cur_frame_start_index = i;
 138             s->cur_frame_offset[i] = s->cur_offset;
 139             s->cur_frame_end[i] = s->cur_offset + buf_size;
 140             s->cur_frame_pts[i] = pts;
 141             s->cur_frame_dts[i] = dts;
 142             s->cur_frame_pos[i] = pos;
 143     }
 144
 145     if (s->fetch_timestamp){
 146         s->fetch_timestamp=0;
 147         s->last_pts = s->pts;
 148         s->last_dts = s->dts;
 149         s->last_pos = s->pos;
 150         ff_fetch_timestamp(s, 0, 0);
 151     }
 152
 153     /* WARNING: the returned index can be negative */
 154     index = s->parser->parser_parse(s, avctx, (const uint8_t **)poutbuf, poutbuf_size, buf, buf_size);
 155     /* update the file pointer */
 156     if (*poutbuf_size) {
 157         /* fill the data for the current frame */
 158         s->frame_offset = s->next_frame_offset;
 159
 160         /* offset of the next frame */
 161         s->next_frame_offset = s->cur_offset + index;
 162         s->fetch_timestamp=1;
 163     }
 164     if (index < 0)
 165         index = 0;
 166     s->cur_offset += index;
 167     return index;
 168 }
 169
 170 int av_parser_change(AVCodecParserContext *s,
 171                      AVCodecContext *avctx,
 172                      uint8_t **poutbuf, int *poutbuf_size,
 173                      const uint8_t *buf, int buf_size, int keyframe){
 174
 175     if(s && s->parser->split){
 176         if((avctx->flags & CODEC_FLAG_GLOBAL_HEADER) || (avctx->flags2 & CODEC_FLAG2_LOCAL_HEADER)){
 177             int i= s->parser->split(avctx, buf, buf_size);
 178             buf += i;
 179             buf_size -= i;
 180         }
 181     }
 182
 183     /* cast to avoid warning about discarding qualifiers */
 184     *poutbuf= (uint8_t *) buf;
 185     *poutbuf_size= buf_size;
 186     if(avctx->extradata){
 187         if(  (keyframe && (avctx->flags2 & CODEC_FLAG2_LOCAL_HEADER))
 188             /*||(s->pict_type != AV_PICTURE_TYPE_I && (s->flags & PARSER_FLAG_DUMP_EXTRADATA_AT_NOKEY))*/
 189             /*||(? && (s->flags & PARSER_FLAG_DUMP_EXTRADATA_AT_BEGIN)*/){
 190             int size= buf_size + avctx->extradata_size;
 191             *poutbuf_size= size;
 192             *poutbuf= av_malloc(size + FF_INPUT_BUFFER_PADDING_SIZE);
 193
 194             memcpy(*poutbuf, avctx->extradata, avctx->extradata_size);
 195             memcpy((*poutbuf) + avctx->extradata_size, buf, buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
 196             return 1;
 197         }
 198     }
 199
 200     return 0;
 201 }
 202
 203 void av_parser_close(AVCodecParserContext *s)
 204 {
 205     if(s){
 206         if (s->parser->parser_close)
 207             s->parser->parser_close(s);
 208         av_free(s->priv_data);
 209         av_free(s);
 210     }
 211 }
 212
 213 /*****************************************************/
 214
 215 int ff_combine_frame(ParseContext *pc, int next, const uint8_t **buf, int *buf_size)
 216 {
 217     if(pc->overread){
 218         av_dlog(NULL, "overread %d, state:%X next:%d index:%d o_index:%d\n",
 219                 pc->overread, pc->state, next, pc->index, pc->overread_index);
 220         av_dlog(NULL, "%X %X %X %X\n", (*buf)[0], (*buf)[1], (*buf)[2], (*buf)[3]);
 221     }
 222
 223     /* Copy overread bytes from last frame into buffer. */
 224     for(; pc->overread>0; pc->overread--){
 225         pc->buffer[pc->index++]= pc->buffer[pc->overread_index++];
 226     }
 227
 228     /* flush remaining if EOF */
 229     if(!*buf_size && next == END_NOT_FOUND){
 230         next= 0;
 231     }
 232
 233     pc->last_index= pc->index;
 234
 235     /* copy into buffer end return */
 236     if(next == END_NOT_FOUND){
 237         void* new_buffer = av_fast_realloc(pc->buffer, &pc->buffer_size, (*buf_size) + pc->index + FF_INPUT_BUFFER_PADDING_SIZE);
 238
 239         if(!new_buffer)
 240             return AVERROR(ENOMEM);
 241         pc->buffer = new_buffer;
 242         memcpy(&pc->buffer[pc->index], *buf, *buf_size);
 243         pc->index += *buf_size;
 244         return -1;
 245     }
 246
 247     *buf_size=
 248     pc->overread_index= pc->index + next;
 249
 250     /* append to buffer */
 251     if(pc->index){
 252         void* new_buffer = av_fast_realloc(pc->buffer, &pc->buffer_size, next + pc->index + FF_INPUT_BUFFER_PADDING_SIZE);
 253
 254         if(!new_buffer)
 255             return AVERROR(ENOMEM);
 256         pc->buffer = new_buffer;
 257         if (next > -FF_INPUT_BUFFER_PADDING_SIZE)
 258             memcpy(&pc->buffer[pc->index], *buf,
 259                    next + FF_INPUT_BUFFER_PADDING_SIZE);
 260         pc->index = 0;
 261         *buf= pc->buffer;
 262     }
 263
 264     /* store overread bytes */
 265     for(;next < 0; next++){
 266         pc->state = (pc->state<<8) | pc->buffer[pc->last_index + next];
 267         pc->state64 = (pc->state64<<8) | pc->buffer[pc->last_index + next];
 268         pc->overread++;
 269     }
 270
 271     if(pc->overread){
 272         av_dlog(NULL, "overread %d, state:%X next:%d index:%d o_index:%d\n",
 273                 pc->overread, pc->state, next, pc->index, pc->overread_index);
 274         av_dlog(NULL, "%X %X %X %X\n", (*buf)[0], (*buf)[1],(*buf)[2],(*buf)[3]);
 275     }
 276
 277     return 0;
 278 }
 279
 280 void ff_parse_close(AVCodecParserContext *s)
 281 {
 282     ParseContext *pc = s->priv_data;
 283
 284     av_freep(&pc->buffer);
 285 }
 286
 287 /*************************/
 288
 289 int ff_mpeg4video_split(AVCodecContext *avctx,
 290                            const uint8_t *buf, int buf_size)
 291 {
 292     int i;
 293     uint32_t state= -1;
 294
 295     for(i=0; i<buf_size; i++){
 296         state= (state<<8) | buf[i];
 297         if(state == 0x1B3 || state == 0x1B6)
 298             return i-3;
 299     }
 300     return 0;
 301 }