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 FFmpeg.
   7  *
   8  * FFmpeg 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  * FFmpeg 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 FFmpeg; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  21  */
  22
  23 #include "parser.h"
  24
  25 static AVCodecParser *av_first_parser = NULL;
  26
  27 AVCodecParser* av_parser_next(AVCodecParser *p){
  28     if(p) return p->next;
  29     else  return av_first_parser;
  30 }
  31
  32 void av_register_codec_parser(AVCodecParser *parser)
  33 {
  34     parser->next = av_first_parser;
  35     av_first_parser = parser;
  36 }
  37
  38 AVCodecParserContext *av_parser_init(int codec_id)
  39 {
  40     AVCodecParserContext *s;
  41     AVCodecParser *parser;
  42     int ret;
  43
  44     if(codec_id == CODEC_ID_NONE)
  45         return NULL;
  46
  47     for(parser = av_first_parser; parser != NULL; parser = parser->next) {
  48         if (parser->codec_ids[0] == codec_id ||
  49             parser->codec_ids[1] == codec_id ||
  50             parser->codec_ids[2] == codec_id ||
  51             parser->codec_ids[3] == codec_id ||
  52             parser->codec_ids[4] == codec_id)
  53             goto found;
  54     }
  55     return NULL;
  56  found:
  57     s = av_mallocz(sizeof(AVCodecParserContext));
  58     if (!s)
  59         return NULL;
  60     s->parser = parser;
  61     s->priv_data = av_mallocz(parser->priv_data_size);
  62     if (!s->priv_data) {
  63         av_free(s);
  64         return NULL;
  65     }
  66     if (parser->parser_init) {
  67         ret = parser->parser_init(s);
  68         if (ret != 0) {
  69             av_free(s->priv_data);
  70             av_free(s);
  71             return NULL;
  72         }
  73     }
  74     s->fetch_timestamp=1;
  75     s->pict_type = FF_I_TYPE;
  76     s->key_frame = -1;
  77     s->convergence_duration = AV_NOPTS_VALUE;
  78     s->dts_sync_point       = INT_MIN;
  79     s->dts_ref_dts_delta    = INT_MIN;
  80     s->pts_dts_delta        = INT_MIN;
  81     return s;
  82 }
  83
  84 void ff_fetch_timestamp(AVCodecParserContext *s, int off, int remove){
  85     int i;
  86
  87     s->dts= s->pts= AV_NOPTS_VALUE;
  88     s->pos= -1;
  89     s->offset= 0;
  90     for(i = 0; i < AV_PARSER_PTS_NB; i++) {
  91         if (   s->cur_offset + off >= s->cur_frame_offset[i]
  92             &&(s->     frame_offset       <  s->cur_frame_offset[i] || !s->frame_offset)
  93             //check is disabled  becausue mpeg-ts doesnt send complete PES packets
  94             && /*s->next_frame_offset + off <*/  s->cur_frame_end[i]){
  95             s->dts= s->cur_frame_dts[i];
  96             s->pts= s->cur_frame_pts[i];
  97             s->pos= s->cur_frame_pos[i];
  98             s->offset = s->next_frame_offset - s->cur_frame_offset[i];
  99             if(remove)
 100                 s->cur_frame_offset[i]= INT64_MAX;
 101             if(s->cur_offset + off < s->cur_frame_end[i])
 102                 break;
 103         }
 104     }
 105 }
 106
 107 /**
 108  *
 109  * @param buf           input
 110  * @param buf_size      input length, to signal EOF, this should be 0 (so that the last frame can be output)
 111  * @param pts           input presentation timestamp
 112  * @param dts           input decoding timestamp
 113  * @param poutbuf       will contain a pointer to the first byte of the output frame
 114  * @param poutbuf_size  will contain the length of the output frame
 115  * @return the number of bytes of the input bitstream used
 116  *
 117  * Example:
 118  * @code
 119  *   while(in_len){
 120  *       len = av_parser_parse(myparser, AVCodecContext, &data, &size,
 121  *                                       in_data, in_len,
 122  *                                       pts, dts);
 123  *       in_data += len;
 124  *       in_len  -= len;
 125  *
 126  *       if(size)
 127  *          decode_frame(data, size);
 128  *   }
 129  * @endcode
 130  *
 131  * @deprecated Use av_parser_parse2() instead.
 132  */
 133 int av_parser_parse(AVCodecParserContext *s,
 134                     AVCodecContext *avctx,
 135                     uint8_t **poutbuf, int *poutbuf_size,
 136                     const uint8_t *buf, int buf_size,
 137                     int64_t pts, int64_t dts)
 138 {
 139     return av_parser_parse2(s, avctx, poutbuf, poutbuf_size, buf, buf_size, pts, dts, AV_NOPTS_VALUE);
 140 }
 141
 142 int av_parser_parse2(AVCodecParserContext *s,
 143                      AVCodecContext *avctx,
 144                      uint8_t **poutbuf, int *poutbuf_size,
 145                      const uint8_t *buf, int buf_size,
 146                      int64_t pts, int64_t dts,
 147                      int64_t pos)
 148 {
 149     int index, i;
 150     uint8_t dummy_buf[FF_INPUT_BUFFER_PADDING_SIZE];
 151
 152     if (buf_size == 0) {
 153         /* padding is always necessary even if EOF, so we add it here */
 154         memset(dummy_buf, 0, sizeof(dummy_buf));
 155         buf = dummy_buf;
 156     } else {
 157         /* add a new packet descriptor */
 158             i = (s->cur_frame_start_index + 1) & (AV_PARSER_PTS_NB - 1);
 159             s->cur_frame_start_index = i;
 160             s->cur_frame_offset[i] = s->cur_offset;
 161             s->cur_frame_end[i] = s->cur_offset + buf_size;
 162             s->cur_frame_pts[i] = pts;
 163             s->cur_frame_dts[i] = dts;
 164             s->cur_frame_pos[i] = pos;
 165     }
 166
 167     if (s->fetch_timestamp){
 168         s->fetch_timestamp=0;
 169         s->last_pts = s->pts;
 170         s->last_dts = s->dts;
 171         s->last_pos = s->pos;
 172         ff_fetch_timestamp(s, 0, 0);
 173     }
 174
 175     /* WARNING: the returned index can be negative */
 176     index = s->parser->parser_parse(s, avctx, (const uint8_t **)poutbuf, poutbuf_size, buf, buf_size);
 177 //av_log(NULL, AV_LOG_DEBUG, "parser: in:%"PRId64", %"PRId64", out:%"PRId64", %"PRId64", in:%d out:%d id:%d\n", pts, dts, s->last_pts, s->last_dts, buf_size, *poutbuf_size, avctx->codec_id);
 178     /* update the file pointer */
 179     if (*poutbuf_size) {
 180         /* fill the data for the current frame */
 181         s->frame_offset = s->next_frame_offset;
 182
 183         /* offset of the next frame */
 184         s->next_frame_offset = s->cur_offset + index;
 185         s->fetch_timestamp=1;
 186     }
 187     if (index < 0)
 188         index = 0;
 189     s->cur_offset += index;
 190     return index;
 191 }
 192
 193 /**
 194  *
 195  * @return 0 if the output buffer is a subset of the input, 1 if it is allocated and must be freed
 196  * @deprecated use AVBitstreamFilter
 197  */
 198 int av_parser_change(AVCodecParserContext *s,
 199                      AVCodecContext *avctx,
 200                      uint8_t **poutbuf, int *poutbuf_size,
 201                      const uint8_t *buf, int buf_size, int keyframe){
 202
 203     if(s && s->parser->split){
 204         if((avctx->flags & CODEC_FLAG_GLOBAL_HEADER) || (avctx->flags2 & CODEC_FLAG2_LOCAL_HEADER)){
 205             int i= s->parser->split(avctx, buf, buf_size);
 206             buf += i;
 207             buf_size -= i;
 208         }
 209     }
 210
 211     /* cast to avoid warning about discarding qualifiers */
 212     *poutbuf= (uint8_t *) buf;
 213     *poutbuf_size= buf_size;
 214     if(avctx->extradata){
 215         if(  (keyframe && (avctx->flags2 & CODEC_FLAG2_LOCAL_HEADER))
 216             /*||(s->pict_type != FF_I_TYPE && (s->flags & PARSER_FLAG_DUMP_EXTRADATA_AT_NOKEY))*/
 217             /*||(? && (s->flags & PARSER_FLAG_DUMP_EXTRADATA_AT_BEGIN)*/){
 218             int size= buf_size + avctx->extradata_size;
 219             *poutbuf_size= size;
 220             *poutbuf= av_malloc(size + FF_INPUT_BUFFER_PADDING_SIZE);
 221
 222             memcpy(*poutbuf, avctx->extradata, avctx->extradata_size);
 223             memcpy((*poutbuf) + avctx->extradata_size, buf, buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
 224             return 1;
 225         }
 226     }
 227
 228     return 0;
 229 }
 230
 231 void av_parser_close(AVCodecParserContext *s)
 232 {
 233     if(s){
 234         if (s->parser->parser_close)
 235             s->parser->parser_close(s);
 236         av_free(s->priv_data);
 237         av_free(s);
 238     }
 239 }
 240
 241 /*****************************************************/
 242
 243 /**
 244  * combines the (truncated) bitstream to a complete frame
 245  * @returns -1 if no complete frame could be created, AVERROR(ENOMEM) if there was a memory allocation error
 246  */
 247 int ff_combine_frame(ParseContext *pc, int next, const uint8_t **buf, int *buf_size)
 248 {
 249 #if 0
 250     if(pc->overread){
 251         printf("overread %d, state:%X next:%d index:%d o_index:%d\n", pc->overread, pc->state, next, pc->index, pc->overread_index);
 252         printf("%X %X %X %X\n", (*buf)[0], (*buf)[1],(*buf)[2],(*buf)[3]);
 253     }
 254 #endif
 255
 256     /* Copy overread bytes from last frame into buffer. */
 257     for(; pc->overread>0; pc->overread--){
 258         pc->buffer[pc->index++]= pc->buffer[pc->overread_index++];
 259     }
 260
 261     /* flush remaining if EOF */
 262     if(!*buf_size && next == END_NOT_FOUND){
 263         next= 0;
 264     }
 265
 266     pc->last_index= pc->index;
 267
 268     /* copy into buffer end return */
 269     if(next == END_NOT_FOUND){
 270         void* new_buffer = av_fast_realloc(pc->buffer, &pc->buffer_size, (*buf_size) + pc->index + FF_INPUT_BUFFER_PADDING_SIZE);
 271
 272         if(!new_buffer)
 273             return AVERROR(ENOMEM);
 274         pc->buffer = new_buffer;
 275         memcpy(&pc->buffer[pc->index], *buf, *buf_size);
 276         pc->index += *buf_size;
 277         return -1;
 278     }
 279
 280     *buf_size=
 281     pc->overread_index= pc->index + next;
 282
 283     /* append to buffer */
 284     if(pc->index){
 285         void* new_buffer = av_fast_realloc(pc->buffer, &pc->buffer_size, next + pc->index + FF_INPUT_BUFFER_PADDING_SIZE);
 286
 287         if(!new_buffer)
 288             return AVERROR(ENOMEM);
 289         pc->buffer = new_buffer;
 290         memcpy(&pc->buffer[pc->index], *buf, next + FF_INPUT_BUFFER_PADDING_SIZE );
 291         pc->index = 0;
 292         *buf= pc->buffer;
 293     }
 294
 295     /* store overread bytes */
 296     for(;next < 0; next++){
 297         pc->state = (pc->state<<8) | pc->buffer[pc->last_index + next];
 298         pc->state64 = (pc->state64<<8) | pc->buffer[pc->last_index + next];
 299         pc->overread++;
 300     }
 301
 302 #if 0
 303     if(pc->overread){
 304         printf("overread %d, state:%X next:%d index:%d o_index:%d\n", pc->overread, pc->state, next, pc->index, pc->overread_index);
 305         printf("%X %X %X %X\n", (*buf)[0], (*buf)[1],(*buf)[2],(*buf)[3]);
 306     }
 307 #endif
 308
 309     return 0;
 310 }
 311
 312 void ff_parse_close(AVCodecParserContext *s)
 313 {
 314     ParseContext *pc = s->priv_data;
 315
 316     av_freep(&pc->buffer);
 317 }
 318
 319 void ff_parse1_close(AVCodecParserContext *s)
 320 {
 321     ParseContext1 *pc1 = s->priv_data;
 322
 323     av_free(pc1->pc.buffer);
 324     av_free(pc1->enc);
 325 }
 326
 327 /*************************/
 328
 329 int ff_mpeg4video_split(AVCodecContext *avctx,
 330                            const uint8_t *buf, int buf_size)
 331 {
 332     int i;
 333     uint32_t state= -1;
 334
 335     for(i=0; i<buf_size; i++){
 336         state= (state<<8) | buf[i];
 337         if(state == 0x1B3 || state == 0x1B6)
 338             return i-3;
 339     }
 340     return 0;
 341 }