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     return s;
  77 }
  78
  79 void ff_fetch_timestamp(AVCodecParserContext *s, int off, int remove){
  80     int i;
  81
  82     s->dts= s->pts= AV_NOPTS_VALUE;
  83     s->offset= 0;
  84     for(i = 0; i < AV_PARSER_PTS_NB; i++) {
  85         if (   s->next_frame_offset + off >= s->cur_frame_offset[i]
  86             &&(s->     frame_offset       <  s->cur_frame_offset[i] || !s->frame_offset)
  87             //check is disabled  becausue mpeg-ts doesnt send complete PES packets
  88             && /*s->next_frame_offset + off <*/  s->cur_frame_end[i]){
  89             s->dts= s->cur_frame_dts[i];
  90             s->pts= s->cur_frame_pts[i];
  91             s->offset = s->next_frame_offset - s->cur_frame_offset[i];
  92             if(remove)
  93                 s->cur_frame_offset[i]= INT64_MAX;
  94         }
  95     }
  96 }
  97
  98 /**
  99  *
 100  * @param buf           input
 101  * @param buf_size      input length, to signal EOF, this should be 0 (so that the last frame can be output)
 102  * @param pts           input presentation timestamp
 103  * @param dts           input decoding timestamp
 104  * @param poutbuf       will contain a pointer to the first byte of the output frame
 105  * @param poutbuf_size  will contain the length of the output frame
 106  * @return the number of bytes of the input bitstream used
 107  *
 108  * Example:
 109  * @code
 110  *   while(in_len){
 111  *       len = av_parser_parse(myparser, AVCodecContext, &data, &size,
 112  *                                       in_data, in_len,
 113  *                                       pts, dts);
 114  *       in_data += len;
 115  *       in_len  -= len;
 116  *
 117  *       if(size)
 118  *          decode_frame(data, size);
 119  *   }
 120  * @endcode
 121  */
 122 int av_parser_parse(AVCodecParserContext *s,
 123                     AVCodecContext *avctx,
 124                     uint8_t **poutbuf, int *poutbuf_size,
 125                     const uint8_t *buf, int buf_size,
 126                     int64_t pts, int64_t dts)
 127 {
 128     int index, i;
 129     uint8_t dummy_buf[FF_INPUT_BUFFER_PADDING_SIZE];
 130
 131     if (buf_size == 0) {
 132         /* padding is always necessary even if EOF, so we add it here */
 133         memset(dummy_buf, 0, sizeof(dummy_buf));
 134         buf = dummy_buf;
 135     } else {
 136         /* add a new packet descriptor */
 137         if(pts != AV_NOPTS_VALUE || dts != AV_NOPTS_VALUE){
 138             i = (s->cur_frame_start_index + 1) & (AV_PARSER_PTS_NB - 1);
 139             s->cur_frame_start_index = i;
 140             s->cur_frame_offset[i] = s->cur_offset;
 141             s->cur_frame_end[i] = s->cur_offset + buf_size;
 142             s->cur_frame_pts[i] = pts;
 143             s->cur_frame_dts[i] = dts;
 144         }
 145     }
 146
 147     if (s->fetch_timestamp){
 148         s->fetch_timestamp=0;
 149         s->last_pts = s->pts;
 150         s->last_dts = s->dts;
 151         ff_fetch_timestamp(s, 0, 0);
 152     }
 153
 154     /* WARNING: the returned index can be negative */
 155     index = s->parser->parser_parse(s, avctx, (const uint8_t **)poutbuf, poutbuf_size, buf, buf_size);
 156 //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);
 157     /* update the file pointer */
 158     if (*poutbuf_size) {
 159         /* fill the data for the current frame */
 160         s->frame_offset = s->next_frame_offset;
 161
 162         /* offset of the next frame */
 163         s->next_frame_offset = s->cur_offset + index;
 164         s->fetch_timestamp=1;
 165     }
 166     if (index < 0)
 167         index = 0;
 168     s->cur_offset += index;
 169     return index;
 170 }
 171
 172 /**
 173  *
 174  * @return 0 if the output buffer is a subset of the input, 1 if it is allocated and must be freed
 175  * @deprecated use AVBitstreamFilter
 176  */
 177 int av_parser_change(AVCodecParserContext *s,
 178                      AVCodecContext *avctx,
 179                      uint8_t **poutbuf, int *poutbuf_size,
 180                      const uint8_t *buf, int buf_size, int keyframe){
 181
 182     if(s && s->parser->split){
 183         if((avctx->flags & CODEC_FLAG_GLOBAL_HEADER) || (avctx->flags2 & CODEC_FLAG2_LOCAL_HEADER)){
 184             int i= s->parser->split(avctx, buf, buf_size);
 185             buf += i;
 186             buf_size -= i;
 187         }
 188     }
 189
 190     /* cast to avoid warning about discarding qualifiers */
 191     *poutbuf= (uint8_t *) buf;
 192     *poutbuf_size= buf_size;
 193     if(avctx->extradata){
 194         if(  (keyframe && (avctx->flags2 & CODEC_FLAG2_LOCAL_HEADER))
 195             /*||(s->pict_type != FF_I_TYPE && (s->flags & PARSER_FLAG_DUMP_EXTRADATA_AT_NOKEY))*/
 196             /*||(? && (s->flags & PARSER_FLAG_DUMP_EXTRADATA_AT_BEGIN)*/){
 197             int size= buf_size + avctx->extradata_size;
 198             *poutbuf_size= size;
 199             *poutbuf= av_malloc(size + FF_INPUT_BUFFER_PADDING_SIZE);
 200
 201             memcpy(*poutbuf, avctx->extradata, avctx->extradata_size);
 202             memcpy((*poutbuf) + avctx->extradata_size, buf, buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
 203             return 1;
 204         }
 205     }
 206
 207     return 0;
 208 }
 209
 210 void av_parser_close(AVCodecParserContext *s)
 211 {
 212     if(s){
 213         if (s->parser->parser_close)
 214             s->parser->parser_close(s);
 215         av_free(s->priv_data);
 216         av_free(s);
 217     }
 218 }
 219
 220 /*****************************************************/
 221
 222 /**
 223  * combines the (truncated) bitstream to a complete frame
 224  * @returns -1 if no complete frame could be created, AVERROR(ENOMEM) if there was a memory allocation error
 225  */
 226 int ff_combine_frame(ParseContext *pc, int next, const uint8_t **buf, int *buf_size)
 227 {
 228 #if 0
 229     if(pc->overread){
 230         printf("overread %d, state:%X next:%d index:%d o_index:%d\n", pc->overread, pc->state, next, pc->index, pc->overread_index);
 231         printf("%X %X %X %X\n", (*buf)[0], (*buf)[1],(*buf)[2],(*buf)[3]);
 232     }
 233 #endif
 234
 235     /* Copy overread bytes from last frame into buffer. */
 236     for(; pc->overread>0; pc->overread--){
 237         pc->buffer[pc->index++]= pc->buffer[pc->overread_index++];
 238     }
 239
 240     /* flush remaining if EOF */
 241     if(!*buf_size && next == END_NOT_FOUND){
 242         next= 0;
 243     }
 244
 245     pc->last_index= pc->index;
 246
 247     /* copy into buffer end return */
 248     if(next == END_NOT_FOUND){
 249         void* new_buffer = av_fast_realloc(pc->buffer, &pc->buffer_size, (*buf_size) + pc->index + FF_INPUT_BUFFER_PADDING_SIZE);
 250
 251         if(!new_buffer)
 252             return AVERROR(ENOMEM);
 253         pc->buffer = new_buffer;
 254         memcpy(&pc->buffer[pc->index], *buf, *buf_size);
 255         pc->index += *buf_size;
 256         return -1;
 257     }
 258
 259     *buf_size=
 260     pc->overread_index= pc->index + next;
 261
 262     /* append to buffer */
 263     if(pc->index){
 264         void* new_buffer = av_fast_realloc(pc->buffer, &pc->buffer_size, next + pc->index + FF_INPUT_BUFFER_PADDING_SIZE);
 265
 266         if(!new_buffer)
 267             return AVERROR(ENOMEM);
 268         pc->buffer = new_buffer;
 269         memcpy(&pc->buffer[pc->index], *buf, next + FF_INPUT_BUFFER_PADDING_SIZE );
 270         pc->index = 0;
 271         *buf= pc->buffer;
 272     }
 273
 274     /* store overread bytes */
 275     for(;next < 0; next++){
 276         pc->state = (pc->state<<8) | pc->buffer[pc->last_index + next];
 277         pc->state64 = (pc->state64<<8) | pc->buffer[pc->last_index + next];
 278         pc->overread++;
 279     }
 280
 281 #if 0
 282     if(pc->overread){
 283         printf("overread %d, state:%X next:%d index:%d o_index:%d\n", pc->overread, pc->state, next, pc->index, pc->overread_index);
 284         printf("%X %X %X %X\n", (*buf)[0], (*buf)[1],(*buf)[2],(*buf)[3]);
 285     }
 286 #endif
 287
 288     return 0;
 289 }
 290
 291 void ff_parse_close(AVCodecParserContext *s)
 292 {
 293     ParseContext *pc = s->priv_data;
 294
 295     av_freep(&pc->buffer);
 296 }
 297
 298 void ff_parse1_close(AVCodecParserContext *s)
 299 {
 300     ParseContext1 *pc1 = s->priv_data;
 301
 302     av_free(pc1->pc.buffer);
 303     av_free(pc1->enc);
 304 }
 305
 306 /*************************/
 307
 308 int ff_mpeg4video_split(AVCodecContext *avctx,
 309                            const uint8_t *buf, int buf_size)
 310 {
 311     int i;
 312     uint32_t state= -1;
 313
 314     for(i=0; i<buf_size; i++){
 315         state= (state<<8) | buf[i];
 316         if(state == 0x1B3 || state == 0x1B6)
 317             return i-3;
 318     }
 319     return 0;
 320 }