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 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         i = (s->cur_frame_start_index + 1) & (AV_PARSER_PTS_NB - 1);
 138         s->cur_frame_start_index = i;
 139         s->cur_frame_offset[i] = s->cur_offset;
 140         s->cur_frame_end[i] = s->cur_offset + buf_size;
 141         s->cur_frame_pts[i] = pts;
 142         s->cur_frame_dts[i] = dts;
 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         ff_fetch_timestamp(s, 0, 0);
 150     }
 151
 152     /* WARNING: the returned index can be negative */
 153     index = s->parser->parser_parse(s, avctx, (const uint8_t **)poutbuf, poutbuf_size, buf, buf_size);
 154 //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);
 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 /**
 171  *
 172  * @return 0 if the output buffer is a subset of the input, 1 if it is allocated and must be freed
 173  * @deprecated use AVBitstreamFilter
 174  */
 175 int av_parser_change(AVCodecParserContext *s,
 176                      AVCodecContext *avctx,
 177                      uint8_t **poutbuf, int *poutbuf_size,
 178                      const uint8_t *buf, int buf_size, int keyframe){
 179
 180     if(s && s->parser->split){
 181         if((avctx->flags & CODEC_FLAG_GLOBAL_HEADER) || (avctx->flags2 & CODEC_FLAG2_LOCAL_HEADER)){
 182             int i= s->parser->split(avctx, buf, buf_size);
 183             buf += i;
 184             buf_size -= i;
 185         }
 186     }
 187
 188     /* cast to avoid warning about discarding qualifiers */
 189     *poutbuf= (uint8_t *) buf;
 190     *poutbuf_size= buf_size;
 191     if(avctx->extradata){
 192         if(  (keyframe && (avctx->flags2 & CODEC_FLAG2_LOCAL_HEADER))
 193             /*||(s->pict_type != FF_I_TYPE && (s->flags & PARSER_FLAG_DUMP_EXTRADATA_AT_NOKEY))*/
 194             /*||(? && (s->flags & PARSER_FLAG_DUMP_EXTRADATA_AT_BEGIN)*/){
 195             int size= buf_size + avctx->extradata_size;
 196             *poutbuf_size= size;
 197             *poutbuf= av_malloc(size + FF_INPUT_BUFFER_PADDING_SIZE);
 198
 199             memcpy(*poutbuf, avctx->extradata, avctx->extradata_size);
 200             memcpy((*poutbuf) + avctx->extradata_size, buf, buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
 201             return 1;
 202         }
 203     }
 204
 205     return 0;
 206 }
 207
 208 void av_parser_close(AVCodecParserContext *s)
 209 {
 210     if(s){
 211         if (s->parser->parser_close)
 212             s->parser->parser_close(s);
 213         av_free(s->priv_data);
 214         av_free(s);
 215     }
 216 }
 217
 218 /*****************************************************/
 219
 220 /**
 221  * combines the (truncated) bitstream to a complete frame
 222  * @returns -1 if no complete frame could be created, AVERROR(ENOMEM) if there was a memory allocation error
 223  */
 224 int ff_combine_frame(ParseContext *pc, int next, const uint8_t **buf, int *buf_size)
 225 {
 226 #if 0
 227     if(pc->overread){
 228         printf("overread %d, state:%X next:%d index:%d o_index:%d\n", pc->overread, pc->state, next, pc->index, pc->overread_index);
 229         printf("%X %X %X %X\n", (*buf)[0], (*buf)[1],(*buf)[2],(*buf)[3]);
 230     }
 231 #endif
 232
 233     /* Copy overread bytes from last frame into buffer. */
 234     for(; pc->overread>0; pc->overread--){
 235         pc->buffer[pc->index++]= pc->buffer[pc->overread_index++];
 236     }
 237
 238     /* flush remaining if EOF */
 239     if(!*buf_size && next == END_NOT_FOUND){
 240         next= 0;
 241     }
 242
 243     pc->last_index= pc->index;
 244
 245     /* copy into buffer end return */
 246     if(next == END_NOT_FOUND){
 247         void* new_buffer = av_fast_realloc(pc->buffer, &pc->buffer_size, (*buf_size) + pc->index + FF_INPUT_BUFFER_PADDING_SIZE);
 248
 249         if(!new_buffer)
 250             return AVERROR(ENOMEM);
 251         pc->buffer = new_buffer;
 252         memcpy(&pc->buffer[pc->index], *buf, *buf_size);
 253         pc->index += *buf_size;
 254         return -1;
 255     }
 256
 257     *buf_size=
 258     pc->overread_index= pc->index + next;
 259
 260     /* append to buffer */
 261     if(pc->index){
 262         void* new_buffer = av_fast_realloc(pc->buffer, &pc->buffer_size, next + pc->index + FF_INPUT_BUFFER_PADDING_SIZE);
 263
 264         if(!new_buffer)
 265             return AVERROR(ENOMEM);
 266         pc->buffer = new_buffer;
 267         memcpy(&pc->buffer[pc->index], *buf, next + FF_INPUT_BUFFER_PADDING_SIZE );
 268         pc->index = 0;
 269         *buf= pc->buffer;
 270     }
 271
 272     /* store overread bytes */
 273     for(;next < 0; next++){
 274         pc->state = (pc->state<<8) | pc->buffer[pc->last_index + next];
 275         pc->overread++;
 276     }
 277
 278 #if 0
 279     if(pc->overread){
 280         printf("overread %d, state:%X next:%d index:%d o_index:%d\n", pc->overread, pc->state, next, pc->index, pc->overread_index);
 281         printf("%X %X %X %X\n", (*buf)[0], (*buf)[1],(*buf)[2],(*buf)[3]);
 282     }
 283 #endif
 284
 285     return 0;
 286 }
 287
 288 void ff_parse_close(AVCodecParserContext *s)
 289 {
 290     ParseContext *pc = s->priv_data;
 291
 292     av_free(pc->buffer);
 293 }
 294
 295 void ff_parse1_close(AVCodecParserContext *s)
 296 {
 297     ParseContext1 *pc1 = s->priv_data;
 298
 299     av_free(pc1->pc.buffer);
 300     av_free(pc1->enc);
 301 }
 302
 303 /*************************/
 304
 305 int ff_mpeg4video_split(AVCodecContext *avctx,
 306                            const uint8_t *buf, int buf_size)
 307 {
 308     int i;
 309     uint32_t state= -1;
 310
 311     for(i=0; i<buf_size; i++){
 312         state= (state<<8) | buf[i];
 313         if(state == 0x1B3 || state == 0x1B6)
 314             return i-3;
 315     }
 316     return 0;
 317 }