libavcodec/aac_ac3_parser.c

   1 /*
   2  * Common AAC and AC3 parser
   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 #include "aac_ac3_parser.h"
  25
  26 int ff_aac_ac3_parse(AVCodecParserContext *s1,
  27                      AVCodecContext *avctx,
  28                      const uint8_t **poutbuf, int *poutbuf_size,
  29                      const uint8_t *buf, int buf_size)
  30 {
  31     AACAC3ParseContext *s = s1->priv_data;
  32     const uint8_t *buf_ptr;
  33     int len, sample_rate, bit_rate, channels, samples;
  34
  35     *poutbuf = NULL;
  36     *poutbuf_size = 0;
  37
  38     buf_ptr = buf;
  39     while (buf_size > 0) {
  40         int size_needed= s->frame_size ? s->frame_size : s->header_size;
  41         len = s->inbuf_ptr - s->inbuf;
  42
  43         if(len<size_needed){
  44             len = FFMIN(size_needed - len, buf_size);
  45             memcpy(s->inbuf_ptr, buf_ptr, len);
  46             buf_ptr      += len;
  47             s->inbuf_ptr += len;
  48             buf_size     -= len;
  49         }
  50
  51         if (s->frame_size == 0) {
  52             if ((s->inbuf_ptr - s->inbuf) == s->header_size) {
  53                 len = s->sync(s->inbuf, &channels, &sample_rate, &bit_rate,
  54                               &samples);
  55                 if (len == 0) {
  56                     /* no sync found : move by one byte (inefficient, but simple!) */
  57                     memmove(s->inbuf, s->inbuf + 1, s->header_size - 1);
  58                     s->inbuf_ptr--;
  59                 } else {
  60                     s->frame_size = len;
  61                     /* update codec info */
  62                     avctx->sample_rate = sample_rate;
  63                     avctx->channels = channels;
  64                     avctx->bit_rate = bit_rate;
  65                     avctx->frame_size = samples;
  66                 }
  67             }
  68         } else {
  69             if(s->inbuf_ptr - s->inbuf == s->frame_size){
  70                 *poutbuf = s->inbuf;
  71                 *poutbuf_size = s->frame_size;
  72                 s->inbuf_ptr = s->inbuf;
  73                 s->frame_size = 0;
  74                 break;
  75             }
  76         }
  77     }
  78     return buf_ptr - buf;
  79 }