libmpdemux/parse_mp4.c

   1 /*
   2  * MP4 file format parser code
   3  *
   4  * Copyright (C) 2002 Felix Buenemann <atmosfear at users.sourceforge.net>
   5  * Code inspired by libmp4 from http://mpeg4ip.sourceforge.net/.
   6  *
   7  * This file is part of MPlayer.
   8  *
   9  * MPlayer is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * MPlayer is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License along
  20  * with MPlayer; if not, write to the Free Software Foundation, Inc.,
  21  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  22  */
  23
  24 #include <stdio.h>
  25 #include <inttypes.h>
  26 #include <stdlib.h>
  27 #include "parse_mp4.h"
  28 #include "mp_msg.h"
  29 #include "stream/stream.h"
  30
  31 //#define MP4_DUMPATOM
  32
  33 #define MP4_DL MSGL_V
  34 #define freereturn(a,b) free(a); return b
  35
  36 int mp4_read_descr_len(stream_t *s) {
  37   uint8_t b;
  38   uint8_t numBytes = 0;
  39   uint32_t length = 0;
  40
  41   do {
  42     b = stream_read_char(s);
  43     numBytes++;
  44     length = (length << 7) | (b & 0x7F);
  45   } while ((b & 0x80) && numBytes < 4);
  46
  47   //printf("MP4 read desc len: %d\n", length);
  48   return length;
  49 }
  50
  51 /* parse the data part of MP4 esds atoms */
  52 int mp4_parse_esds(unsigned char *data, int datalen, esds_t *esds) {
  53   /* create memory stream from data */
  54   stream_t *s = new_memory_stream(data, datalen);
  55   uint16_t len;
  56 #ifdef MP4_DUMPATOM
  57   {int i;
  58   printf("ESDS Dump (%dbyte):\n", datalen);
  59   for(i = 0; i < datalen; i++)
  60     printf("%02X ", data[i]);
  61   printf("\nESDS Dumped\n");}
  62 #endif
  63   memset(esds, 0, sizeof(esds_t));
  64
  65   esds->version = stream_read_char(s);
  66   esds->flags = stream_read_int24(s);
  67   mp_msg(MSGT_DEMUX, MP4_DL,
  68       "ESDS MPEG4 version: %d  flags: 0x%06X\n",
  69       esds->version, esds->flags);
  70
  71   /* get and verify ES_DescrTag */
  72   if (stream_read_char(s) == MP4ESDescrTag) {
  73     /* read length */
  74     len = mp4_read_descr_len(s);
  75
  76     esds->ESId = stream_read_word(s);
  77     esds->streamPriority = stream_read_char(s);
  78     mp_msg(MSGT_DEMUX, MP4_DL,
  79         "ESDS MPEG4 ES Descriptor (%dBytes):\n"
  80         " -> ESId: %d\n"
  81         " -> streamPriority: %d\n",
  82         len, esds->ESId, esds->streamPriority);
  83
  84     if (len < (5 + 15)) {
  85       freereturn(s,1);
  86     }
  87   } else {
  88     esds->ESId = stream_read_word(s);
  89     mp_msg(MSGT_DEMUX, MP4_DL,
  90         "ESDS MPEG4 ES Descriptor (%dBytes):\n"
  91         " -> ESId: %d\n", 2, esds->ESId);
  92   }
  93
  94   /* get and verify DecoderConfigDescrTab */
  95   if (stream_read_char(s) != MP4DecConfigDescrTag) {
  96     freereturn(s,1);
  97   }
  98
  99   /* read length */
 100   len = mp4_read_descr_len(s);
 101
 102   esds->objectTypeId = stream_read_char(s);
 103   esds->streamType = stream_read_char(s);
 104   esds->bufferSizeDB = stream_read_int24(s);
 105   esds->maxBitrate = stream_read_dword(s);
 106   esds->avgBitrate = stream_read_dword(s);
 107   mp_msg(MSGT_DEMUX, MP4_DL,
 108       "ESDS MPEG4 Decoder Config Descriptor (%dBytes):\n"
 109       " -> objectTypeId: %d\n"
 110       " -> streamType: 0x%02X\n"
 111       " -> bufferSizeDB: 0x%06X\n"
 112       " -> maxBitrate: %.3fkbit/s\n"
 113       " -> avgBitrate: %.3fkbit/s\n",
 114       len, esds->objectTypeId, esds->streamType,
 115       esds->bufferSizeDB, esds->maxBitrate/1000.0,
 116       esds->avgBitrate/1000.0);
 117
 118   esds->decoderConfigLen=0;
 119
 120   if (len < 15) {
 121     freereturn(s,0);
 122   }
 123
 124   /* get and verify DecSpecificInfoTag */
 125   if (stream_read_char(s) != MP4DecSpecificDescrTag) {
 126     freereturn(s,0);
 127   }
 128
 129   /* read length */
 130   esds->decoderConfigLen = len = mp4_read_descr_len(s);
 131
 132   esds->decoderConfig = malloc(esds->decoderConfigLen);
 133   if (esds->decoderConfig) {
 134     stream_read(s, esds->decoderConfig, esds->decoderConfigLen);
 135   } else {
 136     esds->decoderConfigLen = 0;
 137   }
 138   mp_msg(MSGT_DEMUX, MP4_DL,
 139       "ESDS MPEG4 Decoder Specific Descriptor (%dBytes)\n", len);
 140
 141   /* get and verify SLConfigDescrTag */
 142   if(stream_read_char(s) != MP4SLConfigDescrTag) {
 143     freereturn(s,0);
 144   }
 145
 146   /* Note: SLConfig is usually constant value 2, size 1Byte */
 147   esds->SLConfigLen = len = mp4_read_descr_len(s);
 148   esds->SLConfig = malloc(esds->SLConfigLen);
 149   if (esds->SLConfig) {
 150     stream_read(s, esds->SLConfig, esds->SLConfigLen);
 151   } else {
 152     esds->SLConfigLen = 0;
 153   }
 154   mp_msg(MSGT_DEMUX, MP4_DL,
 155       "ESDS MPEG4 Sync Layer Config Descriptor (%dBytes)\n"
 156       " -> predefined: %d\n", len, esds->SLConfig[0]);
 157
 158   /* will skip the remainder of the atom */
 159   freereturn(s,0);
 160
 161 }
 162
 163 /* cleanup all mem occupied by mp4_parse_esds */
 164 void mp4_free_esds(esds_t *esds) {
 165   if(esds->decoderConfigLen)
 166     free(esds->decoderConfig);
 167   if(esds->SLConfigLen)
 168     free(esds->SLConfig);
 169 }
 170
 171 #undef freereturn
 172 #undef MP4_DL
 173