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 #if HAVE_MALLOC_H
  27 #include <malloc.h>
  28 #endif
  29 #include <stdlib.h>
  30 #include "parse_mp4.h"
  31 #include "mp_msg.h"
  32 #include "stream/stream.h"
  33
  34 //#define MP4_DUMPATOM
  35
  36 #define MP4_DL MSGL_V
  37 #define freereturn(a,b) free(a); return b
  38
  39 int mp4_read_descr_len(stream_t *s) {
  40   uint8_t b;
  41   uint8_t numBytes = 0;
  42   uint32_t length = 0;
  43
  44   do {
  45     b = stream_read_char(s);
  46     numBytes++;
  47     length = (length << 7) | (b & 0x7F);
  48   } while ((b & 0x80) && numBytes < 4);
  49
  50   //printf("MP4 read desc len: %d\n", length);
  51   return length;
  52 }
  53
  54 /* parse the data part of MP4 esds atoms */
  55 int mp4_parse_esds(unsigned char *data, int datalen, esds_t *esds) {
  56   /* create memory stream from data */
  57   stream_t *s = new_memory_stream(data, datalen);
  58   uint16_t len;
  59 #ifdef MP4_DUMPATOM
  60   {int i;
  61   printf("ESDS Dump (%dbyte):\n", datalen);
  62   for(i = 0; i < datalen; i++)
  63     printf("%02X ", data[i]);
  64   printf("\nESDS Dumped\n");}
  65 #endif
  66   memset(esds, 0, sizeof(esds_t));
  67
  68   esds->version = stream_read_char(s);
  69   esds->flags = stream_read_int24(s);
  70   mp_msg(MSGT_DEMUX, MP4_DL,
  71       "ESDS MPEG4 version: %d  flags: 0x%06X\n",
  72       esds->version, esds->flags);
  73
  74   /* get and verify ES_DescrTag */
  75   if (stream_read_char(s) == MP4ESDescrTag) {
  76     /* read length */
  77     len = mp4_read_descr_len(s);
  78
  79     esds->ESId = stream_read_word(s);
  80     esds->streamPriority = stream_read_char(s);
  81     mp_msg(MSGT_DEMUX, MP4_DL,
  82         "ESDS MPEG4 ES Descriptor (%dBytes):\n"
  83         " -> ESId: %d\n"
  84         " -> streamPriority: %d\n",
  85         len, esds->ESId, esds->streamPriority);
  86
  87     if (len < (5 + 15)) {
  88       freereturn(s,1);
  89     }
  90   } else {
  91     esds->ESId = stream_read_word(s);
  92     mp_msg(MSGT_DEMUX, MP4_DL,
  93         "ESDS MPEG4 ES Descriptor (%dBytes):\n"
  94         " -> ESId: %d\n", 2, esds->ESId);
  95   }
  96
  97   /* get and verify DecoderConfigDescrTab */
  98   if (stream_read_char(s) != MP4DecConfigDescrTag) {
  99     freereturn(s,1);
 100   }
 101
 102   /* read length */
 103   len = mp4_read_descr_len(s);
 104
 105   esds->objectTypeId = stream_read_char(s);
 106   esds->streamType = stream_read_char(s);
 107   esds->bufferSizeDB = stream_read_int24(s);
 108   esds->maxBitrate = stream_read_dword(s);
 109   esds->avgBitrate = stream_read_dword(s);
 110   mp_msg(MSGT_DEMUX, MP4_DL,
 111       "ESDS MPEG4 Decoder Config Descriptor (%dBytes):\n"
 112       " -> objectTypeId: %d\n"
 113       " -> streamType: 0x%02X\n"
 114       " -> bufferSizeDB: 0x%06X\n"
 115       " -> maxBitrate: %.3fkbit/s\n"
 116       " -> avgBitrate: %.3fkbit/s\n",
 117       len, esds->objectTypeId, esds->streamType,
 118       esds->bufferSizeDB, esds->maxBitrate/1000.0,
 119       esds->avgBitrate/1000.0);
 120
 121   esds->decoderConfigLen=0;
 122
 123   if (len < 15) {
 124     freereturn(s,0);
 125   }
 126
 127   /* get and verify DecSpecificInfoTag */
 128   if (stream_read_char(s) != MP4DecSpecificDescrTag) {
 129     freereturn(s,0);
 130   }
 131
 132   /* read length */
 133   esds->decoderConfigLen = len = mp4_read_descr_len(s);
 134
 135   esds->decoderConfig = malloc(esds->decoderConfigLen);
 136   if (esds->decoderConfig) {
 137     stream_read(s, esds->decoderConfig, esds->decoderConfigLen);
 138   } else {
 139     esds->decoderConfigLen = 0;
 140   }
 141   mp_msg(MSGT_DEMUX, MP4_DL,
 142       "ESDS MPEG4 Decoder Specific Descriptor (%dBytes)\n", len);
 143
 144   /* get and verify SLConfigDescrTag */
 145   if(stream_read_char(s) != MP4SLConfigDescrTag) {
 146     freereturn(s,0);
 147   }
 148
 149   /* Note: SLConfig is usually constant value 2, size 1Byte */
 150   esds->SLConfigLen = len = mp4_read_descr_len(s);
 151   esds->SLConfig = malloc(esds->SLConfigLen);
 152   if (esds->SLConfig) {
 153     stream_read(s, esds->SLConfig, esds->SLConfigLen);
 154   } else {
 155     esds->SLConfigLen = 0;
 156   }
 157   mp_msg(MSGT_DEMUX, MP4_DL,
 158       "ESDS MPEG4 Sync Layer Config Descriptor (%dBytes)\n"
 159       " -> predefined: %d\n", len, esds->SLConfig[0]);
 160
 161   /* will skip the remainder of the atom */
 162   freereturn(s,0);
 163
 164 }
 165
 166 /* cleanup all mem occupied by mp4_parse_esds */
 167 void mp4_free_esds(esds_t *esds) {
 168   if(esds->decoderConfigLen)
 169     free(esds->decoderConfig);
 170   if(esds->SLConfigLen)
 171     free(esds->SLConfig);
 172 }
 173
 174 #undef freereturn
 175 #undef MP4_DL
 176