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