libmpdemux/parse_mp4.c

   1 /* parse_mp4.c - MP4 file format parser code
   2  * This file is part of MPlayer, see http://mplayerhq.hu/ for info.
   3  * (c)2002 by Felix Buenemann <atmosfear at users.sourceforge.net>
   4  * File licensed under the GPL, see http://www.fsf.org/ for more info.
   5  * Code inspired by libmp4 from http://mpeg4ip.sourceforge.net/.
   6  */
   7
   8 #include <stdio.h>
   9 #include <inttypes.h>
  10 #ifdef HAVE_MALLOC_H
  11 #include <malloc.h>
  12 #endif
  13 #include <stdlib.h>
  14 #include "parse_mp4.h"
  15 #include "mp_msg.h"
  16 #include "stream/stream.h"
  17
  18 //#define MP4_DUMPATOM
  19
  20 #define MP4_DL MSGL_V
  21 #define freereturn(a,b) free(a); return b
  22
  23 int mp4_read_descr_len(stream_t *s) {
  24   uint8_t b;
  25   uint8_t numBytes = 0;
  26   uint32_t length = 0;
  27
  28   do {
  29     b = stream_read_char(s);
  30     numBytes++;
  31     length = (length << 7) | (b & 0x7F);
  32   } while ((b & 0x80) && numBytes < 4);
  33
  34   //printf("MP4 read desc len: %d\n", length);
  35   return length;
  36 }
  37
  38 /* parse the data part of MP4 esds atoms */
  39 int mp4_parse_esds(unsigned char *data, int datalen, esds_t *esds) {
  40   /* create memory stream from data */
  41   stream_t *s = new_memory_stream(data, datalen);
  42   uint16_t len;
  43 #ifdef MP4_DUMPATOM
  44   {int i;
  45   printf("ESDS Dump (%dbyte):\n", datalen);
  46   for(i = 0; i < datalen; i++)
  47     printf("%02X ", data[i]);
  48   printf("\nESDS Dumped\n");}
  49 #endif
  50   memset(esds, 0, sizeof(esds_t));
  51
  52   esds->version = stream_read_char(s);
  53   esds->flags = stream_read_int24(s);
  54   mp_msg(MSGT_DEMUX, MP4_DL,
  55       "ESDS MPEG4 version: %d  flags: 0x%06X\n",
  56       esds->version, esds->flags);
  57
  58   /* get and verify ES_DescrTag */
  59   if (stream_read_char(s) == MP4ESDescrTag) {
  60     /* read length */
  61     len = mp4_read_descr_len(s);
  62
  63     esds->ESId = stream_read_word(s);
  64     esds->streamPriority = stream_read_char(s);
  65     mp_msg(MSGT_DEMUX, MP4_DL,
  66         "ESDS MPEG4 ES Descriptor (%dBytes):\n"
  67         " -> ESId: %d\n"
  68         " -> streamPriority: %d\n",
  69         len, esds->ESId, esds->streamPriority);
  70
  71     if (len < (5 + 15)) {
  72       freereturn(s,1);
  73     }
  74   } else {
  75     esds->ESId = stream_read_word(s);
  76     mp_msg(MSGT_DEMUX, MP4_DL,
  77         "ESDS MPEG4 ES Descriptor (%dBytes):\n"
  78         " -> ESId: %d\n", 2, esds->ESId);
  79   }
  80
  81   /* get and verify DecoderConfigDescrTab */
  82   if (stream_read_char(s) != MP4DecConfigDescrTag) {
  83     freereturn(s,1);
  84   }
  85
  86   /* read length */
  87   len = mp4_read_descr_len(s);
  88
  89   esds->objectTypeId = stream_read_char(s);
  90   esds->streamType = stream_read_char(s);
  91   esds->bufferSizeDB = stream_read_int24(s);
  92   esds->maxBitrate = stream_read_dword(s);
  93   esds->avgBitrate = stream_read_dword(s);
  94   mp_msg(MSGT_DEMUX, MP4_DL,
  95       "ESDS MPEG4 Decoder Config Descriptor (%dBytes):\n"
  96       " -> objectTypeId: %d\n"
  97       " -> streamType: 0x%02X\n"
  98       " -> bufferSizeDB: 0x%06X\n"
  99       " -> maxBitrate: %.3fkbit/s\n"
 100       " -> avgBitrate: %.3fkbit/s\n",
 101       len, esds->objectTypeId, esds->streamType,
 102       esds->bufferSizeDB, esds->maxBitrate/1000.0,
 103       esds->avgBitrate/1000.0);
 104
 105   esds->decoderConfigLen=0;
 106
 107   if (len < 15) {
 108     freereturn(s,0);
 109   }
 110
 111   /* get and verify DecSpecificInfoTag */
 112   if (stream_read_char(s) != MP4DecSpecificDescrTag) {
 113     freereturn(s,0);
 114   }
 115
 116   /* read length */
 117   esds->decoderConfigLen = len = mp4_read_descr_len(s);
 118
 119   esds->decoderConfig = malloc(esds->decoderConfigLen);
 120   if (esds->decoderConfig) {
 121     stream_read(s, esds->decoderConfig, esds->decoderConfigLen);
 122   } else {
 123     esds->decoderConfigLen = 0;
 124   }
 125   mp_msg(MSGT_DEMUX, MP4_DL,
 126       "ESDS MPEG4 Decoder Specific Descriptor (%dBytes)\n", len);
 127
 128   /* get and verify SLConfigDescrTag */
 129   if(stream_read_char(s) != MP4SLConfigDescrTag) {
 130     freereturn(s,0);
 131   }
 132
 133   /* Note: SLConfig is usually constant value 2, size 1Byte */
 134   esds->SLConfigLen = len = mp4_read_descr_len(s);
 135   esds->SLConfig = malloc(esds->SLConfigLen);
 136   if (esds->SLConfig) {
 137     stream_read(s, esds->SLConfig, esds->SLConfigLen);
 138   } else {
 139     esds->SLConfigLen = 0;
 140   }
 141   mp_msg(MSGT_DEMUX, MP4_DL,
 142       "ESDS MPEG4 Sync Layer Config Descriptor (%dBytes)\n"
 143       " -> predefined: %d\n", len, esds->SLConfig[0]);
 144
 145   /* will skip the remainder of the atom */
 146   freereturn(s,0);
 147
 148 }
 149
 150 /* cleanup all mem occupied by mp4_parse_esds */
 151 void mp4_free_esds(esds_t *esds) {
 152   if(esds->decoderConfigLen)
 153     free(esds->decoderConfig);
 154   if(esds->SLConfigLen)
 155     free(esds->SLConfig);
 156 }
 157
 158 #undef freereturn
 159 #undef MP4_DL
 160