ref: a432dd721ceda6bf59e4a51d338cb8920d245219
dir: /common/mp4ff/mp4atom.c/
/*
** FAAD2 - Freeware Advanced Audio (AAC) Decoder including SBR decoding
** Copyright (C) 2003-2005 M. Bakker, Nero AG, http://www.nero.com
**
** This program is free software; you can redistribute it and/or modify
** it under the terms of the GNU General Public License as published by
** the Free Software Foundation; either version 2 of the License, or
** (at your option) any later version.
**
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
** GNU General Public License for more details.
**
** You should have received a copy of the GNU General Public License
** along with this program; if not, write to the Free Software
** Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
**
** Any non-GPL usage of this software or parts of this software is strictly
** forbidden.
**
** The "appropriate copyright message" mentioned in section 2c of the GPLv2
** must read: "Code from FAAD2 is copyright (c) Nero AG, www.nero.com"
**
** Commercial non-GPL licensing of this software is possible.
** For more info contact Nero AG through Mpeg4AAClicense@nero.com.
**
** $Id: mp4atom.c,v 1.28 2008/12/23 01:24:49 menno Exp $
**/
#include <stdlib.h>
#ifndef _WIN32
#include "config.h"
#else
#include <tchar.h>
#include <windows.h>
#endif
#ifdef HAVE_GETPWUID
# include <pwd.h>
#endif
#ifdef HAVE_STRING_H
# include <string.h>
#endif
#include "mp4ffint.h"
#define COPYRIGHT_SYMBOL ((int8_t)0xA9)
/* parse atom header size */
static int32_t mp4ff_atom_get_size(const int8_t *data)
{
uint32_t result;
uint32_t a, b, c, d;
a = (uint8_t)data[0];
b = (uint8_t)data[1];
c = (uint8_t)data[2];
d = (uint8_t)data[3];
result = (a<<24) | (b<<16) | (c<<8) | d;
//if (result > 0 && result < 8) result = 8;
return (int32_t)result;
}
/* comnapre 2 atom names, returns 1 for equal, 0 for unequal */
static int32_t mp4ff_atom_compare(const int8_t a1, const int8_t b1, const int8_t c1, const int8_t d1,
const int8_t a2, const int8_t b2, const int8_t c2, const int8_t d2)
{
if (a1 == a2 && b1 == b2 && c1 == c2 && d1 == d2)
return 1;
else
return 0;
}
static uint8_t mp4ff_atom_name_to_type(const int8_t a, const int8_t b,
const int8_t c, const int8_t d)
{
if (a == 'm')
{
if (mp4ff_atom_compare(a,b,c,d, 'm','o','o','v'))
return ATOM_MOOV;
else if (mp4ff_atom_compare(a,b,c,d, 'm','i','n','f'))
return ATOM_MINF;
else if (mp4ff_atom_compare(a,b,c,d, 'm','d','i','a'))
return ATOM_MDIA;
else if (mp4ff_atom_compare(a,b,c,d, 'm','d','a','t'))
return ATOM_MDAT;
else if (mp4ff_atom_compare(a,b,c,d, 'm','d','h','d'))
return ATOM_MDHD;
else if (mp4ff_atom_compare(a,b,c,d, 'm','v','h','d'))
return ATOM_MVHD;
else if (mp4ff_atom_compare(a,b,c,d, 'm','p','4','a'))
return ATOM_MP4A;
else if (mp4ff_atom_compare(a,b,c,d, 'm','p','4','v'))
return ATOM_MP4V;
else if (mp4ff_atom_compare(a,b,c,d, 'm','p','4','s'))
return ATOM_MP4S;
else if (mp4ff_atom_compare(a,b,c,d, 'm','e','t','a'))
return ATOM_META;
} else if (a == 't') {
if (mp4ff_atom_compare(a,b,c,d, 't','r','a','k'))
return ATOM_TRAK;
else if (mp4ff_atom_compare(a,b,c,d, 't','k','h','d'))
return ATOM_TKHD;
else if (mp4ff_atom_compare(a,b,c,d, 't','r','e','f'))
return ATOM_TREF;
else if (mp4ff_atom_compare(a,b,c,d, 't','r','k','n'))
return ATOM_TRACK;
else if (mp4ff_atom_compare(a,b,c,d, 't','m','p','o'))
return ATOM_TEMPO;
} else if (a == 's') {
if (mp4ff_atom_compare(a,b,c,d, 's','t','b','l'))
return ATOM_STBL;
else if (mp4ff_atom_compare(a,b,c,d, 's','m','h','d'))
return ATOM_SMHD;
else if (mp4ff_atom_compare(a,b,c,d, 's','t','s','d'))
return ATOM_STSD;
else if (mp4ff_atom_compare(a,b,c,d, 's','t','t','s'))
return ATOM_STTS;
else if (mp4ff_atom_compare(a,b,c,d, 's','t','c','o'))
return ATOM_STCO;
else if (mp4ff_atom_compare(a,b,c,d, 's','t','s','c'))
return ATOM_STSC;
else if (mp4ff_atom_compare(a,b,c,d, 's','t','s','z'))
return ATOM_STSZ;
else if (mp4ff_atom_compare(a,b,c,d, 's','t','z','2'))
return ATOM_STZ2;
else if (mp4ff_atom_compare(a,b,c,d, 's','k','i','p'))
return ATOM_SKIP;
else if (mp4ff_atom_compare(a,b,c,d, 's','i','n','f'))
return ATOM_SINF;
else if (mp4ff_atom_compare(a,b,c,d, 's','c','h','i'))
return ATOM_SCHI;
} else if (a == COPYRIGHT_SYMBOL) {
if (mp4ff_atom_compare(a,b,c,d, COPYRIGHT_SYMBOL,'n','a','m'))
return ATOM_TITLE;
else if (mp4ff_atom_compare(a,b,c,d, COPYRIGHT_SYMBOL,'A','R','T'))
return ATOM_ARTIST;
else if (mp4ff_atom_compare(a,b,c,d, COPYRIGHT_SYMBOL,'w','r','t'))
return ATOM_WRITER;
else if (mp4ff_atom_compare(a,b,c,d, COPYRIGHT_SYMBOL,'a','l','b'))
return ATOM_ALBUM;
else if (mp4ff_atom_compare(a,b,c,d, COPYRIGHT_SYMBOL,'d','a','y'))
return ATOM_DATE;
else if (mp4ff_atom_compare(a,b,c,d, COPYRIGHT_SYMBOL,'t','o','o'))
return ATOM_TOOL;
else if (mp4ff_atom_compare(a,b,c,d, COPYRIGHT_SYMBOL,'c','m','t'))
return ATOM_COMMENT;
else if (mp4ff_atom_compare(a,b,c,d, COPYRIGHT_SYMBOL,'g','e','n'))
return ATOM_GENRE1;
}
if (mp4ff_atom_compare(a,b,c,d, 'e','d','t','s'))
return ATOM_EDTS;
else if (mp4ff_atom_compare(a,b,c,d, 'e','s','d','s'))
return ATOM_ESDS;
else if (mp4ff_atom_compare(a,b,c,d, 'f','t','y','p'))
return ATOM_FTYP;
else if (mp4ff_atom_compare(a,b,c,d, 'f','r','e','e'))
return ATOM_FREE;
else if (mp4ff_atom_compare(a,b,c,d, 'h','m','h','d'))
return ATOM_HMHD;
else if (mp4ff_atom_compare(a,b,c,d, 'v','m','h','d'))
return ATOM_VMHD;
else if (mp4ff_atom_compare(a,b,c,d, 'u','d','t','a'))
return ATOM_UDTA;
else if (mp4ff_atom_compare(a,b,c,d, 'i','l','s','t'))
return ATOM_ILST;
else if (mp4ff_atom_compare(a,b,c,d, 'n','a','m','e'))
return ATOM_NAME;
else if (mp4ff_atom_compare(a,b,c,d, 'd','a','t','a'))
return ATOM_DATA;
else if (mp4ff_atom_compare(a,b,c,d, 'd','i','s','k'))
return ATOM_DISC;
else if (mp4ff_atom_compare(a,b,c,d, 'g','n','r','e'))
return ATOM_GENRE2;
else if (mp4ff_atom_compare(a,b,c,d, 'c','o','v','r'))
return ATOM_COVER;
else if (mp4ff_atom_compare(a,b,c,d, 'c','p','i','l'))
return ATOM_COMPILATION;
else if (mp4ff_atom_compare(a,b,c,d, 'c','t','t','s'))
return ATOM_CTTS;
else if (mp4ff_atom_compare(a,b,c,d, 'd','r','m','s'))
return ATOM_DRMS;
else if (mp4ff_atom_compare(a,b,c,d, 'f','r','m','a'))
return ATOM_FRMA;
else if (mp4ff_atom_compare(a,b,c,d, 'p','r','i','v'))
return ATOM_PRIV;
else if (mp4ff_atom_compare(a,b,c,d, 'i','v','i','v'))
return ATOM_IVIV;
else if (mp4ff_atom_compare(a,b,c,d, 'u','s','e','r'))
return ATOM_USER;
else if (mp4ff_atom_compare(a,b,c,d, 'k','e','y',' '))
return ATOM_KEY;
/* added by AJS */
else if (mp4ff_atom_compare(a,b,c,d, 'a','A','R','T'))
return ATOM_ALBUM_ARTIST;
else
return ATOM_UNKNOWN;
}
/* read atom header, return atom size, atom size is with header included */
uint64_t mp4ff_atom_read_header(mp4ff_t *f, uint8_t *atom_type, uint8_t *header_size)
{
uint64_t size;
int32_t ret;
int8_t atom_header[8];
ret = mp4ff_read_data(f, atom_header, 8);
if (ret != 8)
return 0;
size = mp4ff_atom_get_size(atom_header);
*header_size = 8;
/* check for 64 bit atom size */
if (size == 1)
{
*header_size = 16;
size = mp4ff_read_int64(f);
}
//printf("%c%c%c%c\n", atom_header[4], atom_header[5], atom_header[6], atom_header[7]);
*atom_type = mp4ff_atom_name_to_type(atom_header[4], atom_header[5], atom_header[6], atom_header[7]);
return size;
}
static int32_t mp4ff_read_stsz(mp4ff_t *f)
{
mp4ff_read_char(f); /* version */
mp4ff_read_int24(f); /* flags */
f->track[f->total_tracks - 1]->stsz_sample_size = mp4ff_read_int32(f);
f->track[f->total_tracks - 1]->stsz_sample_count = mp4ff_read_int32(f);
if (f->track[f->total_tracks - 1]->stsz_sample_size == 0)
{
int32_t i;
f->track[f->total_tracks - 1]->stsz_table =
(int32_t*)malloc(f->track[f->total_tracks - 1]->stsz_sample_count*sizeof(int32_t));
for (i = 0; i < f->track[f->total_tracks - 1]->stsz_sample_count; i++)
{
f->track[f->total_tracks - 1]->stsz_table[i] = mp4ff_read_int32(f);
}
}
return 0;
}
static int32_t mp4ff_read_esds(mp4ff_t *f)
{
uint8_t tag;
uint32_t temp;
mp4ff_read_char(f); /* version */
mp4ff_read_int24(f); /* flags */
/* get and verify ES_DescrTag */
tag = mp4ff_read_char(f);
if (tag == 0x03)
{
/* read length */
if (mp4ff_read_mp4_descr_length(f) < 5 + 15)
{
return 1;
}
/* skip 3 bytes */
mp4ff_read_int24(f);
} else {
/* skip 2 bytes */
mp4ff_read_int16(f);
}
/* get and verify DecoderConfigDescrTab */
if (mp4ff_read_char(f) != 0x04)
{
return 1;
}
/* read length */
temp = mp4ff_read_mp4_descr_length(f);
if (temp < 13) return 1;
f->track[f->total_tracks - 1]->audioType = mp4ff_read_char(f);
mp4ff_read_int32(f);//0x15000414 ????
f->track[f->total_tracks - 1]->maxBitrate = mp4ff_read_int32(f);
f->track[f->total_tracks - 1]->avgBitrate = mp4ff_read_int32(f);
/* get and verify DecSpecificInfoTag */
if (mp4ff_read_char(f) != 0x05)
{
return 1;
}
/* read length */
f->track[f->total_tracks - 1]->decoderConfigLen = mp4ff_read_mp4_descr_length(f);
if (f->track[f->total_tracks - 1]->decoderConfig)
free(f->track[f->total_tracks - 1]->decoderConfig);
f->track[f->total_tracks - 1]->decoderConfig = malloc(f->track[f->total_tracks - 1]->decoderConfigLen);
if (f->track[f->total_tracks - 1]->decoderConfig)
{
mp4ff_read_data(f, f->track[f->total_tracks - 1]->decoderConfig, f->track[f->total_tracks - 1]->decoderConfigLen);
} else {
f->track[f->total_tracks - 1]->decoderConfigLen = 0;
}
/* will skip the remainder of the atom */
return 0;
}
static int32_t mp4ff_read_mp4a(mp4ff_t *f)
{
uint64_t size;
int32_t i;
uint8_t atom_type = 0;
uint8_t header_size = 0;
for (i = 0; i < 6; i++)
{
mp4ff_read_char(f); /* reserved */
}
/* data_reference_index */ mp4ff_read_int16(f);
mp4ff_read_int32(f); /* reserved */
mp4ff_read_int32(f); /* reserved */
f->track[f->total_tracks - 1]->channelCount = mp4ff_read_int16(f);
f->track[f->total_tracks - 1]->sampleSize = mp4ff_read_int16(f);
mp4ff_read_int16(f);
mp4ff_read_int16(f);
f->track[f->total_tracks - 1]->sampleRate = mp4ff_read_int16(f);
mp4ff_read_int16(f);
size = mp4ff_atom_read_header(f, &atom_type, &header_size);
if (atom_type == ATOM_ESDS)
{
mp4ff_read_esds(f);
}
return 0;
}
static int32_t mp4ff_read_stsd(mp4ff_t *f)
{
int32_t i;
uint8_t header_size = 0;
mp4ff_read_char(f); /* version */
mp4ff_read_int24(f); /* flags */
f->track[f->total_tracks - 1]->stsd_entry_count = mp4ff_read_int32(f);
for (i = 0; i < f->track[f->total_tracks - 1]->stsd_entry_count; i++)
{
uint64_t skip = mp4ff_position(f);
uint64_t size;
uint8_t atom_type = 0;
size = mp4ff_atom_read_header(f, &atom_type, &header_size);
skip += size;
if (atom_type == ATOM_MP4A)
{
f->track[f->total_tracks - 1]->type = TRACK_AUDIO;
mp4ff_read_mp4a(f);
} else if (atom_type == ATOM_MP4V) {
f->track[f->total_tracks - 1]->type = TRACK_VIDEO;
} else if (atom_type == ATOM_MP4S) {
f->track[f->total_tracks - 1]->type = TRACK_SYSTEM;
} else {
f->track[f->total_tracks - 1]->type = TRACK_UNKNOWN;
}
mp4ff_set_position(f, skip);
}
return 0;
}
static int32_t mp4ff_read_stsc(mp4ff_t *f)
{
int32_t i;
mp4ff_read_char(f); /* version */
mp4ff_read_int24(f); /* flags */
f->track[f->total_tracks - 1]->stsc_entry_count = mp4ff_read_int32(f);
f->track[f->total_tracks - 1]->stsc_first_chunk =
(int32_t*)malloc(f->track[f->total_tracks - 1]->stsc_entry_count*sizeof(int32_t));
f->track[f->total_tracks - 1]->stsc_samples_per_chunk =
(int32_t*)malloc(f->track[f->total_tracks - 1]->stsc_entry_count*sizeof(int32_t));
f->track[f->total_tracks - 1]->stsc_sample_desc_index =
(int32_t*)malloc(f->track[f->total_tracks - 1]->stsc_entry_count*sizeof(int32_t));
for (i = 0; i < f->track[f->total_tracks - 1]->stsc_entry_count; i++)
{
f->track[f->total_tracks - 1]->stsc_first_chunk[i] = mp4ff_read_int32(f);
f->track[f->total_tracks - 1]->stsc_samples_per_chunk[i] = mp4ff_read_int32(f);
f->track[f->total_tracks - 1]->stsc_sample_desc_index[i] = mp4ff_read_int32(f);
}
return 0;
}
static int32_t mp4ff_read_stco(mp4ff_t *f)
{
int32_t i;
mp4ff_read_char(f); /* version */
mp4ff_read_int24(f); /* flags */
f->track[f->total_tracks - 1]->stco_entry_count = mp4ff_read_int32(f);
f->track[f->total_tracks - 1]->stco_chunk_offset =
(int32_t*)malloc(f->track[f->total_tracks - 1]->stco_entry_count*sizeof(int32_t));
for (i = 0; i < f->track[f->total_tracks - 1]->stco_entry_count; i++)
{
f->track[f->total_tracks - 1]->stco_chunk_offset[i] = mp4ff_read_int32(f);
}
return 0;
}
static int32_t mp4ff_read_ctts(mp4ff_t *f)
{
int32_t i;
mp4ff_track_t * p_track = f->track[f->total_tracks - 1];
if (p_track->ctts_entry_count) return 0;
mp4ff_read_char(f); /* version */
mp4ff_read_int24(f); /* flags */
p_track->ctts_entry_count = mp4ff_read_int32(f);
p_track->ctts_sample_count = (int32_t*)malloc(p_track->ctts_entry_count * sizeof(int32_t));
p_track->ctts_sample_offset = (int32_t*)malloc(p_track->ctts_entry_count * sizeof(int32_t));
if (p_track->ctts_sample_count == 0 || p_track->ctts_sample_offset == 0)
{
if (p_track->ctts_sample_count) {free(p_track->ctts_sample_count);p_track->ctts_sample_count=0;}
if (p_track->ctts_sample_offset) {free(p_track->ctts_sample_offset);p_track->ctts_sample_offset=0;}
p_track->ctts_entry_count = 0;
return 0;
}
else
{
for (i = 0; i < f->track[f->total_tracks - 1]->ctts_entry_count; i++)
{
p_track->ctts_sample_count[i] = mp4ff_read_int32(f);
p_track->ctts_sample_offset[i] = mp4ff_read_int32(f);
}
return 1;
}
}
static int32_t mp4ff_read_stts(mp4ff_t *f)
{
int32_t i;
mp4ff_track_t * p_track = f->track[f->total_tracks - 1];
if (p_track->stts_entry_count) return 0;
mp4ff_read_char(f); /* version */
mp4ff_read_int24(f); /* flags */
p_track->stts_entry_count = mp4ff_read_int32(f);
p_track->stts_sample_count = (int32_t*)malloc(p_track->stts_entry_count * sizeof(int32_t));
p_track->stts_sample_delta = (int32_t*)malloc(p_track->stts_entry_count * sizeof(int32_t));
if (p_track->stts_sample_count == 0 || p_track->stts_sample_delta == 0)
{
if (p_track->stts_sample_count) {free(p_track->stts_sample_count);p_track->stts_sample_count=0;}
if (p_track->stts_sample_delta) {free(p_track->stts_sample_delta);p_track->stts_sample_delta=0;}
p_track->stts_entry_count = 0;
return 0;
}
else
{
for (i = 0; i < f->track[f->total_tracks - 1]->stts_entry_count; i++)
{
p_track->stts_sample_count[i] = mp4ff_read_int32(f);
p_track->stts_sample_delta[i] = mp4ff_read_int32(f);
}
return 1;
}
}
static int32_t mp4ff_read_mvhd(mp4ff_t *f)
{
int32_t i;
mp4ff_read_char(f); /* version */
mp4ff_read_int24(f); /* flags */
/* creation_time */ mp4ff_read_int32(f);
/* modification_time */ mp4ff_read_int32(f);
f->time_scale = mp4ff_read_int32(f);
f->duration = mp4ff_read_int32(f);
/* preferred_rate */ mp4ff_read_int32(f); /*mp4ff_read_fixed32(f);*/
/* preferred_volume */ mp4ff_read_int16(f); /*mp4ff_read_fixed16(f);*/
for (i = 0; i < 10; i++)
{
/* reserved */ mp4ff_read_char(f);
}
for (i = 0; i < 9; i++)
{
mp4ff_read_int32(f); /* matrix */
}
/* preview_time */ mp4ff_read_int32(f);
/* preview_duration */ mp4ff_read_int32(f);
/* poster_time */ mp4ff_read_int32(f);
/* selection_time */ mp4ff_read_int32(f);
/* selection_duration */ mp4ff_read_int32(f);
/* current_time */ mp4ff_read_int32(f);
/* next_track_id */ mp4ff_read_int32(f);
return 0;
}
#if 0
static int32_t mp4ff_read_tkhd(mp4ff_t *f)
{
uint8_t version;
uint32_t flags;
version = mp4ff_read_char(f); /* version */
flags = mp4ff_read_int24(f); /* flags */
if (version==1)
{
mp4ff_read_int64(f);//creation-time
mp4ff_read_int64(f);//modification-time
mp4ff_read_int32(f);//track-id
mp4ff_read_int32(f);//reserved
f->track[f->total_tracks - 1]->duration = mp4ff_read_int64(f);//duration
}
else //version == 0
{
mp4ff_read_int32(f);//creation-time
mp4ff_read_int32(f);//modification-time
mp4ff_read_int32(f);//track-id
mp4ff_read_int32(f);//reserved
f->track[f->total_tracks - 1]->duration = mp4ff_read_int32(f);//duration
if (f->track[f->total_tracks - 1]->duration == 0xFFFFFFFF)
f->track[f->total_tracks - 1]->duration = 0xFFFFFFFFFFFFFFFF;
}
mp4ff_read_int32(f);//reserved
mp4ff_read_int32(f);//reserved
mp4ff_read_int16(f);//layer
mp4ff_read_int16(f);//pre-defined
mp4ff_read_int16(f);//volume
mp4ff_read_int16(f);//reserved
//matrix
mp4ff_read_int32(f); mp4ff_read_int32(f); mp4ff_read_int32(f);
mp4ff_read_int32(f); mp4ff_read_int32(f); mp4ff_read_int32(f);
mp4ff_read_int32(f); mp4ff_read_int32(f); mp4ff_read_int32(f);
mp4ff_read_int32(f);//width
mp4ff_read_int32(f);//height
return 1;
}
#endif
static int32_t mp4ff_read_mdhd(mp4ff_t *f)
{
uint32_t version;
version = mp4ff_read_int32(f);
if (version==1)
{
mp4ff_read_int64(f);//creation-time
mp4ff_read_int64(f);//modification-time
f->track[f->total_tracks - 1]->timeScale = mp4ff_read_int32(f);//timescale
f->track[f->total_tracks - 1]->duration = mp4ff_read_int64(f);//duration
}
else //version == 0
{
uint32_t temp;
mp4ff_read_int32(f);//creation-time
mp4ff_read_int32(f);//modification-time
f->track[f->total_tracks - 1]->timeScale = mp4ff_read_int32(f);//timescale
temp = mp4ff_read_int32(f);
f->track[f->total_tracks - 1]->duration = (temp == (uint32_t)(-1)) ? (uint64_t)(-1) : (uint64_t)(temp);
}
mp4ff_read_int16(f);
mp4ff_read_int16(f);
return 1;
}
#ifdef USE_TAGGING
static int32_t mp4ff_read_meta(mp4ff_t *f, const uint64_t size)
{
uint64_t subsize, sumsize = 0;
uint8_t atom_type;
uint8_t header_size = 0;
mp4ff_read_char(f); /* version */
mp4ff_read_int24(f); /* flags */
while (sumsize < (size-(header_size+4)))
{
subsize = mp4ff_atom_read_header(f, &atom_type, &header_size);
if (subsize <= header_size+4)
return 1;
if (atom_type == ATOM_ILST)
{
mp4ff_parse_metadata(f, (uint32_t)(subsize-(header_size+4)));
} else {
mp4ff_set_position(f, mp4ff_position(f)+subsize-header_size);
}
sumsize += subsize;
}
return 0;
}
#endif
int32_t mp4ff_atom_read(mp4ff_t *f, const int32_t size, const uint8_t atom_type)
{
uint64_t dest_position = mp4ff_position(f)+size-8;
if (atom_type == ATOM_STSZ)
{
/* sample size box */
mp4ff_read_stsz(f);
} else if (atom_type == ATOM_STTS) {
/* time to sample box */
mp4ff_read_stts(f);
} else if (atom_type == ATOM_CTTS) {
/* composition offset box */
mp4ff_read_ctts(f);
} else if (atom_type == ATOM_STSC) {
/* sample to chunk box */
mp4ff_read_stsc(f);
} else if (atom_type == ATOM_STCO) {
/* chunk offset box */
mp4ff_read_stco(f);
} else if (atom_type == ATOM_STSD) {
/* sample description box */
mp4ff_read_stsd(f);
} else if (atom_type == ATOM_MVHD) {
/* movie header box */
mp4ff_read_mvhd(f);
} else if (atom_type == ATOM_MDHD) {
/* track header */
mp4ff_read_mdhd(f);
#ifdef USE_TAGGING
} else if (atom_type == ATOM_META) {
/* iTunes Metadata box */
mp4ff_read_meta(f, size);
#endif
}
mp4ff_set_position(f, dest_position);
return 0;
}