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|
/*****************************************************************
|
| AP4 - ctts Atoms
|
| Copyright 2002-2008 Axiomatic Systems, LLC
|
|
| This file is part of Bento4/AP4 (MP4 Atom Processing Library).
|
| Unless you have obtained Bento4 under a difference license,
| this version of Bento4 is Bento4|GPL.
| Bento4|GPL 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, or (at your option)
| any later version.
|
| Bento4|GPL 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 Bento4|GPL; see the file COPYING. If not, write to the
| Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA
| 02111-1307, USA.
|
****************************************************************/
/*----------------------------------------------------------------------
| includes
+---------------------------------------------------------------------*/
#include "Ap4CttsAtom.h"
#include "Ap4AtomFactory.h"
#include "Ap4Utils.h"
/*----------------------------------------------------------------------
| dynamic cast support
+---------------------------------------------------------------------*/
AP4_DEFINE_DYNAMIC_CAST_ANCHOR(AP4_CttsAtom)
/*----------------------------------------------------------------------
| AP4_CttsAtom::Create
+---------------------------------------------------------------------*/
AP4_CttsAtom*
AP4_CttsAtom::Create(AP4_UI32 size, AP4_ByteStream& stream)
{
AP4_UI08 version;
AP4_UI32 flags;
if (AP4_FAILED(AP4_Atom::ReadFullHeader(stream, version, flags))) return NULL;
if (version > 1) return NULL;
return new AP4_CttsAtom(size, version, flags, stream);
}
/*----------------------------------------------------------------------
| AP4_CttsAtom::AP4_CttsAtom
+---------------------------------------------------------------------*/
AP4_CttsAtom::AP4_CttsAtom() :
AP4_Atom(AP4_ATOM_TYPE_CTTS, AP4_FULL_ATOM_HEADER_SIZE+4, 0, 0)
{
m_LookupCache.sample = 0;
m_LookupCache.entry_index = 0;
}
/*----------------------------------------------------------------------
| AP4_CttsAtom::AP4_CttsAtom
+---------------------------------------------------------------------*/
AP4_CttsAtom::AP4_CttsAtom(AP4_UI32 size,
AP4_UI08 version,
AP4_UI32 flags,
AP4_ByteStream& stream) :
AP4_Atom(AP4_ATOM_TYPE_CTTS, size, version, flags)
{
m_LookupCache.sample = 0;
m_LookupCache.entry_index = 0;
AP4_UI32 entry_count;
stream.ReadUI32(entry_count);
m_Entries.SetItemCount(entry_count);
unsigned char* buffer = new unsigned char[entry_count*8];
AP4_Result result = stream.Read(buffer, entry_count*8);
if (AP4_FAILED(result)) {
delete[] buffer;
return;
}
//bool use_quicktime_format = false;
//AP4_SI32 quicktime_min_offset = 0;
for (unsigned i=0; i<entry_count; i++) {
m_Entries[i].m_SampleCount = AP4_BytesToUInt32BE(&buffer[i*8 ]);
AP4_UI32 offset = AP4_BytesToUInt32BE(&buffer[i*8+4]);
//if (offset & 0x80000000) {
// use_quicktime_format = true;
// AP4_SI32 noffset = (AP4_SI32)offset;
// if (noffset < quicktime_min_offset) quicktime_min_offset = noffset;
//}
m_Entries[i].m_SampleOffset = offset;
}
delete[] buffer;
// in the quicktime format, the offsets can be positive or negative, so
// we need to adjust for them here
//if (use_quicktime_format) {
// for (unsigned i=0; i<entry_count; i++) {
// m_Entries[i].m_SampleOffset -= quicktime_min_offset;
// }
//}
}
/*----------------------------------------------------------------------
| AP4_CttsAtom::AddEntry
+---------------------------------------------------------------------*/
AP4_Result
AP4_CttsAtom::AddEntry(AP4_UI32 count, AP4_UI32 cts_offset)
{
m_Entries.Append(AP4_CttsTableEntry(count, cts_offset));
m_Size32 += 8;
return AP4_SUCCESS;
}
/*----------------------------------------------------------------------
| AP4_CttsAtom::GetCtsOffset
+---------------------------------------------------------------------*/
AP4_Result
AP4_CttsAtom::GetCtsOffset(AP4_Ordinal sample, AP4_UI32& cts_offset)
{
// default value
cts_offset = 0;
// sample indexes start at 1
if (sample == 0) return AP4_ERROR_OUT_OF_RANGE;
// check the lookup cache
AP4_Ordinal lookup_start = 0;
AP4_Ordinal sample_start = 0;
if (sample >= m_LookupCache.sample) {
// start from the cached entry
lookup_start = m_LookupCache.entry_index;
sample_start = m_LookupCache.sample;
}
for (AP4_Ordinal i = lookup_start; i < m_Entries.ItemCount(); i++) {
AP4_CttsTableEntry& entry = m_Entries[i];
// check if we have reached the sample
if (sample <= sample_start+entry.m_SampleCount) {
// we are within the sample range for the current entry
cts_offset = entry.m_SampleOffset;
// update the lookup cache
m_LookupCache.entry_index = i;
m_LookupCache.sample = sample_start;
return AP4_SUCCESS;
}
// update the upper bound
sample_start += entry.m_SampleCount;
}
// sample is greater than the number of samples
return AP4_ERROR_OUT_OF_RANGE;
}
/*----------------------------------------------------------------------
| AP4_CttsAtom::WriteFields
+---------------------------------------------------------------------*/
AP4_Result
AP4_CttsAtom::WriteFields(AP4_ByteStream& stream)
{
AP4_Result result;
// write the entry count
AP4_Cardinal entry_count = m_Entries.ItemCount();
result = stream.WriteUI32(entry_count);
if (AP4_FAILED(result)) return result;
// write the entries
for (AP4_Ordinal i=0; i<entry_count; i++) {
// sample count
result = stream.WriteUI32(m_Entries[i].m_SampleCount);
if (AP4_FAILED(result)) return result;
// time offset
result = stream.WriteUI32(m_Entries[i].m_SampleOffset);
if (AP4_FAILED(result)) return result;
}
return AP4_SUCCESS;
}
/*----------------------------------------------------------------------
| AP4_CttsAtom::InspectFields
+---------------------------------------------------------------------*/
AP4_Result
AP4_CttsAtom::InspectFields(AP4_AtomInspector& inspector)
{
inspector.AddField("entry_count", m_Entries.ItemCount());
if (inspector.GetVerbosity() >= 2) {
char header[32];
char value[64];
for (AP4_Ordinal i=0; i<m_Entries.ItemCount(); i++) {
AP4_FormatString(header, sizeof(header), "entry %8d", i);
AP4_FormatString(value, sizeof(value), "count=%d, offset=%d",
m_Entries[i].m_SampleCount,
m_Entries[i].m_SampleOffset);
inspector.AddField(header, value);
}
}
return AP4_SUCCESS;
}
|
