void MP4DescriptorProperty::Read(MP4File* pFile, u_int32_t index)
{
ASSERT(index == 0);
if (m_implicit) {
return;
}
u_int64_t start = pFile->GetPosition();
while (true) {
// enforce size limitation
if (m_sizeLimit && pFile->GetPosition() >= start + m_sizeLimit) {
break;
}
u_int8_t tag;
try {
pFile->PeekBytes(&tag, 1);
}
catch (MP4Error* e) {
if (pFile->GetPosition() >= pFile->GetSize()) {
// EOF
delete e;
break;
}
throw e;
}
// check if tag is in desired range
if (tag < m_tagsStart || tag > m_tagsEnd) {
break;
}
MP4Descriptor* pDescriptor =
AddDescriptor(tag);
pDescriptor->Read(pFile);
}
// warnings
if (m_mandatory && m_pDescriptors.Size() == 0) {
VERBOSE_READ(pFile->GetVerbosity(),
printf("Warning: Mandatory descriptor 0x%02x missing\n",
m_tagsStart));
} else if (m_onlyOne && m_pDescriptors.Size() > 1) {
VERBOSE_READ(pFile->GetVerbosity(),
printf("Warning: Descriptor 0x%02x has more than one instance\n",
m_tagsStart));
}
}
void MP4RtpAtom::Read()
{
if (!strcmp(m_pParentAtom->GetType(), "stsd")) {
AddPropertiesStsdType();
ReadStsdType();
} else if (!strcmp(m_pParentAtom->GetType(), "hnti")) {
AddPropertiesHntiType();
ReadHntiType();
} else {
VERBOSE_READ(m_pFile->GetVerbosity(),
printf("rtp atom in unexpected context, can not read"));
}
Skip(); // to end of atom
}
void MP4DrefAtom::Read()
{
/* do the usual read */
MP4Atom::Read();
// check that number of children == entryCount
MP4Integer32Property* pCount =
(MP4Integer32Property*)m_pProperties[2];
if (m_pChildAtoms.Size() != pCount->GetValue()) {
VERBOSE_READ(GetVerbosity(),
MP4Printf("Warning: dref inconsistency with number of entries"));
/* fix it */
pCount->SetReadOnly(false);
pCount->SetValue(m_pChildAtoms.Size());
pCount->SetReadOnly(true);
}
}
MP4SampleId MP4Track::GetSampleIdFromTime(
MP4Timestamp when,
bool wantSyncSample)
{
u_int32_t numStts = m_pSttsCountProperty->GetValue();
MP4SampleId sid = 1;
MP4Duration elapsed = 0;
for (u_int32_t sttsIndex = 0; sttsIndex < numStts; sttsIndex++) {
u_int32_t sampleCount =
m_pSttsSampleCountProperty->GetValue(sttsIndex);
u_int32_t sampleDelta =
m_pSttsSampleDeltaProperty->GetValue(sttsIndex);
if (sampleDelta == 0 && sttsIndex < numStts - 1) {
VERBOSE_READ(m_pFile->GetVerbosity(),
printf("Warning: Zero sample duration, stts entry %u\n",
sttsIndex));
}
MP4Duration d = when - elapsed;
if (d <= sampleCount * sampleDelta) {
MP4SampleId sampleId = sid;
if (sampleDelta) {
sampleId += (d / sampleDelta);
}
if (wantSyncSample) {
return GetNextSyncSample(sampleId);
}
return sampleId;
}
sid += sampleCount;
elapsed += sampleCount * sampleDelta;
}
throw new MP4Error("time out of range",
"MP4Track::GetSampleIdFromTime");
return 0; // satisfy MS compiler
}
void MP4ContentIdDescriptor::Read(MP4File* pFile)
{
ReadHeader(pFile);
/* read the first property, 'compatiblity' */
ReadProperties(pFile, 0, 1);
/* if compatiblity != 0 */
if (((MP4Integer8Property*)m_pProperties[0])->GetValue() != 0) {
/* we don't understand it */
VERBOSE_READ(pFile->GetVerbosity(),
printf("incompatible content id descriptor\n"));
return;
}
/* read the next four properties */
ReadProperties(pFile, 1, 4);
/* which allows us to reconfigure ourselves */
Mutate();
/* read the remaining properties */
ReadProperties(pFile, 5);
}
