void aiContext::getTimeSampling(int i, aiTimeSamplingData& dst)
{
auto ts = m_archive.getTimeSampling(i);
auto tst = ts->getTimeSamplingType();
dst.numTimes = (int)ts->getNumStoredTimes();
if (tst.isUniform() || tst.isCyclic()) {
int numCycles = int(m_archive.getMaxNumSamplesForTimeSamplingIndex(i) / tst.getNumSamplesPerCycle());
dst.type = tst.isUniform() ? aiTimeSamplingType_Uniform : aiTimeSamplingType_Cyclic;
dst.interval = (float)tst.getTimePerCycle();
dst.startTime = (float)ts->getStoredTimes()[0];
dst.endTime = dst.startTime + dst.interval * (numCycles - 1);
dst.numTimes = (int)ts->getNumStoredTimes();
dst.times = const_cast<double*>(&ts->getStoredTimes()[0]);
}
else if (tst.isAcyclic()) {
dst.type = aiTimeSamplingType_Acyclic;
dst.startTime = (float)ts->getSampleTime(0);
dst.endTime = (float)ts->getSampleTime(ts->getNumStoredTimes() - 1);
dst.numTimes = (int)ts->getNumStoredTimes();
dst.times = const_cast<double*>(&ts->getStoredTimes()[0]);
}
}
status_t SampleTable::findSampleAtTime(
uint64_t req_time, uint64_t scale_num, uint64_t scale_den,
uint32_t *sample_index, uint32_t flags) {
buildSampleEntriesTable();
if (mSampleTimeEntries == NULL) {
return ERROR_OUT_OF_RANGE;
}
uint32_t left = 0;
uint32_t right_plus_one = mNumSampleSizes;
while (left < right_plus_one) {
uint32_t center = left + (right_plus_one - left) / 2;
uint64_t centerTime =
getSampleTime(center, scale_num, scale_den);
if (req_time < centerTime) {
right_plus_one = center;
} else if (req_time > centerTime) {
left = center + 1;
} else {
*sample_index = mSampleTimeEntries[center].mSampleIndex;
return OK;
}
}
uint32_t closestIndex = left;
if (closestIndex == mNumSampleSizes) {
if (flags == kFlagAfter) {
return ERROR_OUT_OF_RANGE;
}
flags = kFlagBefore;
} else if (closestIndex == 0) {
if (flags == kFlagBefore) {
// normally we should return out of range, but that is
// treated as end-of-stream. instead return first sample
//
// return ERROR_OUT_OF_RANGE;
}
flags = kFlagAfter;
}
switch (flags) {
case kFlagBefore:
{
--closestIndex;
break;
}
case kFlagAfter:
{
// nothing to do
break;
}
default:
{
CHECK(flags == kFlagClosest);
// pick closest based on timestamp. use abs_difference for safety
if (abs_difference(
getSampleTime(closestIndex, scale_num, scale_den), req_time) >
abs_difference(
req_time, getSampleTime(closestIndex - 1, scale_num, scale_den))) {
--closestIndex;
}
break;
}
}
*sample_index = mSampleTimeEntries[closestIndex].mSampleIndex;
return OK;
}
