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/*
* Copyright 2008 CoreMedia AG, Hamburg
*
* Licensed under the Apache License, Version 2.0 (the License);
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an AS IS BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.coremedia.iso.boxes;
import com.coremedia.iso.IsoTypeReader;
import com.coremedia.iso.IsoTypeWriter;
import com.googlecode.mp4parser.AbstractFullBox;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import static com.googlecode.mp4parser.util.CastUtils.l2i;
/**
* This box contains a compact version of a table that allows indexing from decoding time to sample number.
* Other tables give sample sizes and pointers, from the sample number. Each entry in the table gives the
* number of consecutive samples with the same time delta, and the delta of those samples. By adding the
* deltas a complete time-to-sample map may be built.<br>
* The Decoding Time to Sample Box contains decode time delta's: <code>DT(n+1) = DT(n) + STTS(n)</code> where STTS(n)
* is the (uncompressed) table entry for sample n.<br>
* The sample entries are ordered by decoding time stamps; therefore the deltas are all non-negative. <br>
* The DT axis has a zero origin; <code>DT(i) = SUM(for j=0 to i-1 of delta(j))</code>, and the sum of all
* deltas gives the length of the media in the track (not mapped to the overall timescale, and not considering
* any edit list). <br>
* The Edit List Box provides the initial CT value if it is non-empty (non-zero).
*/
public class TimeToSampleBox extends AbstractFullBox {
public static final String TYPE = "stts";
List<Entry> entries = Collections.emptyList();
public TimeToSampleBox() {
super(TYPE);
}
protected long getContentSize() {
return 8 + entries.size() * 8;
}
@Override
public void _parseDetails(ByteBuffer content) {
parseVersionAndFlags(content);
int entryCount = l2i(IsoTypeReader.readUInt32(content));
entries = new ArrayList<Entry>(entryCount);
for (int i = 0; i < entryCount; i++) {
entries.add(new Entry(IsoTypeReader.readUInt32(content), IsoTypeReader.readUInt32(content)));
}
}
@Override
protected void getContent(ByteBuffer byteBuffer) {
writeVersionAndFlags(byteBuffer);
IsoTypeWriter.writeUInt32(byteBuffer, entries.size());
for (Entry entry : entries) {
IsoTypeWriter.writeUInt32(byteBuffer, entry.getCount());
IsoTypeWriter.writeUInt32(byteBuffer, entry.getDelta());
}
}
public List<Entry> getEntries() {
return entries;
}
public void setEntries(List<Entry> entries) {
this.entries = entries;
}
public String toString() {
return "TimeToSampleBox[entryCount=" + entries.size() + "]";
}
public static class Entry {
long count;
long delta;
public Entry(long count, long delta) {
this.count = count;
this.delta = delta;
}
public long getCount() {
return count;
}
public long getDelta() {
return delta;
}
public void setCount(long count) {
this.count = count;
}
public void setDelta(long delta) {
this.delta = delta;
}
@Override
public String toString() {
return "Entry{" +
"count=" + count +
", delta=" + delta +
'}';
}
}
/**
* Decompresses the list of entries and returns the list of decoding times.
*
* @return decoding time per sample
*/
public static long[] blowupTimeToSamples(List<TimeToSampleBox.Entry> entries) {
long numOfSamples = 0;
for (TimeToSampleBox.Entry entry : entries) {
numOfSamples += entry.getCount();
}
assert numOfSamples <= Integer.MAX_VALUE;
long[] decodingTime = new long[(int) numOfSamples];
int current = 0;
for (TimeToSampleBox.Entry entry : entries) {
for (int i = 0; i < entry.getCount(); i++) {
decodingTime[current++] = entry.getDelta();
}
}
return decodingTime;
}
}
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