protected static long getDuration(Track track) {
long duration = 0;
for (TimeToSampleBox.Entry entry : track.getDecodingTimeEntries()) {
duration += entry.getCount() * entry.getDelta();
}
return duration;
}
/**
* we try to get the nearest synchronized sample to our desired start time. Afterwards, we are
* ready to crop each track of the video.
*/
private double correctTimeToNextSyncSample(Track track, double cropVidPlace, boolean nextPlace) {
double[] timeOfSyncSamples = new double[track.getSyncSamples().length];
long currentSample = 0;
double currentTime = 0;
for (int i = 0; i < track.getDecodingTimeEntries().size(); i++) {
TimeToSampleBox.Entry entry = track.getDecodingTimeEntries().get(i);
for (int j = 0; j < entry.getCount(); j++) {
if (Arrays.binarySearch(track.getSyncSamples(), currentSample + 1) >= 0) {
// samples always start with 1 but we start with zero therefore +1
timeOfSyncSamples[Arrays.binarySearch(track.getSyncSamples(), currentSample + 1)] =
currentTime;
}
currentTime += (double) entry.getDelta() / (double) track.getTrackMetaData().getTimescale();
currentSample++;
}
}
double previous = 0;
for (double timeOfSyncSample : timeOfSyncSamples) {
if (timeOfSyncSample > cropVidPlace) {
if (nextPlace) {
return timeOfSyncSample;
} else {
return previous;
}
}
previous = timeOfSyncSample;
}
return timeOfSyncSamples[timeOfSyncSamples.length - 1];
}
private static long[] getTimes(Movie m, Track track) {
long[] syncSamples = track.getSyncSamples();
long[] syncSampleTimes = new long[syncSamples.length];
Queue<TimeToSampleBox.Entry> timeQueue =
new LinkedList<TimeToSampleBox.Entry>(track.getDecodingTimeEntries());
int currentSample = 1; // first syncsample is 1
long currentDuration = 0;
long currentDelta = 0;
int currentSyncSampleIndex = 0;
long left = 0;
long timeScale = 1;
for (Track track1 : m.getTracks()) {
if (track1.getHandler().equals(track.getHandler())) {
if (track1.getTrackMetaData().getTimescale() != track.getTrackMetaData().getTimescale()) {
timeScale = lcm(timeScale, track1.getTrackMetaData().getTimescale());
}
}
}
while (currentSample <= syncSamples[syncSamples.length - 1]) {
if (currentSample++ == syncSamples[currentSyncSampleIndex]) {
syncSampleTimes[currentSyncSampleIndex++] = currentDuration * timeScale;
}
if (left-- == 0) {
TimeToSampleBox.Entry entry = timeQueue.poll();
left = entry.getCount() - 1;
currentDelta = entry.getDelta();
}
currentDuration += currentDelta;
}
return syncSampleTimes;
}
protected void createStts(Track track, SampleTableBox stbl) {
TimeToSampleBox.Entry lastEntry = null;
List<TimeToSampleBox.Entry> entries = new ArrayList<TimeToSampleBox.Entry>();
for (long delta : track.getSampleDurations()) {
if (lastEntry != null && lastEntry.getDelta() == delta) {
lastEntry.setCount(lastEntry.getCount() + 1);
} else {
lastEntry = new TimeToSampleBox.Entry(1, delta);
entries.add(lastEntry);
}
}
TimeToSampleBox stts = new TimeToSampleBox();
stts.setEntries(entries);
stbl.addBox(stts);
}
/**
* all the trimming happens in this method.
*
* <p>STEP A ==>> For each track in the video, we first get the start time for all the tracks.
*
* <p>STEP B ==>> For each track in the video, we crop the tracks with a 'start time' and 'end
* time' and add it to the Movie object.
*
* <p>STEP C ==>> Finally write the newly created movie to the disk.
*/
private String cropSelectedVideo() {
FileInputStream fileInputStream = null;
FileChannel fileChannel = null;
try {
File videoFile = new File(mFullPathToVideoFile);
fileInputStream = new FileInputStream(videoFile);
fileChannel = fileInputStream.getChannel();
Movie movie = MovieCreator.build(fileChannel);
if (movie == null) {
return null;
} else {
List<Track> tracks = movie.getTracks();
movie.setTracks(new LinkedList<Track>());
boolean timeCorrected = false;
if ((tracks == null) && (tracks.size() <= 0)) {
return null;
} else {
/**
* here we try to find a track that has sync samples. Since we can only start decoding at
* such a sample we should make sure that the start of the fragment is exactly the such a
* frame.
*/
for (Track track : tracks) {
if (track.getSyncSamples() != null && track.getSyncSamples().length > 0) {
if (timeCorrected) {
/**
* This exception here can be false position in case we have multiple tracks with
* sync sample at exactly the same position. E.g. a single movie containing multiple
* qualities of the same video.
*/
} else {
mStartTime = correctTimeToNextSyncSample(track, mStartTime, false);
mEndTime = correctTimeToNextSyncSample(track, mEndTime, true);
timeCorrected = true;
}
}
}
for (Track track : tracks) {
long currentVidSample = 0;
double currentTime = 0;
long startVidSample = -1;
long endVidSample = -1;
for (int i = 0; i < track.getDecodingTimeEntries().size(); i++) {
TimeToSampleBox.Entry myEntry = track.getDecodingTimeEntries().get(i);
for (int j = 0; j < myEntry.getCount(); j++) {
// I am trying to find the start time and end time when the trimmimg occurs
if (currentTime <= mStartTime) {
// our current video sample is before the starting time for the crop
// if the startVidSample is equal to the length of the video,
// an error happened, and we should throw an exception
startVidSample =
currentVidSample; // the new begining of the video will be set to this place
// of the video
} else if (currentTime <= mEndTime) {
// our current video sample is after the starting time for the crop
// but before the end time of the crop
endVidSample =
currentVidSample; // the new end of the video will be set to this place of the
// video
} else {
// our current video sample is after the end time of the cropping
// we just stop this this loop
break;
}
// getDelta() : the amount of time the current video sample covers
currentTime +=
(double) myEntry.getDelta() / (double) track.getTrackMetaData().getTimescale();
currentVidSample++;
}
}
movie.addTrack(new CroppedTrack(track, startVidSample, endVidSample));
}
}
}
IsoFile isoFile = new DefaultMp4Builder().build(movie);
/** STEP C ==>> After we created the Movie, we have to place it into a nonvolatile memory. */
return Util.placeFileInNonVolatileDrive(isoFile, mVideFolderPath, "trim_output");
} catch (Exception e) {
Log.e(TAG, "IO ERROR: " + e);
} finally {
if (fileInputStream != null) {
try {
fileInputStream.close();
} catch (IOException e) {
Log.e(TAG, "IO ERROR: " + e);
}
}
if (fileChannel != null) {
try {
fileChannel.close();
} catch (IOException e) {
Log.e(TAG, "IO ERROR: " + e);
}
}
}
return null;
}
