java-使用mp4parser剪切mp4.无法过去时间与SyncSample校正
内容导读
互联网集市收集整理的这篇技术教程文章主要介绍了java-使用mp4parser剪切mp4.无法过去时间与SyncSample校正,小编现在分享给大家,供广大互联网技能从业者学习和参考。文章包含5181字,纯文字阅读大概需要8分钟。
内容图文
![java-使用mp4parser剪切mp4.无法过去时间与SyncSample校正](/upload/InfoBanner/zyjiaocheng/677/0919c991fb9d4995a601cd6b37b18091.jpg)
我正在编写一个Android应用程序,并且有很多5-15秒的.mp4文件要剪辑.我一直在尝试使用塞巴斯蒂安·安妮斯(Sebastian Annies)的mp4parser,遵循此处给出的示例代码:ShortenExample.
这是我正在使用的代码(与上面的示例代码非常相似):
public static void clip(Sprinkle sprinkle, double start, double end) throws IOException {
Movie movie = MovieCreator.build(sprinkle.getLocalVideoPath());
// Save all tracks then remove them from movie
List<Track> tracks = movie.getTracks();
movie.setTracks(new LinkedList<Track>());
boolean timeCorrected = false;
// 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 new fragment is exactly
// such a frame
for (Track track : tracks) {
if (track.getSyncSamples() != null && track.getSyncSamples().length > 0) {
if (timeCorrected) {
// This exception here could be a false positive in case we have multiple tracks
// with sync samples at exactly the same positions. E.g. a single movie containing
// multiple qualities of the same video (Microsoft Smooth Streaming file)
Log.v("clip", "track.getSyncSamples().length: " + track.getSyncSamples().length);
throw new RuntimeException("The startTime has already been corrected by another track with SyncSample. Not Supported.");
}
Log.v("syncSample", "start before: " + start);
Log.v("syncSample", "end before: " + end);
start = correctTimeToSyncSample(track, start, false);
end = correctTimeToSyncSample(track, end, true);
Log.v("syncSample", "start after: " + start);
Log.v("syncSample", "end after: " + end);
timeCorrected = true;
}
}
for (Track track : tracks) {
long currentSample = 0;
double currentTime = 0;
double lastTime = 0;
long startSample = -1;
long endSample = -1;
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 (currentTime > lastTime && currentTime <= start) {
// current sample is still before the new starttime
startSample = currentSample;
}
if (currentTime > lastTime && currentTime <= end) {
// current sample is after the new start time and still before the new endtime
endSample = currentSample;
}
lastTime = currentTime;
currentTime += (double) entry.getDelta() / (double) track.getTrackMetaData().getTimescale();
currentSample++;
}
}
movie.addTrack(new AppendTrack(new CroppedTrack(track, startSample, endSample)));
}
long start1 = System.currentTimeMillis();
Container out = new DefaultMp4Builder().build(movie);
long start2 = System.currentTimeMillis();
File file = Constants.getEditsDir();
FileOutputStream fos = new FileOutputStream(file.getPath() + String.format("output-%f-%f.mp4", start, end));
FileChannel fc = fos.getChannel();
out.writeContainer(fc);
fc.close();
fos.close();
long start3 = System.currentTimeMillis();
System.err.println("Building IsoFile took : " + (start2 - start1) + "ms");
System.err.println("Writing IsoFile took : " + (start3 - start2) + "ms");
System.err.println("Writing IsoFile speed : " + (new File(String.format("output-%f-%f.mp4", start, end)).length() / (start3 - start2) / 1000) + "MB/s");
}
private static double correctTimeToSyncSample(Track track, double cutHere, boolean next) {
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 > cutHere) {
if (next) {
return timeOfSyncSample;
} else {
return previous;
}
}
previous = timeOfSyncSample;
}
return timeOfSyncSamples[timeOfSyncSamples.length - 1];
}
我似乎无法防止出现错误“ startTime已被SyncSample的其他轨道纠正.不支持.”从发生.当我记录正在遍历的轨道时,getHandler()返回“ vide”,“ soun”,然后在涉及“提示”时崩溃.如果我将这一部分注释掉:
if (timeCorrected) {
// This exception here could be a false positive in case we have multiple tracks
// with sync samples at exactly the same positions. E.g. a single movie containing
// multiple qualities of the same video (Microsoft Smooth Streaming file)
Log.v("clip", "track.getSyncSamples().length: " + track.getSyncSamples().length);
throw new RuntimeException("The startTime has already been corrected by another track with SyncSample. Not Supported.");
}
然后程序进入该行时,由于索引超出范围错误而崩溃
Container out = new DefaultMp4Builder().build(movie);
我究竟做错了什么?
解决方法:
您收到IndexOutOfBoundsException,因为到达时startSample或endSample的值错误(例如,仍为-1)
Container out = new DefaultMp4Builder().build(movie);
在我的示例中,对于小于2秒的剪辑过程使用起始值会导致以下结果:if(currentTime> lastTime&& currentTime< = start)从未达到真实值,因此startSample并未从其更新初始值为-1.一种解决方案是将startSample的初始值从-1更改为0.
内容总结
以上是互联网集市为您收集整理的java-使用mp4parser剪切mp4.无法过去时间与SyncSample校正全部内容,希望文章能够帮你解决java-使用mp4parser剪切mp4.无法过去时间与SyncSample校正所遇到的程序开发问题。 如果觉得互联网集市技术教程内容还不错,欢迎将互联网集市网站推荐给程序员好友。
内容备注
版权声明:本文内容由互联网用户自发贡献,该文观点与技术仅代表作者本人。本站仅提供信息存储空间服务,不拥有所有权,不承担相关法律责任。如发现本站有涉嫌侵权/违法违规的内容, 请发送邮件至 gblab@vip.qq.com 举报,一经查实,本站将立刻删除。
内容手机端
扫描二维码推送至手机访问。