Android 检测视频文件何时真正写入?
cwac摄影机库具有在保存照片之前调用的事件挂钩:Android 检测视频文件何时真正写入?,android,video,commonsware-cwac,cwac-camera,Android,Video,Commonsware Cwac,Cwac Camera,cwac摄影机库具有在保存照片之前调用的事件挂钩: @Override public void saveImage(PictureTransaction xact, byte[] image) {} 我是否忽略了这一点,或者是否没有接收器可以告诉我视频文件何时被保存 更多背景信息:有两种方法可以结束视频。一是打电话 .stopRecording(); 另一种方法是将记录器配置为max duration/max filesize(在这种情况下,录制停止,而不显式调用stopRecording(
@Override public void saveImage(PictureTransaction xact, byte[] image) {}
我是否忽略了这一点,或者是否没有接收器可以告诉我视频文件何时被保存
更多背景信息:有两种方法可以结束视频。一是打电话
.stopRecording();
另一种方法是将记录器配置为max duration/max filesize(在这种情况下,录制停止,而不显式调用stopRecording():
在这两种情况下,在我看来,Android需要大约100到200毫秒来完成文件
mediaRecorder.setOnInfoListener(new MediaRecorder.OnInfoListener() {
@Override public void onInfo(MediaRecorder mr, int what, int extra) {}
}
要检测文件何时完成,或者在调用stopRecording()后立即尝试读取它。我尝试使用FileObserver来检测media recorder何时实际关闭文件,效果很好
我想讨论这个问题,如果有人有同样的经验,如果有一种方式cwac摄像机如何检测和信号记录的文件
--
我刚刚在Android文档中提到了这一点
停止是异步进行的,不能保证在通知侦听器时记录器已经停止
这解释了为什么文件有时没有正确关闭,这意味着使用FileObserver可能是在写入文件后访问该文件的唯一安全有效的方法
所以我们需要这样的东西来检测事件
@Override protected File getVideoPath() {
File file = super.getVideoPath(); // assemble the video path
fileObserverPath = file.getAbsolutePath();
fileObserver = new FileObserver(fileObserverPath, FileObserver.CLOSE_WRITE) {
@Override public void onEvent(int event, String videoPath) {
System.out.println("**** CameraHost: write closed");
if (fileObserver != null) { // defensive
fileObserver.stopWatching();
fileObserver = null;
}
// process the file here
}
};
fileObserver.startWatching();
return file;
}
--
我继续向CameraHost添加了以下代码以获取计时:
@Override public void configureRecorderOutput(int cameraId, MediaRecorder recorder) {
System.out.println("**** CameraHost: configureRecorderOutput");
recorder.setMaxDuration(Constants.FRAMEPLAYER_MAX_RECORDING_LENGTH_PER_FRAME_MSEC);
recorder.setOnInfoListener(new MediaRecorder.OnInfoListener() {
@Override public void onInfo(MediaRecorder mr, int what, int extra) {
switch (what) {
case MediaRecorder.MEDIA_RECORDER_INFO_MAX_DURATION_REACHED: {
System.out.println("**** CameraHost: MEDIA_RECORDER_INFO_MAX_DURATION_REACHED");
break;
}
}
}
});
super.configureRecorderOutput(cameraId, recorder);
}
时间:
11-20 07:33:28.974 32602-32602/cc.closeup.android I/System.out﹕ **** CameraHost: configureRecorderOutput
11-20 07:33:31.064 32602-32602/cc.closeup.android I/System.out﹕ **** CameraHost: MEDIA_RECORDER_INFO_MAX_DURATION_REACHED
11-20 07:33:31.084 32602-32602/cc.closeup.android I/System.out﹕ **** CameraHost: MEDIA_RECORDER_INFO_MAX_DURATION_REACHED
11-20 07:33:36.914 32602-32655/cc.closeup.android I/System.out﹕ **** CameraHost: write closed
11-20 07:33:36.914 32602-32655/cc.closeup.android I/System.out﹕ **** CameraHost: write closed
有两件事很奇怪:
11-20 09:41:25.748 3398-3398/cc.closeup.android I/System.out﹕ **** CameraHost: onInfo: mr = android.media.MediaRecorder@41c9da88, what = 800, extra 0
11-20 09:41:25.748 3398-3398/cc.closeup.android I/System.out﹕ **** CameraHost: MEDIA_RECORDER_INFO_MAX_DURATION_REACHED
11-20 09:41:25.748 3398-3398/cc.closeup.android I/System.out﹕ **** CameraHost: onInfo: mr = android.media.MediaRecorder@41c9da88, what = 536871912, extra 0
11-20 09:41:25.778 3398-3398/cc.closeup.android I/System.out﹕ **** CameraHost: onInfo: mr = android.media.MediaRecorder@41c9da88, what = 800, extra 0
11-20 09:41:25.778 3398-3398/cc.closeup.android I/System.out﹕ **** CameraHost: MEDIA_RECORDER_INFO_MAX_DURATION_REACHED
11-20 09:41:25.778 3398-3398/cc.closeup.android I/System.out﹕ **** CameraHost: onInfo: mr = android.media.MediaRecorder@41c9da88, what = 268436456, extra 0
我在另一台设备上运行了此操作,其中媒体\u记录器\u信息\u最大\u持续时间\u到达事件也会引发两次,但根本不会引发未记录的what=?事件。特定于供应商的实现
[来自三星Galaxy注2:]
11-20 09:46:42.711 25699-25699/cc.closeup.android I/System.out﹕ **** CameraHost: onInfo: mr = android.media.MediaRecorder@42831c30, what = 800, extra 0
11-20 09:46:42.711 25699-25699/cc.closeup.android I/System.out﹕ **** CameraHost: MEDIA_RECORDER_INFO_MAX_DURATION_REACHED
11-20 09:46:42.776 25699-25699/cc.closeup.android I/System.out﹕ **** CameraHost: onInfo: mr = android.media.MediaRecorder@42831c30, what = 800, extra 0
11-20 09:46:42.776 25699-25699/cc.closeup.android I/System.out﹕ **** CameraHost: MEDIA_RECORDER_INFO_MAX_DURATION_REACHED
我一直在发帖
--
关于1,录制实际上已停止(录制的文件有1秒长),但FileObserver()显然只在很久以后调用,也就是在我显式调用cameraView.stop()之后
我试图直接在事件中传递的MediaRecorder上调用stop(),它在Android中有效,但在cwac中无效
--
关于1,我进一步深入研究了这一点,它看起来像是一直写入视频文件,直到我显式调用cameraView.stop()-然后它才被截断到1秒并关闭
// startRecording() called here
11-20 11:29:49.072 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:49.072 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 32, videoPath = media0.mp4
11-20 11:29:49.082 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:49.082 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:49.082 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:49.082 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:49.082 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:49.082 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:51.132 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:51.132 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:51.132 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:51.132 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:51.132 4987-4987/cc.closeup.android I/System.out﹕ **** CameraHost: MEDIA_RECORDER_INFO_MAX_DURATION_REACHED
11-20 11:29:51.142 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:51.142 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:51.142 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:51.142 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:51.142 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
(...)
11-20 11:29:51.182 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:51.182 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:51.182 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:51.192 4987-4987/cc.closeup.android I/System.out﹕ **** CameraHost: MEDIA_RECORDER_INFO_MAX_DURATION_REACHED
11-20 11:29:51.192 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:51.192 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:51.192 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:51.192 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:51.192 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
(...)
11-20 11:29:51.252 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:51.262 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:51.262 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:51.262 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:51.262 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:51.262 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
// stopRecording() called here
11-20 11:29:52.492 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:52.492 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:52.492 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:52.492 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:52.572 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:52.572 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:52.572 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:52.572 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:52.572 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:52.572 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:52.572 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
(...)
11-20 11:29:52.582 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:52.582 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:52.582 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:52.582 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:52.582 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:52.582 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:52.582 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:52.582 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:52.582 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:52.582 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:52.582 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:52.582 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:52.582 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:52.582 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:52.582 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:52.582 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:52.582 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:52.582 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 2, videoPath = media0.mp4
11-20 11:29:52.582 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: FileObserver: onEvent: event = 8, videoPath = media0.mp4
11-20 11:29:52.582 4987-5167/cc.closeup.android I/System.out﹕ **** CameraHost: write closed: videoPath = media0.mp4
FileObserver可用于检测文件的最终写入时间。它可以挂接到CameraHost中的getVideoDirectory()覆盖中:
@Override protected File getVideoDirectory() {
fileObserver = new FileObserver(videoDirectory.getAbsolutePath(), FileObserver.CLOSE_WRITE) {
@Override public void onEvent(int event, String videoPath) {
System.out.println("**** CameraHost: FileObserver: onEvent: event = " + event + ", videoPath = " + videoPath);
if (fileObserver != null && videoPath != null && event == FileObserver.CLOSE_WRITE) { // do not process directory
System.out.println("**** CameraHost: write closed: videoPath = " + videoPath);
// fileObserver.stopWatching(); // TODO this needs to be closed somewhere
// fileObserver = null;
raiseVideo(videoPath);
}
}
};
fileObserver.startWatching();
return videoDirectory;
}
FileObserver有一个限制,即它仅在显式调用stopRecording()时才能准确工作。如果由于达到预定义的文件大小或持续时间而终止录制,则会太晚引发它(另请参见)
使用recorder.setOnInfo Listener()不起作用,因为它可能会在文件实际写入磁盘之前报告文件已完成
@Override protected File getVideoDirectory() {
fileObserver = new FileObserver(videoDirectory.getAbsolutePath(), FileObserver.CLOSE_WRITE) {
@Override public void onEvent(int event, String videoPath) {
System.out.println("**** CameraHost: FileObserver: onEvent: event = " + event + ", videoPath = " + videoPath);
if (fileObserver != null && videoPath != null && event == FileObserver.CLOSE_WRITE) { // do not process directory
System.out.println("**** CameraHost: write closed: videoPath = " + videoPath);
// fileObserver.stopWatching(); // TODO this needs to be closed somewhere
// fileObserver = null;
raiseVideo(videoPath);
}
}
};
fileObserver.startWatching();
return videoDirectory;
}