CODEWITHSUNDEEP
androidfilevideomediarecorder
Stefan H Singer
Stefan H Singer

Reputation: 5504

How to know when MediaRecorder has finished writing data to file

We're using MediaRecorder to record video to a file on the external storage using setOutputFile() before doing the actual recording.

Everything works fine, but the main issue is that as soon as the recording is done, we want to start playing the recorded video back in a VideoView.

How to know when the file is ready to be read and played back?

Upvotes: 19

Views: 8155

Answers (6)

Ron
Ron

Reputation: 24235

The FileObserver class suits your needs perfectly. Here is the documentation. It's easy to use. When a observed file is closed after writing, the onEvent callback is called with CLOSE_WRITE as the parameter.

MyFileObserver fb = new MyFileObserver(mediaFile_path, FileObserver.CLOSE_WRITE);
fb.startWatching();

class MyFileObserver extends FileObserver {

    public MyFileObserver (String path, int mask) {
        super(path, mask);
    }

    public void onEvent(int event, String path) {
        // start playing
    }
}

Don't forget to call stopWatching().

Upvotes: 21

Sani Elfishawy
Sani Elfishawy

Reputation: 663

In my tests irrespective of the size of the recording mediaRecorder.stop() is a blocking method that only returns after the file has been completely written and closed by the media recorder.

So JPMs answer is actually correct.

You can verify this by calling File.length() immediately after stop(). You will find that the output file length is the final length of the file at this point. In other words media recorder does not write anything further to the file after stop() has returned.

Upvotes: 2

Caner
Caner

Reputation: 59258

I haven't tried this myself but this might work:

public void release () Since: API Level 1

Releases resources associated with this MediaRecorder object. It is good practice to call this method when you're done using the MediaRecorder.

If it does what it says, then I guess if you call this and after this method returns you know the file is ready.

Upvotes: 1

Ash
Ash

Reputation: 1721

We solved similar problem with the following algo:

while (file not complete)
    sleep for 1 sec
    read the fourth byte of the file
    if it is not 0 (contains 'f' of the 'ftyp' header) then
        file is complete, break

The key point is that MediaRecorder writes the ftyp box at the very last moment. If it is in place, then the file is complete.

Upvotes: 5

Franziskus Karsunke
Franziskus Karsunke

Reputation: 5208

A dirty way would be to check the lastModified() value of the File and open the VideoView if the File wasn't modified for 2 seconds.

Upvotes: 0

JPM
JPM

Reputation: 9296

Apparently there is no way to detect when the recording has stopped in Media player, but there is a stop() that you can override if you create a custom class that implements MediaRecorder. here I would do something like this:

public class MyRecorder implements MediaRecorder {
    public boolean stopped;

    .... implement all the methods that MediaRecorder has making 
         sure to call super for each method.

    @Override
    public void myStop() {
        this.stopped = true;
        super.stop(); 
    }
}

Then you can access the boolean to see if it has stopped recording.

Upvotes: 0

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