CODEWITHSUNDEEP
androidvideorecordvideo-capturemediarecorder
rosu alin
rosu alin

Reputation: 5830

Pause media recorder programmatically. Camera.apk from samsung galaxy has `this.mMediaRecorder.pause();` does not work in my code

Now, i have made a library to concatenate 2 videos, using the mp4parser library. And with this i can pause and resume recording a video (after it records the second video, it appends it to the first one). Now, my boss told me to do a wrapper, and use this for the phones that do not have hardware support for pausing a video. For phones that have that (Samsung Galaxy S2 and Samsung Galaxy S1 can pause a video recording , with their camera application), i need to do this with no libraries, so it would be fast. How can I implement this native, if as seen on the media recorder state diagram, http://developer.android.com/reference/android/media/MediaRecorder.html , there is no pause state?

I have decompiled the Camera.apk app from an Samsung Galaxe Ace, and the code has in the CamcorderEngine.class a method like this:

public void doPauseVideoRecordingSync()
{
Log.v("CamcorderEngine", "doPauseVideoRecordingSync");
if (this.mMediaRecorder == null)
{
  Log.e("CamcorderEngine", "MediaRecorder is not initialized.");
  return;
}
if (!this.mMediaRecorderRecording)
{
  Log.e("CamcorderEngine", "Recording is not started yet.");
  return;
}
try
{
  this.mMediaRecorder.pause();
  enableAlertSound();
  return;
}
catch (RuntimeException localRuntimeException)
{
  Log.e("CamcorderEngine", "Could not pause media recorder. ", localRuntimeException);
  enableAlertSound();
}

}

If I try this.mMediaRecorder.pause(); in my code, it does not work, how is this possible, they use the same import (android.media.MediaRecorder). Have they rewritten the whole code at a system level?

Is it possible to take the input stream of the second video (while recording it), and directly append this data to my first video? for my concatenate method, i use 2 parameters (the 2 videos, which both are FileInputStream), is it possible to take the InputStream from the recording function and pass it as the second parameter?

Upvotes: 4

Views: 2617

Answers (1)

Paul E
Paul E

Reputation: 157

If I try this.mMediaRecorder.pause();

The MediaRecorder class does not have a pause() function, so this is obvious that there is a custom MediaRecorder class on this specific device. This is not something unusual, as the only thing required from the OEMs is to pass the "android compatability tests" on the device; there is no restriction on adding functionality.

Is it possible to take the input stream of the second video (while recording it), and directly append this data to my first video?

I am not sure if you can do this, because the video stream is encoded data (codec header, key frames, and so on), and just combining 2 streams into 1 file will not produce a valid video file in my opinion.

Basically what you can do:

  1. get raw data images from camera preview surface (see Camera.setPreviewCallback())
  2. use a android.media.MediaCodec to encode the video
  3. and then use an OutputFilStream to write to the file.

This will give you the flexability you want, as in this case you in you app decide which frames get into encoder, and which do not. However, it maybe an overkill for your specific project, as well as some performance issues may rise.

PS. Oh, an by the way, try taking a look at the MediaMuxer - maybe it can help you too. developer.android.com/reference/android/media/MediaMuxer.html

Upvotes: 2

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