Affdex Android SDK - Save and use CameraDetector

Question

Mostly I want to know if there is a fundamental conflict that I can't share the same resource with the library, if so, I will need to take a different approach.

My goal is to have low quality video with the detector's meta data saved at the same time, so that I can do some post processing and slicing without much of a delay.

Based on the CameraDetectorDemo - camera detector

I have been initializing a MediaRecorder, but it saves a black screen if I start it before the detector, and it crashes on start (with code -19) if I start it after the detector. The detector is attaching the preview, maybe it is to do with that.

I added some buttons to control these functions:

protected void cameraInit() {
    String state = Environment.getExternalStorageState();
    if (!Environment.MEDIA_MOUNTED.equals(state)) {
        Log.d(LOG_TAG, "Drive not mounted - cannot write video");
        return;
    }

    File file = new File(getExternalFilesDir(Environment.DIRECTORY_MOVIES), "demo.gp3");

    Log.d(LOG_TAG, String.format("Camera Initializing. Setting output to: %s", file.getAbsolutePath()));

    // Set sources
    recorder.setAudioSource(MediaRecorder.AudioSource.MIC);
    recorder.setVideoSource(MediaRecorder.VideoSource.CAMERA);

    // Set profile
    recorder.setProfile(CamcorderProfile.get(CamcorderProfile.QUALITY_LOW));

    // Set output profile
    recorder.setOutputFile(file.getAbsolutePath());

    // Set preview output
    recorder.setPreviewDisplay(cameraPreview.getHolder().getSurface());



    try {
        this.recorder.prepare();
    } catch (IOException e) {
        Log.e(LOG_TAG, "IO exception on camera Initialization");
        e.printStackTrace();
    } catch (IllegalStateException e) {
        // This is thrown if the previous calls are not called with the
        // proper order
        Log.e(LOG_TAG, "Failed to initialize things properly :(  ");
        e.printStackTrace();
    }
}

protected void cameraStart() {
    Log.d(LOG_TAG, "Camera Start");
    this.recorder.start();
}

protected void cameraStop() {
    Log.d(LOG_TAG, "Camera Stop");
    this.recorder.stop();
}

score 1 · Accepted Answer · answered Jul 19 '16 at 11:07

1

The Affdex SDK's CameraDetector needs access to the camera to get its preview frames and process them, so that's not going to work if the MediaRecorder has control of the camera.

Probably your best bet is to take preview frames from the camera, feed them to an Affdex FrameDetector for processing, and also save them to a video file via a MediaCodec and MediaMuxer, although I haven't tried that.

answered Jul 19 '16 at 11:07

Andy Dennie

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Hm, I wonder if I can set the mediarecorder to use the same surface as the CameraDetector and record from that? – exrhizo Jul 20 '16 at 16:38
I don't think so, as I recall, I think that when MediaRecorder starts recording, it takes control of the camera, so CameraDetector won't get preview frames after that point. – Andy Dennie Jul 20 '16 at 18:29

Affdex Android SDK - Save and use CameraDetector

1 Answers1