Ndtyjky

I'm integrating the Camera2 API to my Android app and test it on Samsung Galaxy Tab S2. I need to work with real time preview frames.
Here is my code:

private val onPreviewAvailableListener = ImageReader.OnImageAvailableListener { reader ->

    if (reader != null) {

        val image = reader.acquireNextImage()

        if (image != null) {

            // do something with image

            image.close()

        }

    }

}



private var mPreviewRequestBuilder: CaptureRequest.Builder? = null

private lateinit var mPreviewSize: Size



private fun configurePreview() {

    // some code here 

    // ... 



    previewImageReader = ImageReader.newInstance(

            mPreviewSize.width,

            mPreviewSize.height,

            ImageFormat.YUV_420_888,

            2

    )

    previewImageReader?.setOnImageAvailableListener(onPreviewAvailableListener, backgroundHandler)



    // some code here 

    // ... 

}



// other code



private fun createCameraPreviewSession() {

    mPreviewRequestBuilder = mCameraDevice?.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW)

    mPreviewRequestBuilder?.addTarget(previewImageReader?.surface)

    mPreviewRequestBuilder?.addTarget(surface) // surfaceView



    mCameraDevice?.createCaptureSession(

                    Arrays.asList(previewImageReader?.surface, surface),

                    object : CameraCaptureSession.StateCallback() { },

                    null /* null handler */

}

I need images in onPreviewAvailableListener to be of a high resolution. And they are. The resolution is not too high. Something about 1280*720. The problem is that my preview TextureView lags as if 15 FPS was set.

Maybe I can decrease the frequency of images coming to onPreviewAvailableListener. I tried setting a flag to only handle every 10-th o 20-th image in onPreviewAvailableListener's onImageAvailable, but nothing changed:

private val onPreviewAvailableListener = object: ImageReader.OnImageAvailableListener {



    private var counter = 10 



    fun onImageAvailable(reader : ImageReader) {

        if (counter % 10 == 0) {

            if (reader != null) {

                val image = reader.acquireNextImage()

                if (image != null) {

                    // do something with image

                    image.close()

                }

            }

        } 

        if (counter == Int.MAX_VALUE) {

            counter = 0

        } else {

            counter++

        }

    }

}

I also tried creating a new background thread specially for onPreviewAvailableListener so that its callback method is called on that thread. Nothing changed either:

previewImageReader?.setOnImageAvailableListener(onPreviewAvailableListener, previewImageReaderHandler) /* it's NOT backgroundHandler */