Poor performance when continuously updating a SurfaceView with pixel data from a ByteBuffer

I am writing an Android app in which a native thread keeps generating image frames (as raw pixel data) at about 60 fps, which are then supposed to be displayed in a SurfaceView. Currently, the thread writes pixel data to a direct ByteBuffer shared between the native thread and the JVM, then invokes a callback via JNI to notify the JVM side that a frame is ready; the buffer is then read into a Bitmap and drawn on the SurfaceView. My code looks roughly like this (full source code would be too big to share):

// this is a call into native code that retrieves  // the width and height of the frame in pixels  // returns something on the order of 320×200  private external fun getFrameDimensions(): (Int, Int)    // a direct ByteBuffer shared between the JVM and the native thread  private val frameBuffer: ByteBuffer    private fun getFrame(): Bitmap {      val (width, height) = getFrameDimensions()        return Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888).apply {          setHasAlpha(false)          copyPixelsFromBuffer(frameBuffer.apply {              order(ByteOrder.nativeOrder())              rewind()          })      }  }    // the SurfaceView widget which should display the image  private lateinit var surfaceView: SurfaceView    private val SCALE = 8    // callback invoked by the native thread  public fun onFrameReady() {      val canvas: Canvas = surfaceView.holder.lockCanvas() ?: return      val bitmap = getFrame()            try {          canvas.drawBitmap(bitmap.scale(              bitmap.width * SCALE,              bitmap.height * SCALE),              0.0f, 0.0f, null          )      } finally {          holder.unlockCanvasAndPost(canvas)      }  }  

The good news is that the above works: the screen updates at roughly the expected frame rate. However, performance is really poor, to the point where the app locks up: it stops responing to e.g. pressing the ◁ button and eventually an ANR message pops up. Clearly I am doing something wrong, but I am not quite able to tell what exactly.

Is there a way to make the above run faster? Preferably I would like to avoid writing more native code than necessary. I would especially like to avoid putting anything Android-specific at the native side of things.

https://stackoverflow.com/questions/65875116/poor-performance-when-continuously-updating-a-surfaceview-with-pixel-data-from-a January 25, 2021 at 03:42AM