How to use mediaMuxer to Record View in Background Thread

Question

i am using MediaMuxer to Record a view as MP4 video file. i successfully implemented this https://github.com/rogererill/LottieRecorderTest. but after that when i was implemetation UI/UX i place Progress Loading View animated. but It got Stuck until this videoencoder processs finished.

i also tried with thread() but app got crashed without any error. can you guys help me in this?

snippet code below where i got error in app:

  fun start() {

      object : Thread() {
          override fun run() {
              super.run()

              while (isRecording()) {
                  recorder.nextFrame(frameCreator.generateFrame())
              }
              recorder.end()
              listener()
             
             

          }
      }.start()


  }

---

  fun nextFrame(currentFrame: Drawable) {
    drainEncoder(false)
    val canvas = inputSurface.lockCanvas(null)
    try {
      canvas.drawColor(Color.TRANSPARENT, PorterDuff.Mode.CLEAR)  // Here you need to set some kind of background. Could be any color
      currentFrame.draw(canvas)
    } finally {
      inputSurface.unlockCanvasAndPost(canvas)
    }
  }

  fun end() {
    drainEncoder(true)
    close()
  }