When I set a gray filter globally in my app, the video played without picture but with sound

Hello,When I set a gray filter globally in my app, the video played without picture but with sound. This is the code that I set up

`fun init() {
mGrayPaint = Paint().apply {
ColorMatrix().apply {
setSaturation(0F)
}.let {
colorFilter = ColorMatrixColorFilter(it)
}
}
}

fun setLayerGrayType(view: View) {
init()
view.setLayerType(View.LAYER_TYPE_HARDWARE, mGrayPaint)
}`