Calculate avarage luminance from an YUV Frame

getAverageLuminance.kt

    fun getAverageLuminance(frame: Frame): Double {
        require(frame.pixelFormat == PixelFormat.YUV) { "Unsupported pixel format. Expected YUV." }

        var totalLuminance = 0.0
        val yBuffer = frame.image.planes[0].buffer
        while (yBuffer.hasRemaining()) {
            @Suppress("MagicNumber")
            totalLuminance += yBuffer.get().toInt() and 0xFF
        }

        return totalLuminance / (frame.width * frame.height)
    }