The stock camera application of redmi note 5 ai when it is recording Video on any resolution HD/FHD it is full of noise. The quality is unucceptable. I downloaded "Camera Iphone 11 OS13" apk and the quality of the video is crystal clear. You can not rely on stock apk for video recording. For those whoare wondering why this is happening, I suggest you to change the application to something different. I hope MIUI 12 resolves this issue.