LG 4K monitor and IPad Pro 3rd generation question

When “mirroring” your iPad screen to an external display or TV, the iPad aspect ratio and resolution is preserved; iPadOS will not attempt to re-scale it’s output to that of the external display. If you wish to distort the image to fill the external display, you must use the controls and rescaling features of the external display itself.

However, when the iPad is directing video output from a media player App, the full media resolution and corresponding aspect ratio will be output to the attached monitor - such as 1080HD or 4k UHD (where supported by both the iPad and external display).

I hope this information and clarification is helpful in understanding the capabilities of your iPad.

As previously stated, when “mirroring” your iPad screen to an external display or TV, the iPad aspect ratio and resolution is preserved; iPadOS does not attempt to re-scale it’s output to that of the external display.

If you monitor doesn’t have capability to re-scale (i.e., “stretch”) the output to full screen, then bars at either edge of the screen are inevitable. Remember, a “stretch” to fit a different aspect ratio will distort shapes. For example, a circle displayed in its native aspect ratio (i.e., that of the iPad) will be stretched to an ellipse on the display of an external monitor. This distortion is generally unwanted when working with graphics of video.