IPad image does not fill TV screen in some applications

You will see black bands when the aspect ratio of the recorded video material does not match the screen aspect ratio of the iPad screen - or an external monitor/TV when connected. As is, you are likely seeing the recorded video exactly as intended.

Your iPad screen aspect ratio (the ratio of width versus hight) is approximately 4:3 - whereas widescreen movie material is often 16:9 (i.e., much wider than it is tall), resulting in a black band above and below the visible image. If the 16:9 material is expanded to fill the screen, one of two things will happen…

a) If the height is simply increased to remove the bands without also widening the screen, this will introduce image distortion; vertical objects will appear artificially tall and thin.

b) If instead the hight and width is increased to remove the bands without introducing image distortion, the left and right edges will be cropped from view. In this situation you have effectively zoomed-in to the visible image - and hidden the edges.

I hope this explanation is helpful with understanding both what you see - and why.

That depends on the aspect ratio and resolution of the content.

The iPad's screen is closer to being a square, your TV's screen is most likely not square, differences must be allowed.

Content may scale if offer in a resolution the TV can display better, otherwise it will show any black bars to compensate.

It can be the answer. And it is. It depends entirely on the content{s resolution and aspect ratio.

You are clearly proving the point, that if the provider has a good resolution and aspect ratio Like PBS, it will work normally,. and if they don't like MHz, then it will not fill the screen.

Contact MHz developers and tell them their content doesn't show up correctly.

You ar seeing expected results of diferent video content resolutions/aspect ratios.

This is entirely expected, normal iPad/video/mirroring behaviour.