Stretch To Fit Picture Quality?

We just purchased a new Samsung UHD TV. We use Channels DVR with Amazon Fire 4K stick connected to a HDHomeRun Quattro. While watching the football game today on Fox, I noticed the picture wasn't as clear as it should be. I went into the Player settings in the Fire Channels App and disabled "stretch to fit". The picture quality is now much better. Is this the expected behavior? If so, I imagine I should keep "stretch to fit" off?

are you watching the HD channel?

Yes - HD Channel. Fox. It was the Bears/Lions Game. I was under the assumption the "stretch to fit" setting was to stretch a SD channel to the 16x9 format. It was strange by disabling the setting, the Fox HD channel picture quality improved.

That's what I thought too. I don't think that setting does anything for me on Apple TV on HD channels.