I am using a HDHomeRun CONNECT Quatro connected to a UK digital aerial, picks up the signal fine, but the recordings appear to come out as 4:3 ratio rather than full screen.
I have disabled “CONVERT VIDEO WHILE RECORDING” and also HW transcoding but it appears the same behaviour persists.
I’ve got the same issue with HDHomeRun connect duo when viewing live tv on android tv client. Did you find a solution to the issue? It’s been a pretty bad experience with live tv in Plex thus far. The squished letterbox view really diminishes the value of live tv. I’ve resorted to the native HDHomeRun application until a fix is available in Plex.
The OP’s video sample is obviously pillarboxed, but Homer doesn’t appear to be distorted at all.
While not directly related, I see this occasionally on ATSC channels. I assume this is incorrect use of Active Format Description by the broadcaster. Unfortunately I’m not aware of a how to determine this from a Plex recording. Thankfully, it’s becoming rare on OTA broadcasts in my area.