Here are the steps to ensure your Smart TV is displaying in HD:

1. Check the source of your content. Make sure you are connected to a High-Definition Multimedia Interface (HDMI) via an HDTV cable.
2. Verify the output resolution of the source to your TV. This must be set to a maximum of 1080p.
3. Change your TV’s picture setting to 16:9.
4. Confirm the cable connection with your source is secure.
5. Adjust your TV's aspect ratio settings.
6. Ensure your TV settings specific component associated with HDTV.