When the AV Mode is enabled (use with non-computers) in the System>PC/AV Mode the HDMI Black Level in the Picture Menu becomes available, as does the Screen Fit setting in the Picture>Picture Size Menu. Also note that the AV and PC mode settings changed the monitors color preset accuracy; the AV mode is significantly less accurate by default, but can be made accurate by selecting the Custom setting in the Picture>Magic Bright menu, and by selecting the Warm setting in the Picture Color>Color Tone menu.
Samsung S32F351 AV Mode vs PC Mode Default Settings:
The HDMI Black Level settings either send out a 0-255 (Normal setting) or 16-235 (Low setting) signal which can make a display either look very washed out, or too dark and devoid of detail when displaying dark scenes.
The Screen Fit Setting available when the AV mode is selected needs to be selected to prevent over-scan or part of the image from being cut off when not connected to a computer.