720x576 is aspect ratio(AR) 4:3 are play correct according that.
720x576 with AR 4:3 with screen aspect ratio(SAR) 16:9 are a problematic once.
HiMedia doesn't have any firmware witch handle correctly 720x576 AR 4:3 with SAR 16:9, a older FW is was just more convenient playing all 720x576 as output detect(set) 16:9/4:3.
Kodi with build in player(VideoPlayer) claim to do this according they settings.