for 1366x768 displays
using 1080i (or p if it supports 1080p input) the player sends a 1920x1080 signal which is downscaled by the tv to 1366x768
using 720p the player downscales from 1920x1080 to 1280x720 then the tv upscales that to 1366x768
in other words use the maximum your tv accepts
using 1080i (or p if it supports 1080p input) the player sends a 1920x1080 signal which is downscaled by the tv to 1366x768
using 720p the player downscales from 1920x1080 to 1280x720 then the tv upscales that to 1366x768
in other words use the maximum your tv accepts