This is a really big link but page 68 has ...http://www.avsforum.com/avs-vb/showthread.php?p=17512496#post17512496
... but before you get overwhelmed.
576i is odd but the TV resolution can report changes from 480p to 1080i, 720p, 1080p etc depending upon the signal sent.
For example, you may have a blu-ray movie where the trailers plays in 480p with 2 channel stereo but when the actual blu-ray movie plays it is in 1080p with 5.1 DTS.
So, one other question is what are the brand, model number of your BD/DVD player? Is it a BD player?
Are you HDMI from the BD/DVD to the Denon?
One thing with LG televisions is that unlike other manufactures the LG CEC link control (SIMLINK or something like that) is that built into the TV not the blu-ray players.
If it is a BD player have you tried it turned off (SIMLINK) to see if it makes any difference?