Samsung LED TV AV mode picture brightness Problem

Hello ifixit....i have samsung 40inch LED TV.....i am facing a strange problem with my TV.....problem is when i am trying to connect DVD player to my TV the picture looks so bright its almost white and also i tried with different DVD players no use but when i switch to TV mode picture clarity is fine and neat...... i am not understanding where problem is ?? is my TV problem or DVD problem or any RCA cabels problems....... please tell me some solution