I have a brand new LG BP220 bluray player hooked up to my LG 47LH40 TV via HDMI. After using the bluray player for a couple hours (regardless if I'm playing from disc, usb or network) and I switch back to antenna input on the TV, the audio will be crackling and out of sync with the video. Audio from the bluray player continues to work fine without any issue.
Unplugging and replugging the HDMI cable, antenna cable or bluray power cable (no ground plug) does not affect the crackling. Only after unplugging and replugging the TV power cable (has ground plug) does the cracking go away.
I have used other HDMI devices (DVR) and RCA devices (DVD player) with this TV without issue. It only started after using the bluray player.