Mac OS X (10.6.6)
Same problem here. iPad 2 + Apple digital AV adapter + 25ft. (thick-gauge) generic HDMI cable + Hitachi 42" HD1080 PlasmaTV. Constant flickering during mirroring and eventually audio disappeared entirely. Identical, but sporadic problem occured when using same setup but iPod Touch 4th gen instead of iPad 2.
Contacted Apple support and they sent me a free replacement AV adapter.
Package arrived in less than 20 hours! Wow! That is FAST!
(actually they goofed and sent me a free iPad 2-specific charging dock instead, but I'm not complaining). One email and a day later, the AV adapter arrived.
Situation improved but only slightly. Now flickering on TV screen is occasional rather than constant. Audio briefly self-mutes randomly also. It seems to be more stable when used in conjunction with the dock. It's much too easy for the AV plug to partially slip out of the input port on the iPad when held on my lap, so standing it in the dock helps to prevent that particular problem. More testing and trouble-shooting is planned.
Yes, iPad2 with HDMI adapter stops working every 10-15mins during video playback through my Phillips LED TV as well. Not great.
Same problem here! The adapter works fine on my friends Philips LCD TV but is useless on my Panasonic Plasma !
So back it goes to the shop!
iPad 2 worked w/HDMI adapter but screen FLASHED after ten minutes
