That prototype is said to run in dev units, which has more memory.
OTOH, Shuhei's explanation is not convincing because they can run PlayTV in the background today. The latest software revision can save H.264 video, probably simple profile, while a game is running. Dealing with audio should be a fraction of that setup.
That said, I still think that the crown jewel is party management, not necessarily voice chat.
this is not true ... i have play tv and when i plan recording it will warning you to quit the game (Operation Flaspoint Dragon Rising)