HDMI audio: blip hiss buzz noise at playback end

HDMI finally made it possible to get all your A/V digital data in one cable. However, connecting a computer to HDMI TV may have some audio problems.
After playback stops or application exits, a very annoying high-pitched sound may be heard, like this one. Sounds like the last note being played continously for about a second.

Unfortunately, there’s not much you can do about this. The HDMI noise is caused by Windows abruptly closing audio transmission, while the receiving device still expects some stream data. This mid-stream cut is decoded into hissing noise for a couple of seconds, until the receiver recognizes that audio has stopped.
This doesn’t happen with a Playstation 3 or XBOX360 or any other HDMI-enabled device, because they seem to maintain constant HDMI transmission. However, Windows disconnects the stream just after playback. To understand it better, imagine the consoles pause transmission without terminating it, and PCs stop it.
While such behavior doesn’t spoil movie experience much, hearing that buzz after each Windows theme sound is just frustrating.
Not all devices are affected, but certain chips and configurations are, most notably Nvidia graphic cards and LG tv-sets. Changing audio output in you player from DirectX to whatever won’t help. Updating soundcard drivers won’t help either, since modern video cards utilize their own built-in sound chips for HDMI audio.
To avoid that sound at the end of playback, you may force your player to first pause, then stop playback. As for Windows system sounds or browser video, the solution is yet to be found.
An incident 120421-000073 has been raised at NVidia support center and escalated to the test lab. The engineers rulled out there’s nothing wrong with drivers and chips. So, that means the LG tv has some problems with HDMI sound input.