Can some one explain why a HDMI based connection from say a ATI 4290 or 5450 card drops audio? This did not happen under catalyst 12.3 but does under 12.4. Have a system with two video cards, 4290 integrated and PCIe based 5450. Each is connected to a HDMI TV via HDMI, only HDMI, no DVI to HDMI conversion or anything else, just straight HDMI. Consistently, the 2nd TV discovered, shows 'not plugged in' as a audio playback device? The default monitor/TV always shows audio enabled/plugged in. If we open Catalyst manager and apply any supported format, the audio shows plugged in. Is there a programmatic or HDMI protocol level reason for this to happen? If the TV is changed from HDMI to other mode, this consistently happens. Or on system reboot, the non-primary monitor/TV this happens. So the question is, is the system Windows is doing (Say Windows 7 Ultimate fully patched/update to date), or something in HDMI, or something in in Catalyst drivers? What does re-applying of a format, do, that re-establishes the audio over HDMI? Is there an API call or CLI tool that can be used to apply the format routine/sequence? So the GUI based apply of format can be avoided? We do a lot of video based work, and some related development, and when we jump from monitor to monitor, for various reasons, this lost of audio support is really a PITA issue. Figure it has to be some type of issue at a programming level, so hence the question to developers, which if anyone, should be able to explain the issue in detail? Thanks.