Purchased a great Sony Vaio Pro 13 ultrabook with excellent hardware running Windows 8 and now updated to 8.1. The Intel® HD Graphics 4400 hardware controls the HDMI output and the audio over the HDMI output.
Using the built-in HDMI output provides video, but no audio. Also, unable to locate audio options for HDMI in the Sound settings control panel of Windows 8.1. The Sony Vaio update tool confirms all the latest software drivers and other patches have been installed, but the issue of no audio over HDMI remains.
After reading through many online posts and blog articles, the root cause appears to be related to the specific Intel Graphics Drivers being used by Sony on this specific model laptop. The Sony Vaio update tool confirmed that the Intel Graphics Drivers 10.18.10.3304 with a date of 9/9/2013 is the latest version. A community post on Sony’s forum shows that other people with a Sony Vaio Pro 13 laptop also experience no audio over HDMI, but they were able to resolve the issue by downloading updated Intel Graphics Drivers from a link on Sony’s web site: http://dlv.update.sony.net/pub/vaio/download/EP0000317186/EP0000317186.exe. The newer Intel Graphics Drivers are version 188.8.131.52.3316 with a date of 10/4/13.
After installing these “updated” Intel Graphics Drivers, I’m able to receive audio over the HDMI connection and I’m able to adjust that option in the Sound settings of the Windows 8.1 control panel.
The only potential concern might be that Sony does not provide future updates for the graphics drivers as my version might be out of sync with the version expected by the Sony Vaio update tool.