Normal issue, isn´t it? I´ve always struggled with this for the ATI/AMD cards (which is a pity... but apart from this, they work grand!)
Anyway... the computer im using is an old i5 750 with 10gb of ram and a AMD r9 285. Before this, I had an old Nvidia 200 card (with HDMI, same cable and tv... worked as a charm).
Now, its a completely different story. As soon as I removed old drivers, rebooted, put in the new graphicscard... and installed all drivers... my TV came up as a different name (W32 ...) and this is the "fun" part:'*
1 - 32W_LCD_TV
The following audio formats are currently supported:
Max number of channels: 0'
HDCP: Not supported
Bit Depths: None
No sample rates
Encoded formats: Dolby digital.
This never changes. Uninstalling all, reinstalling, using beta drivers, trying the Realtek HDMI 2.7 oldie drivers, with my built in soundcard installed or not installed.... It never works. Been sitting around 10 hours now in total, soon to be pulling out my hair to get this to work.... im soon giving up and turning to the dark side (nVidia) ... and i dont want to.