Can I use HDMI for audio only without video?

Solution 1:

If all you want is to have your desktop confined to your computer's screen, go to System Preferences > Displays > Arrangement, and check Mirror Displays. That'll make it so that your HDMI display only acts as a mirror of the desktop you already have, rather than an extension of it.

Solution 2:

There is no way to transmit only audio data via HDMI.

The HDMI white paper (page 10) notes that the signal is sent in HDMI packets consisting of both audio and video. Despite all the pins, there are no separate audio and video signals, so there are also no HDMI A/V splitter cables.

The only way to get around this is to send blank video data (e.g. a black screen). I'm not sure exactly why you want only the audio, but here are my suggestions:

• If you're connecting it to an audio receiver, just send it along without worrying about the video.
• If you're connecting it to a TV, and don't want the TV to show your desktop, you can extend your desktop (turn off mirroring) and either have a blank desktop show up or put up any image you want on full screen while you do whatever you need to do on your MBP screen. That part's really up to you.

Hope that's helpful.