If my memory serves me right, quite a few people in this forum use a TV—especially an OLED TV—as a monitor. Four years ago, after I solved the issues with 4K 120Hz high refresh rate and color output from my Mac over HDMI, I was perfectly happy:
But I was always bothered by another problem:
Volume control
I don't know what Apple was thinking, or whether they just didn't think it was worth building a separate volume control for HDMI passthrough, but the fact is: once you connect a display device via HDMI, its volume simply can't be controlled.
This creates a problem: if you open YouTube to watch a video, you can indeed adjust the current video's volume using YouTube's built-in volume control, but if you open Apple Music or Spotify, you have to adjust their individual volumes one by one.
Meanwhile, the system's global volume—normally controlled by the keyboard shortcut, which is both convenient and intuitive—is unusable. This is especially frustrating when you frequently move between desktop and laptop use; the disconnect is particularly painful.
Then three years ago, as machines like the M2 rolled out, native HDMI gained support for the HDMI-CEC protocol, making automatic screen on/off possible. So I needed to reach for the TV remote to turn the TV on and off far less often—but every time I needed global volume adjustment, I still had to pull out the remote.
I also tried customizing Smart TV control via Hammerspoon, but found the script unstable and still not well compatible with the system's volume control, so I gave up.
Until recently, while adjusting dynamic resolution, I re-downloaded BetterDisplay and discovered that the new version of this gem actually supports HDMI-CEC control:
This is exactly the tool to solve this problem!
Of course, my actual audio setup is a bit more complex than just direct control. My TV sends audio back via HDMI (eARC) to an Apple TV, and the Apple TV connects to HomePods, so audio from any device can be output to the HomePods with almost no latency. (Side note: I've heard that now you can get extremely low latency connecting directly to HomePods without an Apple TV, but my testing didn't succeed.)
So in my actual setup, I selected Audio System:
Finally, in the keyboard settings section, enable native volume key control (requires enabling system accessibility permissions—restart the app once):
Then you can control volume +/- and mute via the keyboard volume keys, and even the TV's mute indicator is preserved when muted.
If your HDMI output goes through an adapter, there's likely no HDMI-CEC, but it also supports configuring LG or Samsung TV protocols—though I haven't tested that path:
Lastly, since we're in the splurge section, I should mention the cost of this software:
0
Yes, the HDMI-CEC feature is free—no need to splurge:
And if you run into problems, just ask Teacher Codex:
I hadn't noticed before that Better Display supports HDMI-CEC. But when you say "free," do you mean this feature works in the free version, or does it require a specific version? Also, CEC implementations vary quite a bit between TV brands—LG and Samsung protocols are configured separately in the software. If you could add some real-world results for different brands later, it would be even more useful.