QCEC implements a libCEC based HDMI-CEC input plugin for Qt
licensed as per usual with Qt modules. libCEC is available under a dual GPL/commercial license. Speak to them.
QCEC is packaged as part of the QPi Arch Linux repo for the Raspberry Pi series of devices.
Don’t expect CEC to work in conjunction with an arbitrary HDMI hub
If code quality improves, I might attempt to upstream this. That said, there is now official API in the kernel for HDMI-CEC, which might provide a better/cleaner interface for our needs.
This has currently been tested and found to function on 2 TVs, and appears to crash standard monitors. (If the plugin is loaded)