For an inexpensive alternative (or a receiver that doesn’t have an IR input port), I’d suggest the BroadLink RM4 Mini.
Development stalled on the unofficial binding, but it still works in 3.4. You can use it to record the IR codes and send them directly from openHAB (all on local network).
More recently, the RM4 devices have been merged into the official Broadlink binding in 3.4. I haven’t tried it, but here’s a post about getting the IR codes.
I’m using an RM4 Mini to control a humidifier. Amusingly, the ON/OFF IR code also turns on my Geneva Labs Model XL sound system, so I made a cover to restrict the beam (tape works just as well).
Feel free to ping me directly when it’s ready for testing (but don’t rush on my account). I’m excited to be your first Chromecast with Google TV customer.